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A numerical investigation was carried out to analyze in details the perforation process of target AA5754-O Aluminum plate when subjected to normal impact at low (up to 25 ms − 1 ) and moderate velocities (ranged between 25 − 50 ms − 1 ). A fully coupled elasto-visco-plastic-damage model is implemented into a user-defined material (VUMAT) subroutine for the commercial finite element code ABAQUS/Explicit. The strain rate effect is considered. Comparison between isotropic J 2 and orthotropic Hill yield criteria associated with isotropic and mixed non-linear isotropic/kinematic hardening was conducted. A parametric study of the effect of anisotropy, plate thickness and impactor nose shapes on ballistic limit and petal forming is carried out. A good agreement is found between numerical and experimental results conducted by other researchers. [ABSTRACT FROM AUTHOR]

Developing an efficient non-associated plasticity criterion fully coupled with isotropic ductile damage is the main contribution of the current research. Two ductile degradation functions with variable degradation exponents are considered in this model, one for elasticity and the other for plasticity. Mixed (isotropic/kinematic) hardening rule and Hill'48 quadratic yield criterion are adopted to describe the elastoplastic material behavior. For this contribution, a VUMAT subroutine including the proposed model has been adopted and implemented in Abaqus/Explicit finite element code. Various experimental tests and finite element simulations are carried out to validate the current model and to predict the damage evolution in notched tensile specimens. In the validation part of this investigation, the quality of the numerical simulation results is assessed by comparison with the experimental ones taking into account the fully coupled non-associated-damage model. The effectiveness of the developed approach is evaluated through comparisons with experimental measurements and numerical models (Hill_S and Hill_R) and show good agreements. This fact indicates that the current model is a useful virtual tool to estimate the formability of anisotropic sheet metals. Numerical prediction is performed in order to reveal the stress triaxiality distributions for single point incremental forming (SPIF). The mentioned study is intended to give a guideline for 5083-aluminum alloy sheet forming. • An improved non-associated plasticity criterion fully coupled with isotropic ductile damage is developed. • Two ductile degradation functions with variable degradation exponents are considered in this model. • Uniaxial tensile tests are carried out to determine the elastoplastic behavior of 5083 aluminum alloy. • Pre-notched specimens are tested to control the magnitude of the fracture strain according to the stress triaxiality. • Experimental–numerical validation proves the accuracy of the current model to describe the elastoplastic behavior material. [ABSTRACT FROM AUTHOR]

In the present work, an elastoplastic-damage model fully coupled with the constitutive equations of the non-associated plasticity is developed, to enrich the existing research results on the non-associated plasticity finite element models. The yield function and the plastic potential are represented independently by two different (Hill, 1948) quadratic functions to describe the anisotropic behavior of 5083-aluminium alloy. The current model develops a first attempt to establish a general formulation with two ductile degradation functions, one for elasticity and the other for plasticity, with variable degradation coefficients. Further, the elastoplastic behavior of 5083-aluminium alloy is determined through uniaxial tensile tests, so that the anisotropic, the isotropic hardening and the damage parameters are acquired. Experimental-numerical confrontation proves the reliability of the current formulation to describe the behavior of 5083-aluminium alloy with good accuracy. Furthermore, a novel numerical optimization procedure is firstly used to analytically identify Lemaître damage parameters in order to limit the non-unicity of these parameters. The adopted optimization procedure offers a compromise between good accuracy and low computational time to determine the damage parameters. [ABSTRACT FROM AUTHOR]