Bolt Failure - which is the biggie? 3

[notTiger]

Hi

Generally bolted fasteners can fail due to mechanical failure (shear/strip) or loosening ...........

Does anyone know of some credible research/report into

1. The relative importance of these and
2. The cost to industry (downtime $)

Cheers

Simon

 

[desertfox]

Hi notTiger

Have a look at this site:-

http://www.boltscience.com/index.htm?

regards

desertfox

 

[notTiger]

Thanks for the link DF

I have looked through this site - great resource - but was thinking there is probably some detailed study out there somewhere? -- NASA ........... PHD thesis .... Shared Commercial Research .......Conference paper ???

Seems fastener failure is a big problem - I have been looking into aspects of vibration ......... and solutions- and wondering how significant it is as a problem ......????????

Cheers

Simon

Cheers Simon

http://www.pukugolf.com

 

[MintJulep]

Start with Bickford's book An Introduction to the Design and Behivior of Bolted Joints.

You need to take a more holistic view. Fasteners don't fail. Joints fail.

The solution to vibration problems is knowledge and proper design.

 

[SlideRuleEra]

While neither of these publications addresses your question, bolt failure, directly, you may find some of the information helpful. Links to free .pdf downloads are on these pages:

"Guide to Design Criteria for Bolted and Riveted Joints"

http://www.boltcouncil.org/guide1.htm

and
"NASA Fastener Design Manual"

http://gltrs.grc.nasa.gov/cgi-bin/GLTRS/browse.pl?1990/RP-1228.html

http://www.SlideRuleEra.net

 

[Warpspeed]

Rather a lot depends upon the application.

Is the bolt a static structural joint, or is it subjected to rapid cyclic stress and therefore metal fatigue ?

It is why there are so many different types and grades of bolts made. The aerospace people go into all this in very great depth.

The actual bolt is never really the problem. First comes the correct design of the joint itself, then selecting a suitable type and grade of bolt, then correct installation.

I doubt very much if you can isolate all bolt failures into a single category and compute cost to industry.

For instance the aircraft industry are absolutely fanatical about threaded fasteners and therefore have very few failures.

Home handymen have bolts bend, strip, or come loose all the time, but that is not the fault of the bolt, so you cannot say the bolt itself actually failed.

 

[BillPSU]

Bolt failure can also be caused by localized loading of a bolted joint. An example is a rotation bearing for a crane. The bolts attaching the bearing will not be stressed evenly and if a mounting surface is not rigid enough flexing of the mounting surfaces will cause bolt failure.
I am aware of such a failure which caused a fatality.