基于比例危险-比例优势模型的加速寿命试验设计

将基于信息的优化方法引入基于非参数模型的加速寿命试验优化设计中,针对恒定应力和步进应力两种应力加载方式,分别给出了基于比例危险-比例优势模型的试验优化设计方法.通过对数似然函数建立Fisher信息矩阵和方差-协方差矩阵,并采用基于信息的优化方法建立最优化问题.这种试验优化设计方法可以有效地提高模型参数评估精度,并且避免了传统的优化方法(即将一个与可靠性相关的函数的渐进方差在一个给定区间内的积分值作为优化目标)当目标函数中给定的积分区间变化时将得到不同优化结果的局限.最后给出了应用该方法进行加速寿命试验优化设计的仿真实例.

Optimum design of accelerated life testing based on proportional hazards-proportional odds model

nformation based optimality criteria were adopted in the optimum design of accelerated life testing (ALT) based on non-parametric model. The optimum design of accelerated life testing based on proportional hazards-proportional odds model was processed for constant stress loading and step stress loading respectively. The optimum problem was established by defining Fisher information matrix and variance-covariance matrix based on log-likelihood function. These optimality criteria could improve the accuracy of model parameter estimates effectively and they avoided the drawbacks of the traditional optimality criteria which minimized the integral of asymptotic variance of a reliability-related function over a specified time period under normal operating condition that might result in different optimum solutions with the varying of the length of the time period. Numerical examples were given to demonstrate these methods.