Analysis of transverse lamina cracks in multi-directionally 0°, ±45° and 90° oriented reinforced laminates and a damage tolerance design of composite plates

Abstract Analytical approach to transverse lamina cracking of ply-groups in a multi-axially (0°, ±45° and 90° oriented) laminated composite material has been proposed in the present paper. Quasi three-dimensional stress and strain analysis of a ply-group with the through-the-width transverse lamina cracks was carried out by using finite differential total force method, assuming periodical arrangement of cracks along the longitudinal direction. Equivalent elastic moduli and Mode I and II energy release rates of the damaged ply group are evaluated. Effects of crack density, in-plane elastic moduli, ply-group thickness and fiber orientation on the equivalent elastic moduli and energy release rate are expressed as interpolation functions, which are applicable to general multi-axial composite laminates. Simple calculation procedure has been proposed for damage tolerance design of laminated composite structures. Keywords: TRANSVERSE CRACKSENERGY RELEASE RATESTIFFNESS REDUCTIONCRACK DENSITY