Triaxility in Gissmo Material
Pushkar patil
Евгений Калентьев
Евгений Калентьев
James M. Kennedy
Dear Pushkar,
Several presentations which may be of interest.
A generalized damage and failure procedure that has been implemented in SAMP was presented. In particular, important effects such as triaxiality, strain rate dependency, regularization and non-proportional loading were considered in SAMP. All required physical material parameters were provided in a user-friendly tabulated way. It was shown that the formalism included many different damage and failure models as special cases, such as the well-known formulations by Johnson-Cook, Chaboche, Lemaitre and Gurson among others:
Du Bois, P.A., Kolling, S., Feucht, M., and Haufe, A., "A Comparative Review of Damage and Failure Models and Tabulated Generalization", 6th European LS-DYNA Users Conference, Gothenburg, Sweden, May, 2007.
http://www.dynalook.com/european-conf-2007/a-comparative-review-of-damage-and-failure-models.pdf
This paper presented the extension and validation of the damage model (GISSMO (Generalized Incremental Stress State dependent damage MOdel). The damage model was extended for 3D usage by utilization of Lode angle parameter. The fracture strain is defined in the stress triaxiality and Lode angle parameter space as a surface. The fracture strain definition was introduced as a table definition:
Basaran, M., Wolkerlin, S.D., Feucht, M., Neukamm, F., and Weichert, D., "An Extension of the GISSMO Damage Model Based on Lode Angle Dependence", 9th German LS-DYNA Forum, Bamberg, Germany, October, 2010.
http://www.dynamore.de/en/downloads/papers/10-forum/papers/B-I-02.pdf
Numerical fracture prediction of metals is of great interest in automotive industry, since it is an effective way to improve crashworthiness of car body parts. In the present thesis, the effect of stress state on damage modeling with the focus on the Lode angle parameter (or third deviatoric stress invariant) was discussed and validated by experimental and numerical studies. The numerical implementation was integrated to the damage model GISSMO (Generalized Incremental Stress State dependent damage MOdel) as an extension, which was proposed by Neukamm et al. [2009]. The model was extended for 3D usage by utilization of the Lode angle parameter. The stress state was defined with two stress state parameters, stress triaxiality and Lode angle parameter uniquely. The material ductility (or fracture strain) was considered as a function of the stress triaxiality and Lode angle parameter:
Basaran, M., "Stress State Dependent Damage Modeling with a Focus on the Lode Angles Influence", Ph.D. Thesis, Fakultat fur Maschinenwesen, Rheinisch-Westfalischen Tecnischen Hochschule Aachen University, Aachen, Germany, July, 2011.
http://darwin.bth.rwth-aachen.de/opus3/volltexte/2011/3833/pdf/3833.pdf
The LCSDG function of the GISSMO damage model in *MAT_ADD_EROSION was used to predict rupture failure. The LCSDG function calculates failure plastic strains based on stress triaxiality, which is determined by the deformation mode:
Hayashi, S., "Prediction of Failure Behaviors in Polymers Under Multiaxial Stress State", 12th International LS-DYNA Users Conference, Dearborn, Michigan, June, 2012.
http://www.dynalook.com/international-conf-2012/constitutivemodeling19-a.pdf
Calibration of failure criteria in GISSMO for metals: (a) several types of tensile experiments using PHS were conducted in order to identify failure strain in different stress states, (b) failure strains were defined in wide range of stress triaxiality using phenomenological material failure model, (c) material instability (critical strain) was modeled, (d) numerical experiments were conducted to reproduce the tensile tests (numerical validation):
Saito, K., Chinzei, S., and Naito, J., "Calibration of Criteria in GISSMO for Material Failure Prediction", 13th German LS-DYNA Forum, Bamberg, Germany, October, 2014.
Sincerely,
James M. Kennedy
KBS2 Inc.
September 10, 2021
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