Combined fracture and delamination: A simple idealized example

Abstract

U nder static pre-stress, small voids located between constituent layers in a laminated composite may extend both as interface flaws and as cracks into the layers themselves. Thus, the material may fail due to the combined effects of delamination (separation) and fracture of the layers. As a first step in understanding this complex process, while minimizing mathematical difficulties, a simple idealized example of such a process is examined. A cruciform brittle crack-flaw combination is assumed to initiate at the interface of perfectly-bonded half-spaces under a uniform anti-plane shear field and to extend with constant speeds. When the crack and wave speeds satisfy a simple relation, straight-forward solutions to the resulting wave propagation problem can be obtained and several crackflaw interaction effects noted. In particular, the stress intensities and energy flux rates at the crack and flaw edges are studied.