承受交变载荷作用的零件或构件,过去一直是采用材料力学公式来进行计算和设计的,有的部门直到今天还在沿用这种传统的方法。材料力学只根据静力试验来分析材料或构件的机械性能(如屈服极限、弹性极限、强度极限等),这些机械性能没有充分反映材料在变应力作用下的特性, Parts or components that are subject to alternating loads have historically been calculated and designed using the mechanics of materials, and some are still using this traditional method to this day. Material mechanics only analyzes the mechanical properties of materials or components based on static tests (such as yield limit, elastic limit, strength limit, etc.), which do not adequately reflect the behavior of the material under stress,