Accelerated reliability demonstration and assurance test design

This paper, shows how the fixed duration and reliability assurance tests, time and cost prohibitive in the past, can be accelerate to achieve two fold advantage: to determine item (product) reliability as it is related to its actual use stresses, and to considerable shorten the test time, to accommodate reasonable cost and tight program schedules. While traditional tests of this type were modeled mathematically to produce the measure of reliability as MTBF with the assumption of all failure rates being constant, there is little or no guidance on what the environmental and operational stresses need to be applied during the test. The accelerated tests described in the paper do not consider mathematics only with the focus was on the accepted risks, the MTBF requirement, confidence in test results, and determination of the appropriate decisions and the required test time. Besides mathematics, the design of the accelerated tests focuses on actual product exposures in their life scenarios, and relationship of life and accelerated stresses for reliability demonstration, produce tests with exact producer's and Consumer's risks, required confidence intervals, and the exact test duration, but with no specifics and a lot less precision in application of stresses expected in their use. Accelerated tests prepared as described in this paper offer twofold advantage: they represent reliability of a product as it is actually used, and the duration of tests is time and cost effective. Also, with this type of test design, all of the tested items are given the lifetime stress exposure.