Optimum design of a degradation test under model mis-specification of Inverse Gaussian and Wiener degradation processes

Abstract

In this era of high reliability in order to enhance product competitiveness manufacturers must have a good understanding of the reliability information of their products There are many ways to collect reliability information If there is a quality characteristic related to the life of the product and it will gradually decline with time then you can collect its degradation data from the experiment to estimate the life-related information of the product This is called degradation experiment Therefore it has become an important issue for manufacturers to construct a degradation model in a degradation experiment and how to improve the efficiency of estimating product’s MTTF(mean-time-to-failure) under limited resources The degradation models Wiener degradation process or gamma degradation process are mostly used to describe the degradation path in the literature In recent years inverse Gaussian process has also been used to construct the degradation model Therefore this paper focuses on the model mis-specification between inverse Gaussian degradation process and Wiener degradation process We investigate the impact on the accuracy and the precision of the product's MTTF and the pth percentile of the lifetime distribution of the product Furthermore we show how to conduct a degradation experiment through experimental design to make the precision of the estimation can be optimal under the model mis-specification Based on Tsai et al (2011) this study discusses the effect of model mis-specification and further explores how experimental design can minimize this impact The result of this study is that the accuracy of the estimation of the model mis-specification cannot be controlled by experimental design but an algorithm can be designed to conduct a degradation experiment to optimize the precision and carry out the optimal test plan Therefore this study reveals the optimal design of degradation experiment for the precision of the estimation of the product’s MTTF and the precision of the estimation of the pth percentile of the lifetime distribution under the limited resources The results show that the algorithm can effectively improve the precision By sensitivity analysis there are some costs that will have some impact on optimal test plan Key words: inverse Gaussian process Wiener process model mis-specification the design of a degradation experiments

Date of Award	2020
Original language	English
Supervisor	Cheng-Hung Hu (Supervisor)