SRC Forum - Message Replies
Forum: Reliability & Maintainability Questions and Answers
Topic: Reliability & Maintainability Questions and Answers
Topic Posted by: Reliability & Maintainability Forum
Organization: System Reliability Center
Date Posted: Mon Aug 31 12:47:36 US/Eastern 1998
Posted by: J Homer
Date posted: Wed May 26 5:42:17 US/Eastern 1999
I am currently involved with a program looking at Accelerated Life Testing and Stress Screening techniques, mainly HALT and HASS. What I require is an understanding of these two methods, especially the multi-axis vibration and its effects. Can anyone provide some information on these subjects or places to look.
Subject: Reliability HALT/HASS Testing
Reply Posted by: Bruce Dudley
Organization: Reliability Analysis Center
Date Posted: Mon Jun 7 12:05:18 US/Eastern 1999
The term HALT was coined in 1988 by Gregg K. Hobbs. HALT is a development test, an enhanced form of step stress testing which is usually carried out to failure. This testing is typically used to identify design weaknesses and manufacturing process problems. The results are used to increase the margin of strength of the design rather than to predict quantitative life or reliability of the product.
HASS is a form of accelerated environmental stress screening. It presents the most intense environment of any seen by the product, but it is typically of a very limited duration. HASS is designed to go to "the fundamental limits of the technology". This is defined as the stress level at which a small increase in stress causes a large increase in the number of fall-out failures.
Additional information can be obtained from the RAC home page which has data sheets called START (selected topics in assurance related technologies) of which one is devoted to ACCELERATED TESTING. Other WEB sites that you might query are:
Books that you might look at are:
Publication by Dr. Wayne Nelson, "Accelerated Testing", John Wiley and sons, 1990
Publication by C.M.Harris, "Shock and Vibration Handbook", McGraw Hill, 1961