Reliability Demonstration for Long-Life Products Based on Hardened Testing Method and Gamma Process

Reliability demonstration testing is widely applied to the industry for the verification of products' certain reliability requirement. However, for long-life and high-reliability products, the sample size and testing time are both unacceptable. To shorten the testing time, the performance degradation data are used to predict whether one sample will fail by the end of the testing. To decrease the sample size or further shorten the testing time, the hardened testing method is considered. Thus, this paper proposes a hardened reliability demonstration testing method with the accelerated degradation model to demonstrate the structural reliability at a high confidence level. First, an accelerated gamma degradation model for the considered problem is formulated. Then, the transformation method of the reliability indexes under different stress levels is proposed. Finally, we develop the optimal testing plan to obtain the stress level, sample size, and average testing time by minimizing the total testing cost, and give the testing termination rules for one sample. A numerical example is given to demonstrate the availability of the proposed method on shortening the testing time and reducing the sample size.