INFLUENCE OF MATERIAL PARAMETERS ON STRAIN-ENERGY RELEASE RATES FOR CROSS-PLY LAMINATES WITH A PREEXISTING TRANSVERSE CRACK

The formation of intraply cracks in continuous fiber reinforced compos ite structures can be tolerated if critical mechanical properties are not reduced below allowable design limits. However, the presence of in traply cracks can lead to the formation of other, more harmful, types of damage. The onset of this late stage damage determines the useful s ervice life of the composite structure. In this paper, the damage prog ression in the vicinity of a pre-existing transverse crack is investig ated for [0/90(3))(s) and [0(2)/90(2)](s) cross-ply laminates. The typ es of damage considered are secondary crack formation, 0/90 interface delamination, split cracks in 0 degrees plies, and delamination induce d by split and transverse cracks. Strain energy release rates (SERR) a ssociated with the onset and propagation of these types of damage are calculated using three dimensional finite element analysis (FEA) of a representative volume containing a pre-existing transverse crack. The implications of this analysis are considered for several polymer matri x and metal matrix composites.