PRISM Forum - Message Replies
Topic: PRISM Questions and Answers
Topic Posted by: SRC
Date Posted: Wed Jan 12 8:33:33 US/Eastern 2000
Topic Description: Welcome to the PRISM forum! Please feel free to post your questions and comments about the PRISM assessment software here.
Posted by: Ralph Listl
Date posted: Mon Feb 27 5:36:41 US/Eastern 2006
Subject: Dormant Temperature
One of the environment factors that is used for calculation is the dormant temperature. If this value is changed (leaving all other parameters unchanged)is has influence on the overall reliability. Could you please give a detailed explanation (formula) where the dormant temperature influences the failure rate and how it is used within the model (what conditions/assumptions are used). Currently we are in a project where this temperature is not defined and we need an understanding which value we should choose for our calculation.
Subject: Temperature dependency
Reply Posted by: David Dylis
Organization: System Reliability Center
Date Posted: Tue Mar 6 5:19:00 US/Eastern 2007
As you identified, a component has a certain inherent failure rate that is affected by application and temperature. Processes that are used in the design, development and manufacturing of a system are also affected by temperature. Poor processes will result in more early life failures than good processes. Temperature is one factor that will precipitate these events. When PRISM was developed data was analyzed and the affect of temperature on failure rate was distributed between the component and process grade portions of the model.
If you have additional questions, feel free to contact me.