A synergistic damage-mechanics analysis of transverse cracking in [±θ/904]s laminates

The deformational response of [±θ/904]s laminates under longitudinal tensile loading is treated by a synergistic approach that combines continuum damage mechanics (CDM) and micromechanics. The constraint of θ° plies on transverse cracks in 90° plies is represented by a crack-opening displacement (COD) parameter in the CDM model and is expressed in terms of the ply properties and ply thickness ratios on the basis of a finite-element calculation. A methodology is proposed for predicting the laminate stiffness variations with crack density and applied strain (or stress) for various values of ply orientation θ and is found to give good results.