Novel concepts for reliability technology

Ryu, Dongsu; Chang, Seog-Weon

doi:10.1016/j.microrel.2004.10.010

Cited by 40 publications

(12 citation statements)

References 9 publications

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“…The ALT was designed to assure a B 1 of 10 years life with about a 60 percent level of confidence if no unit fails during 40,000 cycles. 2) For the ALT experiments, a simplified vapor compression refrigeration cycle was fabricated. It consisted of an evaporator, compressor, condenser, and capillary tube.…”

Section: Methodsmentioning

confidence: 99%

“…2) The procedures for the compressor reliability design can be summarized as (1)load analysis of the refrigeration cycle; (2) fabrication of ALT equipment; and (3) performance of several ALT tests to predict reliability. For the loads of the compressor, it is important to use a parameter design, the traditional thermodynamic cycle model, [3][4][5] 2 nd refrigerant properties at each state.…”

Section: Introductionmentioning

confidence: 99%

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Improving the Reliability of a Reciprocating Compressor for Applications in a Refrigerator

Woo¹,

Chu²,

Ahn³

2007

Korean. J. Mater. Res.

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To enhance the reliability of a newly designed reciprocating compressor applied in a domestic compressor, accelerated life tests were developed using new definitions of the sample size and the B 1 life index. In 1 st accelerated life testing, the compressor was locked due to the fracture of the suction reed valve. The failure modes and mechanisms of the suction reed valve in the accelerated tests were found to be similar to that of the failed product in the field. The root cause of the failure was the overlap between the suction reed valve and the valve plate in the suction port. The missing parameters in the design phase were modified by expanding the trespan size, introducing tumbling process, changing the material and thickness for the valve, introducing a ball peening and brushing process for the valve plate. In 2 nd accelerated life testing, the compressor was locked due to the interference between the crank shaft and thrust washer. The corrective plan was to heat treat the crank shaft. The B 1 life of the compressor improved from 1.5 to 12.9 years.

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Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Improving the Reliability of a Reciprocating Compressor for Applications in a Refrigerator

Woo¹,

Chu²,

Ahn³

2007

Korean. J. Mater. Res.

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“…For a 60% confidence level, the first term in eqn (14) can be approximated to (r + 1) [10]. By Taylor expansion, if the cumulative failure rate, x, is below 20 percent, the second term ln approaches to x., it can be represented as: …”

Section: Load Analysismentioning

confidence: 99%

Improving Reliability of Product Subjected to Random Vibration During Transportation

Woo¹

2017

WIT Transactions on the Built Environment

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To enhance the reliability of newly designed product like refrigerator subjected to random vibrations in transportation, new reliability methodology, including load analysis and parametric Accelerated Life Testing (ALT), was presented. As a case study, refrigerator subjected to random vibration during transportation is studied to improve reliability. In first parametric ALT, the reliability of refrigerators was targeted to have B1 life in transportation. We found to be the damage of the compressor rubber mounts and the fractured connecting tubes between the compressor and condenser. The shape of failures in 1 st ALT and the failed samples in field are the same. The failures of connecting tube were caused by the design flaws of the compressor rubber mount. To correct these problems, the rubber mounts and the connecting tube were reshaped to protect the refrigerator from random vibration. Because there were no problems in 2 nd ALT, we knew that parametric ALTs were effective and the refrigerator was guaranteed to have B1 life in transportation.

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“…Thus, it becomes more difficult to evaluate the characteristic life using Equation (4). The distribution of failed samples should follow the Poisson distribution for small samples [18]. For a 60% confidence level, the characteristic life can be redefined as…”

Section: Parametric Alt With Bx Life and Sample Sizementioning

confidence: 99%