Fatigue damage of APC-2 composite assessed from material degradation and non-destructive evaluation data

Quasi-isotropic 45 degrees APC-2 specimens are fatigued under constant ampl itude stress reversal load condition. Fatigue induced degradation of the me chanical properties is correlated to data obtained from non-destructive eva luation. C-scan readings were used to define a generic damage severity fact or D. It refers to the current fatigue damage state and accounts for the va rying severity of damage at the different specimen locations. Analytical ex pressions are developed to relate D to the axial stiffness, residual streng th and interlaminar shear strength. An indication of damage tolerance can t hus be made for evaluating the integrity of structural components. (C) 1999 Elsevier Science Ltd. All rights reserved.