Abstract

Kirk and Fred discuss the world of reliability predictions and the issue of predictions when many, if not most of the causes of unreliability, are surprises.

Key Points

Join Kirk and Fred as they discuss use of good design rules and building in some margins of safety, but yet when the systems fail it’s usually a surprise.
Topics include:

• It’s hard to know what safety factor, or strength margin, is really needed due to future variations in manufacturing and assembly. It is very difficult to know what the variations will be with only a hand-full of early prototypes as samples.
• There are many “design for” or what is known as DFx, , where the good design rules for environment, manufacturing and reliability, among other rules. These rules are necessary to make reliability designs.
• Boeing has had its share of many significant failures, as has happened in the Boeing  Max 8 MCAS, and the recent door plug failure on the MAX 9. Assembly or manufacturing errors may have been the cause of these failures.
• Do all you can during the design stage using CAD and multi-physics simulators to verify based on ideal components. Those software tools are getting much more capable. And then when you have actual physical hardware to test, use stress to find weaknesses that were not anticipated.

Enjoy an episode of Speaking of Reliability. Where you can join friends as they discuss reliability topics. Join us as we discuss topics ranging from design for reliability techniques to field data analysis approaches.

SOR 938 Predicting the UnknownsKirk Gray

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Show Notes

You can now purchase the most recent recording of Kirk Gray’s Hobbs Engineering 8 (two 4 hour sessions) hour Webinar “Rapid and Robust Reliability Development 2022 HALT & HASS Methodologies Online Seminar” from this link.

Please click on this link to access a relatively new analysis of traditional reliability prediction methods article from the US ARMY and CALCE titled  “Reliability Prediction – Continued Reliance on a Misleading Approach”

For more information on the newest discovery testing methodology here is a link to the book “Next Generation HALT and HASS: Robust design of Electronics and Systems” written by Kirk Gray and John Paschkewitz.