Analysis of Contact Stress and Fatigue Crack Growth of Transmission Shaft

The finite element model and fracture mechanic theory are applied to analyze the contact stress and fatigue crack growth (FCG) path in three dimensions for a transmission shaft, which owns the initial crack and runs with the periodic load. The study found that the periodic load generates a non-proportional stress intensity factor history (SIF) output in the root of the splines. A modified method based on Hertz theory and AGMA (American Gear Manufacture Association) standard is utilized to analyze contact stress with considering the crack growth. From this, it is feasible to predict FCG path in three dimensions for a cracked component. The comparison between the simulation and experiment illustrates that the crack growth path is sensitive to the location and magnitude of loads. Contact regions of stress and fracture mechanic parameters should be deeply analyzed and known before predicting FCG path in three dimensions.