Forum: Reliability & Maintainability Questions and Answers
Posted by: Dave White (white@spectralsolutions )
Date posted: Fri Jun 4 17:06:40 US/Eastern 1999
Subject: Life Cycle Environmental Profile
Help! I am trying to create a Life Cycle Environmental Profile (LCEP) to help guide a series of qualification tests. The LCEP defines all of the environmental stresses that the product is likely to encounter from manufacturing, shipping, storage, installation, and use. I have been able to get reasonably good data on all of these environments except for installation. The product is a tower mounted reciever front end module, approximately 100 lbs. My problem is that the installation environment can vary quite a bit (from wall mounted to several hundred feet up whatever style of tower imaginable). I anticipate mechanical shock as the unit is hauled up the tower will be the main concern. Does anyone out there have any experience that could help? If I can not find existing data I plan to attempt a rough "worst case" estimate. Does this seem reasonable? Thanks for any help you can give me (I'm fairly new to reliability engineering)
Posted by: Matt Wiltshire (firstname.lastname@example.org )
Date posted: Thu May 27 11:51:59 US/Eastern 1999
Subject: MIL-STD-810E Salt Fog Test
How many hours would the MIL-STD-810E Salt Fog Test (48 hours, 5% salt solution, 95 degrees F) be equivalent to in a worst case land environment such as the coast of Florida in the summer and a bast case in Nebraska (if there is a better one let me know)? If numbers can be directly applied to the 48 hour test, can it be applied linearly to an extended test (much > 48 hours)? Can you recommend any studies that address this?
Thanks, Matt Wiltshire
Posted by: J Homer
Date posted: Wed May 26 5:42:17 US/Eastern 1999
I am currently involved with a program looking at Accelerated Life Testing and Stress Screening techniques, mainly HALT and HASS. What I require is an understanding of these two methods, especially the multi-axis vibration and its effects. Can anyone provide some information on these subjects or places to look.
Posted by: Roberto Poli (email@example.com )
Date posted: Tue May 18 6:35:32 US/Eastern 1999
Subject: Power on -off cycle failure rate
I'm using a software, based upon Mil-Hdbk 217 to evaluate MTTF of a domestic equipment. I need information about components failure rate during power on- off cycles. I have seen that Mil -Hdbk 217 doesn't consider power on-off stress parameters.
Does this kind database exist? Any answer will be very appreciated. Thank you.
Posted by: Michelle Hackmann (firstname.lastname@example.org )
Date posted: Wed May 12 17:42:11 US/Eastern 1999
Subject: MTBF improvements thru accel life tests
I used a Reliability Software package to evaluate a complex
telecommunication system. The MTBF results were lower than expected. Are there accelerated life tests or anything else that may be implemented in order to improve the MTBF number?