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Forum: Reliability & Maintainability Questions and Answers

Topic: Reliability & Maintainability Questions and Answers

Topic Posted by: Reliability & Maintainability Forum (src_forum@alionscience.com )
Organization: System Reliability Center
Date Posted: Mon Aug 31 12:47:36 US/Eastern 1998

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Original Message:

Posted by: Stev Myers (sdmyers&collins.rockwell.com )
Date posted: Sat Feb 12 22:25:16 US/Eastern 2000
Subject: Failure Rate Conversion
Message:
I have an MTBF figure for an LRU operating in A(IC) Airborne Inhabited Cargo enviroment of 6,000 hrs. I am going to operate it in the G(M) Ground Mobile enviroment. Does anyone know the conversion factor I use to translate A(IC) to G(M)?


Reply:

Subject: Failure Rate Conversion
Reply Posted by: Steve Myers (sdmyers@collins.rockwell.com )
Organization: Rockwell Australia Pty Limited
Date Posted: Sun Feb 13 1:30:30 US/Eastern 2000
Message:
I went to Appendix E of the Reliability Toolkit: Commercial Practices Edition and for "Surface Mount Tech. Circuit Boards" got a conversion of 3.38. i.e. my MTBF in A(IC) was 6000 hrs in G(M) is 20280 hrs. Am I on the right track???


Reply:

Subject: Reliability Conversion Factors
Reply Posted by: Jon K. Ilseng (Jon_K_Ilseng@raytheon.com )
Organization: Raytheon Systems Company
Date Posted: Tue Feb 15 17:55:11 US/Eastern 2000
Message:
Steve, Regarding your question on converting the MTBF for an Airborne Inhabited Cargo environment to a Ground Mobile environment. Page 176 of the Reliability Toolkit: Commerical Practices Edition has a table of Environmental Conversion Factors. To convert from a AIC to a Ground Mobile environment, multiply the AIC MTBF by 0.7. This should help.


Reply:

Subject: installer
Reply Posted by: . .
Date Posted: Sat Apr 6 8:05:38 US/Eastern 2002
Message:
Hi I am trying to find a failure rate model similar to other mechanical models in the Carderock mechanical reliability handbook. I realize that NPRD-95 has a direct tv installer couple of data points for bellows but they are GF environment (ours is naval unsheltered) and the failure rate is given independent of number of cycles, material, etc. I would expect those parameters to play a large part in the failure of a bellows. Thanks for your time. Bob Valerius


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