不同应力比下渗碳齿轮钢多重竞争疲劳失效模型构建

Construction of a Multiple Competing Fatigue Failure Model for Carburized Gear Steel with Different Stress Ratios

在应力比为-1,0和0.3的情况下,对渗碳齿轮钢进行了轴向加载试验,研究其超高周疲劳性能.试样的疲劳失效形式为:表面失效、内部无细晶粒区(Fine granular area,FGA)失效和内部有FGA失效.为描述齿轮钢在变应力比及表面强化处理下的竞争失效机理,建立了包含三种失效模式的多重竞争疲劳失效模型.结果表明,三种疲劳失效模式的失效概率与试验数据吻合较好,为阐明齿轮钢超高周疲劳状态下疲劳裂纹萌生竞争机制提出新的评估方法.

In the cases of stress ratios R of-1,0 and 0.3 respectively,the ultra-high cycle fatigue behaviors of carburized gear steel were studied by axial loading test.Based on the fracture morphology,the fatigue failure modes of the specimens can be divided into surface failure,internal failure without FGA(fine granular area)and internal failure with FGA.In order to describe the competitive failure mechanism of gear steel under variable stress ratios and surface hardening treatments,a multiple competitive fatigue failure model including three failure modes was established in this paper.The results show that the failure probabilities of the three fatigue failure modes are in good agreement with the experimental data,which indicates that the proposed method is valid for explaining the competition mechanism of fatigue crack initiation of gear steel under ultra-high cycle fatigue regimes.