Fatigue damage mechanics of composite materials III: prediction of post-fatigue strength

A damage-based model for post-fatigue notch strength is presented. The model is an extension of a method developed previously to predict the notch strength of laminated composites. A simple finite element representation of the notch tip damage zone is used to obtain the localized damage-modified stress distribution. A uniaxial tensile stress failure criterion is applied to the 0° plies from which the laminate strength is evaluated. In conjunction with the fatigue damage growth law described in Part II, residual strength is calculated as a function of the applied loading conditions, specimen geometry and lay-up for (90/0)s, (90/0)2s and (902/02)s T300/914C carbon-fibre/epoxy laminates subjected to tension-tension fatigue cycling