TY - CHAP A1 - Paredes, Marcelo A1 - Keim, Vincent A1 - Nonn, Aida A1 - Wierzbicki, Tomasz T1 - Effect of plasticity parameter on the crack propagation in steel pipelines T2 - Proceedings of the conference on Technology for future and ageing piplines, Ghent, Belgium Y1 - 2018 ER - TY - JOUR A1 - Boyce, Brad L. A1 - Kramer, Sharlotte L. B. A1 - Bosiljevac, T. R. A1 - Corona, Edmundo A1 - Moore, J. A. A1 - Elkhodary, Khalil A1 - Simha, C. Hari Manoj A1 - Williams, Bruce W. A1 - Cerrone, Albert R. A1 - Nonn, Aida A1 - Hochhalter, Jacob D. A1 - Bomarito, Geoffrey F. A1 - Warner, James E. A1 - Carter, Bruce J. A1 - Warner, Derek H. A1 - Ingraffea, Anthony R. A1 - Zhang, T. A1 - Fang, X. A1 - Lua, Jim A1 - Chiaruttini, Vincent A1 - Maziere, Matthieu A1 - Feld-Payet, Sylvia A1 - Yastrebov, Vladislav A. A1 - Besson, Jacques A1 - Chaboche, Jean Louis A1 - Lian, J. A1 - Di, Y. A1 - Wu, Bei A1 - Novokshanov, Denis A1 - Vajragupta, Napat A1 - Kucharczyk, Pawel A1 - Brinnel, Viktoria A1 - Doebereiner, Benedikt A1 - Muenstermann, Sebastian A1 - Neilsen, Michael K. A1 - Dion, Kristin A1 - Karlson, Kyle N. A1 - Foulk, James Wesley A1 - Brown, Arthur A. A1 - Veilleux, Michael G. A1 - Bignell, John L. A1 - Sanborn, Scott E. A1 - Jones, Chris A. A1 - Mattie, Patrick D. A1 - Pack, Keunhwan A1 - Wierzbicki, Tomasz A1 - Chi, Sheng-Wei A1 - Lin, S.-P. A1 - Mahdavi, Ashkan A1 - Predan, Jozef A1 - Zadravec, Janko A1 - Gross, Andrew J. A1 - Ravi-Chandar, KRISHNASWAMY A1 - Xue, Liang T1 - The second Sandia Fracture Challenge: predictions of ductile failure under quasi-static and moderate-rate dynamic loading JF - International journal of fracture N2 - Ductile failure of structural metals is relevant to a wide range of engineering scenarios. Computational methods are employed to anticipate the critical conditions of failure, yet they sometimes provide inaccurate and misleading predictions. Challenge scenarios, such as the one presented in the current work, provide an opportunity to assess the blind, quantitative predictive ability of simulation methods against a previously unseen failure problem. Rather than evaluate the predictions of a single simulation approach, the Sandia Fracture Challenge relies on numerous volunteer teams with expertise in computational mechanics to apply a broad range of computational methods, numerical algorithms, and constitutive models to the challenge. This exercise is intended to evaluate the state of health of technologies available for failure prediction. In the first Sandia Fracture Challenge, a wide range of issues were raised in ductile failure modeling, including a lack of consistency in failure models, the importance of shear calibration data, and difficulties in quantifying the uncertainty of prediction [see Boyce et al. (Int J Fract 186:5-68, 2014) for details of these observations]. This second Sandia Fracture Challenge investigated the ductile rupture of a Ti-6Al-4V sheet under both quasi-static and modest-rate dynamic loading (failure in 0.1 s). Like the previous challenge, the sheet had an unusual arrangement of notches and holes that added geometric complexity and fostered a competition between tensile- and shear-dominated failure modes. The teams were asked to predict the fracture path and quantitative far-field failure metrics such as the peak force and displacement to cause crack initiation. Fourteen teams contributed blind predictions, and the experimental outcomes were quantified in three independent test labs. Additional shortcomings were revealed in this second challenge such as inconsistency in the application of appropriate boundary conditions, need for a thermomechanical treatment of the heat generation in the dynamic loading condition, and further difficulties in model calibration based on limited real-world engineering data. As with the prior challenge, this work not only documents the 'state-of-the-art' in computational failure prediction of ductile tearing scenarios, but also provides a detailed dataset for non-blind assessment of alternative methods. KW - Alloy KW - BEHAVIOR KW - CRACK-PROPAGATION KW - DAMAGE KW - Deformation KW - Fracture KW - HIGH-STRAIN-RATE KW - KERNEL PARTICLE METHODS KW - Metal KW - MODEL KW - Modeling KW - Plasticity KW - POLYCRYSTALLINE AL 6061-T6 KW - PREDICTION KW - ROOM-TEMPERATURE KW - Rupture KW - simulation KW - STRENGTH STEEL SHEETS KW - Tearing Y1 - 2016 U6 - https://doi.org/10.1007/s10704-016-0089-7 IS - 198, 1-2 SP - 5 EP - 100 PB - Springer ER - TY - JOUR A1 - Kofiani, Kirki A1 - Nonn, Aida A1 - Wierzbicki, Tomasz T1 - New calibration method for high and low triaxiality and validation on SENT specimens of API X70 JF - International Journal of Pressure Vessels and Piping N2 - The determination of the exact mechanical properties of material is essential for an optimal and safe design of linepipes. It is especially important for the prevention of over-engineering and the reliable assessment of complex accidental loading, such as extreme bending due to loss of buoyancy of support, or abrupt ground movement. Currently, the focus of research in offshore deepwater installations and linepipes is towards pre-cracked structures with high triaxiality stress states and complex loading histories. At the same time, low triaxiality stress states must be correctly studied in order to represent shear dominated failure in pipes. A comprehensive experimental and numerical program was undertaken to determine the mechanical properties of the traditional API X70 grade of steel. The material was characterized for anisotropic plasticity, fracture initiation and uncracked ductility for various states of stress. The same material was also used for pre-cracked fracture toughness assessment. The experimental program included flat and round specimens. The first type of tests on flat butterfly-shaped, central hole, notched and circular disk specimens; were selected to address the low stress triaxiality range. Tests on round notched bar specimens and SENT fracture mechanics tests extended the characterization and verification process to higher stress triaxiality values. This program covered a wide range of stress conditions and demonstrated their effect on the material resistance to crack extension. Each test conducted was numerically simulated using solid finite element models, matching the exact geometric and loading history features. The numerical simulation provided information on the local stress and strain fields around the location of the potential or existing cracks. Based on the above hybrid experimental/numerical technique tailored for pipe applications, the MMC fracture model was calibrated. The model relates the material ductility not only to stress triaxiality but also to the Lode parameter. The predictive capabilities of the MMC were then evaluated in the case of SENT testing, used extensively in the pipeline industry. It was shown that the present fracture model calibration can describe fracture behavior of SENT experiments. KW - Ductile fracture KW - SENT tests KW - Offshore API grade KW - X70 KW - Modified Mohr – Coulomb model KW - Triaxiality and Lode angle dependence Y1 - 2013 U6 - https://doi.org/10.1016/j.ijpvp.2013.07.004 VL - 111-112 SP - 187 EP - 201 ER - TY - CHAP A1 - Nonn, Aida A1 - Paredes, Marcelo A1 - Keim, Vincent A1 - Wierzbicki, Tomasz T1 - Comparison of Fracture Models to Quantify the Effects of Material Plasticity on the Ductile Fracture Propagation in Pipelines T2 - Proceedings of the 2018 12th International Pipeline Conference, Volume 3: Operations, Monitoring, and Maintenance, Materials and Joining, September 24-28, 2018, Calgary, Alberta, Canada N2 - Various numerical approaches have been developed in the last years aimed to simulate the ductile fracture propagation in pipelines transporting CO2 or natural gas. However, a reliable quantification of the influence of material plasticity on the fracture resistance is still missing. Therefore, more accurate description of the material plasticity on the ductile fracture propagation is required based on a suitable numerical methodology. In this study, different plasticity and fracture models are compared regarding the ductile fracture propagation in X100 pipeline steel with the objective to quantify the influence of plasticity parameters on the fracture resistance. The plastic behavior of the investigated material is considered by the quadratic yield surface in conjunction with a non-associated quadratic plastic flow potential. The strain hardening can be appropriately described by the mixed Swift-Voce law. The simulations of ductile fracture are conducted by an uncoupled, modified Mohr-Coulomb (MMC) and the micromechanically based Gurson-Tvergaard-Needleman (GTN) models. In contract to the original GTN model, the MMC model is capable of describing ductile failure over wide range of stress states. Thus, ductile fracture resistance can be estimated for various load and fracture scenarios. Both models are used for the simulation of fracture propagation in DWTT and 3D pressurized pipe sections. The results from the present work can serve as a basis for establishing the correlation between plasticity parameters and ductile fracture propagation. Y1 - 2018 U6 - https://doi.org/10.1115/IPC2018-78366 ER - TY - CHAP A1 - Nonn, Aida A1 - Paredes, Marcelo A1 - Nordhagen, H. O. A1 - Munkejord, S. T. A1 - Wierzbicki, Tomasz T1 - Challenges in fluid-structure modeling of crack propagation and arrest in modern steel pipelines T2 - 14th International Congress on Fracture (ICF14), 18-23 June 2017, Rhodes, Greece Y1 - 2017 SP - 1351 EP - 1352 ER - TY - CHAP A1 - Kofiani, Kirki A1 - Nonn, Aida A1 - Wierzbicki, Tomasz A1 - Kalwa, Christoph A1 - Walters, Carey T1 - Experiments and fracture modeling of high-strength pipelines for high and low stress triaxiality T2 - 22nd International Society of Offshore and Polar Engineering 2012 (ISOPE 2012), Rhodes, Greece, June 2012 N2 - This paper provides results from a comprehensive study on mechanical characterization of high-strength pipeline steel, grade X100 using experimental and numerical methods. The material was characterized for anisotropic plasticity, fracture initiation for various states of stress, (pre-cracked) fracture toughness and uncracked ductility. The experimental program included tests on flat butterfly-shaped, central hole, notched and circular disk specimens for low stress triaxiality levels; as well as tests on round notched bar specimens and SENT fracture mechanics tests, for high values of stress triaxiality. This program covered a wide range of stress conditions and demonstrated its effect on the material resistance. Parallel to the experimental study, detailed numerical investigations were carried out to simulate all different experimental tests. Using an inverse method, a 3-parameter calibration was performed on the Modified Mohr-Coulomb (MMC) fracture model. Subsequently, the predictive capabilities of the MMC were evaluated by the comparison to the fracture toughness tests results, used extensively in the pipeline industry. The capabilities of the MIT fracture model have been demonstrated on an example of high strength offshore steel, X100. The outcome of this study was not only to provide, the overall characterization of the fracture behavior of this material as an example, but also to present the methodology on how to use the MMC model as a practical tool in pipeline design. Y1 - 2012 ER - TY - CHAP A1 - Xue, Lufeng A1 - Paredes, Marcelo A1 - Nonn, Aida A1 - Wierzbicki, Tomasz T1 - Modeling of Crack Propagation in Defective X100 Line Pipes T2 - ASME 2020 39th International Conference on Ocean, Offshore and Arctic Engineering: August 3-7, 2020, virtual, online N2 - A comprehensive experimental program is carried out to determine material parameters for fracture initiation and propagation in X100 pipeline steels. The quadratic Hill’48 yield function along with an isotropic hardening are used to describe plastic flow at large deformation and a phenomenological fracture criterion to predict fracture initiation. Fracture mechanics SENT specimens are used to calibrate post-initiation softening parameters necessary for ductile crack propagation in thick components. Once the material model parameters set is complete a final comparison is conducted with ring expansion test on same material. KW - Berg KW - Bruchmechanik KW - Pipeline KW - plastisches Fließen KW - Rissausbreitung KW - Versuchsprogramm KW - Werkstoffmodell KW - Werkstoffparameter Y1 - 2020 SN - 978-0-7918-8434-8 U6 - https://doi.org/10.1115/OMAE2020-18048 PB - American Society of Mechanical Engineers CY - New York ER - TY - JOUR A1 - Nonn, Aida A1 - Kiss, Bálint A1 - Pezeshkian, Weria A1 - Tancogne-Dejean, Thomas A1 - Cerrone, Albert R. A1 - Kellermayer, Miklos A1 - Bai, Yuanli A1 - Li, Wei A1 - Wierzbicki, Tomasz T1 - Inferring mechanical properties of the SARS-CoV-2 virus particle with nano-indentation tests and numerical simulations JF - Journal of the mechanical behavior of biomedical materials N2 - The pandemic caused by the SARS-CoV-2 virus has claimed more than 6.5 million lives worldwide. This global challenge has led to accelerated development of highly effective vaccines tied to their ability to elicit a sustained immune response. While numerous studies have focused primarily on the spike (S) protein, less is known about the interior of the virus. Here we propose a methodology that combines several experimental and simulation techniques to elucidate the internal structure and mechanical properties of the SARS-CoV-2 virus. The mechanical response of the virus was analyzed by nanoindentation tests using a novel flat indenter and evaluated in comparison to a conventional sharp tip indentation. The elastic properties of the viral membrane were estimated by analytical solutions, molecular dynamics (MD) simulations on a membrane patch and by a 3D Finite Element (FE)-beam model of the virion's spike protein and membrane molecular structure. The FE-based inverse engineering approach provided a reasonable reproduction of the mechanical response of the virus from the sharp tip indentation and was successfully verified against the flat tip indentation results. The elastic modulus of the viral membrane was estimated in the range of 7-20 MPa. MD simulations showed that the presence of proteins significantly reduces the fracture strength of the membrane patch. However, FE simulations revealed an overall high fracture strength of the virus, with a mechanical behavior similar to the highly ductile behavior of engineering metallic materials. The failure mechanics of the membrane during sharp tip indentation includes progressive damage combined with localized collapse of the membrane due to severe bending. Furthermore, the results support the hypothesis of a close association of the long membrane proteins (M) with membrane-bound hexagonally packed ribonucleoproteins (RNPs). Beyond improved understanding of coronavirus structure, the present findings offer a knowledge base for the development of novel prevention and treatment methods that are independent of the immune system. Y1 - 2023 U6 - https://doi.org/10.1016/j.jmbbm.2023.106153 SN - 1751-6161 VL - 148 PB - Elsevier ER - TY - JOUR A1 - Xue, Lufeng A1 - Keim, Vincent A1 - Paredes, Marcelo A1 - Nonn, Aida A1 - Wierzbicki, Tomasz T1 - Anisotropic effects on crack propagation in pressurized line pipes under running ductile fracture scenarios JF - Engineering fracture mechanics N2 - The current analyses present results of running ductile fracture propagation in high strength X100 line pipe steels under the influence of anisotropy. Mechanical anisotropy is commonly available in pipe products as a result of the manufacturing process, especially, those subjected to hot/cold-worked deformation. The outcomes of the present analyses show that its effect on the behavior of running ductile fracture in cracked pipes undergoing depressurization is meaningful. For instance, the Crack-Tip Opening Angle (CTOA) not only exhibits a strong dependence to the pipe's diameter size, but also to the material's anisotropy nature when compared to a hypothetical isotropic material. Moreover, laboratory scale tests such as those performed on Battelle Drop Weight Tear (BDWT) samples provide useful information about initiation of ductile crack propagation when the anisotropy features are taken into account in the material description. KW - BEHAVIOR KW - Fracture anisotropy KW - INITIATION KW - MODEL KW - Non-associated flow rule KW - PREDICTION KW - Rate dependent MMC Model KW - Running ductile fracture KW - STATE KW - STEEL KW - STRAIN-RATE KW - TOUGHNESS Y1 - 2021 U6 - https://doi.org/10.1016/j.engfracmech.2021.107748 VL - 249 PB - Elsevier ER -