Abstract: For problems of accelerated life test design under multiple stresses, aiming at constant stresses accelerated life test method, by using uniformly orthogonal test theory, the combined mode of different stresses and testing times are determined. According to the proposed rule of accelerated life test plans optimum design, minimum variance of product’s life estimated value at normal working stresses is taken as design target, test stress levels of each accelerated factor and distribution proportion of test samples are adopted as design variables, the optimum design mathematic model of accelerated life test plan under multiple stresses is built by using maximum likelihood estimation theory. The result about the optimum design of accelerated life test plan under multiple stresses of electrical connectors shows that the optimized test plan can raise estima-tion precision of test data, reduce test times, also cut down the numbers of test samples and shorten the test time under the same degree of confidence.

Key words: Accelerated life test, Multiple stresses, Optimum design