Nonparametric model for step-stress accelerated life testing

A nonparametric model of the interval estimation is proposed, The estimation is based on results of step-stress accelerated life testing, The approach includes: application of a linear model of damage accumulation, which is proved to be equivalent to the assumptions accepted in numerous papers; estimation of the time transformation function, wing the test results for all the load levels; application of a nonparametric approach for interval estimation of reliability measures, based on the assumption that life-time distribution under the constant load has increasing failure rate. A numerical example uses initial data obtained on the basis of statistical simulation thus verifying the proposed approach.