基于D优化的多应力加速退化试验设计

针对多数产品受到多种应力影响的情况，研究恒定应力和步进应力两种施加方式下多应力加速退化试验优化设计方法。以随机过程对产品性能退化建模，分析试验剖面，对恒定应力加速退化试验，采用均匀设计和均匀正交设计理论确定应力的组合方式；对步进应力加速退化试验，各应力均采用步进方式。基于D优化方法，以模型参数估计方差最小为目标，以试验费用为约束，建立优化模型，给出最优的各应力水平，各应力水平下的样本分配、试验时间分配和监测间隔。最后给出应用该方法的仿真算例。

Design of accelerated degradation testing with multiple stresses based on D optimality

Most products are affected by multiple stresses simultaneously,so it is necessary to study the optimal method for the accelerated degradation testing(ADT) with multiple stresses.This method is proposed for constant stress loading and step stress loading,respectively.Stochastic process is used to model the perfor-mance degradation of products.For the constant stress ADT(CSADT),uniform design and uniformly orthogonal design theory are used to determine the combined mode of diffident stresses,and for step stress ADT(SSADT),each stress is arranged in a step way.Under the constraint of the total experimental cost,the optimum problem is established with the objective that minimizing the variance of the estimation of model parameters based on D optimality,and optimal test variables including stress levels,sample size,testing time and the interval of performance inspection at each stress level are given.Finally,simulation examples are presented to illustrate the proposed method.