关键词: 两部件并联系统, 故障相关性, 拟定期更换策略, 动态计划

Abstract: To research the coexist of type Ⅰ and Ⅱ failure interaction and the influence of random variation on system reliability and maintain cost in maintain plan,the reliability model of system and a quasi-periodic dynamic Preventive Replacement (PR) policy were established aiming at the two-unit parallel system with type Ⅰ and Ⅱ failure interaction.In the model,the hazard rate of unit B was increased by a failure of unit A as a minor failure with probability p,and the failure of unit B was caused by probability 1-p as a catastrophic failure.A failure of unit A was caused by the failure of B as a catastrophic failure with probability θ2.An unplanned replacement was performed when the system failed,and a preventive replacement was executed stochastically in an implemented period with a given length.A certification for the existence and uniqueness of the optimal implemented period was given,which could minimize the long run cost rate,and a condition that a running period was greater than an implemented period was presented.Numerical results showed that failure dependence parameters and the length of the implemented period should be decreased as soon as possible to meet the practical requirements,which could increase mean operating time and decrease long running cost rate.

Key words: two-unit parallel system, failure interaction, quasi-periodic replacement policy, dynamic plan