PSI - Issue 46

Seong-woo Woo et al. / Procedia Structural Integrity 46 (2023) 169–174 Seong-woo Woo et al. / Structural Integrity Procedia 00 (2021) 000–000

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Table 1. Consequences of ALTs

4. Conclusions To upgrade the lifetime of the cooling enclosure in a refrigerator, we proposed the following systematic reliability procedure: (1) place the whole parametric ALT scheme, (2) perform the parametric ALT with corrective action plans, and (3) check if the last design of the product fulfils the lifetime target. As a test occasion, we investigated the lifetime design of a cooling enclosure returned from the market. In the market and the first ALT, the cooling enclosure in a refrigerator was pitted because of the cotton adhesive tape with high concentrated chloride. As corrective actions, the cooling enclosure was modified as follows: (1) enlarging the distance of the contraction tube, C1, from 50.0 mm to 200.0 mm; (2) exchanging the cotton adhesive tape, C2, to the generic transparent tape. As a result, there were no issues during the second ALT. The cooling enclosure in a refrigerator was reassured to attain the lifetime target of B1 life 10 years. By scrutinizing products returned from the field and conducting parametric ALT with design alternations, the developed systematic reliability procedure manifests to be successful in upgrading the designs of cooling enclosure in a refrigerator. This systematic reliability procedure can be employed to other mechanical products such as air-plane, automobiles, and construction machines. To utilize this systematic method, designers should comprehend why products fail during their lifetime. That is to say, if there are design flaws in the structure which are subjected to repeated loads, the system will fail before its expected lifetime. Engineers would need to identify the load attribute of a mechanical system so that the parametric ALT can be carried out until the desired mission cycles under elevated stress conditions. In the end, engineers can utilize parametric ALT to discover the design issues of a mechanical product and alter them. References

Woo, S., Pecht, M., O’Neal, D., 2020. Reliability design and case study of the domestic compressor subjected to repetitive internal stresses, Reliability Engineering and System Safety. 193. 106604.