An improved Miner’s rule for fatigue damage calculation was presented in this paper, based on that the fatigue limit of materials gradually descends with the increase of damage accumulation in materials during loading process. A parameter was introduced to gradually modify the S-N curve of a specimen in the process of damage accumulation for the specimen. The relationship between the fatigue limit of the damaged specimen and the fatigue limit of the original specimen was deduced. The influence of load interaction between multistage cyclic loadings and loading sequence on cumulative fatigue damage of material was taken into account. Finally, damage calculation and precision comparison were performed for two fatigue tests with different loadings. The results show that the proposed method has higher accuracy than traditional Miner’s rule. According to the data of fatigue tests some random load spectra were simulated, in which the fatigue life of the specimen was more close to its real life. That not only showed the accuracy of the method, but also extended the applied scope of the method.%基于疲劳加载过程中材料的疲劳极限由于损伤的出现而呈现逐渐下降的规律，提出了关于疲劳损伤计算的修正的 Miner 准则。在该方法中，引进一个参数来不断修正损伤过程中试件的 S-N 曲线，推导受损试件的疲劳极限与初始试件的疲劳极限之间的关系，使载荷间的相互作用及载荷加载顺序对材料累积损伤的影响得到考虑。通过对两个不同加载方式的疲劳试验的计算和误差比较，验证了该方法比传统的 Miner 准则具有更高的计算精度。同时，根据其中一种加载方式的疲劳实验数据模拟多种随机载荷谱，利用修正的 Miner 准则法进行计算，得知随机载荷下的疲劳寿命更接近试件的实际寿命，进一步证明该方法的正确性，从而拓展了该方法的使用范围。
展开▼
