NONPARAMETRIC APPROACH TO RAMP STRESS TESTS UNDER INTERMITTENT INSPECTION

摘要

This paper considers nonparametric estimation of lifetime distribution based on grouped data from ramp stress tests under intermittent inspection in which test items are inspected only at specified points in time. It is assumed that the time transformation function relating stress to lifetime is a version of inverse power law and a certain cumulative exposure model for the effect of changing stress holds. Two nonparametric methods of estimating the lifetime distribution at use condition are proposed. Numerical studies are performed to compare these and maximum likelihood methods and show that the proposed methods are comparable to the maximum likelihood method for small sample size.