Study on Reliability Design of the Hinge Kit System Subjected to Repetitive Loading
0Study on Reliability Design of the Hinge Kit System Subjected to Repetitive Loading in a Commercial Refrigerator
This chapter develops parametric accelerated life testing (ALT) as a systematic reliability method to produce the reliability quantitative (RQ) specifications—mission cycle—for recognizing missing design defects in mechanical products such as hinge kit system (HKS) in a commercial refrigerator. It includes: (1) A parametric ALT plan formed on the system BX lifetime, (2) a fatigue failure and design, (3) customized ALTs with design alternatives, and (4) an assessment of whether the last design(s) of the system fulfills the objective BX lifetime. A BX life concept, a generalized life-stress model, and a sample size equation are suggested. Failure sites in the HKS were identified through returned products from the field. After lifetime of the new HKS was targeted to be B1 10 years, the first ALT confirmed a failure that occurred at the housing of HKS. The missing design parameters of HKS housing for the refrigerator were that it had no support ribs in the original design. The supporting structure of HKS in the refrigerator was modified based on the action plan. Cracks were identified in a second ALT that was generated in the torsional shaft. Due to it having squared off corners, the HKS torsional shaft did not have not enough strength to withstand repetitive stresses. The shaft was modified as a consequence of the ALTs. The lifetime of the redesigned HKS is now guaranteed as B1 10 years. The design methods - load analysis and three ALTs were very effective in identifying the missing design parameters during the design phase. The robust design method presented in this paper might be applicable to the other mechanical systems.
#robustness #parameter #design #load #analysis #life #testing