Search Results

The basic idea of accelerated life testing (ALT) is to expose test units of a product to harsher-than-normal operating conditions to expedite failures so that the failure time distribution of the product and the associated life-stress relationship can be determined in a short time period. However, ALT often consumes significant amounts of energy. To avoid waste of energy in a wide spectrum of product development processes, we explore a new experimental design methodology that improves the reliability estimation precision of an ALT experiment while minimizing the total energy consumption of the experiment. The resulting optimally designed ALT experiment depends not only on the reliability of the product to be tested but also on the characteristics of the test equipment and the capability of its controller. A numerical example is provided to demonstrate the use of the methodology in practice.

Accelerated life testing (ALT) is widely used to determine the failure time distribution of a product and the associated life-stress relationship in order to predict the product's reliability under normal operating conditions. Many types of stress loadings such as constant-stress, step-stress and cyclic-stress can be utilized when conducting ALT. Extensive research has been conducted on the analysis of ALT data obtained under a specified stress loading. However, the equivalency of ALT experiments involving different stress loadings has not been investigated. In this paper, a definition is provided for the equivalency of various ALT plans involving different stress loadings. Based on this definition, general equivalent ALT plans and some special types of equivalent ALT plans are explored. For demonstration, a constant-stress ALT and a ramp-stress ALT for miniature lamps are presented and their equivalency is investigated.