Development of an explicit three-dimensional progressive mixed-mode I+II damage model

Abstract

A progressive mixed-mode I+II damage model was implemented in an explicit finite element code aiming to simulate damage initiation and growth in solid elements. A bilinear and a smoother linear-polynomial softening laws were implemented in the explicit code. Computational analyses using the bilinear softening law revealed numerical instabilities on the load-displacement curves. Those numerical instabilities were absent when the linear-polynomial softening law was used which points to that law as more appropriate. The explicit based method was compared with an implicit model incorporating cohesive zone analysis. The comparison consisted on the simulation of interlaminar fracture characterization tests in carbon-epoxy laminates. The double cantilever beam, end-notched flexure and single-leg bending fracture tests were numerically simulated to test the performance of the proposed model under mode I, mode II and mixed-mode I+II loading. It was verified that the explicit and implicit models produce results in close agreement and capture well the toughness used as input in the numerical simulations.