Implementation and Validation of a Gurson Damage Model Modified for Shear Loading: Effect of Void Growth Rate and Mesh Size on the Predicted Behavior

Abstract

is an open access repository that collects the work of Arts et Métiers ParisTech researchers and makes it freely available over the web where possible. Abstract. The optimization of automotive security components requires good knowledge of the material state after fabrication, particularly with respect to damage that may have been done to the material by the manufacturing process. To achieve this, numerical simulation of the fabrication process is often undertaken. However, classical continuum damage models, like the Gurson [3] model, are not appropriate for the simulation of the blanking by punching operation because the material damage is primarily the result of shear stresses. This work is focused on the use and validation of a modified Gurson type damage model capable of modeling this process, which has recently been proposed by Nahshan [7]. After a brief description of the modification, the implementation and the validation of the modified Gurson model is detailed. A comparison between the original Gurson model and the modified model is presented in order to highlight the importance of the modification for a pure shear stress state and to show that the two models are equivalent for a purely hydrostatic stress state. It is also shown that the results from the modified model are dependent on the finite element mesh size.

Anisotropic Gurson‐Tvergaard‐Needleman plasticity and damage model for finite element analysis of elastic‐plastic problems

“…Parametric studies of ductile damage using the GTN model for various metals show that each parameter has a significant effect on the predicted results. However, the GTN model parameters of , as well as the hardening parameters that provide a damage‐free stress‐strain curve for the matrix material are obtained through curve fitting .…”

“…In this modified model, which is currently referred to as the GTN model, the damage‐induced plastic instability (or necking) process is governed by the growth of existing voids, nucleation of new voids during deformation, and micro‐crack coalescence in the neck region. The GTN model is widely used in analyzing many different plastic deformation processes . Matrix material has been frequently identified in recent years as anisotropic, and microvoids of nonspherical shapes in different orientations exist within the anisotropic matrix.…”

“…Several approximate yield criteria such as quadratic and nonquadratic yield criteria by Hill Hosford, and Barlat and Lian, for anisotropic ductile materials are available in literature. Numerical implementations and subsequent studies of the combination of earlier GTN model with some of the newer yield criteria can be found in other works . Furthermore, the GTN model has been extended and transformed from an isotropic matrix material to an anisotropic matrix based on the algorithm presented by Aravas .…”

“…The GTN model is widely used in analyzing many different plastic deformation processes. [6][7][8][9][10][11][12][13][14][15][16][17][18][19][20] Matrix material has been frequently identified in recent years as anisotropic, and microvoids of nonspherical shapes in different orientations exist within the anisotropic matrix. Several approximate yield criteria such as quadratic and nonquadratic yield criteria by Hill 21,22 Hosford, 23 and Barlat and Lian, 24 for anisotropic ductile materials are available in literature.…”

Study of the influence of cold working on mechanical behavior and ductile fracture of 5754 aluminum alloy: experimental and numerical simulations

“…The results of investigation of mechanical damage of 5754-H111 aluminum alloy has indicated that damage and fracture are mostly results of nucleating, growing and coalescing of micro cavities or micro voids. In order to predict the ductile fracture process, several theoretical models using local approaches have been presented in the literature (Betegon et al, 1997;Corigliano et al, 2000;Imad et al, 2003;Achouri et al, 2012). So, the selection of an adapted micromechanical model allows understanding of the fracture mechanism of 5457-H111 aluminum alloy.…”