Influence of delaminations on fluid diffusion in multidirectional composite laminates – Theory and experiments

Abstract

Multidirectional composite laminates are often used in marine and offshore applications. Upon cyclic loading, cracks appear early in the off-axis plies and generate delaminations, which accelerate fluid diffusion. In this work, a theoretical model was developed for the prediction of fluid diffusion in laminates having cracks and delaminations. The model is based on the definition of a representative volume element subjected to Fickian diffusion. The geometry and dimensions of the representative volume element are determined by the crack density and the length of delaminations. Experiments were performed on both statically loaded samples having transverse cracks and fatigue loaded samples having transverse cracks and delaminations. The presence of delaminations increased the apparent diffusivity of the laminate by 5.4 times. The experimental results showed good agreement with the theory.