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序 言 在航空发动机上不少部件的失效是由于低循环疲劳引起的。疲劳裂纹是在构件处于大范围屈服乃至整体屈服的情况下萌生和扩展的。一般说来,发动机部件的总寿命由两部分组成:工程裂纹的形成寿命和扩展寿命。在低周疲劳中,前者占总寿命的80％以上,一旦宏观裂纹出现,由于高的应力集中,使构件经历相当少的循环就破断。宏观裂纹扩展范围很小,采用通常控制应力或应变的方法不易测出扩展
Preface The failure of many components on aero engines is due to low cycle fatigue. Fatigue crack initiation and expansion in the case of a wide range of yielding or even yielding. In general, the total life of engine components consists of two parts: the formation of engineering cracks life and extended life. In the low cycle fatigue, the former accounted for more than 80% of the total life expectancy, once the macro-cracks appear, due to high stress concentration, so that the components through a relatively small cycle to break. Macroscopic crack propagation is very small, the use of the usual method of controlling stress or strain is not easy to measure the expansion