Flexural behavior and damage evolution of pultruded fibre-reinforced composite by acoustic emission test and a new progressive damage model

Abstract

In this paper, a progressive damage model was proposed to predict the flexural behavior of pultruded fibre-reinforced composite (PFRC). The model consists of the 3D strain-based damage criteria, the cohesive model and the damage evolution model, which has been validated by experiment with acoustic emission technology. The dominated failure mode and the damage evolution of PFRC were clarified. The predicted flexural elastic modulus, flexural strength, damage modes and the damage evolution by the proposed model agree much better to the experimental results than the existing model. It is found that the damage of the PFRC includes three stages: the undamaged elastic stage, the damage initiation stage dominated by the matrix damage and delamination, the damage propagation stage including the fibre damage, the matrix damage and the delamination. The tensile matrix damage and delamination occurred first before the peak load, followed by the tensile fibre damage. The distributions of each damage modes are similar for each layer. The outer layer of glass/epoxy damaged worst, and followed by the middle layer of the wound glass/epoxy and the internal layer of carbon/epoxy.