Seong-woo Woo

Design for Reliability of Refrigerator Components Subject to Repetitive Loads in Use

A general method for reliability design of a mechanical system is proposed. A case study is presented for a frozen food drawer and handle system used in a residential refrigerator. The system had been failing when subjected to repetitive loads under normal consumer usage in the field. The mode and mechanism of the failure was fracturing which originated in a design flaw. Data from failed products in the field, accelerated life tests, and corrective action plans were used to identify the key control parameters for the drawer and handle system. The missing or improper design parameter in the original design was the system’s inability to endure the normal repetitive stresses in the field. After a tailored series of accelerated life tests with corrective action plans, the B1 life of the new drawer and handle system is now guaranteed to be over ten years with a yearly failure rate of 0.1 percent.Copyright

Reliability Design and Case Study of a Refrigerator Compressor Subjected to Repetitive Loads

A newly designed crankshaft of a compressor for a side-by-side (SBS) refrigerator was studied. Using mass and energy conservation balances, a variety of compressor loads typically found in a refrigeration cycle were analyzed. The laboratory failure modes and mechanisms were compressor locking and crankshaft wear. These were similar to those of the failed samples in the field. Failure analysis, accelerated life testing (ALT), and corrective actions were used to identify the key reliability parameters. The design parameters of the crankshaft included the hole locations and the groove of the crankshaft used for oil lubrication, crankshaft hardness, and thrust washer interference. Based on the analysis and design changes, the B1 life of the new design is now over ten years with a yearly failure