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Reliability design of mechanical systems such as compressor subject to repetitive stresses


MOJ Civil Engineering
Seongwoo Woo, Wassie Molla

Abstract

Parametric accelerated life testing (ALT) is developed as a reliability methodology to correct the designs of a mechanical system subjected to repetitive pressure loading. An accelerated load was applied to selected samples to uncover the design parameters affecting reliability during the design process of a compressor. The developed method consisted of a parametric ALT plan, load analysis, a tailored series of parametric ALTs with action plans, and evaluation of the final compressor design to ensure the reliability criteria were satisfied. As a test case, reciprocating compressors from French-door refrigerators returned from the field were studied. Disassembling the failed compressors revealed that the suction reed valve had fractured. In the first ALT, the failed samples from the field were reproduced. The root cause of the failure came from the sharp edges of the valve plate and an overlap between the suction reed valve and the valve plate. As corrective actions, the valve plate in the compressor system was modified to increase the trepan size and a ball pinning process was added. There were no problems during the second ALT. After these parametric ALTs with corrective action plans were conducted, the modified compressor was expected to achieve the reliability of a 10years life with an accumulated failure rate of 1%.

Keywords

reliability design, suction reed valve, fracture, parametric accelerated life testing, faulty designs

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