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

170

2

Nomenclature BX

Time which is a cumulated failure rate of X%: durability index

Concentration of chlorine

Cl

E

Effort

E a

Activation energy, eV Testing cycles (or cycles)

h k n r S T

Boltzmann’s constant, 8.62 × 10 −5 eV/deg

Number of test samples

Pitted numbers of the evaporator tubing in the test

Stress

Temperature, K Time to failure Voltage difference

TF

 V

Subscripts 0

Normal stress conditions Accelerated stress conditions

1

1. Introduction To keep food fresh, refrigerator in most cases utilizes the vapor-compression refrigeration system which experiences the phase changes of the refrigerant. That is, as a customer stores the food in the refrigerator, the refrigerant runs through the evaporator tubing to keep the temperature in a cooling enclosure constant and then conserve the food fresh. A refrigerator is made up of some dissimilar modules – cabinet, doors, internal fixtures (shelves and drawers), sensors and controls, motor or compressor, condenser and evaporator, water supply device, and the other parts (Fig. 1).

Fig. 1. Refrigerator and cost-downed Cooling Enclosure

This investigation is to propose a new systematic reliability method for mechanical product like a cooling enclosure system in a commercially produced refrigerator subjected to repetitive water condensation on the evaporator tubing and its corrosion. It includes: (1) a parametric ALT procedure, (2) a load examination, (3) an adapted parametric ALTs with the design alternations, and (4) evaluating whether the last design(s) of the product attains the lifetime target. As a test occasion, cooling enclose in a refrigerator returned from the market was investigated.