Damage in composite laminates with off-axis plies Academic Article uri icon


  • Damage in off-axis plies of composite laminates is studied by examining the configuration [0/ ± θ4/0( 1/2 )](s) with θ=25, 40, 55, 70 and 90 subjected to tensile loading in the axial direction. It is found that for the values of θ, where the stress in the off-axis plies normal to the fibers is tensile, ply cracks lying along fibers initiate and increase in number, while for other θ values the plies do not undergo this damage, as expected. However, the overall laminate elastic moduli are also found to change for the θ values where no ply cracks exist. It is postulated that a shear-induced degradation of the off-axis plies is responsible for the observed laminate moduli changes. The prediction of changes in these moduli by using the ply shear modulus measured on [±θ4](s) appears to support this postulate. For the case of moduli changes caused by ply cracks the recently proposed synergistic damage-mechanics approach [1] is applied. The implications of the findings of this work on a class of continuum damage-mechanics formulations proposed in the literature are discussed.

published proceedings

  • Composites Science and Technology

author list (cited authors)

  • Varna, J

citation count

  • 164

complete list of authors

  • Varna, J

publication date

  • November 1999