基于6σ的动车组转向架构架非概率可靠性分析

Non-probabilistic reliability analysis based on six sigma of MEU bogie frame

针对转向架构架静强度实验结果仅对测试件有效,不能准确反映整批构架的结构强度是否满足要求的问题,提出一种基于6σ的非概率可靠性分析方法。首先,通过对转向架构架进行结构强度分析,确定受力较大部位的区间变量,并基于参数化模型对其进行D-最优试验设计,建立表征转向架构架结构特征的多项式响应面函数。其次,结合6σ原则和Chebyshev不等式,建立描述区间变量的分段函数模型,给出新模型中区间变量的生成策略和非概率可靠度的计算方法。最后,以动车组转向架构架为研究对象,对其进行结构可靠性分析,并与传统的分析方法进行对比。研究结果表明:在信息缺乏或小样本的条件下,分段函数模型更好地反映整批构架的结构可靠性,弥补了基于均匀分布假定相对保守的缺陷,同时,解决了由测试次数少导致的实验结果的局限性。

Aiming at the problem that the static strength test results of the bogie frame are effective only for the test piece, and can't accurately reflect whether the structural strength of the entire batch of structures meets the requirements, a non-probabilistic reliability analysis method based on 6 Sigma was proposed. Firstly, the structural strength analysis of the bogie frame was made to determine the interval variable of larger force of the part, and the D-optimal test design was carried out on the basis of the parameterized model and the polynomial response surface function was established to characterize the bogie frame structure characteristics. Secondly, combining the 6 Sigma principle and the Chebyshev inequality, a piecewise function model describing interval variables was established, and the generation strategy of inter area variables and the calculation method of non-probabilistic reliability were given. Finally, taking the EMU bogie frame as the research object, the structural reliability analysis was carried out and compared with the traditional analysis method. The results show that under the condition of lack of information or small sample, the piecewise function model reflects the structural reliability of the whole batch structure better and makes up for the relatively conservative defects based on the assumption of uniform distribution. At the same time, it solved the limitations of the experimental results caused by fewer testing times.