Presenting an explicit step-by-step algorithm for lemaitre's ductile damage model with the crack closure effect in tensile-compressive loadings

Abstract

Continuum damage mechanics (CDM) studies the deterioration of mechanical properties in materials that leads to material failure. The Lemaitre’s ductile damage model is known as a suitable criterion for damage growth in ductile materials. The standard Lemaitre’s model cannot accurately predict the damage growth in most of bulk metal forming processes with a combination of tension and compression loadings. In this paper, first, an explicit step-by-step algorithm of the Lemaitre’s ductile damage model conjugated with the crack closure effect in compressive loadings is provided and directly presented for the computational implementations. Then, employing the proposed algorithm, a user-defined material subroutine is developed and implemented. In the following, a few bulk metal forming processes under compressive loadings are numerically simulated. Finally, the numerical simulation results are compared with the prediction results of the standard model and also experimental tests. The comparison confirms the high precision of the modified model vs. the standard model. Hence, it is concluded that the modified Lemaitre’s model can truly predict the damage behavior of ductile materials in bulk metal forming processes with combined tensile and compressive loadings.