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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: Zhili Kuang (kzlkp@163.net )
Organization:CEPREI
Date posted: Fri Oct 25 1:13:29 US/Eastern 2002
Subject: High Reliability
Message:
Hello! For high reliability equipment, who can offer the information (paper, book, reference etc.) about the HALT & HASS theory and practice, and the evaluation method of accelerated life testing (ALT) about assemble & equipment. Thanks.


Reply:

Subject: HALT/HASS Testing
Reply Posted by: BWD (bdudley@alionscience.com )
Organization: RAC
Date Posted: Wed Oct 30 14:39:05 US/Eastern 2002
Message:
The term HALT was coined by Gregg K. Hobbs and is a development test concept. The testing is typically used to identify design or component weaknesses and manufacturing process problems by increasing the stress until failure occurs. The results of the stress testing are used to increase the margin of strength of the design rather than to predict quantitative life or reliability of the product. Correlation of this type of test data to actual use is very difficult, as some of the failures modes exposed may not occur in the normal operating or non-operating envelope. Accelerated tests that allow one to extrapolate test data usually conform to one of the fixed standards such as constant temperature tests, reparative mechanical fatigue tests, high voltage tests, humidity tests or a combination test. All of these tests are performed within the maximum limits, so the failure modes should be representative of the normal envelop. Additional information on accelerated testing can be seen on the RAC home page which calls out data sheets for the START (selected topics in assurance related technologies) reports. Other information includes Wayne Nelson's book "Accelerated Testing " and C.M. Harris's book "Shock and Vibration".


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