Hello,

I need to model a rubber bellow in a pipe line. (see attached - DN250 Series NT1) Could you please tell me the modeling procedure?

What values should I indicated?
Could someone send me a .CAESAR II file with the model that clearing?
I'm lost...

thank you very much
I am French. I'm sorry for my english ...

Rarka

We've already discussed this, search for:

How to model rubber anti vibration joint fro pumps

Hi,

I saw this post. However, I find it hard to analyze my results.
Here is my ".C 2" file
I model the rubber bellow without tie rods.
Does the model seems correct to you?
Node 10 is the pump flange.

Thank you in advance

Rarka

when I activate EFFECTIVE ID (about 320mm), I find very high forces at node 10.

Is this normal?
This means that the pump flange will have support these efforts?

Thank you!

Rarka

Rarka,

The problem you are dealing with is the Longitudinal Pressure thrust created by an unrestrained expansion joint. I've attached a bulletin discussing this topic. In your case, since the joint does not have tie rods, the pressure thrust is applicable and you should enter the effective ID.

You may wish to consider moving the joint to the Y-axis and incorporating tie rods. The joint would absorb lateral mvt (X & Z) and the axial (Y) mvt would have to be absorbed by pipe bending.

Thank you for your reply.

Your axes are they the same as mine?
See attached

My new model, I indicated the effective area of 320mm.
I have major efforts at the anchor (node 120 and 10).
This means that the pump flange (node 10) will have to support these efforts?

Thank you
Rarka

Sorry, I didn't not that you are using the Z axis as vertical. So, I'd suggest you put a joint in the Z axis and add tie rods. In this way, it will absorb movements in the X & Y axis.

In your current model, the restraint nodes will have to resist the pressure thrust.