High-cycle fatigue testing under different stress conditions must be performed in fatigue test methodology, and this requires expenditure both of money and time. The high-cycle fatigue test methodology also has the limitation of being a statistical approach to assessing estimated life that is not based on material properties. Thus to evaluate the estimated life of structural materials in transmissions in use, we need a novel assessment method that is economical, effective, easy to apply, and based on the material properties. In this study, we derive the relation between rupture stress and tensile properties taking into account fatigue rupture time, and developed a methodology for evaluating the estimated life of structural materials of transmission. Using this methodology, we performed stress rupture and fatigue tests for automatic transmission UD drum steels.

不同应力条件下的高周疲劳试验必须采用疲劳试验方法，这既需要金钱，也需要时间。高周疲劳测试方法也有局限性，即作为一种统计方法来评估不基于材料特性的估计寿命。因此，为了评估在用变速器中结构材料的估计寿命，我们需要一种经济、有效、易于应用且基于材料特性的新型评估方法。在这项研究中，我们在考虑疲劳断裂时间的情况下推导出断裂应力和拉伸性能之间的关系，并开发了一种评估传动结构材料的估计寿命的方法。使用这种方法，