极小子样加速寿命试验设计和可靠性分析方法

METHOD FOR ACCELERATED LIFE TEST DESIGN AND RELIABILITY ANALYSIS WITH VERY SMALL SAMPLE

根据寿命破坏率和剩余强度破坏率相等的原理,建立加速应力水平与正常应力水平下寿命分布之间的关系式,提出一种极小子样加速寿命试验设计和可靠性分析方法。该方法能够在极小子样的情况下,根据可靠性要求确定加速应力水平和试验截止时间,并通过加速寿命试验对正常应力水平下的产品可靠性进行验证;也可以根据高应力水平下的加速寿命试验数据,对正常应力水平下产品的寿命和可靠性进行评估。详细讨论定时无失效试验、定时截尾试验和定数截尾试验三种常用加速寿命试验的设计方法,并针对工程上常用的Weibull分布和正态分布分别推导出加速寿命试验设计、可靠性评估和寿命预测公式。与传统的加速寿命试验分析方法相比,所提出的方法更加适用于极小子样的情况,尤其是整机和部件的加速寿命试验。

Based on the principle of failure probability equality between life and residual strength, the life distribution relationship between accelerated stress and normal stress was established. Accordingly, a method for accelerated life test design and reliability analysis with very small sample had been proposed. The method could determine the accelerated stress level and censored time for the accelerated test, according to the given reliability index. Also, verification and assessment of life and reliability under normal stress level could be done by accelerated life test. Meanwhile, design methods for the fixed time truncated zero-failure test, the type- I censoring life test and the type-II censoring life test had been discussed in detail. Considering Weibull distribution and Normal distribution, the two most widely used distributions in engineering, the formulae for accelerated life test design, reliability assessment and life prediction had been derived. To compare with the traditional accelerated life test method, the proposed method is more suitable for the test with very small sample, especially for the accelerated life test of whole structure and component.