非线性步进加速退化数据的可靠性评估方法

针对步进应力加速退化试验(SSADT)场合下的非线性退化数据,考虑个体之间的性能退化差异,提出了基于Wiener过程的退化数据可靠性评估方法。首先,分析了步进应力加速退化试验过程及其性能退化数据模型。然后,运用非线性Wiener过程描述产品的非线性退化过程,采用时间尺度变换模型进行线性变换;将Wiener过程的漂移系数随机化处理,提出考虑了个体差异的非线性退化数据建模;根据所收集的步进应力加速退化数据,采用两步极大似然估计法确定模型中的未知参数。最后,结合某激光器的实例对比分析表明,所建模型的拟合性较好,评估结果真实准确。

Reliability assessment method of nonlinear step-stress accelerated degradation data

Aiming at nonlinear degradation data in the occasion of step-stress accelerated degradation test (SSADT), a reliability assessment method for degradation data based on Wiener process is put forward in consideration of individual performance degradation variation. Firstly, the process and performance degradation data model of SSADT are analyzed. Secondly, the nonlinear Wiener process is used to describe the nonlinear degradation process of products. The time scale model is used to change nonlinear data into linear data, and the drift coefficient of Wiener process is regarded as a random variable. A lifetime model of nonlinear degradation data is built in consideration of individual variation. According to the collected SSADT data, the two-step maximum likelihood estimation method is used to determine the unknown parameters in the lifetime model. Finally, an example of laser degradation data is analyzed to show that the presented model is matching well and the assessment result is more accurate.