Fatigue crack growth in degrading elastic components of nonlinear structural systems under random loading

Based on fracture mechanics and theory of random processes, a probabilistic approach is proposed to analyze fatigue crack growth, fatigue life and rel iability of degrading elastic structural components in nonlinear structural systems. Both the material resistance to fatigue crack growth and the time -history of stress are assumed to be random. The effect of slow degradation of structural stiffness due to fatigue crack growth is taken into account. Analytical expressions are obtained for the special case where the random stress is a narrow-band process. Numerical examples are given for two nonli near structural systems important in practice assuming the randomized Paris -Erdogan type crack growth law is applicable. To validate the approach, the results are compared with those obtained from simulation. (C) 1999 Publish ed by Elsevier Science Ltd. All rights reserved.