当前的形变和断裂研究有两种趋势:一是研究微观机理,探讨它和宏观力学行为的关系:二是测定材料在接近实际使用条件下的力学性能,在计算机帮助下对零件进行准确的应力应变分析,然后估算并预测寿命。这两种趋势相辅相成,互相促进,使当前的疲劳研究十分活跃。从历史上看,五十年代前,金属疲劳的研究主要是经验性的:由基本的S—N曲线开始,到研究平均应力、缺口、环境和表面状态的影响等等。这些工作提供了大量有用的数据,但由于是经验性的,在普遍应用上受到一定 There are two trends in current research on deformation and fracture: one is to study the microscopic mechanism and discuss the relationship between it and macroscopic mechanical behavior; the other is to determine the mechanical properties of the material near the actual conditions of use. Accurate stress on the part with the help of computer Strain analysis then estimates and predicts life expectancy. These two trends complement each other and promote each other, making the current fatigue study very active. Historically, the study of metal fatigue was mainly empirical before the 1950s: starting with the basic S-N curve, studying the effects of average stress, indentation, environmental and surface conditions, and so on. These efforts provide a wealth of useful data, but because of their empirical nature, they are subject to certain common applications