RBE Forces

[roman.gebhard5MV47]

I have a bolt connection like this:

I modelled it like this: with a RBE2 element with its master point in the middle of the connection.

I have 4 of these bolt connections on the whole frame.

On these 4 bolt connections is mounted another frame which i also modelled with RBE2 Elements.

I defined this master point of the RBE2 on the gravity point of the second frame with its mass as a concentrated mass.

I was able to get the solutions i wanted on the acual frame.

but now i want to look at the bolt in detail.

So i actually want the forces first which are here:

I was able to determine the node numbers:

But in the FNO reader if i try to look at the INTERNAL forces these 4 node numbers are missing!

Also the MPC forces are all 0 at the master points. on the slave points there are not zero.

But i need the values of these 4 master points.

I have no idea how to determine them. Please help! Thanks a lot.

[roman.gebhard5MV47]

I solved it with this kind of modelling the bolt connection and then read out the beam results:

So erstellen Sie eine Stiftverbindung zwischen Verbindungen in Inventor Nastran (autodesk.de)

But this is more time-consuming and more accuarcy which i actually dont need.

So i would realy like to know how get the forces out of the master point of a RBE2 element

and not how to determine the forces with another way, because i already would to get to know this in the past several times.

[John_Holtz]

Hi @roman.gebhard5MV47 

I think your are expecting too much from the rigid connector. Let's talk about the first bolt. There is no force at the center point because all the forces in the "spokes" of the connector are equal and opposite.

When you attach one rigid connector to another, it becomes one big rigid connector. The only "center point" is where the concentrated mass is located. (If you have gravity turned on, you should see an MPC force at that center point which holds up the concentrated mass.)

The method you used is probably the simplest solution. 

John