Evaluation of the In-situ Damage and Strength Properties of Thin-ply CFRP Laminates by Micro-scale Finite Element Analysis

Abstract

This study develops a micro-scale simulation scheme to predict in-situ damage and strength properties of CFRP laminates with various ply thicknesses. The in-situ properties depend not only on the microstructure (fiber configuration, volume fraction, etc.) but also on the constraint effect from neighboring plies (i.e., ply thickness, stacking sequence, etc.). In order to capture both of the initiation and the propagation of the transverse cracks, the microscopic random fiber configuration and the constraint effect from neighboring plies should be carefully taken into account. To this end, this study considers the representative volume element which consists of the “inhomogeneous” ply in which the fiber and the matrix were individually modelled by the solid elements and the “homogenized” plies which were homogeneously modelled by the shell elements. In the inhomogeneous ply, the matrix damage and the debonding between fiber and matrix were modelled to reproduce transverse crack propagation. The validity of the proposed tool was evaluated by comparing the predicted cracking behavior with the results of unidirectional tensile tests on cross-ply laminates having different 90º ply thicknesses. Finally, the effects of ply thickness on the in-situ damage and strength properties of cross-ply laminates were examined by the proposed scheme.