基于故障统计和材料退化的机械系统可靠性评估

Reliability assessment of mechanical system based on fault statistics and material degradation

目前,机械系统可靠性试验的评估模型主要是基于已触发故障的数据特点,而对于具有高可靠性且在试验中没有出现故障的子系统的情况,仅仅依据故障数据样本来评估可靠性则可能偏离实际值较大。针对此问题,选取定时截尾的可靠性试验,将故障统计和材料退化相结合,采用极大似然估计法和蠕变失效时间模型,分别对可靠性试验中发生故障的子系统和零故障的子系统进行寿命估计,综合估算出系统的平均寿命。最后,通过案例分析,验证了该方法的有效性和合理性。

At present, the evaluation model of reliability test of mechanical system is mainly estab-lished based on the characteristics of the triggered faults. However, for the subsystems with high reli-ability and no faults in tests, the reliability assessment only on the basis of fault samples may lead to a larger deviation from the actual value. Aimed at this problem, fault statistics and material degrada-tion are combined for the reliability analysis in a type I censoring reliability test. Maximum likelihood estimate and creep failure time model are respectively applied to assess the lifetime of different subsys-tems with and without fault. The average lifetime of system is estimated comprehensively. Then a case is given to verify the validity and rationality of the method.