结合单元试验数据的指数型串联系统定时截尾试验可靠性评估方法

武器装备可靠性试验会产生单元试验数据和系统试验数据，在定型阶段目前通常的可靠性评估方法只是统计系统试验时间，并不考虑单元试验时间，单元故障数要么直接统计进最后的故障数据中（严苛但不严谨的方法），要么舍弃（浪费信息的方法）。为科学利用单元试验数据，基于指数型串联系统可靠性模型，引入定时截尾试验方案下失效率的近似Fiducial概率密度，将单元可靠性试验产生的故障数和试验时间折合到系统可靠性意义下的等效故障数和试验时间。分析结果表明：利用单元试验数据可补充系统试验数据的不足,减少试验消耗，提高可靠性评估精度;定时截尾和定数截尾二者利用单元试验数据的公式是有差异的，在定时截尾下仍然套用定数截尾的单元数据折合公式是值得商榷的。

Evaluation Method of Exponential Series System Reliability Based on Fixed Time Truncated Test and the Combinationof System and Its Units Test Data

The test data of system and its units are provided through the reliability test of weapon. At the stage of approval test, the common evaluation method is to take the system test time into account but not considering the units test time, and the failure number in units test is either added directly into the total failure number (very severe but unscientific) or discarded (information waste). Based on the reliability model of exponential series system, the failure number and total time of units test are converted into the equivalent failure number and time of system by introducing the approximation formula of fiducial probability density of failure rate under fixed time truncated test scheme. The result indicates that the units test data can be used to supplement the system test data, reduce the cost of test, and improve the evaluation accuracy of reliability. The result also shows that the conversion formula of units data of fixed number truncated test is different from that of fixed time truncated test, and applying mechanically the conversion formula of fixed number truncated test is not worth advocating for the fixed time truncated test.