2017
|
Pongratz, C.; Ehrlich, I. DampSIM: Lebensdauerüberwachung von faserverstärkten Kunststoffen auf Basis der strukurdynamischen Werkstoffdämpfung. Leichtbau Forschungsbericht Ostbayerische Hochschule Regensburg VMK Verlag für Marketing & Kommunikation GmbH & Co. KG, Forschungsbericht 2017, 2017, ISBN: 978-3-9818209-3-5. @techreport{Pongratz2017,
title = {DampSIM: Lebensdauerüberwachung von faserverstärkten Kunststoffen auf Basis der strukurdynamischen Werkstoffdämpfung.},
author = {C. Pongratz and I. Ehrlich},
editor = {Ostbayerische Technische Hochschule},
isbn = {978-3-9818209-3-5},
year = {2017},
date = {2017-06-01},
address = {VMK Verlag für Marketing & Kommunikation GmbH & Co. KG},
institution = {Ostbayerische Hochschule Regensburg},
abstract = {Im Fokus der Untersuchungen steht die Strukturintegrität von Bauteilen aus faserverstärktenKunststoffen. Im realen Anwendungsfall können diese Strukturen Schlag- oder Impactbelastungenunterliegen, die häufig kaum sichtbare oder unsichtbare Schäden im Inneren des Bauteils ver -ursachen. Diese Schäden stellen deshalb ein besonderes Sicherheitsrisiko dar. Ziel des Forschungs-projekts ist die effiziente Detektion solcher Schäden. Als Indikator des Materialzustands wird einvibrationsbasierter Ansatz angewendet, der zusätzlich zu den Eigenfrequenzen die struktur -dynamische Werkstoffdämpfung einbindet.},
type = {Forschungsbericht 2017},
keywords = {},
pubstate = {published},
tppubtype = {techreport}
}
Im Fokus der Untersuchungen steht die Strukturintegrität von Bauteilen aus faserverstärktenKunststoffen. Im realen Anwendungsfall können diese Strukturen Schlag- oder Impactbelastungenunterliegen, die häufig kaum sichtbare oder unsichtbare Schäden im Inneren des Bauteils ver -ursachen. Diese Schäden stellen deshalb ein besonderes Sicherheitsrisiko dar. Ziel des Forschungs-projekts ist die effiziente Detektion solcher Schäden. Als Indikator des Materialzustands wird einvibrationsbasierter Ansatz angewendet, der zusätzlich zu den Eigenfrequenzen die struktur -dynamische Werkstoffdämpfung einbindet. |
Romano, M. Charakterisierung von gewebeverstärkten Einzellagen aus kohlenstofffaserverstärktem Kunststoff (CFK) mit Hilfe einer mesomechanischen Kinematik sowie strukturdynamischen Versuchen Leichtbau Promotionsarbeit Universität der Bundeswehr München, 2017, ISBN: 978-3-8440-5177-3. @phdthesis{Romano2017b,
title = {Charakterisierung von gewebeverstärkten Einzellagen aus kohlenstofffaserverstärktem Kunststoff (CFK) mit Hilfe einer mesomechanischen Kinematik sowie strukturdynamischen Versuchen},
author = {M. Romano},
editor = {OTH Regensburg},
url = {https://www.shaker.de/de/content/catalogue/index.asp?lang=de&ID=8&ISBN=978-3-8440-5177-3&search=yes},
doi = {10.2370/9783844051773},
isbn = {978-3-8440-5177-3},
year = {2017},
date = {2017-04-01},
school = {Universität der Bundeswehr München},
abstract = {Die vorliegende Arbeit behandelt die analytische und numerische Identifikation einer mesomechanischen Kinematik in gewebeverstärkten Einzellagen sowie deren Validierung über die Strukturdynamik von flachen stabförmigen Probekörpern aus kohlenstofffaserverstärktem Kunststoff (CFK). Unter der Voraussetzung, dass das wiederholte Wirken der Kinematik Energie dissipiert, trägt sie bei zyklischer viskoelastischer Deformation zusätzlich zur reinen viskoelastischen Werkstoffdämpfung in gewebeverstärkten Einzellagen bei.
Die analytischen und numerischen Untersuchungen beschränken sich auf die Betrachtung des ebenen, zweidimensionalen Zusammenhangs einer vollständigen Ondulation bzw. einer repräsentativen Sequenz in Dickenrichtung. Zur Parameteridentifikation werden die geometrischen Abmessungen in definierten Schritten variiert. Dafür wird der Grad der Ondulation in gewebeverstärkten Einzellagen Õ=A/L als dimensionslose Kennzahl eingeführt. Zur Validierung der dämpfungserhöhenden Wirkung der in den analytischen und numerischen Untersuchung identifizierten mesomechanischen Kinematik in gewebeverstärkten Einzellagen werden in experimentellen strukturdynamischen Untersuchungen frei abklingende Transversalschwingungen von einseitig fest eingespannten Probekörpern untersucht. Im Detail werden flache stabförmige Probekörper aus kohlenstofffaserverstärktem Epoxidharz mit Lagenaufbauten aus 0°-unidirektionalen und gewebeverstärkten Einzellagen untersucht. Die Ergebnisse der experimentellen strukturdynamischen Untersuchungen dienen schließlich der Validierung des analytischen Modells und der numerischen Berechnungen. Die dämpfungserhöhende Wirkung der identifizierten mesomechanischen Kinematik wird schließlich in Abhängigkeit des eingeführten Grades der Ondulation Õ quantifiziert. },
keywords = {},
pubstate = {published},
tppubtype = {phdthesis}
}
Die vorliegende Arbeit behandelt die analytische und numerische Identifikation einer mesomechanischen Kinematik in gewebeverstärkten Einzellagen sowie deren Validierung über die Strukturdynamik von flachen stabförmigen Probekörpern aus kohlenstofffaserverstärktem Kunststoff (CFK). Unter der Voraussetzung, dass das wiederholte Wirken der Kinematik Energie dissipiert, trägt sie bei zyklischer viskoelastischer Deformation zusätzlich zur reinen viskoelastischen Werkstoffdämpfung in gewebeverstärkten Einzellagen bei.
Die analytischen und numerischen Untersuchungen beschränken sich auf die Betrachtung des ebenen, zweidimensionalen Zusammenhangs einer vollständigen Ondulation bzw. einer repräsentativen Sequenz in Dickenrichtung. Zur Parameteridentifikation werden die geometrischen Abmessungen in definierten Schritten variiert. Dafür wird der Grad der Ondulation in gewebeverstärkten Einzellagen Õ=A/L als dimensionslose Kennzahl eingeführt. Zur Validierung der dämpfungserhöhenden Wirkung der in den analytischen und numerischen Untersuchung identifizierten mesomechanischen Kinematik in gewebeverstärkten Einzellagen werden in experimentellen strukturdynamischen Untersuchungen frei abklingende Transversalschwingungen von einseitig fest eingespannten Probekörpern untersucht. Im Detail werden flache stabförmige Probekörper aus kohlenstofffaserverstärktem Epoxidharz mit Lagenaufbauten aus 0°-unidirektionalen und gewebeverstärkten Einzellagen untersucht. Die Ergebnisse der experimentellen strukturdynamischen Untersuchungen dienen schließlich der Validierung des analytischen Modells und der numerischen Berechnungen. Die dämpfungserhöhende Wirkung der identifizierten mesomechanischen Kinematik wird schließlich in Abhängigkeit des eingeführten Grades der Ondulation Õ quantifiziert. |
Siegl, M.; Ehrlich, I. Transformation of the Mechanical Properties of Fiber-Reinforced Plastic Tubes from the Cartesian Coordinate System into the Cylindrical Coordinate System for the Application of Bending Models. Leichtbau Artikel In: Athens Journal of Τechnology & Engineering, Bd. 4, Nr. 1, S. 47-62, 2017, ISSN: 2241-8237. @article{Siegl2017,
title = {Transformation of the Mechanical Properties of Fiber-Reinforced Plastic Tubes from the Cartesian Coordinate System into the Cylindrical Coordinate System for the Application of Bending Models.},
author = {M. Siegl and I. Ehrlich},
editor = {P. Petratos and N. Mourtos and T. Trafalis and T. Attard and V. Sisiopiku},
url = {https://www.athensjournals.gr/technology/2017-4-1-4-Siegl.pdf},
doi = {10.30958/AJTE.3-4-1},
issn = {2241-8237},
year = {2017},
date = {2017-03-01},
journal = {Athens Journal of Τechnology & Engineering},
volume = {4},
number = {1},
pages = {47-62},
abstract = {Fiber-reinforced plastic (FRP) tubes are used in many different industries, such as electrical engineering and pipeline construction. The tubes are frequently subjected to bending loads, depending on the application. In order that the dimensioning of the tubes can be ensured, analytical bending models are used to calculate the resulting stresses, strains and displacements in the individual layers of the laminate. This enables the making of a statement about the failure of the fiber-reinforced tube by choosing an appropriate failure criterion. For the use of these bending models, it is necessary to understand the respective underlying theory. The theory provides the basis for the mathematical description of the mechanical properties for a single-layered tube and using the relationships between the stresses and strains that occur in the Cylindrical coordinate system for this calculation step. For this reason, a redefinition of the compliance matrix from the transformation about the winding angle to the Cylindrical coordinate system and a modification of the stress and strain vectors is necessary, because the defined Cartesian coordinate system of the model cannot be used for wounded FRP tubes. The transformation causes an exchange of entries in the compliance matrix, which remain in the correct relationship between the particular stress and strains. This step is not specified and may lead to incorrect results due to the incorrect entry of compliances. The present publication refers to sketch on this issue and represent a simplification of the changeover to the level required by the bending models notation of vectors in the form of a permutation. In addition, a new name for the pre-acquisition of the redefined compliances is given to prevent confusion when entering the material law of a bending model. Finally, the permuted and redefined compliances are proved in an example to determine their accuracy.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Fiber-reinforced plastic (FRP) tubes are used in many different industries, such as electrical engineering and pipeline construction. The tubes are frequently subjected to bending loads, depending on the application. In order that the dimensioning of the tubes can be ensured, analytical bending models are used to calculate the resulting stresses, strains and displacements in the individual layers of the laminate. This enables the making of a statement about the failure of the fiber-reinforced tube by choosing an appropriate failure criterion. For the use of these bending models, it is necessary to understand the respective underlying theory. The theory provides the basis for the mathematical description of the mechanical properties for a single-layered tube and using the relationships between the stresses and strains that occur in the Cylindrical coordinate system for this calculation step. For this reason, a redefinition of the compliance matrix from the transformation about the winding angle to the Cylindrical coordinate system and a modification of the stress and strain vectors is necessary, because the defined Cartesian coordinate system of the model cannot be used for wounded FRP tubes. The transformation causes an exchange of entries in the compliance matrix, which remain in the correct relationship between the particular stress and strains. This step is not specified and may lead to incorrect results due to the incorrect entry of compliances. The present publication refers to sketch on this issue and represent a simplification of the changeover to the level required by the bending models notation of vectors in the form of a permutation. In addition, a new name for the pre-acquisition of the redefined compliances is given to prevent confusion when entering the material law of a bending model. Finally, the permuted and redefined compliances are proved in an example to determine their accuracy. |
Romano, M.; Ehrlich, I.; Gebbeken, N. Parametric characterization of a mesomechanic kinematic caused by ondulation in fabric reinforced composites: analytical and numerical investigations. Leichtbau Artikel In: Frattura ed Integrità Strutturale (Fracture and Structural Integrity), Bd. 11, Nr. 39, S. 226-247, 2017, ISSN: 1971-8993. @article{Romano2017,
title = {Parametric characterization of a mesomechanic kinematic caused by ondulation in fabric reinforced composites: analytical and numerical investigations.},
author = {M. Romano and I. Ehrlich and N. Gebbeken},
url = {http://www.fracturae.com/index.php/fis/article/view/IGF-ESIS.39.22
http://www.fracturae.com/index.php/fis/article/view/IGF-ESIS.39.22/1860
http://www.fracturae.com/index.php/fis/article/download/IGF-ESIS.39.22/1860
http://www.gruppofrattura.it/pdf/fig/numero39/#234},
doi = {10.3221/IGF-ESIS.39.22 },
issn = {1971-8993},
year = {2017},
date = {2017-01-01},
journal = {Frattura ed Integrità Strutturale (Fracture and Structural Integrity)},
volume = {11},
number = {39},
pages = {226-247},
abstract = {A parametric characterization of a mesomechanic kinematic caused by ondulation in fabric reinforced composites is investigated by analytical and numerical investigations. Due to the definition of plain representative sequences of balanced plain-weave fabric reinforced single layers based on sines the variable geometric parameters are the amplitude and the length of the ondulation. The mesomechanic kinematic can be observed in both the analytic model and the FE-analyses. The analytic model yields hyperbolic correlations due to the strongly simplifying presumptions that neglect elasticity. In contrast the FE-analyses yield linear correlations in much smaller amounts due to the consideration of elastic parts, yet distinctly.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
A parametric characterization of a mesomechanic kinematic caused by ondulation in fabric reinforced composites is investigated by analytical and numerical investigations. Due to the definition of plain representative sequences of balanced plain-weave fabric reinforced single layers based on sines the variable geometric parameters are the amplitude and the length of the ondulation. The mesomechanic kinematic can be observed in both the analytic model and the FE-analyses. The analytic model yields hyperbolic correlations due to the strongly simplifying presumptions that neglect elasticity. In contrast the FE-analyses yield linear correlations in much smaller amounts due to the consideration of elastic parts, yet distinctly. |
2016
|
Wätzig, A.; Schmid, V.; Ehrlich, I. Damage Modelling of Adhesive Joints Using the Cohesive Zone Model. Leichtbau Proceedings Article In: Mottok, J.; Reichenberger, M.; Stolle, R. (Hrsg.): Applied Research Conference 2016 – ARC 2016, Pro Business Verlag, Berlin, 2016, ISBN: 9783864604942. @inproceedings{Wätzig2016,
title = {Damage Modelling of Adhesive Joints Using the Cohesive Zone Model. },
author = {A. Wätzig and V. Schmid and I. Ehrlich},
editor = {J. Mottok and M. Reichenberger and R. Stolle},
isbn = {9783864604942},
year = {2016},
date = {2016-06-24},
booktitle = {Applied Research Conference 2016 – ARC 2016},
publisher = {Pro Business Verlag},
address = {Berlin},
keywords = {},
pubstate = {published},
tppubtype = {inproceedings}
}
|
Nübler, S.; Schmid, V.; Ehrlich, I. FEM-Simulation of a Tube to Flange Joint under Bending Load. Leichtbau Proceedings Article In: Mottok, J.; Reichenberger, M.; Stolle, R. (Hrsg.): Applied Research Conference 2016 – ARC 2016, Pro Business Verlag, Berlin, 2016, ISBN: 9783864604942. @inproceedings{Nübler2016,
title = {FEM-Simulation of a Tube to Flange Joint under Bending Load.},
author = {S. Nübler and V. Schmid and I. Ehrlich},
editor = {J. Mottok and M. Reichenberger and R. Stolle},
isbn = {9783864604942},
year = {2016},
date = {2016-06-24},
booktitle = {Applied Research Conference 2016 – ARC 2016},
publisher = {Pro Business Verlag},
address = {Berlin},
keywords = {},
pubstate = {published},
tppubtype = {inproceedings}
}
|
Steinmann, S.; Ehrlich, I. Investigation of transverse impact stress in fiber reinforced plastics under high-velocity impact and determination of the experimental procedure. Leichtbau Proceedings Article In: Mottok, J.; Reichenberger, M.; Stolle, R. (Hrsg.): Applied Research Conference 2016 – ARC 2016, Ostbayerische Technische Hochschule Regensburg Pro Business Verlag, Berlin, 2016, ISBN: 9783864604942. @inproceedings{Steinmann2016,
title = {Investigation of transverse impact stress in fiber reinforced plastics under high-velocity impact and determination of the experimental procedure.},
author = {S. Steinmann and I. Ehrlich},
editor = {J. Mottok and M. Reichenberger and R. Stolle},
isbn = {9783864604942},
year = {2016},
date = {2016-06-24},
booktitle = {Applied Research Conference 2016 – ARC 2016},
publisher = {Pro Business Verlag},
address = {Berlin},
organization = {Ostbayerische Technische Hochschule Regensburg},
abstract = {The examination of material properties under a transverse impact stress is interpreted as an important regular feature for components of fiber-reinforced plastics. In many applications the knowledge of this material stress is not sufficiently available. The transverse impact is defined as a critical material stress, which can lead to failure of the material with a variety of failure modes. In the research project Hybrid Impact Safety, supported by the Bavarian Research Foundation (Bayerische Forschungsstiftung), different materials of fiber reinforced plastics and their layered structures are examined regarding their impact resistance and the incoming failure modes. The materials basalt fiber-, carbon fiber-, and glass fiber-reinforced plastic, are loaded transversely in different speed ranges and the absorbed energy is determined. ABRATE describe the speed ranges for velocity investigations on fiber-reinforced plastics. The load operation in ballistic speed range with low masses is defined as a dynamic process, and the lower speed range with high masses as a quasi-static process. The relation of the applied energy to the projected area of damage caused by the transverse impact is detected. The dissipated energies, depending on the materials, are compared and evaluated. The layered structure is crucial for the spread of the damaged area and residual energy restrained in the material. The findings of the monolithic materials give conclusions about the damage propagation under impact loads and help to identify the damage in the material. The highvelocity-impact is performed by a ballistic gun system. The speed range is between 350 m/s and 450 m/s. This work defines an experimental procedure for high velocity impact, the conditions of the experiment and carrying out the material tests in a highvelocity speed range. The aim is to increase the impact resistance and minimize the damage spread by a target array of different materials in a single layered structure. },
keywords = {},
pubstate = {published},
tppubtype = {inproceedings}
}
The examination of material properties under a transverse impact stress is interpreted as an important regular feature for components of fiber-reinforced plastics. In many applications the knowledge of this material stress is not sufficiently available. The transverse impact is defined as a critical material stress, which can lead to failure of the material with a variety of failure modes. In the research project Hybrid Impact Safety, supported by the Bavarian Research Foundation (Bayerische Forschungsstiftung), different materials of fiber reinforced plastics and their layered structures are examined regarding their impact resistance and the incoming failure modes. The materials basalt fiber-, carbon fiber-, and glass fiber-reinforced plastic, are loaded transversely in different speed ranges and the absorbed energy is determined. ABRATE describe the speed ranges for velocity investigations on fiber-reinforced plastics. The load operation in ballistic speed range with low masses is defined as a dynamic process, and the lower speed range with high masses as a quasi-static process. The relation of the applied energy to the projected area of damage caused by the transverse impact is detected. The dissipated energies, depending on the materials, are compared and evaluated. The layered structure is crucial for the spread of the damaged area and residual energy restrained in the material. The findings of the monolithic materials give conclusions about the damage propagation under impact loads and help to identify the damage in the material. The highvelocity-impact is performed by a ballistic gun system. The speed range is between 350 m/s and 450 m/s. This work defines an experimental procedure for high velocity impact, the conditions of the experiment and carrying out the material tests in a highvelocity speed range. The aim is to increase the impact resistance and minimize the damage spread by a target array of different materials in a single layered structure. |
Faber, M.; Kastenmeier, A.; Ehrlich, I. Three-dimensional finite element analysis of a composite tube with multi-row bolted joints. Leichtbau Proceedings Article In: Mottok, J.; Reichenberger, M.; Stolle, R. (Hrsg.): Applied Research Conference 2016 – ARC 2016, Technische Hochschule Augsburg Pro Business Verlag 2016 , Augsburg, 2016, ISBN: 9783864604942. @inproceedings{Faber2016,
title = {Three-dimensional finite element analysis of a composite tube with multi-row bolted joints.},
author = {M. Faber and A. Kastenmeier and I. Ehrlich},
editor = {J. Mottok and M. Reichenberger and R. Stolle},
isbn = {9783864604942},
year = {2016},
date = {2016-06-22},
booktitle = {Applied Research Conference 2016 – ARC 2016},
publisher = {Pro Business Verlag 2016 },
address = {Augsburg},
organization = {Technische Hochschule Augsburg},
keywords = {},
pubstate = {published},
tppubtype = {inproceedings}
}
|
Pongratz, C.; Ehrlich, I. Structural Dynamic Analysis of Thin Composite Plates Using Noncontact Measurement and Excitation. Leichtbau Proceedings Article In: Mottok, J.; Reichenberger, J.; Scharfenberg, G.; Ziemann, O. (Hrsg.): Applied Research Conference 2016 – ARC 2016, S. 351-358, Ostbayerische Technische Hochschule Regensburg Pro Business Verlag, Berlin, 2016, ISBN: 978-3-86460-494-2. @inproceedings{Pongratz2016b,
title = {Structural Dynamic Analysis of Thin Composite Plates Using Noncontact Measurement and Excitation.},
author = {C. Pongratz and I. Ehrlich},
editor = {J. Mottok and J. Reichenberger and G. Scharfenberg and O. Ziemann},
isbn = {978-3-86460-494-2},
year = {2016},
date = {2016-06-22},
booktitle = {Applied Research Conference 2016 – ARC 2016},
pages = {351-358},
publisher = {Pro Business Verlag},
address = {Berlin},
organization = {Ostbayerische Technische Hochschule Regensburg},
abstract = {A wide field of applications for fiber-reinforced plastics exists in the aeronautics as well as in the automotive industry due to the superior specific stiffness and strength these materials offer. A drawback of fiber-reinforced plastics is their vulnerability to so called delamination damages. Those damages are a particular safety issue as they are virtually invisible from the outside. A structural health monitoring principle is researched and tested, which aims to allow structure integrity statements without permanent monitoring or during operation, based on the vibrational behavior. The first step to achieve this is to determine the properties describing the vibrational behavior of intact composite plates. The modal properties were determined using a Laser Scanning Vibrometer. The specimen plates were measured on a free-free bearing. Excitation is provided by sound waves emitted from a speaker placed underneath the plate. By combining the excitation via speaker with the Laser Scanning Vibrometer, a non-contact excitation and measurement setup is gained. Utilizing this setup, different carbon fiber-reinforced plastic plates were measured and analyzed. The obtained results are discussed and the structural dynamic properties of different plates compared.},
keywords = {},
pubstate = {published},
tppubtype = {inproceedings}
}
A wide field of applications for fiber-reinforced plastics exists in the aeronautics as well as in the automotive industry due to the superior specific stiffness and strength these materials offer. A drawback of fiber-reinforced plastics is their vulnerability to so called delamination damages. Those damages are a particular safety issue as they are virtually invisible from the outside. A structural health monitoring principle is researched and tested, which aims to allow structure integrity statements without permanent monitoring or during operation, based on the vibrational behavior. The first step to achieve this is to determine the properties describing the vibrational behavior of intact composite plates. The modal properties were determined using a Laser Scanning Vibrometer. The specimen plates were measured on a free-free bearing. Excitation is provided by sound waves emitted from a speaker placed underneath the plate. By combining the excitation via speaker with the Laser Scanning Vibrometer, a non-contact excitation and measurement setup is gained. Utilizing this setup, different carbon fiber-reinforced plastic plates were measured and analyzed. The obtained results are discussed and the structural dynamic properties of different plates compared. |
Pongratz, C.; Schlamp, M.; Jungbauer, B.; Ehrlich, I. Detection of Delamination Damages in Thin Composite Plates using Noncontact Measurement of Structural Dynamic Behavior Leichtbau Artikel In: Athens Journal of Τechnology & Engineering, Bd. 3, Nr. 4, S. 315-331, 2016, ISSN: 2241-8237. @article{Pongratz2016,
title = {Detection of Delamination Damages in Thin Composite Plates using Noncontact Measurement of Structural Dynamic Behavior},
author = {C. Pongratz and M. Schlamp and B. Jungbauer and I. Ehrlich},
editor = {P. Petratos and N. Mourtos and T. Trafalis and T. Attard and V. Sisiopiku},
url = {https://www.athensjournals.gr/technology/2016-3-4-3-Pongratz.pdf},
doi = {10.30958/AJTE.3-4-3},
issn = {2241-8237},
year = {2016},
date = {2016-06-20},
booktitle = {Proceedings of the 4th Annual International Conference on Industrial, Systems and Design Engineering},
journal = {Athens Journal of Τechnology & Engineering},
volume = {3},
number = {4},
pages = {315-331},
address = {Athens, Greece},
abstract = {Plate-shaped composite structures are typically implemented in a variety of applications related to the aeronautics or automotive industry. Subjected to real environmental conditions, those structures may be burdened by impact loads. Low-velocity impacts in particular are a high safety issue since they can cause barely visible or invisible damages inside the structure. The caused defects vary from notches and cracks to delaminations underneath the surface. Their common consequence is a significant reduction of compression and fatigue strength. To determine the integrity of composite structures, different principles, mainly ultrasonic testing, can be used. Because these methods are typically time consuming, a faster and more easily applied integral test method might offer advantages. Such a test method can be gained byanalyzing the vibrational behavior of composite structures. Using the vibrational analysis approach, not only the response frequencies are considered, but also other modal properties, especially the modal damping. The single measurement of the response frequencies might prove an insufficient damage indication because their frequency shift is subtle and is strongly dependent on its present bearing. For the experimental tests, plate-shaped specimens were chosen due to the simple geometry and relevance to applications. By using structural dynamic measurements and analysis, intact as well as impact damaged plates were measured. For the contact-less measurements of the vibrating specimens, a Laser Scanning Vibrometer is used. The plate-shaped specimens are oscillated by acoustic excitation. The necessary bearing is realized in the form of a thread suspension or, more generalized, a free boundary condition. This minimizes any hampering of the evolving modes of vibration. The obtained results of the conducted measurements are compared and discussed.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Plate-shaped composite structures are typically implemented in a variety of applications related to the aeronautics or automotive industry. Subjected to real environmental conditions, those structures may be burdened by impact loads. Low-velocity impacts in particular are a high safety issue since they can cause barely visible or invisible damages inside the structure. The caused defects vary from notches and cracks to delaminations underneath the surface. Their common consequence is a significant reduction of compression and fatigue strength. To determine the integrity of composite structures, different principles, mainly ultrasonic testing, can be used. Because these methods are typically time consuming, a faster and more easily applied integral test method might offer advantages. Such a test method can be gained byanalyzing the vibrational behavior of composite structures. Using the vibrational analysis approach, not only the response frequencies are considered, but also other modal properties, especially the modal damping. The single measurement of the response frequencies might prove an insufficient damage indication because their frequency shift is subtle and is strongly dependent on its present bearing. For the experimental tests, plate-shaped specimens were chosen due to the simple geometry and relevance to applications. By using structural dynamic measurements and analysis, intact as well as impact damaged plates were measured. For the contact-less measurements of the vibrating specimens, a Laser Scanning Vibrometer is used. The plate-shaped specimens are oscillated by acoustic excitation. The necessary bearing is realized in the form of a thread suspension or, more generalized, a free boundary condition. This minimizes any hampering of the evolving modes of vibration. The obtained results of the conducted measurements are compared and discussed. |
Niedernhuber, M.; Holtmannspötter, J.; Ehrlich, I. Fiber-oriented repair geometries for composite materials. Leichtbau Artikel In: Composites Part B, Bd. 94, S. 327-337, 2016. @article{Niedernhuber2016,
title = {Fiber-oriented repair geometries for composite materials. },
author = {M. Niedernhuber and J. Holtmannspötter and I. Ehrlich},
url = {https://doi.org/10.1016/j.compositesb.2016.03.027
http://www.sciencedirect.com/science/article/pii/S1359836816300518
},
doi = {10.1016/j.compositesb.2016.03.027},
year = {2016},
date = {2016-04-01},
journal = {Composites Part B},
volume = {94},
pages = {327-337},
abstract = {In this paper, the idea of fiber-oriented repair geometries for carbon fiber reinforced plastics (CFRP) is investigated. It considers the differing mechanical properties of unidirectional fiber reinforced material by excluding overlapping regions perpendicular to the fiber direction of the particular layer.
A mechanical and numerical comparison of tensile strength of stepped joints with continuous step lengths per ply and stepped joints with reduced step lengths in plies with fiber orientation differing from load direction is performed.
Finite element simulations show similar shear stresses. Mechanical tests of CFRP laminates with stepped joints show no significant deviation in tensile strength, in spite of a joint length reduction of nearly 40%. This leads to the possibility of a significant reduction of repair area.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
In this paper, the idea of fiber-oriented repair geometries for carbon fiber reinforced plastics (CFRP) is investigated. It considers the differing mechanical properties of unidirectional fiber reinforced material by excluding overlapping regions perpendicular to the fiber direction of the particular layer.
A mechanical and numerical comparison of tensile strength of stepped joints with continuous step lengths per ply and stepped joints with reduced step lengths in plies with fiber orientation differing from load direction is performed.
Finite element simulations show similar shear stresses. Mechanical tests of CFRP laminates with stepped joints show no significant deviation in tensile strength, in spite of a joint length reduction of nearly 40%. This leads to the possibility of a significant reduction of repair area. |
Cerrone, A. R.; Nonn, A.; Hochhalter, J. D.; Bomarito, G. F.; Warner, J. E.; Carter, B. J.; Warner, D. H.; Ingraffea, A. R. Predicting failure of the Second Sandia Fracture Challenge geometry with a real-world, time constrained, over-the-counter methodology Werkstoffsimulation Artikel In: International Journal of Fracture, Bd. 198, Nr. 1, S. 117-126, 2016, ISSN: 1573-2673. @article{Cerrone2016,
title = {Predicting failure of the Second Sandia Fracture Challenge geometry with a real-world, time constrained, over-the-counter methodology},
author = {A. R. Cerrone and A. Nonn and J. D. Hochhalter and G. F. Bomarito and J. E. Warner and B. J. Carter and D. H. Warner and A. R. Ingraffea},
url = {https://doi.org/10.1007/s10704-016-0086-x},
doi = {10.1007/s10704-016-0086-x},
issn = {1573-2673},
year = {2016},
date = {2016-03-01},
journal = {International Journal of Fracture},
volume = {198},
number = {1},
pages = {117-126},
abstract = {An over-the-counter methodology to predict fracture initiation and propagation in the challenge specimen of the Second Sandia Fracture Challenge is detailed herein. This pragmatic approach mimics that of an engineer subjected to real-world time constraints and unquantified uncertainty. First, during the blind prediction phase of the challenge, flow and failure locus curves were calibrated for Ti--6Al--4V with provided tensile and shear test data for slow (0.0254 mm/s) and fast (25.4 mm/s) loading rates. Thereafter, these models were applied to a 3D finite-element mesh of the non-standardized challenge geometry with nominal dimensions to predict, among other items, crack path and specimen response. After the blind predictions were submitted to Sandia National Labs, they were improved upon by addressing anisotropic yielding, damage initiation under shear dominance, and boundary condition selection.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
An over-the-counter methodology to predict fracture initiation and propagation in the challenge specimen of the Second Sandia Fracture Challenge is detailed herein. This pragmatic approach mimics that of an engineer subjected to real-world time constraints and unquantified uncertainty. First, during the blind prediction phase of the challenge, flow and failure locus curves were calibrated for Ti--6Al--4V with provided tensile and shear test data for slow (0.0254 mm/s) and fast (25.4 mm/s) loading rates. Thereafter, these models were applied to a 3D finite-element mesh of the non-standardized challenge geometry with nominal dimensions to predict, among other items, crack path and specimen response. After the blind predictions were submitted to Sandia National Labs, they were improved upon by addressing anisotropic yielding, damage initiation under shear dominance, and boundary condition selection. |
2015
|
Putzer, M.; Ehrlich, I.; Rasmussen, J.; Gebbeken, N.; Dendorfer, S. Sensitivity of lumbar spine loading to anatomical parameters. Leichtbau Artikel In: Journal of Biomechanics, Bd. 49, Nr. 6, S. 953-958, 2015. @article{Putzer2015,
title = {Sensitivity of lumbar spine loading to anatomical parameters.},
author = {M. Putzer and I. Ehrlich and J. Rasmussen and N. Gebbeken and S. Dendorfer},
url = {https://www.sciencedirect.com/science/article/pii/S0021929015006338},
doi = {10.1016/j.jbiomech.2015.11.003 },
year = {2015},
date = {2015-12-01},
journal = {Journal of Biomechanics},
volume = {49},
number = {6},
pages = {953-958},
abstract = {Musculoskeletal simulations of lumbar spine loading rely on a geometrical representation of the anatomy. However, this data has an inherent inaccuracy. This study evaluates the influence of defined geometrical parameters on lumbar spine loading utilising five parametrised musculoskeletal lumbar spine models for four different postures. The influence of the dimensions of vertebral body, disc, posterior parts of the vertebrae as well as the curvature of the lumbar spine was studied. Additionally, simulations with combinations of selected parameters were conducted. Changes in L4/L5 resultant joint force were used as outcome variable. Variations of the vertebral body height, disc height, transverse process width and the curvature of the lumbar spine were the most influential.
These parameters can be easily acquired from X-rays and should be used to morph a musculoskeletal lumbar spine model for subject-specific approaches with respect to bone geometry. Furthermore, the model was very sensitive to uncommon configurations and therefore, it is advised that stiffness properties of discs and ligaments should be individualised.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Musculoskeletal simulations of lumbar spine loading rely on a geometrical representation of the anatomy. However, this data has an inherent inaccuracy. This study evaluates the influence of defined geometrical parameters on lumbar spine loading utilising five parametrised musculoskeletal lumbar spine models for four different postures. The influence of the dimensions of vertebral body, disc, posterior parts of the vertebrae as well as the curvature of the lumbar spine was studied. Additionally, simulations with combinations of selected parameters were conducted. Changes in L4/L5 resultant joint force were used as outcome variable. Variations of the vertebral body height, disc height, transverse process width and the curvature of the lumbar spine were the most influential.
These parameters can be easily acquired from X-rays and should be used to morph a musculoskeletal lumbar spine model for subject-specific approaches with respect to bone geometry. Furthermore, the model was very sensitive to uncommon configurations and therefore, it is advised that stiffness properties of discs and ligaments should be individualised. |
Schmid, V.; Bruland, M.; Ehrlich, I.; Kastenmeier, A. Entwicklung und Regelung eines hydraulischen Biegeprüfstands. Leichtbau Proceedings Article In: Rahman, J.; Heinze, R. (Hrsg.): Virtuelle Instrumente in der Praxis 2015 – Begleitband zum 20. VIP-Kongress, S. 407-412, VDE Verlag GmbH, Berlin/Offenbach, 2015, ISBN: 978-3800736690. @inproceedings{Schmid2015,
title = {Entwicklung und Regelung eines hydraulischen Biegeprüfstands.},
author = {V. Schmid and M. Bruland and I. Ehrlich and A. Kastenmeier},
editor = {J. Rahman and R. Heinze},
isbn = {978-3800736690},
year = {2015},
date = {2015-10-01},
booktitle = {Virtuelle Instrumente in der Praxis 2015 – Begleitband zum 20. VIP-Kongress},
pages = {407-412},
publisher = {VDE Verlag GmbH},
address = {Berlin/Offenbach},
keywords = {},
pubstate = {published},
tppubtype = {inproceedings}
}
|
Baumer, A.; Kastenmeier, A.; Ehrlich, I. A Numerical Study of Reinforced Bolted Composite Joints. Leichtbau Proceedings Article In: Mottok, J.; Reichenberger, M.; Scharfenberg, J.; Ziemann, O. (Hrsg.): Applied Research Conference 2015 – ARC 2015, S. 278–282, Ostbayerische Technische Hochschule Regensburg Book-On-Demand Verlag, 2015, ISBN: 978-3863869458. @inproceedings{Baumer2015,
title = {A Numerical Study of Reinforced Bolted Composite Joints.},
author = {A. Baumer and A. Kastenmeier and I. Ehrlich},
editor = {J. Mottok and M. Reichenberger and J. Scharfenberg and O. Ziemann},
isbn = {978-3863869458},
year = {2015},
date = {2015-07-16},
booktitle = {Applied Research Conference 2015 – ARC 2015},
pages = {278--282},
publisher = {Book-On-Demand Verlag},
organization = {Ostbayerische Technische Hochschule Regensburg},
abstract = {The Finite Element Analysis (FEA) is an effective tool to save time and costs in the development phase of engineering disciplines. Thus the dimensioning can easily be tested and adapted with a simulation instead of expensive experiments. Manufacturing and testing of fiber-reinforced plastic components is very extensive because of their specific material properties, in comparison to metal components. This is one of the main reasons why almost each complex structure of composite material is investigated with a Finite Element Analysis. The aim of this applied research project is the analytical and numerical investigation of reinforced bolted joints at structures of carbon fiber-reinforced plastics (CFRP). Bolted joints are a relatively simple technique to join two parts of different materials with each other. However, the bolt hole reduces the bearing cross-section and induces enormous stress concentrations. That is why reinforcing bolted composite joints is necessary. In this project, it is realized with reinforcement inserts which are integrated into the laminate layup. A superior research project is investigating the load application in highly stressed tubular composite structures. Before the reinforced bolted joints are applied at tubular geometries, the reinforcing effect is investigated at plane CFRP-components in this work. Therefore, at first various laminate layups without reinforcement inserts are compared to an unidirectional (UD) laminate. After that, the inserts are integrated into the simulation of UD-laminae and compared to non-reinforced ones. Next step is the integration of reinforced laminae into an entire laminate layup to prove the general reinforcement at the load introduction spot.},
keywords = {},
pubstate = {published},
tppubtype = {inproceedings}
}
The Finite Element Analysis (FEA) is an effective tool to save time and costs in the development phase of engineering disciplines. Thus the dimensioning can easily be tested and adapted with a simulation instead of expensive experiments. Manufacturing and testing of fiber-reinforced plastic components is very extensive because of their specific material properties, in comparison to metal components. This is one of the main reasons why almost each complex structure of composite material is investigated with a Finite Element Analysis. The aim of this applied research project is the analytical and numerical investigation of reinforced bolted joints at structures of carbon fiber-reinforced plastics (CFRP). Bolted joints are a relatively simple technique to join two parts of different materials with each other. However, the bolt hole reduces the bearing cross-section and induces enormous stress concentrations. That is why reinforcing bolted composite joints is necessary. In this project, it is realized with reinforcement inserts which are integrated into the laminate layup. A superior research project is investigating the load application in highly stressed tubular composite structures. Before the reinforced bolted joints are applied at tubular geometries, the reinforcing effect is investigated at plane CFRP-components in this work. Therefore, at first various laminate layups without reinforcement inserts are compared to an unidirectional (UD) laminate. After that, the inserts are integrated into the simulation of UD-laminae and compared to non-reinforced ones. Next step is the integration of reinforced laminae into an entire laminate layup to prove the general reinforcement at the load introduction spot. |
Niebauer, M.; Schmid, V.; Ehrlich, I. Failure Criteria of Adhesively Bonded Joints: A Review. Leichtbau Proceedings Article In: Mottok, J.; Reichenberger, M.; Scharfenberg, J.; Ziemann, O. (Hrsg.): Applied Research Conference 2015 – ARC 2015, S. 347–351, Ostbayerische Technische Hochschule Regensburg Book-On-Demand Verlag, 2015, ISBN: 978-3863869458. @inproceedings{Niebauer2015,
title = {Failure Criteria of Adhesively Bonded Joints: A Review.},
author = {M. Niebauer and V. Schmid and I. Ehrlich},
editor = {J. Mottok and M. Reichenberger and J. Scharfenberg and O. Ziemann},
isbn = {978-3863869458},
year = {2015},
date = {2015-07-16},
booktitle = {Applied Research Conference 2015 – ARC 2015},
pages = {347--351},
publisher = {Book-On-Demand Verlag},
organization = {Ostbayerische Technische Hochschule Regensburg},
abstract = {Failure criteria and predicting the critical stress state of adhesively bonded joints is one of the fundamental issues and aspects of designing adhesive bonds. Such adhesive bonded joints are used in many different applications and because of the aim to save resources and energy, engineers have to find new ways of design. A part of this can be the lightweight construction, where it is useful to design with light adhesive bonded joints. Because of this engineers have to know about the performance of such connections. This paper provides a literature review on failure criteria and strength prediction on adhesively bonded joints. The review covers articles published from 1973 until 2013 and divides the topic into several categories such as critical elastic stress states, fracture mechanics, adhesive failure due to plasticity and damage mechanics. In addition, relevant design aspects and details are discussed and available approaches, appropriate for analytical and numerical solutions are identified. },
keywords = {},
pubstate = {published},
tppubtype = {inproceedings}
}
Failure criteria and predicting the critical stress state of adhesively bonded joints is one of the fundamental issues and aspects of designing adhesive bonds. Such adhesive bonded joints are used in many different applications and because of the aim to save resources and energy, engineers have to find new ways of design. A part of this can be the lightweight construction, where it is useful to design with light adhesive bonded joints. Because of this engineers have to know about the performance of such connections. This paper provides a literature review on failure criteria and strength prediction on adhesively bonded joints. The review covers articles published from 1973 until 2013 and divides the topic into several categories such as critical elastic stress states, fracture mechanics, adhesive failure due to plasticity and damage mechanics. In addition, relevant design aspects and details are discussed and available approaches, appropriate for analytical and numerical solutions are identified. |
Romano, M.; Eisenried, M.; Jungbauer, B.; Ehrlich, I.; Gebbeken, N. Influence of parameters of the production process on the material quality of unidirectionally reinforced prepregs. Leichtbau Artikel In: Journal of Achievements in Materials and Manufacturing Engineering (JAMME), Bd. 68, Nr. 1, S. 32-44, 2015, ISSN: 1734-8412. @article{Romano2015,
title = {Influence of parameters of the production process on the material quality of unidirectionally reinforced prepregs.},
author = {M. Romano and M. Eisenried and B. Jungbauer and I. Ehrlich and N. Gebbeken},
url = {http://jamme.acmsse.h2.pl/vol68_1/6815.pdf},
issn = {1734-8412},
year = {2015},
date = {2015-01-01},
journal = {Journal of Achievements in Materials and Manufacturing Engineering (JAMME)},
volume = {68},
number = {1},
pages = {32-44},
abstract = {The aim of the prepreg production device is to impregnate different types of reinforcement fibers with an arbitrarily selectable thermoset matrix system that completely satisfies the requirements for autoclave processing. As the prepreg production device is designed and built up modularly every module corresponds one step in the process. To identify the parameters of the production process and investigate its sensitivity on the material quality of both the prepreg as an uncured semi-finished product and the composite as the cured material experimental investigations regarding the resin flow, fiber volume content, mass per unit area and void content are carried out. Overall four material combinations have been investigated, where in each case the selected impregnation temperature and the width of the impregnation gap has been reproducibly varied in selected steps. The experimental characterization of the prepregs and of the composite material is carried out according to German standards. Used parameters clearly affect the material properties, so that a proper impregnation and curing process can be achieved by optimizing the parameter to desired values.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
The aim of the prepreg production device is to impregnate different types of reinforcement fibers with an arbitrarily selectable thermoset matrix system that completely satisfies the requirements for autoclave processing. As the prepreg production device is designed and built up modularly every module corresponds one step in the process. To identify the parameters of the production process and investigate its sensitivity on the material quality of both the prepreg as an uncured semi-finished product and the composite as the cured material experimental investigations regarding the resin flow, fiber volume content, mass per unit area and void content are carried out. Overall four material combinations have been investigated, where in each case the selected impregnation temperature and the width of the impregnation gap has been reproducibly varied in selected steps. The experimental characterization of the prepregs and of the composite material is carried out according to German standards. Used parameters clearly affect the material properties, so that a proper impregnation and curing process can be achieved by optimizing the parameter to desired values. |
2014
|
Dinnebier, D.; Ehrlich, I. The effects of severe temperature changes and high humidity on porous CFRP. Leichtbau Artikel In: Journal of Achievements in Materials and Manufacturing Engineering (JAMME), Bd. 67, Nr. 1, S. 5–19, 2014. @article{Dinnebier2014,
title = {The effects of severe temperature changes and high humidity on porous CFRP.},
author = {D. Dinnebier and I. Ehrlich},
year = {2014},
date = {2014-11-01},
journal = {Journal of Achievements in Materials and Manufacturing Engineering (JAMME)},
volume = {67},
number = {1},
pages = {5--19},
abstract = {A route to manufacture porous carbon fiber reinforced plastic (CFRP) for study purposes is described. The porous CFRP is characterized using standard techniques such as matrix digestion as well as the more sophisticated method of high resolution Microfocus X-Ray Tomography (μCT). A comparison of the results of those methods is presented. The mass gains of specimens with a wide range of porosity have been measured both in constant humidity and in alternating environments. It could be shown that severe temperature changes can temporarily increase the moisture content of porous CFRP. However, after the return to a constant environment, the moisture content returns back to saturation levels. Furthermore, it could be shown by X-Ray Tomography that even under severe climatic conditions no permanent liquid water condensates inside the pores. Using Microfocus Computed Tomography it could be shown that even after nearly a year under hot-wet conditions and more than 150 severe temperature cycles there is no liquid water detectable inside the pores.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
A route to manufacture porous carbon fiber reinforced plastic (CFRP) for study purposes is described. The porous CFRP is characterized using standard techniques such as matrix digestion as well as the more sophisticated method of high resolution Microfocus X-Ray Tomography (μCT). A comparison of the results of those methods is presented. The mass gains of specimens with a wide range of porosity have been measured both in constant humidity and in alternating environments. It could be shown that severe temperature changes can temporarily increase the moisture content of porous CFRP. However, after the return to a constant environment, the moisture content returns back to saturation levels. Furthermore, it could be shown by X-Ray Tomography that even under severe climatic conditions no permanent liquid water condensates inside the pores. Using Microfocus Computed Tomography it could be shown that even after nearly a year under hot-wet conditions and more than 150 severe temperature cycles there is no liquid water detectable inside the pores. |
Dinnebier, D.; Ehrlich, I. The Effects of Severe Temperature Changes and High Humidity on Porous CFRP. Leichtbau Proceedings Article In: Meran, C. (Hrsg.): Proceedings of the 15th International Materials Symposium (IMSP’2014), S. 433–440, Pamukkale University (Denizli, Turkey) 2014. @inproceedings{Dinnebier2014b,
title = {The Effects of Severe Temperature Changes and High Humidity on Porous CFRP.},
author = {D. Dinnebier and I. Ehrlich},
editor = {C. Meran},
year = {2014},
date = {2014-10-01},
booktitle = {Proceedings of the 15th International Materials Symposium (IMSP’2014)},
pages = {433--440},
organization = {Pamukkale University (Denizli, Turkey)},
keywords = {},
pubstate = {published},
tppubtype = {inproceedings}
}
|
Ehrlich, I.; Dinnebier, D.; Jost, C. Comparison of Impact Delaminations in CFRP Using Ultrasonic Testing, Microfocus Computed X-Ray Tomography and Micrographic Cross-Section. Leichtbau Proceedings Article In: Meran, C. (Hrsg.): Proceedings of the 15th International Materials Symposium (IMSP’2014), S. 441–450, Pamukkale University (Denizli, Turkey) 2014. @inproceedings{Ehrlich2014,
title = {Comparison of Impact Delaminations in CFRP Using Ultrasonic Testing, Microfocus Computed X-Ray Tomography and Micrographic Cross-Section.},
author = {I. Ehrlich and D. Dinnebier and C. Jost},
editor = {C. Meran},
year = {2014},
date = {2014-10-01},
booktitle = {Proceedings of the 15th International Materials Symposium (IMSP’2014)},
pages = {441--450},
organization = {Pamukkale University (Denizli, Turkey)},
keywords = {},
pubstate = {published},
tppubtype = {inproceedings}
}
|
Romano, M.; Hoinkes, C.; Ehrlich, I.; Höcherl, J.; Gebbeken, N. Influence of the impactor on the experimentally determined energy dissipation properties of fiber-reinforced plastics with hybrid layups under high velocity impact loads. Leichtbau Proceedings Article In: Meran, C. (Hrsg.): Proceedings of the 15th International Materials Symposium (IMSP’2014), S. 650–664, Pamukkale University (Denizli, Turkey) 2014. @inproceedings{Romano2014c,
title = {Influence of the impactor on the experimentally determined energy dissipation properties of fiber-reinforced plastics with hybrid layups under high velocity impact loads. },
author = {M. Romano and C. Hoinkes and I. Ehrlich and J. Höcherl and N. Gebbeken},
editor = {C. Meran},
year = {2014},
date = {2014-10-01},
booktitle = {Proceedings of the 15th International Materials Symposium (IMSP’2014)},
pages = {650--664},
organization = {Pamukkale University (Denizli, Turkey)},
keywords = {},
pubstate = {published},
tppubtype = {inproceedings}
}
|
Romano, M.; Micklitz, M.; Olbrich, F.; Bierl, R.; Ehrlich, I.; Gebbeken, N. Experimental investigation of damping properties of unidirectionally and fabric reinforced plastics by the free decay method. Leichtbau Proceedings Article In: Meran, C. (Hrsg.): Proceedings of the 15th International Materials Symposium (IMSP’2014), S. 665–679, Pamukkale University (Denizli, Turkey) 2014. @inproceedings{Romano2014d,
title = {Experimental investigation of damping properties of unidirectionally and fabric reinforced plastics by the free decay method.},
author = {M. Romano and M. Micklitz and F. Olbrich and R. Bierl and I. Ehrlich and N. Gebbeken },
editor = {C. Meran},
url = {http://imsp.pau.edu.tr/IMSP2014_Proceedings_Final_security.pdf
},
year = {2014},
date = {2014-10-01},
urldate = {2014-10-01},
booktitle = {Proceedings of the 15th International Materials Symposium (IMSP’2014)},
pages = {665--679},
organization = {Pamukkale University (Denizli, Turkey)},
keywords = {},
pubstate = {published},
tppubtype = {inproceedings}
}
|
Nonn, A.; Brauer, H.; Großpietsch, D. Establishing the correlation between impact energies for different sized specimens using damage models Werkstoffsimulation Proceedings Article In: 10th International Pipeline Conference 2014 (IPC 2014), Calgary, Canada, 2014. @inproceedings{Nonn2014b,
title = {Establishing the correlation between impact energies for different sized specimens using damage models},
author = {A. Nonn and H. Brauer and D. Großpietsch},
doi = {10.1115/IPC2014-33164},
year = {2014},
date = {2014-09-29},
booktitle = {10th International Pipeline Conference 2014 (IPC 2014)},
address = {Calgary, Canada},
abstract = {The safety assessment of flawed pressurized pipes requires the knowledge of toughness properties which are usually provided in terms of impact energy from standard full-sized CVN notch specimens. For pipes with wall thickness less than 10mm different Charpy standards allow for the application of sub-sized specimens. However, it is still not fully clear how the impact energy from sub-sized specimens can be used to evaluate the fracture resistance of the pipes and how this energy correlates to the one from the full-sized specimen. Although different empirical correlations between sub-sized and full-sized specimens exist in the literature their validity is questionable since they are based on the results for older generation of steels. In the recent years the application of damage mechanics models has been promoted to assess the fracture behavior and deformation capacity of pipelines. The main advantage of these models can be found in their capability to link the damage evolution and the underlying stress/strain condition.
In this paper damage mechanics approach is applied to describe fracture behavior of X65 pipeline material. Within the damage mechanics approach, Gurson-Tvergaard-Needleman (GTN) model is considered to be adequate for the simulation of ductile fracture. For brittle fracture, GTN model is extended by a propagation criterion which examines if the cleavage fracture stress is reached by the maximal principal stresses. The model parameters are calibrated and verified by means of load-displacement curves obtained from instrumented impact tests on different sized CVN specimens. This damage model is subsequently employed to simulate ductile-brittle transition behavior.},
keywords = {},
pubstate = {published},
tppubtype = {inproceedings}
}
The safety assessment of flawed pressurized pipes requires the knowledge of toughness properties which are usually provided in terms of impact energy from standard full-sized CVN notch specimens. For pipes with wall thickness less than 10mm different Charpy standards allow for the application of sub-sized specimens. However, it is still not fully clear how the impact energy from sub-sized specimens can be used to evaluate the fracture resistance of the pipes and how this energy correlates to the one from the full-sized specimen. Although different empirical correlations between sub-sized and full-sized specimens exist in the literature their validity is questionable since they are based on the results for older generation of steels. In the recent years the application of damage mechanics models has been promoted to assess the fracture behavior and deformation capacity of pipelines. The main advantage of these models can be found in their capability to link the damage evolution and the underlying stress/strain condition.
In this paper damage mechanics approach is applied to describe fracture behavior of X65 pipeline material. Within the damage mechanics approach, Gurson-Tvergaard-Needleman (GTN) model is considered to be adequate for the simulation of ductile fracture. For brittle fracture, GTN model is extended by a propagation criterion which examines if the cleavage fracture stress is reached by the maximal principal stresses. The model parameters are calibrated and verified by means of load-displacement curves obtained from instrumented impact tests on different sized CVN specimens. This damage model is subsequently employed to simulate ductile-brittle transition behavior. |
Nonn, A.; Erdelen-Peppler, M.; Wessel, W.; Niklasch, D.; Mahn, D. How to assure fracture-propagation control for seamless gas pipelines? Werkstoffsimulation Proceedings Article In: 10th International Pipeline Conference 2014 (IPC 2014), Calgary, Canada, 2014. @inproceedings{Nonn2014c,
title = {How to assure fracture-propagation control for seamless gas pipelines?},
author = {A. Nonn and M. Erdelen-Peppler and W. Wessel and D. Niklasch and D. Mahn},
doi = {10.1115/IPC2014-33169},
year = {2014},
date = {2014-09-29},
booktitle = {10th International Pipeline Conference 2014 (IPC 2014)},
address = {Calgary, Canada},
abstract = {Fracture propagation control in gas transmission gas pipelines belongs to the major design requirements for safe operation at high internal pressures. However, the current tests such as Drop-Weight-Tear Test (DWTT) and full-scale West-Jefferson (WJ) test reach the limits of their applicability with respect to transition temperature evaluation for seamless quenched and tempered small diameter pipes reflecting nowadays alloying concepts related to mechanical properties. Hereby, different geometry and material effects are evident which might lead to misinterpretation and unreliability of testing results. This paper aims to discuss open issues addressed in the literature and in own experimental findings with respect to reliability and transferability of testing methods, fracture parameters and their representativeness of seamless quenched and tempered pipeline behavior. By applying damage mechanics approach, it is possible to quantify the prevailing stress state and thus to understand the mechanisms controlling specific fracture appearance (ductile or brittle). Furthermore, studies were performed with objective to quantify the effect of different parameters (geometry, material and loading) on the fracture performance of the pipeline. The results from these investigations will serve as a basis for a safe pipeline design against propagating fracture.},
keywords = {},
pubstate = {published},
tppubtype = {inproceedings}
}
Fracture propagation control in gas transmission gas pipelines belongs to the major design requirements for safe operation at high internal pressures. However, the current tests such as Drop-Weight-Tear Test (DWTT) and full-scale West-Jefferson (WJ) test reach the limits of their applicability with respect to transition temperature evaluation for seamless quenched and tempered small diameter pipes reflecting nowadays alloying concepts related to mechanical properties. Hereby, different geometry and material effects are evident which might lead to misinterpretation and unreliability of testing results. This paper aims to discuss open issues addressed in the literature and in own experimental findings with respect to reliability and transferability of testing methods, fracture parameters and their representativeness of seamless quenched and tempered pipeline behavior. By applying damage mechanics approach, it is possible to quantify the prevailing stress state and thus to understand the mechanisms controlling specific fracture appearance (ductile or brittle). Furthermore, studies were performed with objective to quantify the effect of different parameters (geometry, material and loading) on the fracture performance of the pipeline. The results from these investigations will serve as a basis for a safe pipeline design against propagating fracture. |
Karbasian, H.; Groß-Weege, J.; Nonn, A.; Zimmermann, S.; Kalwa, C. Assessment of collapse resistance of UOE pipes – comparison of full-scale and ring collapse tests Werkstoffsimulation Proceedings Article In: 10th International Pipeline Conference 2014 (IPC 2014), Calgary, Canada, 2014. @inproceedings{Karbasian2014,
title = {Assessment of collapse resistance of UOE pipes – comparison of full-scale and ring collapse tests},
author = {H. Karbasian and J. Groß-Weege and A. Nonn and S. Zimmermann and C. Kalwa},
year = {2014},
date = {2014-09-29},
booktitle = {10th International Pipeline Conference 2014 (IPC 2014)},
address = {Calgary, Canada},
keywords = {},
pubstate = {published},
tppubtype = {inproceedings}
}
|
Baumer, A.; Kastenmeier, A.; Ehrlich, I. Investigation of Bolted Composite Joints with Different Reinforcement Elements at the Bolt Hole. Leichtbau Proceedings Article In: Ziemann, O.; Mottok, J.; Pforr, J. (Hrsg.): Applied Research Conference 2014 – ARC 2014, S. 255–258, Shaker-Verlag, 2014, ISBN: 978-3844028751. @inproceedings{Baumer2014,
title = {Investigation of Bolted Composite Joints with Different Reinforcement Elements at the Bolt Hole.},
author = {A. Baumer and A. Kastenmeier and I. Ehrlich},
editor = {O. Ziemann and J. Mottok and J. Pforr},
isbn = {978-3844028751},
year = {2014},
date = {2014-07-15},
booktitle = {Applied Research Conference 2014 – ARC 2014},
pages = {255--258},
publisher = {Shaker-Verlag},
abstract = {Nowadays, there are hardly any structures without joints. On this occasion connections of composite materials with metallic components depict a particular challenge in the structural design. Bolted joints pose a significant weak point in the composite structure because of the strength step from composite to metal and the notch effect of the bolt hole. Nevertheless, such joints are often used in the vehicle and special vehicle construction, as these form-fitting joints can be implemented relatively simple and inexpensively. However, for highly stressed composite structures bolted joints show an insufficient strength. To improve the mechanical properties of the joint, there are various methods for reinforcing the bolt hole in the fiber reinforced plastic. The aim of this research project is to simulate different reinforced bolted joints on CRP (Carbon fiber Reinforced Plastic) pipe structures with the finite-element-method, manufacturing prototypes with the filament winding technique and then to examine experimentally in view of the mechanical properties, e.g. bearing and tensile strength. Before the tests are carried out on pipe structures, first of all the process of manufacturing and testing of reinforced bolted joints is developed for plane samples. These plane bolted joint samples of steel and CRP are tested for tension and bearing strength.},
keywords = {},
pubstate = {published},
tppubtype = {inproceedings}
}
Nowadays, there are hardly any structures without joints. On this occasion connections of composite materials with metallic components depict a particular challenge in the structural design. Bolted joints pose a significant weak point in the composite structure because of the strength step from composite to metal and the notch effect of the bolt hole. Nevertheless, such joints are often used in the vehicle and special vehicle construction, as these form-fitting joints can be implemented relatively simple and inexpensively. However, for highly stressed composite structures bolted joints show an insufficient strength. To improve the mechanical properties of the joint, there are various methods for reinforcing the bolt hole in the fiber reinforced plastic. The aim of this research project is to simulate different reinforced bolted joints on CRP (Carbon fiber Reinforced Plastic) pipe structures with the finite-element-method, manufacturing prototypes with the filament winding technique and then to examine experimentally in view of the mechanical properties, e.g. bearing and tensile strength. Before the tests are carried out on pipe structures, first of all the process of manufacturing and testing of reinforced bolted joints is developed for plane samples. These plane bolted joint samples of steel and CRP are tested for tension and bearing strength. |
Romano, M.; Hoinkes, C.; Ehrlich, I.; Höcherl, J.; Gebbeken, N. Experimental investigation of fibre reinforced plastics with hybrid layups under high-velocity impact loads. Leichtbau Artikel In: Frattura ed Integrità Strutturale (Fracture and Structural Integrity), Bd. 8, Nr. 29, S. 385-398, 2014, ISSN: 1971-8993. @article{Romano2014,
title = {Experimental investigation of fibre reinforced plastics with hybrid layups under high-velocity impact loads. },
author = {M. Romano and C. Hoinkes and I. Ehrlich and J. Höcherl and N. Gebbeken},
url = {http://www.fracturae.com/index.php/fis/article/view/IGF-ESIS.29.34
http://www.fracturae.com/index.php/fis/article/view/IGF-ESIS.29.34/1219
http://www.fracturae.com/index.php/fis/article/download/IGF-ESIS.29.34/1219
},
doi = {10.3221/IGF-ESIS.29.34 },
issn = {1971-8993},
year = {2014},
date = {2014-07-09},
journal = {Frattura ed Integrità Strutturale (Fracture and Structural Integrity)},
volume = {8},
number = {29},
pages = {385-398},
abstract = {This paper deals with experimental investigations concerning energy dissipation capacity of different kinds of reinforcement fibres in monolithic and hybrid layups under high-velocity impact loads. The investigated kinds of fibres are carbon, glass and basalt fibres. Therefore test panels, using the same thermoset resin, were built up and cured by autoclave processing. The fibre volume content of the test panels has been determined. Furthermore the influence of a separating layer at selected positions in the hybrid stacked panels was investigated. The results show the influence and the energy dissipation capacity of each single kind of fibre and the enhanced properties for the hybrid layups by hybrid stacking sequences and the use of a separating core material.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
This paper deals with experimental investigations concerning energy dissipation capacity of different kinds of reinforcement fibres in monolithic and hybrid layups under high-velocity impact loads. The investigated kinds of fibres are carbon, glass and basalt fibres. Therefore test panels, using the same thermoset resin, were built up and cured by autoclave processing. The fibre volume content of the test panels has been determined. Furthermore the influence of a separating layer at selected positions in the hybrid stacked panels was investigated. The results show the influence and the energy dissipation capacity of each single kind of fibre and the enhanced properties for the hybrid layups by hybrid stacking sequences and the use of a separating core material. |
Scheider, I.; Nonn, A.; Völling, A.; Mondry, A.; Kalwa, C. A damage mechanics based evaluation of dynamic fracture resistance in gas pipelines Werkstoffsimulation Proceedings Article In: 20th European Conference on Fracture (ECF 20), Trondheim, Norway, 2014. @inproceedings{Scheider2014,
title = {A damage mechanics based evaluation of dynamic fracture resistance in gas pipelines},
author = {I. Scheider and A. Nonn and A. Völling and A. Mondry and C. Kalwa},
year = {2014},
date = {2014-06-30},
booktitle = {20th European Conference on Fracture (ECF 20)},
address = {Trondheim, Norway},
abstract = {Investigation of running ductile fracture in gas transmission pipelines and the derivation of reliable crack arrest prediction methods belong to major topics in pipeline research. The yet available crack arrest criterion, known as the Battelle Two-Curve Method (BTCM), leads to reliable predictions up to grade X70 line pipe steels for which it has been validated. This includes specific limits in terms of mechanical properties, pressure and geometry. The application of this criterion to modern pipeline steels, i.e. especially grades X80 and beyond in combination with larger diameters and high pressure, has led to mispredictions of the BTCM. Hence, in order to ensure safe design of pipelines, new methods are required based on in depth knowledge and appropriate characterization of material resistance. This paper presents a procedure for the assessment of dynamic ductile fracture resistance based on combined experimental and numerical investigations. The procedure involves quasi-static and dynamic drop- weight tear testing (DWTT) on modified specimens with pre-fatigued crack for grades X65, X80 and X100 materials, and the application of cohesive zone (CZ) and Gurson-Tveergard-Needleman (GTN) models to describe ductile material damage. The damage model parameters are calibrated on basis of DWTT results and subsequently used to simulate dynamic crack propagation in a pipeline. The influence of material properties (strain hardening, toughness), pipe geometry, usage factor and decompression behaviour on ductile fracture propagation behaviour is studied and evaluated. The results will contribute to an enhanced understanding of major parameters controlling ductile fracture propagation and will help to establish a reliable procedure for safe design of new high-capacity pipelines with regard to crack arrest.},
keywords = {},
pubstate = {published},
tppubtype = {inproceedings}
}
Investigation of running ductile fracture in gas transmission pipelines and the derivation of reliable crack arrest prediction methods belong to major topics in pipeline research. The yet available crack arrest criterion, known as the Battelle Two-Curve Method (BTCM), leads to reliable predictions up to grade X70 line pipe steels for which it has been validated. This includes specific limits in terms of mechanical properties, pressure and geometry. The application of this criterion to modern pipeline steels, i.e. especially grades X80 and beyond in combination with larger diameters and high pressure, has led to mispredictions of the BTCM. Hence, in order to ensure safe design of pipelines, new methods are required based on in depth knowledge and appropriate characterization of material resistance. This paper presents a procedure for the assessment of dynamic ductile fracture resistance based on combined experimental and numerical investigations. The procedure involves quasi-static and dynamic drop- weight tear testing (DWTT) on modified specimens with pre-fatigued crack for grades X65, X80 and X100 materials, and the application of cohesive zone (CZ) and Gurson-Tveergard-Needleman (GTN) models to describe ductile material damage. The damage model parameters are calibrated on basis of DWTT results and subsequently used to simulate dynamic crack propagation in a pipeline. The influence of material properties (strain hardening, toughness), pipe geometry, usage factor and decompression behaviour on ductile fracture propagation behaviour is studied and evaluated. The results will contribute to an enhanced understanding of major parameters controlling ductile fracture propagation and will help to establish a reliable procedure for safe design of new high-capacity pipelines with regard to crack arrest. |
Nonn, A.; Erdelen-Peppler, M.; Wessel, W.; Mahn, D. How reliable are the current testing procedures for the safety assurance against crack propagation in seamless gas pipelines Werkstoffsimulation Proceedings Article In: The 33rd International Conference on Ocean, Offshore and Arctic Engineering 2014 (OMAE 2014), San-Francisco, USA, 2014. @inproceedings{Nonn2014,
title = {How reliable are the current testing procedures for the safety assurance against crack propagation in seamless gas pipelines},
author = {A. Nonn and M. Erdelen-Peppler and W. Wessel and D. Mahn},
year = {2014},
date = {2014-06-08},
booktitle = {The 33rd International Conference on Ocean, Offshore and Arctic Engineering 2014 (OMAE 2014)},
address = {San-Francisco, USA},
abstract = {The worldwide growing energy demand with the exploration of new gas fields has promoted the development of high toughness seamless pipeline steels which should sustain the increasing demands resulting from the complex loading situations. One of the most important prerequisites for safe installation and operation of long distance gas transmission pipelines is the detailed knowledge and characterization of their fracture performance for specific applications. However, recent industry experience has revealed concerns related to the limitations and reliability of current test methods for brittle-to-ductile transition evaluation. Regarding the transition temperature evaluation, the critical issues involve Drop-Weight Tear Testing (DWTT) and full-scale West-Jefferson (WJ) test applied to the smaller pipes with diameter less than 500mm. The DWTT leads frequently to invalid results in terms of abnormal fracture appearance and inverse fracture occurrence. It is still not clear if this behavior is only owed to a testing effect, which material characteristics cause it and how far it reflects the full-scale behavior. Similar observations were made for the West-Jefferson tests, which could not be assessed in the standard manner either. Again, the question was towards testing effects and the behavior of the pipeline transporting gaseous media remains unanswered. Therefore, this paper aims at identifying open questions on basis of a literature study and own experimental results and showing possible ways forward in demonstrating safety in design against propagating fracture.},
keywords = {},
pubstate = {published},
tppubtype = {inproceedings}
}
The worldwide growing energy demand with the exploration of new gas fields has promoted the development of high toughness seamless pipeline steels which should sustain the increasing demands resulting from the complex loading situations. One of the most important prerequisites for safe installation and operation of long distance gas transmission pipelines is the detailed knowledge and characterization of their fracture performance for specific applications. However, recent industry experience has revealed concerns related to the limitations and reliability of current test methods for brittle-to-ductile transition evaluation. Regarding the transition temperature evaluation, the critical issues involve Drop-Weight Tear Testing (DWTT) and full-scale West-Jefferson (WJ) test applied to the smaller pipes with diameter less than 500mm. The DWTT leads frequently to invalid results in terms of abnormal fracture appearance and inverse fracture occurrence. It is still not clear if this behavior is only owed to a testing effect, which material characteristics cause it and how far it reflects the full-scale behavior. Similar observations were made for the West-Jefferson tests, which could not be assessed in the standard manner either. Again, the question was towards testing effects and the behavior of the pipeline transporting gaseous media remains unanswered. Therefore, this paper aims at identifying open questions on basis of a literature study and own experimental results and showing possible ways forward in demonstrating safety in design against propagating fracture. |
Hoinkes, C.; Romano, M.; Ehrlich, I.; Höcherl, J.; Gebbeken, N. Investigation of fibre reinforced plastics with monolithic and hybrid stacking sequences under high-velocity impact loads. Leichtbau Proceedings Article In: Ziemann, O.; Mottok, J.; Pforr, J. (Hrsg.): Applied Research Conference 2014 – ARC 2014, Shaker-Verlag, 2014, ISBN: 978-3844028751. @inproceedings{Hoinkes2014,
title = {Investigation of fibre reinforced plastics with monolithic and hybrid stacking sequences under high-velocity impact loads.},
author = {C. Hoinkes and M. Romano and I. Ehrlich and J. Höcherl and N. Gebbeken},
editor = {O. Ziemann and J. Mottok and J. Pforr},
isbn = {978-3844028751},
year = {2014},
date = {2014-06-01},
booktitle = {Applied Research Conference 2014 – ARC 2014},
publisher = {Shaker-Verlag},
abstract = {This study deals with the experimental investigation concerning the energy dissipation capacity of reinforcement fibres in monolithic and hybrid layups, with and without a separating layer, under high-velocity impact loads. The investigated kinds of fibres are carbon, glass and basalt fabrics in a twill 2/2 construction. The test panels have been impregnated with the same thermoset resin. Curing was done by autoclave processing. The resulting fibre volume content of the test panels have been determined both analytically by weighting and experimentally by chemical extraction and calcination. The impact loadwas applied by accelarating bearing balls with weighted propellant in a sabot. The measured values are the velocities of the bearing balls as the impactor before and after the penetration of the test panels. The results show the energy sissipation capacity of each single kind of fibre in the monolithic layups as well as the enhanced properties of the hybrid stacked layups.},
keywords = {},
pubstate = {published},
tppubtype = {inproceedings}
}
This study deals with the experimental investigation concerning the energy dissipation capacity of reinforcement fibres in monolithic and hybrid layups, with and without a separating layer, under high-velocity impact loads. The investigated kinds of fibres are carbon, glass and basalt fabrics in a twill 2/2 construction. The test panels have been impregnated with the same thermoset resin. Curing was done by autoclave processing. The resulting fibre volume content of the test panels have been determined both analytically by weighting and experimentally by chemical extraction and calcination. The impact loadwas applied by accelarating bearing balls with weighted propellant in a sabot. The measured values are the velocities of the bearing balls as the impactor before and after the penetration of the test panels. The results show the energy sissipation capacity of each single kind of fibre in the monolithic layups as well as the enhanced properties of the hybrid stacked layups. |
Fritz, B.; Schmid, V.; Ehrlich, I. Analytical and numerical shear stress analysis of adhesive structural bonded joints under tension load. Leichtbau Proceedings Article In: Ziemann, O.; Mottok, J.; Pforr, J. (Hrsg.): Applied Research Conference 2014 – ARC 2014, S. 266–271, Ostbayerische Technische Hochschule Regensburg Shaker-Verlag, 2014, ISBN: 978-3844028751. @inproceedings{Fritz2014,
title = {Analytical and numerical shear stress analysis of adhesive structural bonded joints under tension load.},
author = {B. Fritz and V. Schmid and I. Ehrlich},
editor = {O. Ziemann and J. Mottok and J. Pforr},
isbn = {978-3844028751},
year = {2014},
date = {2014-06-01},
booktitle = {Applied Research Conference 2014 – ARC 2014},
pages = {266--271},
publisher = {Shaker-Verlag},
organization = {Ostbayerische Technische Hochschule Regensburg},
abstract = {Force transmission is a critical zone in the construction of technical components, especially if these contain parts of fibre-reinforced plastics. The aim of this research is to improve and enhance the force transmission for a structural tubular adhesive bonded joint under axial load. Therefore a finite element model is being developed to compare different analytical calculation approaches. First investigations are based on a geometric simple single lap joint with an adhesive layer of epoxy resin. This model is examined analytical for several different calculation approaches, especially Volkerson and Goland & Reissner. The analytical results are compared to finite element analysis, particulary for shear stress distribution and the shear stress concentration factor. As a next step, the experience for the single lap joint is transferred for the calculation of tubular adhesive lap joints. Just as like for single lap joints, analytical approaches (Pugno) are investigated and the results compared to finite element analysis. Special interest is attended to disagreements and simplifying assumptions analytic models have to assume. In these cases finite element analysis (FEA) can deliver results that correlate more precise in analysis for actual shear stresses. In this paper special focus is placed on the shear stress distribution over length and width of the adhesive layer and the influence of the shear-stress-concentration factor. Furthermore, other parameters (geometry, stiffness, material) that have influence on the stress distribution are analyzed and evaluated in future investigations.},
keywords = {},
pubstate = {published},
tppubtype = {inproceedings}
}
Force transmission is a critical zone in the construction of technical components, especially if these contain parts of fibre-reinforced plastics. The aim of this research is to improve and enhance the force transmission for a structural tubular adhesive bonded joint under axial load. Therefore a finite element model is being developed to compare different analytical calculation approaches. First investigations are based on a geometric simple single lap joint with an adhesive layer of epoxy resin. This model is examined analytical for several different calculation approaches, especially Volkerson and Goland & Reissner. The analytical results are compared to finite element analysis, particulary for shear stress distribution and the shear stress concentration factor. As a next step, the experience for the single lap joint is transferred for the calculation of tubular adhesive lap joints. Just as like for single lap joints, analytical approaches (Pugno) are investigated and the results compared to finite element analysis. Special interest is attended to disagreements and simplifying assumptions analytic models have to assume. In these cases finite element analysis (FEA) can deliver results that correlate more precise in analysis for actual shear stresses. In this paper special focus is placed on the shear stress distribution over length and width of the adhesive layer and the influence of the shear-stress-concentration factor. Furthermore, other parameters (geometry, stiffness, material) that have influence on the stress distribution are analyzed and evaluated in future investigations. |
Bruland, M.; Schmid, V.; Ehrlich, I. Analyzing and Testing of a Single Solution of Self-cutting Thread Inserts in Composites. Leichtbau Proceedings Article In: Ziemann, O.; Mottok, J.; Pforr, J. (Hrsg.): Applied Research Conference 2014 – ARC 2014, S. 286–288, Shaker-Verlag, 2014, ISBN: 978-3844028751. @inproceedings{Bruland2014,
title = {Analyzing and Testing of a Single Solution of Self-cutting Thread Inserts in Composites.},
author = {M. Bruland and V. Schmid and I. Ehrlich},
editor = {O. Ziemann and J. Mottok and J. Pforr},
isbn = {978-3844028751},
year = {2014},
date = {2014-06-01},
booktitle = {Applied Research Conference 2014 – ARC 2014},
pages = {286--288},
publisher = {Shaker-Verlag},
abstract = {This paper gives a summary of the analysis and the testing of a single solution of self-cutting thread inserts in semi-manufactured composites for shape cutting. The used composites and inserts are for commercial use. As composites are not designed for drilling and withstanding internal compressive stress, there are some challenges involved when attempting to place an insert. },
keywords = {},
pubstate = {published},
tppubtype = {inproceedings}
}
This paper gives a summary of the analysis and the testing of a single solution of self-cutting thread inserts in semi-manufactured composites for shape cutting. The used composites and inserts are for commercial use. As composites are not designed for drilling and withstanding internal compressive stress, there are some challenges involved when attempting to place an insert. |
Niedernhuber, M.; Ehrlich, I.; Holtmannspötter, J. Fiber-Oriented Repair of Fiber Reinforced Plastics: Investigations on Tensile Specimens Leichtbau Proceedings Article In: Ziemann, O.; Mottok, J.; Pforr, J. (Hrsg.): Applied Research Conference 2014 – ARC 2014, S. 298–302, Ostbayerische Technische Hochschule Regensburg Shaker-Verlag, 2014, ISBN: 978-3844028751. @inproceedings{Niedernhuber2014,
title = {Fiber-Oriented Repair of Fiber Reinforced Plastics: Investigations on Tensile Specimens},
author = {M. Niedernhuber and I. Ehrlich and J. Holtmannspötter},
editor = {O. Ziemann and J. Mottok and J. Pforr},
isbn = {978-3844028751},
year = {2014},
date = {2014-06-01},
booktitle = {Applied Research Conference 2014 – ARC 2014},
pages = {298--302},
publisher = {Shaker-Verlag},
organization = {Ostbayerische Technische Hochschule Regensburg},
abstract = {To minimize the repair area for fiber reinforced plastics (FRP), a new scarfing method is under investigation. For unidirectional plies, the idea is to perform a stepped scarf in fiber direction only. In theory, the repair area can be reduced up to 50 percent. Repair geometries generated with this method display varying overlap lengths in specific directions. With tensile tests of specimens according to german standards, a first comparison of mechanical values and joint strength between fiber-oriented scarfs and traditionally stepped scarfs in carbon fiber reinforced plastics (CFRP) was carried out. Mechanical values of the joint specimens showed only minor differences to intact laminates. The tensile strength of the stepped scarf and fiber-oriented scarf joints were around 50 % relative to the intact laminate. Our results show that the shorter overlap lengths in the plies of the fiber-oriented joints did not lead to the failure of specimen, instead, the butt joint on the outer surfaces of the specimens seem to be the initial point of failure.},
keywords = {},
pubstate = {published},
tppubtype = {inproceedings}
}
To minimize the repair area for fiber reinforced plastics (FRP), a new scarfing method is under investigation. For unidirectional plies, the idea is to perform a stepped scarf in fiber direction only. In theory, the repair area can be reduced up to 50 percent. Repair geometries generated with this method display varying overlap lengths in specific directions. With tensile tests of specimens according to german standards, a first comparison of mechanical values and joint strength between fiber-oriented scarfs and traditionally stepped scarfs in carbon fiber reinforced plastics (CFRP) was carried out. Mechanical values of the joint specimens showed only minor differences to intact laminates. The tensile strength of the stepped scarf and fiber-oriented scarf joints were around 50 % relative to the intact laminate. Our results show that the shorter overlap lengths in the plies of the fiber-oriented joints did not lead to the failure of specimen, instead, the butt joint on the outer surfaces of the specimens seem to be the initial point of failure. |
Micklitz, M.; Romano, M.; Ehrlich, I.; Gebbeken, N. The influence of ondulations in fabric reinforced layers on the damping properties of fibre-reinforced plastics Leichtbau Proceedings Article In: Ziemann, O.; Mottok, J.; Pforr, J. (Hrsg.): Applied Research Conference 2014 – ARC 2014, S. 306–310, Ostbayerische Technische Hochschule Regensburg Shaker-Verlag, 2014, ISBN: 978-3844028751. @inproceedings{Micklitz2014,
title = {The influence of ondulations in fabric reinforced layers on the damping properties of fibre-reinforced plastics},
author = {M. Micklitz and M. Romano and I. Ehrlich and N. Gebbeken},
editor = {O. Ziemann and J. Mottok and J. Pforr},
isbn = {978-3844028751},
year = {2014},
date = {2014-06-01},
booktitle = {Applied Research Conference 2014 – ARC 2014},
pages = {306--310},
publisher = {Shaker-Verlag},
organization = {Ostbayerische Technische Hochschule Regensburg},
abstract = {Ondulations in fabric-reinforced single layers are caused by alternatingly crossing of warp and fill yarns. In order to determine the influence of the ondulations in fabrics on the damping properties of fibre-reinforced plastics, the structural dynamic properties of fabric-reinforced and unidirectionally reinforced Plastics are investigated. Therefore, vibration experiments are carried outby the free-decay method. Fabric-reinforced and unidriectionally reinforced flat beamlike specimens were cut out of test panels by waterjet cutting. The test panels were impregnated via pre-impregnation in case of the fabric-reinforced material, and filament winding in case of the unidirectionally reinforced material. In both cases the same thermoset resin has been used, in order to ensure maximum comparability between the different specimens. In order to additionally obtain comparable fibre volume contents of approx. 60 %, curing was done by autoclave processing. In detail the structural mechanical investigations are carried out by the free decay of fixed-free specimens after reproducible displacement excitations. The vibrating structure has been measured by a laser scanning vibrometer PSV 400 from Polytec. The evaluation of the results for the specimen with unidirectional and fabric reinforcement yields enhanced damping properties.},
keywords = {},
pubstate = {published},
tppubtype = {inproceedings}
}
Ondulations in fabric-reinforced single layers are caused by alternatingly crossing of warp and fill yarns. In order to determine the influence of the ondulations in fabrics on the damping properties of fibre-reinforced plastics, the structural dynamic properties of fabric-reinforced and unidirectionally reinforced Plastics are investigated. Therefore, vibration experiments are carried outby the free-decay method. Fabric-reinforced and unidriectionally reinforced flat beamlike specimens were cut out of test panels by waterjet cutting. The test panels were impregnated via pre-impregnation in case of the fabric-reinforced material, and filament winding in case of the unidirectionally reinforced material. In both cases the same thermoset resin has been used, in order to ensure maximum comparability between the different specimens. In order to additionally obtain comparable fibre volume contents of approx. 60 %, curing was done by autoclave processing. In detail the structural mechanical investigations are carried out by the free decay of fixed-free specimens after reproducible displacement excitations. The vibrating structure has been measured by a laser scanning vibrometer PSV 400 from Polytec. The evaluation of the results for the specimen with unidirectional and fabric reinforcement yields enhanced damping properties. |
Gomez, D. Ibanez; Kastenmeier, A.; Ehrlich, I. Development and construction of a winding machine for the production of composite tubes. Leichtbau Proceedings Article In: Ziemann, O.; Mottok, J.; Pforr, J. (Hrsg.): Applied Research Conference 2014 – ARC 2014, S. 315–318, Ostbayerische Technische Hochschule Regensburg Shaker-Verlag, 2014, ISBN: 978-3844028751. @inproceedings{IbanezGomez2014,
title = {Development and construction of a winding machine for the production of composite tubes.},
author = {D. Ibanez Gomez and A. Kastenmeier and I. Ehrlich},
editor = {O. Ziemann and J. Mottok and J. Pforr},
isbn = {978-3844028751},
year = {2014},
date = {2014-06-01},
booktitle = {Applied Research Conference 2014 – ARC 2014},
pages = {315--318},
publisher = {Shaker-Verlag},
organization = {Ostbayerische Technische Hochschule Regensburg},
abstract = {The project is about the development and construction of a filament winding machine. The aim of the project is that the laboratory of composite technology of the Ostbayerische Technische Hochschule Regensburg is able to produce composite tube specimens in laboratory scale, so that different tube geometries can be manufactured. With a own machine the lab is able to produce many different specimens. Furthermore, the lab is able to test in additional machines different force transmissions or respectively connections of the tubes with metal flanges. Presently there is no possibility for the lab to produce tube specimens. In fact the winding technology already exists on the market, but for the lab it is important to have a machine with the right properties. For example the functions of the machine must be adjusted to the specifications of the tube specimens. The machine is constructed of four modules: a pre-load-, an impregnation-, a slide- and a mandrel-module. The function of the pre-load module is to aplly a defined load to the rovings. In the impregnation module the rovings are wetted with resin. The combination of the slide- and mandrel-module enables the define depositting of the rovings on the mandrel. The VDI guideline 2221 is used to develop the winding machine. In this guideline the approach of the development is defined. The first step is to define the requirements. After that a theoretical solution has to be found and this solution has to be elaborated. Finally, the concept has to be optimized for the assembly.},
keywords = {},
pubstate = {published},
tppubtype = {inproceedings}
}
The project is about the development and construction of a filament winding machine. The aim of the project is that the laboratory of composite technology of the Ostbayerische Technische Hochschule Regensburg is able to produce composite tube specimens in laboratory scale, so that different tube geometries can be manufactured. With a own machine the lab is able to produce many different specimens. Furthermore, the lab is able to test in additional machines different force transmissions or respectively connections of the tubes with metal flanges. Presently there is no possibility for the lab to produce tube specimens. In fact the winding technology already exists on the market, but for the lab it is important to have a machine with the right properties. For example the functions of the machine must be adjusted to the specifications of the tube specimens. The machine is constructed of four modules: a pre-load-, an impregnation-, a slide- and a mandrel-module. The function of the pre-load module is to aplly a defined load to the rovings. In the impregnation module the rovings are wetted with resin. The combination of the slide- and mandrel-module enables the define depositting of the rovings on the mandrel. The VDI guideline 2221 is used to develop the winding machine. In this guideline the approach of the development is defined. The first step is to define the requirements. After that a theoretical solution has to be found and this solution has to be elaborated. Finally, the concept has to be optimized for the assembly. |
Romano, M.; Hoinkes, C.; Ehrlich, I.; Höcherl, J.; Gebbeken, N. Experimental investigation of energy dissipation properties of fibre reinforced plastics with hybrid layups under high-velocity impact loads. Leichtbau Artikel In: Journal of Achievements in Materials and Manufacturing Engineering (JAMME), Bd. 64, Nr. 1, S. 14–20, 2014. @article{Romano2014b,
title = {Experimental investigation of energy dissipation properties of fibre reinforced plastics with hybrid layups under high-velocity impact loads.},
author = {M. Romano and C. Hoinkes and I. Ehrlich and J. Höcherl and N. Gebbeken},
url = {http://jamme.acmsse.h2.pl/vol64_1/6411.pdf},
year = {2014},
date = {2014-05-01},
journal = {Journal of Achievements in Materials and Manufacturing Engineering (JAMME)},
volume = {64},
number = {1},
pages = {14--20},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
|
Valentino, P.; Sgambitterra, E.; Furgiuele, F.; Romano, M.; Ehrlich, I.; Gebbeken, N. Mechanical characterization of basalt woven fabric composites: numerical and experimental investigation. Leichtbau Artikel In: Frattura ed Integrità Strutturale (Fracture and Structural Integrity), Bd. 8, Nr. 28, S. 1-11, 2014, ISSN: 1971-8993. @article{Valentino2014,
title = {Mechanical characterization of basalt woven fabric composites: numerical and experimental investigation.},
author = {P. Valentino and E. Sgambitterra and F. Furgiuele and M. Romano and I. Ehrlich and N. Gebbeken},
url = {http://www.gruppofrattura.it/ors/index.php/fis/article/view/1229
http://www.gruppofrattura.it/ors/index.php/fis/article/view/1229/1182
http://www.gruppofrattura.it/ors/index.php/fis/article/download/1229/1182
},
doi = {10.3221/IGF-ESIS.28.01},
issn = {1971-8993},
year = {2014},
date = {2014-04-08},
journal = {Frattura ed Integrità Strutturale (Fracture and Structural Integrity)},
volume = {8},
number = {28},
pages = {1-11},
abstract = {Basalt fabric composite, with different twill wave reinforcements, i.e. twill 2/2 and twill 1/3, have been studied in this work by means of experimental tests and numerical finite element (FE) simulations. As fabric reinforcements show repeating undulations of warp and fill yarn, simple mixtures law cannot be applied. As a consequence, the mesoscopic scale, lying between the microscopic and the macroscopic one, has to be taken into account to mechanically characterize a fabric reinforced composite. The aim of this work is to evaluate the stiffness of a fabric reinforced composite in warp and fill direction. In particular a numerical FE model, assuming elliptical sections and sinusoidal shape of the yarns, has been implemented and experimental tests have been carried out in order to validate the proposed model. Finally, the strength and the failure modes of the composite material, for each analysed structure and textile orientation, have been experimentally investigated.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Basalt fabric composite, with different twill wave reinforcements, i.e. twill 2/2 and twill 1/3, have been studied in this work by means of experimental tests and numerical finite element (FE) simulations. As fabric reinforcements show repeating undulations of warp and fill yarn, simple mixtures law cannot be applied. As a consequence, the mesoscopic scale, lying between the microscopic and the macroscopic one, has to be taken into account to mechanically characterize a fabric reinforced composite. The aim of this work is to evaluate the stiffness of a fabric reinforced composite in warp and fill direction. In particular a numerical FE model, assuming elliptical sections and sinusoidal shape of the yarns, has been implemented and experimental tests have been carried out in order to validate the proposed model. Finally, the strength and the failure modes of the composite material, for each analysed structure and textile orientation, have been experimentally investigated. |
Romano, M.; Micklitz, M.; Olbrich, F.; Bierl, R.; Ehrlich, I.; Gebbeken, N. Experimental investigation of damping properties of unidirectionally and fabric reinforced plastics by the free decay method Leichtbau Artikel In: Journal of Achievements in Materials and Manufacturing Engineering (JAMME), Bd. 63, Nr. 2, S. 65-80, 2014, ISSN: 1734-8412. @article{Romano2014e,
title = {Experimental investigation of damping properties of unidirectionally and fabric reinforced plastics by the free decay method},
author = {M. Romano and M. Micklitz and F. Olbrich and R. Bierl and I. Ehrlich and N. Gebbeken
},
url = {http://www.journalamme.org/index.php?id=250
http://www.journalamme.org/vol63_2/6323.pdf
},
issn = {1734-8412},
year = {2014},
date = {2014-04-01},
urldate = {2014-04-01},
journal = {Journal of Achievements in Materials and Manufacturing Engineering (JAMME)},
volume = {63},
number = {2},
pages = {65-80},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
|
Cerrone, A.; Wawrzynek, P.; Nonn, A.; Paulino, G. H.; Ingraffea, A. Implementation and verification of the Park–Paulino–Roesler cohesive zone model in 3D Werkstoffsimulation Artikel In: Engineering Fracture Mechanics, Bd. 120, S. 26 - 42, 2014, ISSN: 0013-7944. @article{Cerrone2014b,
title = {Implementation and verification of the Park–Paulino–Roesler cohesive zone model in 3D},
author = {A. Cerrone and P. Wawrzynek and A. Nonn and G. H. Paulino and A. Ingraffea},
url = {http://www.sciencedirect.com/science/article/pii/S0013794414000770},
doi = {https://doi.org/10.1016/j.engfracmech.2014.03.010},
issn = {0013-7944},
year = {2014},
date = {2014-01-01},
journal = {Engineering Fracture Mechanics},
volume = {120},
pages = {26 - 42},
abstract = {The Park–Paulino–Roesler (PPR) potential-based model is a cohesive constitutive model formulated to be consistent under a high degree of mode-mixity. Herein, the PPR’s generalization to three-dimensions is detailed, its implementation in a finite element framework is discussed, and its use in single-core and high performance computing (HPC) applications is demonstrated. The PPR model is shown to be an effective constitutive model to account for crack nucleation and propagation in a variety of applications including adhesives, composites, linepipe steel, and microstructures.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
The Park–Paulino–Roesler (PPR) potential-based model is a cohesive constitutive model formulated to be consistent under a high degree of mode-mixity. Herein, the PPR’s generalization to three-dimensions is detailed, its implementation in a finite element framework is discussed, and its use in single-core and high performance computing (HPC) applications is demonstrated. The PPR model is shown to be an effective constitutive model to account for crack nucleation and propagation in a variety of applications including adhesives, composites, linepipe steel, and microstructures. |
Valentino, P.; Romano, M.; Ehrlich, I.; Furgiuele, F.; Gebbeken, N. Mechanische Charakterisierung von basaltfaser-verstärkten Kunststoffen mit Gewebeverstärkung – Numerische und experimentelle Untersuchungen. Leichtbau Forschungsbericht Ostbayerische Hochschule Regensburg inixmedia GmbH Marketing & Medienberatung, Forschungsbericht 2013, 2014. @techreport{Valentino2014b,
title = {Mechanische Charakterisierung von basaltfaser-verstärkten Kunststoffen mit Gewebeverstärkung – Numerische und experimentelle Untersuchungen.},
author = {P. Valentino and M. Romano and I. Ehrlich and F. Furgiuele and N. Gebbeken},
editor = {Ostbayerische Technische Hochschule},
year = {2014},
date = {2014-01-01},
address = {inixmedia GmbH Marketing & Medienberatung},
institution = {Ostbayerische Hochschule Regensburg},
abstract = {This paper describes the results of tensile tests and finite element (FE) calculations with representative volume elements (RVEs) of basalt fibre reinforced plastic with two different types of fabric reinforcements. As fabric reinforcements show repeating ondulations of warp and fill yarn, simple mixtures laws reach their limits. The aim of this work is to determine the stiffness of a fabric reinforced composite in warp and fill direction with numerical investigations. The tensile tests and the FE-calculations have been carried out for two different types of basalt fabrics, namely twill 2/2 and twill 1/3. The comparison between the experimental data and the results of the FE-calculations are provided in order to support the validity of the proposed model.},
type = {Forschungsbericht 2013},
keywords = {},
pubstate = {published},
tppubtype = {techreport}
}
This paper describes the results of tensile tests and finite element (FE) calculations with representative volume elements (RVEs) of basalt fibre reinforced plastic with two different types of fabric reinforcements. As fabric reinforcements show repeating ondulations of warp and fill yarn, simple mixtures laws reach their limits. The aim of this work is to determine the stiffness of a fabric reinforced composite in warp and fill direction with numerical investigations. The tensile tests and the FE-calculations have been carried out for two different types of basalt fabrics, namely twill 2/2 and twill 1/3. The comparison between the experimental data and the results of the FE-calculations are provided in order to support the validity of the proposed model. |
Eisenried, M.; Romano, M.; Jungbauer, B.; Ehrlich, I.; Gebbeken, N. Herstellung von unidirektional verstärkten Prepregs im Labormaßstab – Einfluss von Fertigungsparametern auf die Materialqualität. Leichtbau Forschungsbericht Ostbayerische Hochschule Regensburg inixmedia GmbH Marketing & Medienberatung, Forschungsbericht 2013, 2014. @techreport{Eisenried2014,
title = {Herstellung von unidirektional verstärkten Prepregs im Labormaßstab – Einfluss von Fertigungsparametern auf die Materialqualität.},
author = {M. Eisenried and M. Romano and B. Jungbauer and I. Ehrlich and N. Gebbeken},
editor = {Ostbayerische Technische Hochschule},
year = {2014},
date = {2014-01-01},
address = {inixmedia GmbH Marketing & Medienberatung},
institution = {Ostbayerische Hochschule Regensburg},
abstract = {A prepreg production device in laboratory scale is used to develop the production process of unidirectionally reinforced prepregs. The aim of the prepreg production machine is to impregnate different types of reinforcement fibers with an arbitrarily selectable thermoset matrix system that completely satisfies the requirements for autoclave processing. To identify the parameters of the production process and investigate its sensitivity on the quality of the semi-finished product, experimental investigations regarding fiber volume content and resin flow while curing are carried out with specimens out of test panels cured in autoclave processing. The investigated parameter is the width of the wiping gap and its effects on fiber volume content and resin flow. The parameter clearly affects both properties so that a proper impregnation and curing process can be achieved by optimizing the parameter to desired values.},
type = {Forschungsbericht 2013},
keywords = {},
pubstate = {published},
tppubtype = {techreport}
}
A prepreg production device in laboratory scale is used to develop the production process of unidirectionally reinforced prepregs. The aim of the prepreg production machine is to impregnate different types of reinforcement fibers with an arbitrarily selectable thermoset matrix system that completely satisfies the requirements for autoclave processing. To identify the parameters of the production process and investigate its sensitivity on the quality of the semi-finished product, experimental investigations regarding fiber volume content and resin flow while curing are carried out with specimens out of test panels cured in autoclave processing. The investigated parameter is the width of the wiping gap and its effects on fiber volume content and resin flow. The parameter clearly affects both properties so that a proper impregnation and curing process can be achieved by optimizing the parameter to desired values. |
Putzer, M.; Rasmussen, J.; Ehrlich, I.; Gebbeken, N.; Dendorfer, S. Muskuloskelettale Simulation zur Untersuchung des Einflusses geometrischer Parameter der Wirbelkörper auf die Belastung der Lendenwirbelsäule. Leichtbau Forschungsbericht Ostbayerische Hochschule Regensburg inixmedia GmbH Marketing & Medienberatung, Forschungsbericht 2013, 2014. @techreport{Putzer2014,
title = {Muskuloskelettale Simulation zur Untersuchung des Einflusses geometrischer Parameter der Wirbelkörper auf die Belastung der Lendenwirbelsäule.},
author = {M. Putzer and J. Rasmussen and I. Ehrlich and N. Gebbeken and S. Dendorfer},
editor = {Ostbayerische Technische Hochschule},
year = {2014},
date = {2014-01-01},
address = {inixmedia GmbH Marketing & Medienberatung},
institution = {Ostbayerische Hochschule Regensburg},
abstract = {Zur Simulation von patientenspezifischen Belastungen in der Lendenwirbelsäule werden muskuloskelettale Modelle mit patientenspezifischer Geometrie verwendet. Diese Daten besitzen allerdings eine inhärente Ungenauigkeit. Diese Studie untersuchte den Einfluss definierter geometrischer Parameter auf die Lasten in der Lendenwirbelsäule anhand eines parametri-sierten muskuloskelettalen Modells in vier verschiedenen Körperhaltungen: aufrecht stehend, vorgebeugt, zur Seite gedreht und zur Seite geneigt. Variiert wurden die Abmessungen des Wirbelkörpers, des Wirbelbogens und der Dornfortsätze sowie die Orientierung der Facettengelenke und die Krümmung der Lendenwirbelsäule. Anschließend wurden die Parameter mit den größten Einflüssen in weiteren Simulationen kombiniert. Die Änderung der Last zwischen L4 und L5 wurde als Ziel der Untersuchung festgelegt. Die größten Lastunterschiede ergaben sich durch die Änderung der Wirbelkörperhöhe, der Band-scheibenhöhe, der Wirbelkörpertiefe und der Krümmung der Lendenwirbelsäule.},
type = {Forschungsbericht 2013},
keywords = {},
pubstate = {published},
tppubtype = {techreport}
}
Zur Simulation von patientenspezifischen Belastungen in der Lendenwirbelsäule werden muskuloskelettale Modelle mit patientenspezifischer Geometrie verwendet. Diese Daten besitzen allerdings eine inhärente Ungenauigkeit. Diese Studie untersuchte den Einfluss definierter geometrischer Parameter auf die Lasten in der Lendenwirbelsäule anhand eines parametri-sierten muskuloskelettalen Modells in vier verschiedenen Körperhaltungen: aufrecht stehend, vorgebeugt, zur Seite gedreht und zur Seite geneigt. Variiert wurden die Abmessungen des Wirbelkörpers, des Wirbelbogens und der Dornfortsätze sowie die Orientierung der Facettengelenke und die Krümmung der Lendenwirbelsäule. Anschließend wurden die Parameter mit den größten Einflüssen in weiteren Simulationen kombiniert. Die Änderung der Last zwischen L4 und L5 wurde als Ziel der Untersuchung festgelegt. Die größten Lastunterschiede ergaben sich durch die Änderung der Wirbelkörperhöhe, der Band-scheibenhöhe, der Wirbelkörpertiefe und der Krümmung der Lendenwirbelsäule. |
2013
|
Eisenried, M.; Romano, M.; Jungbauer, B.; Ehrlich, I.; Gebbeken, N. Influence of parameters of the production process on the material quality of unidirectionally reinforced prepregs. Leichtbau Proceedings Article In: Ziemann, O.; Bogner, W.; Mottok, J. (Hrsg.): Applied Research Conference 2013 – ARC 2013, S. 70–75, Ostbayerische Technische Hochschule Regensburg Shaker-Verlag, 2013, ISBN: 978-3844022742. @inproceedings{Eisenried2013,
title = {Influence of parameters of the production process on the material quality of unidirectionally reinforced prepregs.},
author = {M. Eisenried and M. Romano and B. Jungbauer and I. Ehrlich and N. Gebbeken},
editor = {O. Ziemann and W. Bogner and J. Mottok},
isbn = {978-3844022742},
year = {2013},
date = {2013-10-17},
booktitle = {Applied Research Conference 2013 – ARC 2013},
pages = {70--75},
publisher = {Shaker-Verlag},
organization = {Ostbayerische Technische Hochschule Regensburg},
abstract = {A prepreg production device in laboratory scale is used to develop the production process of unidirectionally reinforced prepregs. The aim of the prepreg production machine is to impregnate different types of reinforcement fibres with an arbitrarily selectable thermoset matrix system that completely satisfies the requirements for autoclave processing. As the prepreg production device is designed and built up modulary every module corresponds to one step in the process. To identify the parameters of the production process and investigate its sensitivity on the quality of the semi-finished product, experimental investigations regarding fiber volume content, resin flow while curing and geometric properties are carried out with specimens out of test panels cured in autoclave processing. The investigated parameter ist the width of the wiping gap and its effects on fiber volume content and resin flow. Both mechanical properties are determined according to german standards. The parameter clearly affects both properties so that a proper impregnation and curing process can be achieved by optimizing the parameter to desired values.},
keywords = {},
pubstate = {published},
tppubtype = {inproceedings}
}
A prepreg production device in laboratory scale is used to develop the production process of unidirectionally reinforced prepregs. The aim of the prepreg production machine is to impregnate different types of reinforcement fibres with an arbitrarily selectable thermoset matrix system that completely satisfies the requirements for autoclave processing. As the prepreg production device is designed and built up modulary every module corresponds to one step in the process. To identify the parameters of the production process and investigate its sensitivity on the quality of the semi-finished product, experimental investigations regarding fiber volume content, resin flow while curing and geometric properties are carried out with specimens out of test panels cured in autoclave processing. The investigated parameter ist the width of the wiping gap and its effects on fiber volume content and resin flow. Both mechanical properties are determined according to german standards. The parameter clearly affects both properties so that a proper impregnation and curing process can be achieved by optimizing the parameter to desired values. |
Nonn, A.; Cerrone, A.; Stallybrass, C.; Meuser, H. Microstructure-based modeling of high-strength linepipe steels Werkstoffsimulation Proceedings Article In: The 6th Pipeline Technology Conference (2013), Ostend, Belgium, 2013. @inproceedings{Nonn2013,
title = {Microstructure-based modeling of high-strength linepipe steels},
author = {A. Nonn and A. Cerrone and C. Stallybrass and H. Meuser},
year = {2013},
date = {2013-10-07},
booktitle = {The 6th Pipeline Technology Conference (2013)},
address = {Ostend, Belgium},
keywords = {},
pubstate = {published},
tppubtype = {inproceedings}
}
|
Nonn, A.; Kalwa, C. Analysis of dynamic ductile fracture propagation in pipeline steels: a damage mechanics approach Werkstoffsimulation Proceedings Article In: The 6th Pipeline Technology Conference (2013), Ostend, Belgium, 2013. @inproceedings{Nonn2013b,
title = {Analysis of dynamic ductile fracture propagation in pipeline steels: a damage mechanics approach},
author = {A. Nonn and C. Kalwa},
year = {2013},
date = {2013-10-07},
booktitle = {The 6th Pipeline Technology Conference (2013)},
address = {Ostend, Belgium},
keywords = {},
pubstate = {published},
tppubtype = {inproceedings}
}
|
Nonn, A.; Kalwa, C. Application of probabilistic fracture mechanics for safety assessment of longitudinally welded linepipes Werkstoffsimulation Proceedings Article In: The 6th Pipeline Technology Conference (2013), Ostend, Belgium, 2013. @inproceedings{Nonn2013c,
title = {Application of probabilistic fracture mechanics for safety assessment of longitudinally welded linepipes},
author = {A. Nonn and C. Kalwa},
year = {2013},
date = {2013-10-07},
booktitle = {The 6th Pipeline Technology Conference (2013)},
address = {Ostend, Belgium},
keywords = {},
pubstate = {published},
tppubtype = {inproceedings}
}
|
Valentino, P.; Romano, M.; Ehrlich, I.; Furgiuele, F.; Gebbeken, N. Mechanical characterization of basalt fibre reinforced plastic with different fabric reinforcements – Tensile tests and FE-calculations with representative volume elements (RVEs). Leichtbau Proceedings Article In: Iacovello, F.; Risitano, G.; Susmel, L. (Hrsg.): Acta Fracturae – XXll Convegno Nazionale IGF (Italiano Gruppo Frattura), Roma, 2013, ISBN: 978-88-95940-47-2. @inproceedings{Valentino2013,
title = {Mechanical characterization of basalt fibre reinforced plastic with different fabric reinforcements – Tensile tests and FE-calculations with representative volume elements (RVEs). },
author = {P. Valentino and M. Romano and I. Ehrlich and F. Furgiuele and N. Gebbeken},
editor = {F. Iacovello and G. Risitano and L. Susmel},
url = {http://www.gruppofrattura.it/pdf/convegni/22/IGFXXII/index.html#/242/},
isbn = {978-88-95940-47-2},
year = {2013},
date = {2013-07-03},
booktitle = {Acta Fracturae – XXll Convegno Nazionale IGF (Italiano Gruppo Frattura)},
address = {Roma},
keywords = {},
pubstate = {published},
tppubtype = {inproceedings}
}
|
Nonn, A.; Wessel, W.; Schmidt, T. Application of finite element analysis for assessment of fracture behavior of modern high toughness seamless pipeline steels Werkstoffsimulation Proceedings Article In: The 23rd International Society of Offshore and Polar Engineering 2013 (ISOPE 2013), Anchorage, USA, 2013. @inproceedings{Nonn2013d,
title = {Application of finite element analysis for assessment of fracture behavior of modern high toughness seamless pipeline steels},
author = {A. Nonn and W. Wessel and T. Schmidt},
year = {2013},
date = {2013-06-30},
booktitle = {The 23rd International Society of Offshore and Polar Engineering 2013 (ISOPE 2013)},
address = {Anchorage, USA},
abstract = {Fracture behavior of seamless pipeline material X65Q acc. to API 5L has been studied both experimentally and numerically at different loading conditions (quasi-static vs. dynamic) and temperatures. The recent findings have shown difficulties in applying well established methods for determination of transition behavior or prediction of ductile crack arrest for the new generation of high-toughness steels. The irregular fracture performance (e.g. so-called "abnormal inverse fracture" appearance, significant scattering in ductile-to-brittle-transition-temperature region, etc.) suggests that the influence of pipe dimensions, loading parameters, crack initiation resistance as well as testing procedure on the fracture behavior has been neither understood nor properly described. This work aims to shed light on these questions regarding the applicability of conventional methods and to better illuminate most relevant parameters affecting fracture behavior of high toughness steels. To achieve this goal, experimental data basis for analysis of fracture behavior in transition and upper shelf regime has been established by conducting quasi-static fracture mechanics tests and dynamic tests on Battelle Drop Weight Tear (BDWT or DWT) specimens at different temperatures. The evaluation of obtained test results in upper shelf has been additionally complemented by numerical simulation of damage behavior. The results highlight the influence of stress conditions on fracture behavior with reference to pipe dimensions and loading conditions and, subsequently, may be used as a basis for revision of existing design methods.},
keywords = {},
pubstate = {published},
tppubtype = {inproceedings}
}
Fracture behavior of seamless pipeline material X65Q acc. to API 5L has been studied both experimentally and numerically at different loading conditions (quasi-static vs. dynamic) and temperatures. The recent findings have shown difficulties in applying well established methods for determination of transition behavior or prediction of ductile crack arrest for the new generation of high-toughness steels. The irregular fracture performance (e.g. so-called "abnormal inverse fracture" appearance, significant scattering in ductile-to-brittle-transition-temperature region, etc.) suggests that the influence of pipe dimensions, loading parameters, crack initiation resistance as well as testing procedure on the fracture behavior has been neither understood nor properly described. This work aims to shed light on these questions regarding the applicability of conventional methods and to better illuminate most relevant parameters affecting fracture behavior of high toughness steels. To achieve this goal, experimental data basis for analysis of fracture behavior in transition and upper shelf regime has been established by conducting quasi-static fracture mechanics tests and dynamic tests on Battelle Drop Weight Tear (BDWT or DWT) specimens at different temperatures. The evaluation of obtained test results in upper shelf has been additionally complemented by numerical simulation of damage behavior. The results highlight the influence of stress conditions on fracture behavior with reference to pipe dimensions and loading conditions and, subsequently, may be used as a basis for revision of existing design methods. |
Nonn, A.; Kalwa, C. Application of damage mechanics approach for crack propagation in pipeline Werkstoffsimulation Proceedings Article In: 19th Biennial JTM on Pipeline Research, Sidney, Australia, 2013. @inproceedings{Nonn2013e,
title = {Application of damage mechanics approach for crack propagation in pipeline},
author = {A. Nonn and C. Kalwa},
year = {2013},
date = {2013-04-29},
booktitle = {19th Biennial JTM on Pipeline Research},
address = {Sidney, Australia},
keywords = {},
pubstate = {published},
tppubtype = {inproceedings}
}
|
Völling, A.; Nonn, A.; Scheider, I. Anwendung des Kohäsivzonenmodells zur Abbildung von duktilem dynamischen Rissfortschritt in Gasfernleitungen Werkstoffsimulation Proceedings Article In: 45. Tagung des AK Bruch, DVM Berichtsband 245, S. 253-262, Berlin, Germany, 2013. @inproceedings{Völling2013,
title = {Anwendung des Kohäsivzonenmodells zur Abbildung von duktilem dynamischen Rissfortschritt in Gasfernleitungen},
author = {A. Völling and A. Nonn and I. Scheider},
year = {2013},
date = {2013-02-19},
booktitle = {45. Tagung des AK Bruch, DVM Berichtsband 245},
pages = {253-262},
address = {Berlin, Germany},
keywords = {},
pubstate = {published},
tppubtype = {inproceedings}
}
|
