Relationship between local stress amplitude at contact edges and fretting fatigue strength of austenitic stainless steel JIS SUS316

• Fretting fatigue strength was greatly reduced compared with plain fatigue strength.
• Fatigue strength became constant if the contact stress exceeded a certain value.
• Fretting fatigue cracks initiated from the shallow regions at the contact edge.
• Local stress condition at the contact edges dominated fretting fatigue strength.
• New experimental method provided stable data and validated FEA.

This study investigated the relationship between local stress amplitude generated at contact edges and the fretting fatigue strength of austenitic stainless steel SUS316. Fretting fatigue strength was examined using a new in-house experimental method. Local stress amplitude at contact edges was evaluated using finite element analysis (FEA) that allows for elastic–plastic behavior as well as contact friction. The fretting phenomenon generated from the application of plain fatigue strength significantly reduced fatigue strength. Although fretting fatigue strength decreased with increased contact stress, it became constant when the contact stress exceeded a specific value. The features of fracture surfaces showed that cracks originated from shallow regions at the contact edges because of stress concentration in that area. The results of FEA showed that local stress amplitude at the contact edges with each contact stress was similar under conditions of various fretting fatigue strengths. This finding suggested that the fretting fatigue strength can be evaluated from a mechanical standpoint by FEA.