Nonn, A.; Paredes, M.; Nordhagen, H. O.; Munkejord, S. T.; Wierzbicki, T. Challenges in fluid-structure modeling of crack propagation and arrest in modern steel pipelines Werkstoffsimulation Proceedings Article In: 14th International Congress on Fracture (ICF14), Rhodes, Greece, 2017. @inproceedings{Nonn2017,
title = {Challenges in fluid-structure modeling of crack propagation and arrest in modern steel pipelines},
author = {A. Nonn and M. Paredes and H. O. Nordhagen and S. T. Munkejord and T. Wierzbicki},
year = {2017},
date = {2017-06-18},
booktitle = {14th International Congress on Fracture (ICF14)},
address = {Rhodes, Greece},
keywords = {},
pubstate = {published},
tppubtype = {inproceedings}
}
|
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. |
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}
}
|
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. |