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: chandu
Date posted: Tue Mar 4 6:33:32 US/Eastern 2003
Subject: PREDICITON OF PARAMETER
I have some laboratory data (accelerated test)for Grade 1 item and Grade 2 item, i have estimated parameters of weibull distribution. For the Grade 1 item i have field data and i have estimated the parameters of weibull distribution.
Here i have a problem in correlating the field data with laboratory data for grade 1 item. How can i correlate this Grade 1 data?
By using this same same logic How can one predict the field data parameters for Grade 2 ?
Please help me in this case....
Subject: Test Extrapolation
Reply Posted by: bwd
Date Posted: Tue Mar 4 16:15:06 US/Eastern 2003
The problem that you try to describe is difficult to understand. It seems that you have performed stress testing and are trying to correlate this with actual operating data. The correlation is showing that the stress data is not in agreement. This indicated to me that you have overstressed the accelerated test parameters resulting in failures that are not observed at normal conditions. Therefore, if grade one and two are similar items similar test conditions will result in overstressing this sample. Since we do not know anything about the grades and items being tested it is impossible to project field parameters based on the failure testing.