基于失效数据的液压系统可靠性和重要性分析

Analysis of importance and reliability in the hydraulic system based on failure data

基于无模型抽样理论和态相关参数(SDP)方法,对某型液压系统寿命的可靠性和重要性进行了分析。以分配准则和距离准则为依据,以经验累积分布函数为约束,直接产生与初始样本(N?20,N为样本容量)不确定信息相一致的大容量样本,得到了寿命区间的系统失效概率曲线。针对部件性能对系统寿命可靠性的影响程度,应用SDP方法求解各输入基于方差的重要性测度,得到部件对系统寿命可靠性的相对重要性排序为:电磁阀>柱塞泵>作动筒>油滤>活门>油箱。表明电磁阀对系统寿命可靠性的影响最大;油箱的影响最小。此结果为改进系统可靠性水平提供依据。

In this paper, a novel technique for the reliability and importance analysis of hydraulic system is presented based on model-free sampling and state dependent parameter(SDP) method. The analysis results provide a reference guideline for the reliability assessment and design of the system. Instead of estimating a distribution function, this new method is applied to operate without a probabilistic model. According to the assignment criterion and distance criterion, the information contained in a small experiment sample is extracted directly to produce a second sample of considerably larger size, and the second sample completely reflects the properties of the original small sample. Due to the method performing without estimating a distribution, the analysis procedure reduces the error of the truncation and numerical fitting. Comparing to the traditional sampling,the model-free sampling specializes in sparse point data. To improve current probability safety assessment of the system, a new variance-based important measure is applied to measure the important effects of the basic components on the whole uncertainty of the lifetime of the system. Combining with advantages of the SDP method, a solution of the importance measures is provided, the importance rank is as follows: solenoid valve > pump > cylinder > oil filter > valve > tank, which illustrates the solenoid valve contributes to system lifetime most, while the tank contributes least. So, useful information can be obtained for system analysts and design engineers to trace the system weaknesses and to guide effective system improvement.