基于Weibull分布的恒加载试验置信样本量的可靠性优化设计

为实现长寿命、高可靠度产品在正常应力水平时可靠性地快速评估,建立Arrhenius—Weibull可靠性统计模型,假定试验各应力水平下Weibull分布型产品的失效机理保持一致,且特征寿命与试验应力水平间满足对数线性加速寿命试验模型。以产品在正常试验应力水平下中位寿命估计值的方差最小为优化目标,以试验应力水平数和大小,试样分配比例以及试验各应力水平下的截尾时间为设计变量,提出了Weibull分布定时截尾恒加载试验可靠性优化方案。获得了用于构造模型参数渐进置信区间的Fisher信息矩阵。算例分析表明:恒加载试验可靠性优化方案具有可行性。

RELIABILITY OPTIMUM DESIGN OF CONFIDENCE SAMPLES FOR CONSTANT-STRESS ACCELERATED LIFE TEST BASED ON WEIBULL DISTRIBUTION

In order to realize the rapid reliability evaluation of long-life and high reliability products at a normal stress level,the reliability statistical model of Arrhenius-Weibull was established,by using the Weibull distributions products with the consistent failure mechanism and a log-linear acceleration life test model between characteristic life and stress level.The minimum variance of the product median lifetime estimate at normal stress level as optimum object was considered,the number and quantity of test stress level,samples allocation proporation and censoring time at each stress level are determined as design variables,put forward a reliability optimum scheme of time-censoring constant-stress ALT(CSALT) for weibull distributions.The Fisher Information Matrix is obtained for constructing asymptotic confidence intervals for the model parameters.As the example analysis shows that the reliability optimum scheme of CSALT is effective.