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针对刚性凸集模型在表达实际参数不确定性时的局限,提出了寿命参数的模糊集合模型及寿命估计方法.根据区间模型的内切和外接椭球确定了模糊集合边界的内、外缘及超椭球尺度参数的隶属函数,建立了疲劳寿命估计的模糊约束集.提出了基于Taylor二次展式和Lagrange条件极值法的寿命估计方法,构建了疲劳寿命的模糊极大集和模糊极小集.给出了模糊凸集约束下疲劳寿命极值求解的模拟算法.通过工程算例,对模糊凸集方法、凸集方法和概率方法进行了比较,结果表明,当统计数据缺乏时,模糊集合方法更贴切实际,计算结果更准确合理,是对凸模型方法和概率方法的发展和完善.
Aiming at the limitation of the rigid convex model in expressing the uncertainty of the actual parameters, the fuzzy set model and the life estimation method of the life parameter are proposed. According to the inscribed and circumscribed ellipsoid of the interval model, the inner and outer edges of the fuzzy set boundary and And the membership function of hyperspectral ellipsoidal scale parameters, the fuzzy constraint set of fatigue life estimation is established.The life estimation method based on Taylor quadratic expansion and Lagrange conditional extreme value method is proposed, and the fuzzy maximal set and fuzzy pole Small sets.A simulation algorithm for solving the extreme value of fatigue life under the constraint of fuzzy convex set is given.Compared with the fuzzy convex set method, the convex set method and the probabilistic method through engineering examples, the results show that when the statistical data is lacking, Fuzzy set method is more realistic and the result is more accurate and reasonable. It is the development and perfection of convex model method and probability method.