This chapter introduces parametric accelerated life testing (ALT) as a systematic reliability method for producing reliability quantitative (RQ) specifications—mission cycle—for identifying missing design defects in mechanical products such as a commercial refrigerator’s hinge kit system (HKS). It consists of the following elements: (1) a parametric ALT plan based on the system BX lifetime, (2) a fatigue failure and design, (3) customized ALTs with design alternatives, and (4) an assessment of whether the system’s most recent design(s) meet the objective BX lifetime. We propose a BX life concept, a generalized life-stress model, and a sample size equation. Return analysis was used to identify failure sites in the HKS. products obtained from the field The first ALT confirmed a failure that occurred at the HKS housing after the new HKS’s lifetime was targeted to be B1 10 years. The lack of support ribs in the original design of the HKS housing for the refrigerator was one of the missing design parameters. Based on the action plan, the supporting structure of HKS in the refrigerator was modified. Cracks were discovered in a second ALT generated in the torsional shaft. The HKS torsional shaft lacked the strength to withstand repetitive stresses due to its squared off corners. As a result of the ALTs, the shaft was modified. The redesigned HKS now has a guaranteed lifetime of B1 10 years. During the design phase, the design methods – load analysis and three ALTs – were very effective in identifying the missing design parameters. The robust design method described in this paper could be applied to other mechanical systems.
Author (s) Details
Dr. Seongwoo Woo
Addis Ababa Science and Technology University, Ethiopia.
Dr. Dennis L. O’Neal
School of Engineering and Computer Science, Baylor University, Waco, TX 76798-7356, USA.
Demise Molawork
Addis Ababa Science and Technology University, Ethiopia.
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