Model of delamination propagation in brittle-matrix composites under cyclic loading

A model of interlaminar fatigue crack growth based on damage accumulation a head of the crack is proposed. Linear cumulative assumption is used for dam age estimation, and a quadratic failure criterion is applied for complex in terlaminar loading. Model parameters are determined from mode I and mode II fatigue tests, and used to predict mixed-mode delamination propagation rat e. Comparison of theoretical prediction with mixed-mode test results for di fferent brittle graphite FRP at several mode- and load ratios show reasonab le agreement.