when to model Spring Cans with Friction,there are some change in the model methord,please to see as follow PIC:
IN the CAESAR 2011 AP ,i think the method is not right for 20 restraint RX RY RZ ,what do you think? thanks lot

rotation restraint is only for X and Z

no, need RY,It just like combin14 in the ansys ,we only need Y with spring rate,other are rigid,but for 20 node in the caesar 2011 AP ,i can't understand the modeling method.

Hi,

yes,

case 1:

pipe connected with shoe or trunnion and shoe or trunnion is just rested in spring can top.spring can bottom is welded or bolted in structure or foundation.

at node 20 bottom of spring can,we have to input except y direction all other degree of freedom is arrested.so Rx,Ry,Rz,x and z is arrested.

case2:
some time pipe connected with shoe or trunnion and shoe or trunnion is rigidly connected with spring can top.spring can bottom is just rested in structure or foundation.

at node 20 bottom of spring can,we have to input except y direction with friction and all other degree of freedom is free.

Venkat,

Are you sure of Case 2 you've mentioned?

I'm yet to encounter a spring can which is neither bolted nor welded to structure.

Enlighten me, if that's the case!!

HI venkatachalam :
thanks for your explanation.but

I know the difference between case1 and case2,otherwise,case1 is come from caesar 2011 AP,CASE2 IS come from the caesar 5.2 AP,I think you can't understand my intent.

thanks lot

Dear Richard,Dave & Experts,

For modeling Foot Mounted Spring with Mu=0.1

If in the attached snap asked by 1st quote Mr ZZW,the Node 5 to 10 will be break up by 5-8 (1/2 OD of pipe = Y distance) = All Properties same as Run piping, & 8-10 the Shoe height or Trunion (Dummy) length, than which properties shall to be consider for this Node 8-10?

If the trunion length is more, shall we have to calculate the Heat transfer rate as per MSS-SP-58?

Because, for the Shoe or Dummy (nodes) properties can not be considered same as run piping, as per my understanding.

Please correct me, if my modeling technique is mismatch with all of you.
Also, reply which properties I can input in Nodes 8-10 ( Trunion).

My system case is Off-shore piping & temp of run pipe is 510 Degree C.Size of Run Pipe is 42" & dummy size is 36",Length of trunion affecting the bending moment also.

I hope to have reply from your experts soon.

Regards
SND

Dear Richard,Dave & Experts,

For modeling Foot Mounted Spring with Mu=0.1

If in the attached snap asked by 1st quote Mr ZZW,the Node 5 to 10 will be break up by 5-8 (1/2 OD of pipe = Y distance) = All Properties same as Run piping, & 8-10 the Shoe height or Trunion (Dummy) length, than which properties shall to be consider for this Node 8-10?

If the trunion length is more, shall we have to calculate the Heat transfer rate as per MSS-SP-58?

Because, for the Shoe or Dummy (nodes) properties can not be considered same as run piping, as per my understanding.

Please correct me, if my modeling technique is mismatch with all of you.
Also, reply which properties I can input in Nodes 8-10 ( Trunion).

My system case is Off-shore piping & temp of run pipe is 510 Degree C.Size of Run Pipe is 42" & dummy size is 36",Length of trunion affecting the bending moment also.

I hope to have reply from your experts soon.

Regards
SND

Those elements don't really exist in the real world - they are "construction elements" used to simulate the length of the spring can. We always suggest the properties of the attached pipe.

This topic is old but I have a question in this regard.
According to "CAESAR II Applications Guide" published in 2013 in the section "Modeling Spring Cans with Friction" there are some discrepancy between note " A CNode to connect to the spring. Except for the vertical spring stiffness, all other displays of freedoms are rigidly connected." and the picture explanation. I've specified these in the attached file.
Which one is correct?
I think I should specify restraint X,Z, RX and RZ at node 10(CNODE 15).Is that correct?

Hi,

No you need to consider Rx, Ry and Rz as well.

Regards,
R.K.

If you expect your support to carry any bending moment and you wish to reflect this in your model, then the various rotational restraints may give you what you wish.
I doubt that the friction shear will establish sufficient load to cause any rotation in this support model. That, along with the probability that the pipe itself will not will generate an overturning moment, makes me think that this modeling is not worth the effort.

agreed, but what if you have a big bore pipe say around 54" and you need to consider the effect of rotation in all direction. Generally we do consider this effect right?

Regards,
R.K.