考虑材料性能分散性的航空发动机结构安全系数确定方法

针对材料性能分散性与航空发动机关重件可靠性之间关系的定量表征问题,结合正态分布和威布尔分布参数特点,研究了不同变异系数和形状参数条件下累积失效概率与安全系数确定方法,获取了材料性能分散性对结构可靠性的影响,给出了不同分散性条件下的安全系数。数值计算结果表明:结构设计选材应充分考虑材料性能分散性的影响;对于分散性较大的材料,单纯增大安全系数并不能保证结构具有足够的可靠性裕度,应采取措施有效降低材料性能分散性,才能从根本上控制结构失效概率水平。

Determining Method of Aeroengine Structure Safety Factor Considering Material Properties Dispersion

In view of the quantitative representation problem of the relationship between the material properties dispersion and the reliability of aeroengine key components,combined with the parameters characteristics of normal distribution and Weibull distribution,the determination method of cumulative failure probability and safety factor was studied under different variation coefficients and shape parameters.The influence of material properties dispersion on structural reliability was obtained,and the safety factors were given under different dispersion conditions.The numerical calculation results show that the influence of material properties dispersion should be fully considered in material selection of structural design.For materials with large dispersion,simply increasing the safety factor can not guarantee that the structure has sufficient reliability margin.Measures should be taken to effectively reduce the material properties dispersion in order to fundamentally control the level of structure failure probability.