LAUSR

For unacceptable computational efficiency and accuracy on the probabilistic analysis of multi-component system with multi-failure modes, this paper proposed multi-extremum response surface method (MERSM). MERSM model was established based on quadratic polynomial function by taking extremum response surface model as the sub-model of multi-response surface method. The dynamic probabilistic analysis of an aeroengine turbine blisk with two components, and their reliability of deformation and stress failures was obtained, based on thermal-structural coupling technique, by considering the nonlinearity of material parameters and the transients of gas flow, gas temperature and rotational speed. The results show that the comprehensive reliability of structure is 0.9904 when the allowable deformations and stresses of blade and disk are 4.78×10–3 m and 1.41×109 Pa, and 1.64×10–3 m and 1.04×109 Pa, respectively. Besides, gas temperature and rotating speed severely influence the comprehensive reliability of system. Through the comparison of methods, it is shown that the MERSM holds higher computational precision and speed in the probabilistic analysis of turbine blisk, and MERSM computational precision satisfies the requirement of engineering design. The efforts of this study address the difficulties on transients and multiple models coupling for the dynamic probabilistic analysis of multi-component system with multi-failure modes.摘要针对多构件多失效模式系统可靠性分析中计算效率和计算精度较差的问题, 提出了多重极值响 应面法, 多重极值响应面是基于二次多项式响应面函数建立的多重极值响应面方程。基于热-结构耦 合技术, 考虑材料属性的非线性和气体载荷、气体温度、转速的瞬态性, 对航空发动机叶盘双构件进 行动态可靠性分析, 得到其变形和应力的可靠性。结果显示: 当叶片-轮盘结构的允许变形量、许用 应力分别为4.78 mm、1.41×109 Pa、1.64 mm 和1.04×109 Pa 时, 结构的综合可靠度为0.9904。此外, 燃气温度和转速对系统的综合可靠性影响较大。通过对比表明, MERSM 在可靠性分析计算中具有较 高的计算精度和速度, 计算精度满足工程设计要求。本文解决了具有多失效模式的多构件系统在瞬态 和耦合时动态可靠性分析的困难。