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Forum: Reliability & Maintainability Questions and Answers

Topic: Reliability & Maintainability Questions and Answers

Topic Posted by: Reliability & Maintainability Forum (src_forum@alionscience.com )
Organization: System Reliability Center
Date Posted: Mon Aug 31 12:47:36 US/Eastern 1998

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Original Message:

Posted by: cadoret katell (katell.cadoret@trixell-thalesgroup.com )
Organization:Trixell - THALES
Date posted: Thu Aug 30 7:51:22 US/Eastern 2001
Subject: Overstress Testings as MEOST
Message:
We need some good informations about overstess testings methods as for exemple MEOST (Multiple Environment Over Stress Tests - Reference in "World Class Quality" of Keki and Adi BHOTE). In particular, we want to know how such a method can be applied in practise and if some website exists about it ? who has developped this method (Shainin ??) ? Are there some laboratories (in USA or in Europe) which are specialists of MEOST ? Thank you for your answer . Katell CADORET (katell.cadoret@trixell-thalesgroup.com)


Reply:

Subject: MEOST Multi Env.Overstress Test
Reply Posted by: B.W. Dudley (bdudley@alionscience.com )
Organization: Reliability Analysis Center
Date Posted: Wed Sep 5 15:28:39 US/Eastern 2001
Message:
Multi-level accelerated life tests (ALTs) MEOST (multiple extreme overstress testing) and traditional step-stress approaches have a number of worth while applications for the analysis of the projected reliability of components and systems. These test methods are considered for many common situations of accelerated life testing (ALT). Some of the main purposes of ALT are to measure projected system life and to identify product weakness in order to improve reliability. These methods may apply well when only a small number of systems are available, when extremely long test time is needed, specialized test equipment is required, when limited environmental chamber capability and/or test fixtures are involved and lastly, when very expensive support equipment represents a serious test limit. Previous accelerated testing methods have had some limited applications in the past. The limits have been sometimes due to poorly described degradation or accumulative fatigue & the subsequent difficulty with the analysis of the failure data themselves. A tight series of ground rule methods to improve the analysis of these multi-level stress tests is necessary. Methods for calculating test parameters are discussed in a paper by James A. Mclinn called Ways to Improve the Analysis of Multi-Level Accelerated Testing. This paper is published in the Quality and Reliability Engineering International, Novemmber/December 1998, volume 14 number 6. As for test laboratories, I suggest that you procure the 2001 ASTM International Directory of testing laboratories. Their telephone number is 610-832-9555. Dorian and Peter Shainin have written papers on Analysis of Experiments and Orthogonal Tables which do analyze multiple stress tests, but I don't know if they are the original developers of this technique.


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