Reliability Analysis of Intermittently Operated Military Equipment

摘要

Intermittently operated military equipment that is mechatronic in nature is usually stored in a de-energized condition between two consecutive operations. Increasingly, storage times are becoming much longer than time spent on missions. During missions, there is no chance for repairs, so any failure-not only a dangerous one-may prevent mission goals from being attained. The probability of failure of such military equipment should be forecast with reasonable accuracy. To this end, we must determine the optimal frequency of diagnostic tests during the storage period. The aim of this article is to adapt the concepts of the IEC 61511, ANSI/ISA-84, and MIL-STD882D standards to the attributes of intermittently operated military equipment. This article points out that in addition to the expensive 2003 redundant hardware architecture, the 1002D hardware architecture is also effective against both safe and dangerous failures. Standards presume a constant failure rate throughout the lifecycle of a piece of equipment. Because of shifts in operating conditions, intermittently operated equipment has a varying failure rate. To calculate the average probability of failure, this article reasons that the jumps in the failure rate can be taken into account with transition matrix conversions, applying the discrete-time Markov model. In the case of intermittently operated military equipment, the circumstances of the diagnostic tests that interrupt the storage are unique. The article proposes the correction of state probabilities for taking into consideration the impact of diagnostic tests, and includes the sequential function chart (SFC) of the recommended calculation methods.