Fretting fatigue crack growth simulation and residual life assessment of railway press-fitted axle

Abstract

To evaluate the inspection interval and safety margin of a railway press-fitted axle with fretting cracks, we conducted a fretting fatigue crack growth simulation and residual life assessment of a railway press-fitted axle by employing an actual load spectrum. The predicted results were compared with the measured crack to examine the effectiveness of various crack orientation criteria for assessing crack growth. Based on the validated crack orientation criteria, a finite element model was built to perform incremental fretting fatigue crack growth analysis. Then, the fretting fatigue crack growth life of the railway axle was predicted using two conventional crack growth rate models and compared with the experimental results. The results indicate that the max(ΔkI*) criterion provides a better approximation of the fretting fatigue crack growth path. The Paris equation can yield excessively conservative prediction life due to the strong load dependence of the effective stress ratio of fretting cracks, which can vary with the crack length and is influenced by press fitting. In contrast, the NASGRO equation yielded prediction results that were closer to the test results and can be utilised to determine the inspection interval. This study can serve as a vital reference for the operation and maintenance strategies for damaged axles with fretting cracks.