Spring cans with friction between bottomshoes and top plate

Posted by: xenogood

Spring cans with friction between bottomshoes and top plate - 06/07/17 03:38 PM

Hi,

The CAESAR II has a guide for Modeling Spring Cans with Friction which is used if these spring cans are allowed to slide on their foundation. The Guide says this modeling technique can also be used in situations where shoe or trunnion slides on top of a bolted spring can but it does not mention how.

How should I model it differently for friction between the bottom of pipe shoes(NODE 10) and top of a bolted spring can (For my case, the spring can is bolted down to the foundation and it does not move).

Please help, thanks.

Posted by: Dave Diehl

Re: Spring cans with friction between bottomshoes and top plate - 06/08/17 07:34 AM

I don't see a good reason to change the model. It should function properly whether sliding occurs at the top or bottom of the can.
Have you tried it?
Posted by: Michael_Fletcher

Re: Spring cans with friction between bottomshoes and top plate - 06/08/17 08:38 AM

The only difference I could envision is if the spring can itself is sliding, it could have a weight and friction associated with it different from pipe alone. But I don't think the example accounts for that.
Posted by: xenogood

Re: Spring cans with friction between bottomshoes and top plate - 06/08/17 09:48 AM

I can't compare it since I don't know how to model it with friction at the bottom of shoes and the top plate of spring can.
Posted by: Dave Diehl

Re: Spring cans with friction between bottomshoes and top plate - 06/08/17 11:56 AM

As Michel Fletcher states, the difference that you can expect from this CAESAR II model - top slide v bottom slide - is the magnitude of the normal load and the friction coefficient. The normal load would only vary by the weight of the spring can.
There a few old posts about this can friction. One interesting point - there is a clearance gap between the load post and the can. There will be no friction until that gap closes. Maybe there's enough gap so that the lateral movement causes no (friction) load.