Qishan Li and Dimitri B. Kececioglu
To design an optimal accelerated degradation test (ADT) plan for light emitting diodes (LEDs).
Abstract
Purpose
To design an optimal accelerated degradation test (ADT) plan for light emitting diodes (LEDs).
Design/methodology/approach
This paper presents a method for the optimum planning of ADTs. The method is applied to the design of an optimal plan for LEDs. An analytical method is developed for obtaining the optimal allocations of test units to minimize the variance of the transformed life estimation at the use stress level; a simulation method is used to help select the optimal test plan and evaluate the test plans' properties. Optimal stress levels, and optimal allocations of test units to the stress levels are determined to minimize the mean squared error (MSE) of the estimated mean life of LEDs at the use stress level.
Findings
Different test plans result in different accuracy. The optimal test plan provides the most efficient use of test resources.
Research limitations/implications
This paper focuses on designing an optimal plan using two test stress levels. Future research may extend to multiple stress levels.
Practical implications
With increasing emphasis on reliability in industry, products are made more robust, and few failures are observed in a reasonable test period. Therefore, assessing product reliability using ADTs becomes very useful. This paper fulfills the need to scientifically design plans for these tests to provide more accurate estimates of the designed‐in and manufactured reliability for the same amount of test resources.
Originality/value
The methodologies developed in this paper can be used for other ADTs. This enables reliability and test engineers to get the most efficient use of their test resources.
Details
Keywords
THE full programme is now available for the International Congress on Metals Engineering to be held 14–18 September 1981 at The University of Aston in Birmingham. The event is…
Abstract
THE full programme is now available for the International Congress on Metals Engineering to be held 14–18 September 1981 at The University of Aston in Birmingham. The event is sponsored by The University in association with The Birmingham Metallurgical Association, The Institute of British Foundrymen, The Institute of Metal Finishing, The Institute of Sheet Metal Engineering, The Institution of Metallurgists and the Metal Society.