Bolts with shell elements

[gregorsky]

Hi,
I would like to model bolt connection between two shell plates with zero distance between. For solid modelling I use bar element with RBE2 (6 dof). I made simple model and compare results for independent node (RBE2) connecting two holes and with short bar element - results are very similar.
What should be choice for that ?

Regards,
Greg

 

[fkmeyers]

In Nastran you can use a CBUSH element.

 

[rb1957]

I'd use a zero length spring, CELAS2 i think. this allows you to control the stiffness of the fastener; an infintiely stiff RBE element will suck up all the load. You can get fastener stiff estimates from Michael Niu's book.

 

[Spirit]

I agree with rb1957, I'd use 6 properly sized springs.
This is also useful if you need to estimate forces passing through the connection.

Regards

DS



'Ability is 10% inspiration and 90% perspiration.'

 

[fkmeyers]

A CBUSH is just that. 6 CELAS elements. It would also handle any small seperation between the nodes.

 

[fbdandloadpath]

If you happen to have load-deflection data for your joint, the CBUSH element can be used with PBUSHT and TABLED1 cards in a nonlinear run.

The hard part is getting the load-deflection curve.