A new finite element approach for modelling ductile damage void nucleation and growth—analysis of loading path effect on damage mechanisms

Abstract

A two-dimensional finite element (FE) model is presented to model the nucleation and void growth stages in ductile damage phenomena on the microstructure scale. This model is based on a level-set (LS) method coupled with an advanced re-meshing strategy. Both nucleation modes (interface debonding and inclusion fracture) are modelled through the introduction of micro-voids according to stress-based criteria. The LS method and mesh adaptation are used to accommodate the topology modification of the microstructure and to model multiple void nucleation and growth for different loading paths. The enhanced FE model is adopted to analyse the key features of the damage mechanisms on the micro-scale. The effects of inclusion orientation and of a complex loading path on nucleation and void growth are addressed. Good agreement is found with available experimental and numerical data found in the literature. The results exhibit that the loading path is a key point in damage growth. The proposed FE framework is an efficient technique to study damage phenomena on both simple and realistic microstructures. In the future, such an approach can be used to calibrate macroscopic ductile damage models for a complex loading path.

Experimental-Numerical Validation Framework for Micromechanical Simulations

“…[44,57,46,58,47] is followed. The ROI selected for the FE simulations has to belong to all DVC ROIs for each analyzed loading step and to be made as large as possible [25].…”

A new body-fitted immersed volume method for the modeling of ductile fracture at the microscale: Analysis of void clusters and stress state effects on coalescence

“…As a P1 formulation was used, this signed distance function was computed at mesh nodes at the initial state, and then the evolution of the interface was taken into account by Lagrangian displacement of the nodes during the computation. Other modifications of the interface such as the consequences of void nucleation were operated directly on the LS function [15]. The LS method is classically used to model fluid-structure interactions.…”

“…That is the reason why a new mesh adaptation framework was developed. The parallel C++ library CimLib, which is used for the present developments, has already been used by multiple authors for simulations based on the LS method [14,15,[18][19][20][21][22]26]. For remeshing operations, the external C (re)mesher MTC was used [16].…”

“…This tool was extended to anisotropic mesh adaptation, for which it was extensively used [14,15,[18][19][20][21][22]26].…”

“…This framework was then extended with void nucleation models and simulations could be pursued after the onset of void nucleation [15]. In this immersed volume framework, a single mesh was used to model the whole heterogeneous material, and the interfaces between matrix, voids and inclusions were not carried by faces of this mesh but by elements for which the behavior was ruled by mixture laws.…”