Modeling dynamic formability of porous ductile sheets subjected to biaxial stretching: Actual porosity versus homogenized porosity

This paper investigates the effect of porous microstructure on necking formability ductile sheets subjected to dynamic in-plane stretching. We have developed an original approach in which finite element calculations include actual void distributions obtained from additively manufactured materials are compared with simulations specimen is modeled Gurson–Tvergaard continuum plasticity theory (Gurson, 1977; Tvergaard, 1982) considers porosity as internal state variable. A key point this work that performed model, initial volume fraction spatially varied according included microstructure. The computations been carried out for different loading conditions, biaxial strain ratios ranging 0 (plane strain) 0.75 (biaxial tension) and rates varying between 10000s?1 60000s?1. shown specific microstructures considered, forming limits model qualitative agreement results distributions, quantitative differences strains being generally less than ?25% (the voids systematically predict greater strains). In addition, spatial distribution necks formed at large very similar homogenized models. demonstrate promote plastic localization, acting preferential sites nucleation fast growing necks. Moreover, provided individualized correlations fraction, maximum size formability, highlighted influence heterogeneity localization.