École Nationale Supérieure de
Techniques Avancées

Abstract

Delamination is the most commonly observed damage mode in laminated composites. Consequently, many models based on the framework of linear elastic fracture mechanics have been developed to predict the propagation of delamination in these structures. Most of these methods are empirical and make use of a phenomenological correlation between the strain energy release rate and the crack growth rate. Nevertheless, recent research suggests that the average strain energy release rate per cycle, rather than the SERR, should be used as the fundamental correlation parameter. This has already been proven for mode I loading in CFRP and adhesive bonds, but has not yet been studied for mixed-mode loading. This work investigates the correlation between the dissipation of strain energy per cycle and crack growth rate under mixed-mode loading. For this purpose, mixed-mode bending were performed for mode mixtures and displacement ratios. To complete the fatigue tests results, some of the fracture surfaces generated during the test were analyzed through Scanning electron Microscopy. As a result, the strain energy release per cycle seems to be a fundamental correlation parameter to char- acterize crack growth in mixed-mode fatigue tests.