Discrete element approach to simulate debonding process in 3D short glass fibre composite materials: Application to PA6/GF30

This paper discusses the development of a numerical approach based on the Discrete Element Method (DEM) to simulate the interfacial debonding in Short Fibre Reinforced Composites (SFRC). For that purpose, we consider a hybrid lattice-particle approach based on a cohesive beam model. Already used to study composite materials, we aim to extend this concept to investigate the damage mechanism of SFRC in particular the PA6/GF30. To do so, a specific technique to estimate the Representative Elementary Volume (REV) of PA6/GF30 is proposed and discussed. The suggested discrete modelling is then validated by comparison with micromechanical approaches and experimental data for elastic behaviour predictions. At this time, the development of a DEM-based framework to model SFRC composite represents one of the novelties of this work. A mixed-mode discrete damage model based on an energetic formulation (which constitutes another originality of this paper) is subsequently discussed. To do so, the cohesive beam model is first implemented and validated through standard delamination problems. Thereafter, the case of SFRC is explored, focusing on the case of UniDirectional (UD) single fibre and aligned short-fibre composites under bending test. Simulation results in terms of onset and propagation of the debonding of fibre/matrix interface confirm the potential of the discrete modelling presented.