Prediction of the stiffness degradation in cross-ply laminates due to transverse matrix-cracking: an energy method approach

This study deals with transverse cracking in cross-ply laminates. A fractur e mechanics analysis, using a strain energy based criterion, was used to mo del the onset of transverse matrix cracking, and the conditions for further damage development. An admissible displacement field, involving unknown fu nctions was assumed, and the principle of minimum potential energy was used to establish these functions. The crack front shape was a part of the assu med displacement field, thus making it possible to minimise the strain ener gy with respect to the crack opening displacement function. In this paper t he aim was to establish a solution to the transverse cracking problem, to u se later in a numerical procedure for the viscoelastic damage predictions f or a cross-ply laminate. The model accounts for residual stresses. A number of finite element solutions were performed to verify the accuracy of the p resented analytical solution. Predictions of stiffness degradation due to m atrix cracking, and matrix cracking as a function of applied stress are pre sented.