关键词: 可修系统, 可变样本容量, 指数加权移动平均均值控制图, 预防维修, 联合经济设计, 灵敏度分析

Abstract: For the repairable system of process mean shift which caused by,failure,a joint economic design model for Variable Sampling Size Exponentially Weighted Moving Average (VSS EWMA) mean chart and Planned Maintenance (PM) was developed.In this model,three renewal-scenarios which were in-control alert signal,out-of-control alert signal and no alert signal were considered.The expected probability of Type-Ⅰ error and Type-Ⅱ error of VSS EWMA mean chart was obtained by Markov Process.To avoid computational difficulties and other issues resulting from the average runs length during out-of-control process,each scenario's cycle cost and cycle time were established by the analysis of each sampling interval process,instead of in-control process and out-of-control process in previous models.Furthermore,a mathematical model was given to minimize the expected cost per unit time.A Monte Carlo simulation experiment was conducted as comparison to ensure the analysis of the presented model.The results of a case indicated that the model had a satisfactory application performance and could optimize system's cost.A sensitivity analysis was performed to demonstrate the effects of model parameters.

Key words: repairable system, variable sampling size, exponentially weighted moving average mean chart, planned maintenance, joint economic design, sensitivity analysis