【摘要】 研究了不同参数的Ⅲ型过载对近门槛区调质 40Cr钢Ⅰ型疲劳门槛的影响。结果表明 :过载后疲劳门槛均会提高 ,其程度随过载比的加大而增加 ;过载次数的有限增多也会使疲劳门槛略有增加 ,但效果将逐渐趋于饱和。过载机制主要有裂尖尾部塑性诱导裂纹闭合和裂尖附近的残余压应力状态更多还原

【Abstract】 The effect of Mode Ⅲ overload with different parameters on Mode Ⅰ fatigue threshold was investigated for Ouenching-Tempering 40Cr steel in the near-threshold region.The results show that,Mode Ⅲ overloading is followed higher Mode Ⅰ fatigue threshold,higher overloding ratio accompanied higher fatigue threshold.Fatigue threshold.Fatigue threshold increases slightly,but is saturated gradually with increasing limitedly overload cycles.The main mechanisms of overload effects are crack closure induced by wake zone plasticity and residual compressive stress around of the crack-tip.更多还原