加速度计贮存寿命与可靠性的步进应力加速退化试验评估方法

针对加速度计长期贮存环境下贮存可靠性无法准确快速评估的难题,应用步进应力加速退化试验方法快速评估某加速度计的贮存可靠性。首先对加速度计实施故障模式影响及危害性分析和故障树分析,确定敏感应力为温度应力,加速模型为阿伦尼斯模型。其次,对其实施步进应力加速退化试验,并建立数学模型拟合其在各温度应力下性能退化曲线,结合失效阀值求解各样本的伪寿命。通过对各应力水平下样本的伪寿命进行分布假设检验,确定其贮存寿命服从威布尔分布,最终利用加速模型外推正常温度下的寿命分布参数,进行正常温度下贮存期寿命和可靠性指标的评估,得到加速度计在贮存140 160 h(16 a)时的可靠度为0.988。

Storage life and reliability evaluation of accelerometer by step stress accelerated degradation testing

The method of step-stress accelerated degradation testing(SSADT) is utilized to evaluate the storage reliability and life of accelerometer.First,based on failure mode effect and criticality analysis(FMECA) as well as fault tree analysis(FTA),it is determined that temperature stress is its sensitive stress,and Arrhenius model is taken as its accelerated model.Then,an appropriate liner model was built with the test data.Combined with the threshold of failure,the storage life of each sample can be calculated.The hypothesis test show that the storage life complies with Weibull distribution pattern.The distribution parameters of the accelerometer under normal temperature are obtained with the accelerated model.The reliability of the accelerometer is 0.988 when it has stored for 140 160 h(16 a).