论文部分内容阅读
疲劳寿命呈现异方差特性,其标准差随弹性应变幅和塑性应变幅的减小而增大,因此在Man-son-Coffin公式中引入标准正态变量μ和线性标准差eσ,σp,将-εN曲线参数表示为标准正态变量μ的函数,建立了低循环疲劳寿命的概率模型.针对某涡轮盘材料,在低循环疲劳试验数据的基础上应用异方差回归分析方法获得了概率模型的参数,应用该模型对涡轮盘销钉孔的低循环疲劳寿命进行了Monte-Carlo数值模拟,获到了寿命的概率分布.得到可靠度0.998 7的概率寿命与轮盘技术寿命相一致,相对误差仅为4%.该模型参数均来自疲劳试验数据的统计分析,寿命预测精度高,具有较好的工程应用前景.
The fatigue life shows heteroscedasticity, and the standard deviation increases with the decrease of elastic strain amplitude and plastic strain amplitude. Therefore, the standard normal variable μ and linear standard deviation eσ, σp are introduced into the Manson-Coffin formula, εN curve parameter is expressed as a function of standard normal variable μ and a probability model of low cycle fatigue life is established.For a turbine disk material, based on the data of low-cycle fatigue test, the parameters of the probability model are obtained by means of heteroscedastic regression analysis , The Monte-Carlo numerical simulation of the low cycle fatigue life of the dowel hole of the turbine disc is carried out by using this model, and the probability distribution of the life span is obtained. The probability life expectancy of the reliability 0.998 7 is consistent with that of the wheel disc technology, with a relative error of only 4 %. The model parameters are from the statistical analysis of fatigue test data, life prediction accuracy is high, with good engineering application prospects.