Adaptive Concurrent Multi-level Modeling of Multi-scale Ductile Failure in Heterogeneous Metallic Materials

Abstract

This work creates a novel adaptive multi-level modeling framework for rate-dependent ductile fracture of heterogeneous aluminum alloys with non-uniform microstructures. The microstructure of aluminum alloys is characterized by a dispersion of brittle heterogeneities such as silicon and intermetallics in a ductile aluminum matrix. These microstructural heterogeneities affect their failure properties like ductility in an adverse manner. The multilevel model invokes two-way coupling, viz. homogenization for upscaled constitutive modeling, and top-down scale-transition in regions of localization and damage. Adaptivity is necessary for incorporating continuous changes in the computational model as a consequence of evolving microstructural deformation and damage. The macroscopic finite element analysis in regions homogeneity incorporates homogenization-based continuum rate-dependent plasticity-damage (HCPD) models. Transcending scales is required in regions of high macroscopic gradients caused by underlying localized plasticity and damage. Complete microscopic analysis using the LEVCFEM is conducted in these regions, which follow the growth of microscopic voids and cracking to cause local ductile fracture. The macroscopic and microscopic simulations are done concurrently in a coupled manner. Physics-based level change criteria are developed to improve the accuracy and efficiency of the model. Numerical simulations are conducted for validations and ductile fracture in a real microstructure is demonstrated.