High-Cycle Fatigue Behavior of Bimetallic Bearing Shell Plates

Sliding bearing shells experience repeated bending loads, and fatigue cracking of the copper-alloy working layer can limit their service life. This study evaluated the high-cycle fatigue behavior of steel-backed copper-alloy plates using reciprocating bending tests and finite element fatigue analysis. Specimens were tested at displacement amplitudes of 1.25, 1.50, 2.00, and 2.50 mm under fully reversed loading, with a run-out limit of 10 million cycles. No macroscopic cracks were observed at amplitudes of 1.25–2.00 mm after 10 million cycles; at 2.50 mm, a visible crack appeared at approximately 8.2 million cycles. As displacement amplitude increased from 1.25 to 2.50 mm, the simulated maximum stress rose from 322.31 to 644.62 MPa, while the minimum fatigue safety factor fell from 3.1676 to 0.79191. At 2.50 mm, the predicted high-stress and low-safety-factor regions corresponded spatially to the experimentally observed cracking region. Fracture-surface observations indicated that cracking began at the copper-alloy surface, advanced toward the copper–steel interface, and was followed by cracking in the steel backing near the interface. These findings identify a critical displacement-amplitude range of 2.00–2.50 mm for the tested configuration and show how combined fatigue testing and simulation can help locate fatigue-critical regions in bimetallic bearing plates.