结构疲劳寿命估计的概率和非概率混合模型研究

Hybrid Probabilistic and Non-probabilistic Model of Fatigue Lifetime Estimation

针对结构同时含有概率参变量和非概率参变量的情况,结合疲劳寿命估计的概率模型和区间模型,把随机参量作为实现值,通过两次寿命分析拟合出寿命下限的概率分布函数,进而得到混合变量时给定置信度下的疲劳寿命下限估计值。通过与区间估计模型比较,混合模型更为精确、可行。

Seeing that stochastic variables and non-probabilistic variables coexist in engineering structures in most eases, a hybrid probabilistie and non-probabilistie model of fatigue lifetime estimation is established. The probability distribution function of lower limit value of fatigue lifetime is fitted through two steps of analysis. The estimated value of the lower limit of fatigue lifetime could be gotten when the confidence level was given. An example illustrated the application of the proposed theory. The result was compared with interval analysis model. It was showed that the results have compatibility with the meanings of probability theory and interval analysis and the model has reasonableness and feasibility.