2017 年 26 巻 p. 131-143
Numerical simulation method for the fatigue crack propagation in the case that the initial defect surface closes by the compressive loading is proposed. Previous fatigue crack opening / closing model based on the strip yield model proposed by Toyosada et al. is improved to consider the closure effect on the initial defect surfaces. This improved numerical simulation procedure for the fatigue crack propagation was verified by comparing with measured fatigue crack propagation histories under various superimposed stress histories.
In addition, numerical case studies were performed to investigate the influence of appearance degree of superimposed stress for the fatigue crack propagation history by applying our improved numerical simulation procedure. These simulation results are suggested that safe side evaluation for the fatigue crack propagation could be obtained by replacing the superimposed stress into the stress with enveloping the superimposed stress.