Improving fatigue of mechanical systems such as freezer drawer subject to repetitive stresses

•Reliability test plans of multi-module product based on its BX life definition.•Acceleration method of mechanical system.•Derivation of sample size equation combined with targeted BX lifetime and accelerated factor.•Accelerated life testing with reproduction of design problems and its action plans.•Evaluation of the final product design to ensure the BX lifetime are satisfied. Parametric accelerated life testing (ALT) as a methodology of reliability tests is suggested as a way to identify and reduce the fatigue failure of mechanical systems. It consists of a parametric accelerated life testing plan, fatigue failure and design, and accelerated testing with action plans to ensure the product achieves its expected lifetime target. A generalized life-stress failure model with an effort concept and sample size equation are derived. As a case study, the reliability of a newly designed freezer drawer is evaluated. In the first accelerated life testing, the handles were fracturing because of a design flaw that appeared during the repetitive openings and closings of the freezer drawer with the food in the drawers. Increasing the total handle width provided an improved design that corrected the failures with the handles. In the second accelerated life testing, the slide rails also fractured because they did not have enough strength to withstand repetitive opening and closing of the drawers with the typical food loads in the drawers. To improve the design of the slide rails, supplementary reinforced ribs, reinforced boss, and an inner chamber were added. After three rounds of parametric accelerated life testing, the modified freezer drawer was expected to achieve the lifetime of B1 life 10 years.