2014
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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. |
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. |
2013
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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. 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}
}
|