Reliability Upsizing: How to adjust for size effect in product life data analysis
In many reliability evaluations, the units placed on life test are reduced-size versions of the actual product. This is often the result of practical limitations such as available test facilities. In the example the authors will consider, electrodes were used in an accelerated test to obtain time-to-failure information on dielectric insulation of generator armature bars that were four times as long as the test electrodes. The term "size" is used in a generic sense. In addition to length, it can, for example, also represent area or volume. In such situations, you must "upsize" the results of the statistical data analysis on the reduced-size test units to the full-size product. This column will cover a simple method to account for the effect of product size on reliability evaluations. These methods can be implemented using popular software packages such as JMP, Minitab and Weibull ++.
This article is published as Doganaksoy, N., Hahn, G.J., and Meeker, W.Q., (2015), Reliability Upsizing: How to adjust for size effect in product life data analysis, Quality Progress, 48, November, 54–57. Posted with permission.