Near Threshold Fatigue Crack Propagation Under Combined Torsion And Tension In Stainless Steel
不锈钢在扭转/拉伸复合载荷下近门槛值的疲劳裂纹扩展行为

Near-threshold fatigue crack propagation tests were conducted under combined torsion and tension on a circumferentially pre-cracked round bar of an austenite stainless steel. The propagation behavior was studied extensively under various combinations of cyclic loads. The threshold condition of fatigue crack extension was expressed by a quarter-elliptic function in terms of the stress intensity factor ranges for mode I and III. The equation can be derived on the basis of the crack-tip displacement criterion. The threshold condition for fracture is also expressed by another quarter-elliptic function.