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: Brett Roundy
Date posted: Thu Jul 1 13:19:50 US/Eastern 2004
Subject: Failure Modes/Mechanisms in FMD-97
Why does the FMD-97 contain both Failure Modes and Failure Mechanisms?
I am performing a FMECA for a customer using Relex 7.7 and the built-in FMD-97 to define the Failure Modes and I noticed that it includes both Modes (such as short, open, etc.) and Mechanisms (electrical overstress, lead damage, etc.).
Aren't Mechanisms usually addressed once the Modes have been sorted by criticality?
Reply Posted by: bwd
Date Posted: Wed Jul 14 14:34:31 US/Eastern 2004
The FMD-97 book incorporated all the information on failure modes and mechanisms available and time was not spent on sorting the causes and modes. We left that work to the engineer. This handbook and others are being up-dated and combined for release in the near future. I will ask the preparing engineer that a differentiation be applied as you are correct that the modes are used in the evaluation of the probability of occurrence and mechanisms may be used for criticality analysis.