THE EFFECT OF SOFT INTERLEAVED LAYERS ON THE COMBINED TRANSVERSE CRACKING DELAMINATION MECHANISMS IN COMPOSITE LAMINATES

The effect of the presence of soft interlayers embedded in a cross-ply laminate on transverse cracking, delamination and their interaction has been studied analytically. The stress field within the adhesive interlayer, close to an existing transverse crack, was numerically analysed. On the basis of this and previous findings a delamination failure criterion is developed and related to the principal maximum stress and its radius vector from the transverse crack tip. Good correlation was found between analytical predictions and previous experimental findings. It is concluded that interfacial delamination is the immediate failure mode triggered by and associated with transverse cracking and that the presence of soft layers has a major effect on reducing stresses and delaying the start of delamination. In this context, increasing the adhesive layer thickness has a beneficial effect up to a certain thickness level. Other geometrical and material effects are also considered. © 1990.