Propagation of edge cracking towards the centre of laminated composite plates subjected to fatigue loading

The aim of this study is to propose and identify a model suitable for describing the damage distribution D(x,N), where x is the distance from an edge and N is the number of cycles, inside an off-axis layer of a laminate and to relate this internal damage with the surface damage D(0,N)=F(N) observable on the specimenʹs edge. The partial differential equation governing crack density D(x,N) is derived with the help of purely kinematical considerations on one hand and of the selected growth rate equation for each individual crack on the other, taking into account the mean crack spacing in the vicinity of the crack tip. A further aspect of the modelling, the relationship between crack density and strain energy release rate, is also investigated in the case of cross-ply laminates.