Porous plasticity revisited: Macroscopic and multiscale modeling

Porous plasticity aims to model the growth and coalescence of voids leading ductile failure. The GTN (1984), resulting from heuristic modifications Gurson's homogenized hollow sphere (1977), is used in numerous publications. Rousselier (1981), developed framework continuum thermodynamics, apparently similar. Both models are effective numerical calculations, but reasons why they perform well were not investigated details existing literature, as regards transition uniaxial deformation, relations between various modes strain localization, finite element discretization, regularization. In present paper, we propose first revisit both compare their fundamentally different mechanical behaviors. For stress triaxiality larger than some critical value, it shown that theoretically cannot achieve localization a plane only pointwise for ultimate state (stress tensor equal zero). void volume fraction (void growth), smaller value. Fortunately, discretization transforms into with an appropriate Cartesian mesh more or less planar sheet integration points can be obtained. at all triaxialities also this characteristic size. Second, multiscale modeling damage (not limited damage) essential way progress laboratory specimen calculations. incorporated polycrystalline based on crystal plasticity, reasonable computation times provided reduced texture small number crystallographic orientations used. It coupled new Coulomb fracture slip system scale secondary nucleation grain scales, respectively. applied aluminum CT KAHN specimens steel round notched specimens.