MAT123 - extending from MAT24
Kara Laing
James M. Kennedy
Dear Kara,
Perhaps this might help:
Cheng, C.S., “Assessment of Failure Modeling with Thinning Strain Criterion in
LS-DYNA”, Paper No. IMECE2003-55100, ASME 2003 International Mechanical
Engineering Congress and Exposition, pp. 1-13, Washington, D.C., November, 2003.
Element deletion based on various failure criteria has been implemented in commercial
finite element analysis packages, e.g. LS-DYNA. However, due to the localized and
nonlinear nature of the material failure, especially for the ductile materials, a good failure
criterion needs to be robust for different mesh definitions and loading conditions. In the
present work, the material model with enhanced failure criterion in LS-DYNA, material
type 123 (MAT123), is investigated. The equations for determining the parameter of the
thinning strain failure criterion are derived based on the assumptions that Yeh et al. [7]
proposed. Simulations of different tests using MAT123 with the thinning strain at failure
calculated show better correlation with the experimental results than the other material
models examined.
http://proceedings.asmedigitalcollection.asme.org/proceeding.aspx?articleid=1595656
Sincerely,
James M. Kennedy
KBS2 Inc.
January 29,2021
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Kara Laing
Has no work really been done on this approach since that 2003? Does this indicate that, actually, it is not practical for the applied setting of product development?
James M. Kennedy
Dear Kara,
I observed that some work was done during 2012 to 2015. However, not much published
Involving theory if any at all.
Popularity of particular material models is often hard to explain.
Perhaps these presentations might be of some help:
Three models were applied on a severely impacted real automotive part, a B-pillar, for three
different mesh sizes. The reliability of prediction was demonstrated for all failure models.
In this study, the simplest MAT_123 failure model was as good as more complex ones as
MAT_224 and CrachFEM. This is explained by the suitable choice of the failure strain based
on the plane strain state condition, assumed to be the most critical and restrictive in crash
application. This illustrates that an adequate calibration of the model is a key issue for an
accurate failure prediction, more than the choice of the failure model itself.
Dietsch, P., Tihay, K., Bui-Van, A., and Cornette, D., “Methodology to Assess Fracture
during Crash Simulation: Fracture Strain Energy and their Calibration”, Metallurgical
Research Technology, Vol. 114, Issue 6, Article 607, September, 2017.
https://www.metallurgical-research.org/articles/metal/pdf/2017/06/metal160088.pdf
Five material fracture models (*MAT_024, *MAT_120_JC, *MAT_123, *MAT_224, and
MMC) available in LS-DYNA were adopted to simulate the fracture behavior of DP590
and DP780 steels in crush loadings. The capability of the five material fracture models for
the fracture prediction was assessed:
Chen, G., "Modeling of Fracture in AHSS Component Crush Tests", Great Designs in Steel 2014,
Livonia, Michigan, May, 2014.
Sincerely,
James M. Kennedy
KBS2 Inc.
February 1, 2021
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