Life Analysis of Wear Fatigue Competition Failure Mechanism of Main Bearing of Boring Machine

The main bearing of a tunneling machine is prone to premature failure under the influence of multiple factors such as wear and fatigue during service, making it difficult to predict its lifetime. In order to calculate the lifespan of the main bearing accurately, a life model is proposed that incorporates a fatigue-wear competition failure mechanism from the failure form. First, a bearing life model based on the continuous damage mechanics theory and the wear theory with surface roughness modification is proposed, and the competitive failure mechanism of bearing fatigue and wear is defined. Then, a finite element model is established by using the APDL software to simulate the contact between rollers and raceways, which helps identify the roller raceway where the bearing experiences initial failure, enabling the numerical solution of the life model. Finally, the analysis of the changes in contact stress and shear stress reveals that, during the first nine cycles, wear causes a decrease in contact stress, which suppresses fatigue failure, and extendes the bearing life. However, starting from the tenth cycle, contact stress increases, and wear accelerates the occurrence of fatigue failure. By considering the interaction of fatigue and wear, the proposed life model better reflects the actual situation.