Effective Elastic Constants of Bidirectional Laminates Containing Transverse Ply Cracks

Abstract

All nine independent effective elastic constants of [0°_m/90°_n]_S laminates containing transverse cracks through the middle 90°_n layers are determined analytically. The cracks are assumed to be evenly spaced and to extend across the entire laminate width. Each of the 0°_m and 90°_n ply clusters are modeled as homogeneous, orthotropic materials with the layers connected through continuity of displacements and tractions at the ply interfaces. A stress based homogeneous plate theory which includes the effect of transverse shear and normal stresses is utilized to model the ply clusters. Elastic moduli and stress distributions are compared to shear lag and other analytical models existing in the literature. Moduli of a [±45°]_S laminate containing a crack parallel to the fibers in the middle plies are obtained by a rotation of elastic properties obtained from a cracked [0°/90°]_S laminate.

Keywords

elastic constants laminate damage plate analysis ply cracking ply discount reduced stiffness stress distribution and transverse cracking

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