Stress analysis near delamination cracks originated from transverse cracking in cross-ply composite laminates using hybrid F.E.M

Abstract

Based upon the Strop formalism for anisotropic elastic materials and upon the method of eigenfunction expansion, the stress redistribution due to delamination cracks originated from transverse cracking is examined for [90/0]s and [0/90]s laminates under extension. The structure of solution in the form of series expansion is determined from the eigenvalue equation resulting from appropriate near field conditions. To complete the solution, use is made of a singular Hybrid F.E. M in conjunction with the eigenfunction series that includes a number of terms enough to represent the elastic state throughout the singular element. The fracture mechanics parametersstress intensity factors and energy release rate-are calculated and the major characteristics of stress distribution are discussed. The stability of delamination cracks is examined from varying ratios of ply thickness in terms of the energy release rate.