Progressive failure analysis of composite laminates based on elastoplastic and elasto-viscoplastic damage models

摘要

In this work, the progressive failure of composite laminates is studied. Firstly, a combined elastoplastic damage model capable of representing the plastic deformations and degradation of material stiffness of composite materials has been developed based on continuum damage mechanics and plasticity theory. To simulate the strain rate-dependent effects, a consistency elasto-viscoplastic damage model that accounts for the strain rate-dependent plastic response and stiffness degradation of composites has also been developed. Based on the return mapping algorithm, implicit numerical integration procedures have been developed for the two damage models. Tangent stiffness tensors consistent with the integration algorithms have been derived separately to ensure the computational efficiency of the Newton-Raphson method for solving nonlinear problems in finite element (FE) analysis. The numerical algorithms are implemented in the FE code Abaqus through user-defined subroutines (UMATs).These damage models have been applied to the progressive failure analyses of notched and un-notched composite laminates subjected to in-plane uniaxial tensile loadings at various strain rates. It has been shown that both the combined elastoplastic damage model and the consistency elasto-viscoplastic damage model proposed in this work provide efficient tools for the progressive failure analysis of composite laminates and are capable of delivering more accurate results than several other existing models.Two individual FE models, which include the first material model for composite plies and a cohesive zone model available in Abaqus for interface layers, have been developed and implemented in progressive failure analyses of composite laminates susceptible to delaminations. The progressive failure analyses of notched laminates under in-plane tensile loading and un-notched laminates exhibiting delaminations under out-of-plane transverse impact loading have been performed. The effects of the composites' layup configurations and numbers of through-holes on the mechanical response of fibre-metal laminates have been studied. Close agreement between the predicted results and test data reported in the literature has been demonstrated. It has been shown that, in many cases, the approaches proposed in this work outperform existing modelling techniques.