一种新的缺口件疲劳寿命分布计算模型

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A new computational model for predicting fatigue life distribution of notched specimens is developed. In this method, factors which have effect on fatigue life distribution of notched specimens are separated into two parts, the non-homogeneity of microstructure and the dispersion of local stress and strain at the notch root. And the stress field intensity is chosen to be the parameter of local stress and strain. The effect of the former part can be obtained through test data of fatigue life of smooth specimens, and that of the latter part is achieved by the Monte Carlo stochastic finite element method. Lastly the effects of the two parts are combined organically, and thus the fa- tigue life distribution of notched specimens is gotten. An example of center hole notched LY12CZ specimens was accomplished. The predicted result is in good agreement with the test result, which demonstrates that this method is effective and practical.提出了一种新的缺口件疲劳寿命分布计算模型。该模型将影响缺口件疲劳寿命分布的因素分成微观结构的不均匀性和缺口根部局部应力应变的分散性两部分，并选择应力场强作为局部应力应变量。前一部分的影响可参考光滑试件的疲劳寿命试验数据获得，后一部分的影响通过蒙特卡洛随机有限元法计算得到，最后将两部分的影响有机结合起来，得到缺口件的疲劳寿命分布。进行了材料LY12CZ的中心孔缺口件的寿命分布算例分析，预测结果与试验结果吻合良好，表明该方法是有效的。