Abstract: Based on the acceleration equation of three undetermined parameters and the design principle of minimizing the maximum likelihood estimation(MLE) asymptotic variance of characteristic life at normal stress level, an optimization model for twin-stress constant accelerated life test for cylinders is built, which provides that product life obeys two-parameter Weibull distribution. An optimization scheme is designed. Dual-stress accelerated life test is carried out, and two different schemes are selected: conventional scheme and optimized scheme. Acceleration stress spectrum and matrix of experimental conditions are determined on the basis of conventional and optimized schemes; parameter estimation and evaluation under various stress conditions are given. Verification based on test data shows that the scheme shortens test period distinctively and reduces test cost without affecting statistical precision.

Key words: Acceleration life test, Cylinder, Optimum design, Twin-stress