Modelling the effect of microstructural randomness on the mechanical response of composite laminates through the application of stochastic cohesive zone elements

Fibre reinforced polymer composites (FRPCs) are being increasingly used in structural applications where high specific strength and stiffness are required. The mechanical performance of FRPCs is affected by multi-mechanism damage evolution under loading which in turn is affected by microstructural randomness in the material. Although the micro-scale fracture of a FRPC is a stochastic process, most analyses of these materials have treated them in a deterministic way. In this paper the effect of stochasticity in FRPCs is investigated through the application of cohesive zone elements in which random properties are introduced. These may be termed ‘stochastic cohesive zone elements’ and are used in this paper to investigate the effect of microstructural randomness on the fracture behaviour of composite double cantilever beams. It is seen from this investigation that microstructure can significantly affect the macroscopic response of FRPC’s, emphasising the need to account for microstructural randomness for accurate prediction of the performance of laminated composite structures.