开始主要以解释热疲劳为目的而进行的低周疲劳研究,现在已被广泛地认识到在常温下对机械结构设计也有很重要的意义。这就是说,在设计承受循环荷重作用的机械零件时,必须有循环变形的应力应变曲线。现已认识到,在应力集中区域产生的高应力、高应变状态的循环应变和塑性应变,是控制疲劳破坏的最重要的力学因素。因此可以认为,根据以上事实确立的疲劳寿命法则是有效的。下式即为Manson—Coffin法则的著名的实验式 Low-cycle fatigue research, primarily aimed at explaining thermal fatigue, has now begun to be widely recognized as having important implications for mechanical design at ambient temperatures. This means that in the design of mechanical parts subjected to cyclic loading, there must be a cyclic deformation of the stress-strain curve. It has been recognized that the high stress and high strain cyclic strain and plastic strain generated in the stress concentration area are the most important mechanical factors for controlling fatigue failure. Therefore, it can be considered that the fatigue life rule established based on the above fact is effective. The following formula is the famous experimental formula of Manson-Coffin’s law