Abstract
Accelerated degradation test (ADT) is widely used to assess the lifetime information (e.g.,p-thquantileor mean-time-to-failure (MTTF))of highly reliable products. Hence,it is a challenging issue for reliabilityengineer to plan an efficientADT test. Recently, Lee (2011) proposedan exponential-dispersion accelerated degradation (EDAD) model and derived the analyticalsolution of optimal sample-size allocation. The advantage of this resultis that EDAD model covers well-knownmodels such as Wiener, Gamma and Inverse Gaussian accelerated degradation model. However, the results are very restricted to the case of the number of the stress levels equal to two. To overcome this difficulty, we will address the problem for the number of the stress levels greater than three. In this thesis, we first demonstrate that anecessary conditionof the sample-size allocationfor 3-stress based on EDAD model is that we only need to assign testing units into two stresses level. Furthermore, we also obtained the optimal sample-sizeallocation formulafor thementioned-above accelerated degradation models. More specifically,under Gamma accelerated degradation model, we must assign testing units at stressesS1 and S3; for Wiener or Inverse Gaussian accelerated degradation model,we may arrange either the stress level in, or depending on different conditions.