Calculate axial load limit of a shrink fit? 2

[Judge]

I'd really appreciate a little help here.
I plan to shrink fit a sleeve into a housing of same material using liquid nitrogen. The housing is stationary, so no torque transmitted, it just has to support the axial load.

I am looking for the formulae to calculate. I have found some online calculators, which tend to deal with force fits but not shrink fits. Although similar, there will be differences in surface finish values & deformation... Also, online calculators don't help me understand.

Any suggestions would be greatly appreciated. Would prefer metric, but can handle imperial units also.

Thank you
J

 

[GregLocock]

The equation is easy F=pressure*surface area*friction. One of those is easy to determine, one is possible to calculate using lame's equation or finite hefalumps, and the third is a guess. I vaguely remember 0.3 for steel on steel, but add a touch of grease and you're in trouble.

Cheers

Greg Locock


New here? Try reading these, they might help FAQ731-376

http://eng-tips.com/market.cfm?

 

[desertfox]

See FAQ 404-1230 on this site[pre][/pre]

“Do not worry about your problems with mathematics, I assure you mine are far greater.” Albert Einstein

 

[Judge]

Thanks for responding desertfox, but could not find that FAQ. Can you post a link please.


Thanks Greg. That's pretty close to what I need.

J

 

[desertfox]

faq404-1230

“Do not worry about your problems with mathematics, I assure you mine are far greater.” Albert Einstein

 

[Judge]

Many thanks desertfox. I have used the excellent tribology calculator in the past, but was unsure of the formulae used.

Great work.

Thank you
J

 

[Judge]

Hi desertfox.
There seems to be a problem with the Pc formula. Uo is missing & it's missing a ] (closing square bracket)

J

 

[desertfox]

Hi Judge

I took a look and can't see a problem , can you highlight it please


“Do not worry about your problems with mathematics, I assure you mine are far greater.” Albert Einstein

 

[Judge]

Hi desertfox.

Uo, poisson's ratio for the outer member, is listed but is not in the equation. Is that a typo or intentional?

Pc=x/[Dc*[((Dc^2+Di^2)/(Ei(Dc^2-Di^2))+((Do^2+Dc^2)/(Eo*(Do^2-Dc^2))-((Ui/Ei)+Ui/Eo))]

The second [ should be a (

Thanks
J

 

[Judge]

Hi desertfox.

I've verified this with the tribology calculator here.

[URL unfurl="true"]http://www.tribology-abc.com/calculators/e3_8.htm[/url]

p =(1000*δ)/(d*(((d^2+di^2)/(Ei*(d^2-di^2))+((do^2+d^2)/(Eo*(do^2-d^2))-((vi/Ei)-(vo/Eo))))))

The 1000 is so you can use GPa instead of MPa.

Changes highlighted in red

This can be pasted into excel as is, just need to name the data cells appropriately.

It's been a good learning day today.

Thanks a lot for your help.

J

 

[desertfox]

Hi Judge

I agree Ui should be Uo, yes there does appear to be a bracket missing also, thanks for that I'll see what I can do to get it corrected.



“Do not worry about your problems with mathematics, I assure you mine are far greater.” Albert Einstein