A Fatigue Crack Growth Prediction Model With Load Interaction Effects Using Crack Closure Concept

Abstract

Crack closure phenomenon is observed in center-cracked tension (CCT) specimens of structural steel JIS SM520B. The remaining plastic deformation in the wake of an advancing crack causing crack closure is a significant factor of the load interaction effects on fatigue crack growth rates. A prediction model based on crack closure concept is used to compute fatigue crack opening stress and consequently effective stress intensity factor range, LIKef f, and correlate it with the measured fatigue crack growth rates. The analytical results are compared with test results under overload conditions. Fatigue crack propagation lives are computed under various load sequences to investigate the load interaction effects.