Accelerated test with unknown acceleration model

This paper discuss accelerated life testing (ALT) methods for life time distribution of highly reliable components. To define the reliability of components at a nominal stress level (s/sub 0/) when no acceleration model is known, a sample population often must be tested until many failures occur leading to extensive test time. In order to reduce the required time to obtain these failures, we suggest exposing the sample to a higher stress level (s/sub 1/) in the beginning of the test. Then, the surviving specimens are subjected to a second step at the nominal stress level (s/sub 0/). For a Weibull lifetime distribution model with unknown parameters, it has been shown that this step-stress test can lead to a great reduction in test time with the same accuracy for the estimation of parameters. This accuracy is compared to those obtained with existing methods of accelerated test processing.