Lay-up effects on the fatigue life of open-hole multidirectional composite laminate specimens subjected to cyclic shear loading

Abstract

Composites have gained widespread use in a range of industrial applications. In many cases, they are subjected to cyclic loads which means their fatigue performance must be evaluated and predicted. Despite their wide use, assessing fatigue performance remains a challenging task due to the heterogenous nature of composites, which results in damage being arrested and redirected as it travels through the interfaces of the composite. Although failure is dependent on lay-up and loading, most fatigue studies have been conducted on uniaxial tensile or compressive loading, and the effect of lay-up is rarely assessed in a systematic manner. Therefore, the present work aims to provide insight into the effect of laminate architecture on damage propagation in multidirectional open-hole composite specimens subjected to cyclic shear loading. Data is collected using full-field, non-contact measurement techniques: high fidelity digital image correlation (DIC) is used to capture surface strains and damage, while thermoelastic stress analysis (TSA) is used to assess surface stresses, with the potential to reveal interior damage evolutions