ABSTRACT

Testing for systems or components with a long expected lifetime, under normal operating conditions, needs a longer time period, which is very costly and impractical. In such situations, accelerated life testing methods are used that lead to failure or degradation of systems or components in a shorter time period. Accelerated life tests, introduced by Chernoff (1962) and Bessler, Chernoff and Marshall (1962), are used during Design and Development, Design Verification and Process Validation stages of a product life cycle. Designing of optimal test plans is a critical step for assuring that accelerated life tests help in prediction of the product reliability accurately, quickly, and economically. Many products have more than one cause of failure referred to as a failure mode or failure mechanism. This situation gives rise to competing risks analysis. For such an analysis, each complete observation must be composed of failure time and corresponding cause of failure. The causes of failure can be independent or depend upon each other. This chapter highlights work done in the literature on the design of accelerated life tests with competing failure modes.