Influence of Root Rotation on Delamination Fracture Toughness of Composites

Large deviations have been observed while analysing composite double cantilever beam (DCB) specimens assuming each cracked half as a simple cantilever beam. This paper examines the effect of rotational spring stiffness ( K ) on the critical fracture energy ( G I C ) considering nonzero slope at the crack-tip of the DCB specimen by modelling each cracked half as the spring-hinged cantilever beam. The critical load estimates of DCB specimens from G I C are found to be in good agreement with in-house and existing test results of different composite material systems.