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: Bhanuprakash
Date posted: Sat Aug 23 7:49:54 US/Eastern 2003
I am working for a tractor industry. I would like to know as to what type of distribution field failure data of mechanical components follows. Is it correct to assume exponential distribution for mechanical failure components.
Subject: Distribution for Mechanical components
Reply Posted by: Nihar
Date Posted: Mon Aug 25 19:52:36 US/Eastern 2003
Traditionally, the failure distribution of mechanical components follow lognormal distribution.
Subject: Tractor reliability
Reply Posted by: Larry George
Organization: Problem Solving Tools
Date Posted: Tue Sep 2 12:52:09 US/Eastern 2003
Sorry. Field reliability doesn't fit mathematically convenient distributions. Use nonparametric statistics to preserve the information in your data and avoid unwarranted assumptions. Then you'll be able to see problems you might not have noticed, evaluate whether to do anything about them, and provide just cause for doing something, if appropriate.
See http://www.fieldreliability.com/FireWayn.htm for one example.
Send your field data, and I will send back nonparametric estimates of field reliability and failure rate functions with diagnostics, free of charge.