Methods to determine stress profile in ALT based on theoretical life models

With the recent products being more reliable, engineers cannot obtain enough failure or degradation information through the design period and even the product lifetime, therefore, accelerated life test (ALT) has become the most popular way to quantify the life characteristics of products. Test design is the most essential topic, such as testing duration, stress profile, data inference, etc. In this paper, a method and procedure based on theoretical life models is proposed to determine the accelerated stress profile. Firstly, the method for theoretical life calculation is put forward based on the main failure mechanism analysis and the theoretical life models. Secondly, the method is provided to determine the accelerated stress profile, including the method to determine the accelerated stress types and the stress range on the basis of the main failure mechanism analysis, the method to determine the acceleration factor and the accelerated stress level based on life quantitative calculation models, and the collaborative analysis method of the accelerated test time while taking the multiple failure mechanisms into consideration. Lastly, the actuator is taken as an example to describe the procedure of the method and the engineering applicability and the validity are verified.