Experimental observations and numerical simulations of curved crack propagation in laminated fiber composites

Fracture experiments were carried out on continuous fiber polymer matrix laminated composite panels to investigate cohesive, through-the-thickness crack propagation. The experiments were designed to examine curved cracks, resulting from either eccentric loading or non-symmetric specimen geometry with respect to the starter crack. The constitutive description of the observed complex diffused damage zone, which from a continuum viewpoint may be considered a macroscopic crack, involves complex/evolving traction–separation relations and mode-mixity conditions. This paper presents some relevant experimental investigations and their numerical modeling using the variational multiscale cohesive method developed by Rudraraju et al. [21] which is an effective framework for simulating cohesive crack evolution and thereby predicting the residual strength of cracked composite panels.