Young's Modulus of Chain

[Ussuri]

I am trying to work out the elongation of a chain under shock loading. To allow me to do this I am looking for the 'effective' young's modulus of chain? Does anyone have any ideas or references?

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[csd72]

Model one link of the chain withsupport and load points at the contacts with the adjacent links. measure the elongation between the 2 contact point under a unit load and divide it by this length to get the strain.

 

[btrueblood]

Ussuri,

Is the chain loaded (taut) prior to receiving the shock? If not, there will be a lot of attenuation of the shock due to friction between the links as they move.

 

[JStephen]

Have you tried contacting the chain manufacturer? I know this kind of information is available for wire rope.

 

[Ussuri]

I have contacted a few chain manufacturers but I am waiting for them to get back to me.

The chain itself is to act as a catching mechanism (backup) so will not be taut prior to loading and hence is an energy related problem.

I suppose I could model the links and work it out from the results but I think I would need to do it in either ansys or abaqus (those being the FE packages we have). The model would need to take account of brunelling at the contact surface, elongation of the link, bending of the link end and possible waisting. The software I have on desktop machine is just general frame analysis software (Staad and FS2000) and I dont think they are up to it. The R&D boys have the FE stuff in a different part of the office.

 

[GregLocock]

"The model would need to take account of brunelling at the contact surface, elongation of the link, bending of the link end and possible waisting."

No it wouldn't.

You were initially after an elastic approximation.

A back of envelope calcu'ation would consider a link of chain, width w, as being a couple of beams in series, width w, in single pont bending and with debatable end fixity.



Cheers

Greg Locock

Please see FAQ731-376 for tips on how to make the best use of Eng-Tips.

 

[csd72]

Greg,

I thought of that, but I think the top horizontal section will be in bending and would cause a very different flexibility to the model you describe.

Best to model one link exactly and then figure out the effective modulus as I stated above.

One more note - the links are welded together to form the loop, you will need to check that this is a full strength weld.

csd

 

[Gumpmaster]

I think Ansys would work quite well. Make sure you get all of the material properties correct.

I would think that you could also send a section of the chain to a materials lab that could give you the load-deflection plot. It should be a fairly easy test to conduct.

Regards,
Rich

 

[GregLocock]

The chain can be reasonably accurately modelled classically as 4 beams, each of which is a pinned beam with a moment M in the appropriate direction, and with the end beams centrally loaded.

For those of us who are lazy and like pretty pictures FEA does quite nicely, for the geometry I chose the deflection was 16 times as great as for a rod under tension.

http://www.geocities.com/greglocock/gallery/chain.png

might work, or if not the top link in

http://www.geocities.com/greglocock/gallery

However, mine was effectively a square cross section, for obvious reasons a circular cross section would bend more, for given area

Cheers

Greg Locock

Please see FAQ731-376 for tips on how to make the best use of Eng-Tips.

 

[GregLocock]

Note that my proportions were fairly silly, a realistic chain has a lot less bending than that. Also the stiffness is non linear due to contact in a real chain.

Cheers

Greg Locock

Please see FAQ731-376 for tips on how to make the best use of Eng-Tips.

 

[nutte]

JStephen, can you point me to a reference for this with wire rope? I've been searching to no avail for the effective area and elastic modulus of wire rope.

 

[transmissiontowers]

Add a "me to" to the info on wire rope MOE. I posted this question in the other topics forum:

http://www.eng-tips.com/viewthread.cfm?qid=192503&page=1

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