Investigation on low cycle fatigue crack propagation in steel under fully random variable amplitude loading

抄録

Low cycle fatigue is a failure mode which is possibly caused by random large strains such as seismic motion. To examine the effects, this study elaborated crack propagation behavior in steel under random amplitude loading. Firstly, study on crack growth rate under constant amplitude conditions was conducted to obtain basic characteristics. Next, several patterns of random amplitude loading were applied. It is discovered that crack growth accelerated when amplitude decreased from high to low levels at tensile portions, compared to that in constant amplitude conditions. Prediction model was constructed with establishing relationship between cyclic J-integral range and crack growth rate and confirmed to give good estimation.