Optimal design of step stress accelerated degradation test and reliability assessment for quartz flexible accelerometers

This paper presents a optimal design approach of step stress accelerated degradation test (SSADT) for quartz flexible accelerometers under the assumption that the degradation of each accelerometer follows a Wiener process and the degradation rate at different stress levels satisfies an Arrhenius function. The asymptotic variance of the p^th percentile of lifetime is adopted as optimization objective and its expression formula is provided using the maximum likelihood estimate (MLE) method. The total experimental cost is chosen as a constraint with its expression formula provided. An algorithm is stated to solve the optimal design problem and a Monte Carlo simulation optimization program is developed based on the algorithm. Then, the optimal test plan is obtained after determining the optimization parameters and the SSADT is conducted based on the optimal test plan. At the end of this paper, using SSADT result data, the reliability of quartz flexible accelerometers is assessed by statistical analysis technique of Wiener process and inverse Gaussian distribution (IGD).