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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: Clay Davis
Date posted: Fri Mar 19 18:31:09 US/Eastern 1999
Subject: MTBF Demonstration
Message:
What are some alternate ways to demonstrate MTBF on computer boards and systems? The traditional method is to run the boards/systems for a certain amount of hours and divide by the failures. I am looking at different methods (say ESS / HALT) that could you extrapolate MTBF from.


Reply:

Subject: Alternate Testing Methods
Reply Posted by: Bruce Dudley (bdudley@alionscience.com )
Organization: Reliability Analysis Center
Date Posted: Mon Apr 5 10:56:22 US/Eastern 1999
Message:
Testing computer boards in an accelerated process is very difficult to control. The number of failure mechanisms on one board could be in the hundreds, when individual part and materials are evaluated. For example, a mirocircuit could have: electro-migration, surface oxide, charge loss, dielectric breakdown, metal corrosion and other mechanisms all working at the same time. Determining the most significant mechanism and the activation energy can be a difficult process. Suggest that you read Wayne Nelson's book on accelerated testing before starting a testing program. Extrapolating from ESS or Halt test data to life expectation is very difficult as the acceleration rate is probably impossible to calculate from these test concepts as they are uncontrolled from an accelertion point of view.


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