Learning Forum

[huizhelucyzhao]

Hi, 

I want to use 1D beam to represent a bolted joint that bolts 3 plates together. I am able to beam the top and bottom plate together. How do I constrain the middle plate? The contacts between all 3 plates are set to be frictionless; without proper constraint, the middle plate is unconstrained in the sliding direction. 

[Shashidhar Reddy]

Hello huizhelucyzhao,

I think you are on the right way. You need to beam the top and bottom plates.

Bonding middle plate to the bolt/beam is not practical.  It has to to be constrained through contact between top and bottom plates. i.e bolt pretension load.

So, the sliding motion may be reduced by choosing frictional contact instead of frictionless.

Also, PLease use adjust to touch in contact setting to avoid rigid body motion while solving it. 

Thank you

 

Regards

Shashidhar,PhD

[huizhelucyzhao]

Thank you very much for your reply. I have used the adjust to touch setting. 

The problem is that without somehow constraining the middle plate in additional to the frictional contacts, when I run modal analysis, the middle plate slides right through the 1D beams. If I constrain the holes of the middle plate using a cylindrical support, the other two plates that are "bolted" together will be the ones sliding. Should I add cylindrical supports to the bolted holes of the other two plates too? Will that cause solver issue? 

[Shashidhar Reddy]

Are you trying to do modal analysis or static analysis?

If you are doing modal analysis, its practical and good to do static analysis first using bolt pretension load and then modal analysis. You can avoid these problems. 

Modal analsysis is a linear analysis. It only considers a contact to be either no saperation contact or bonded contact.  

If you are not doing bolt pretension analysis, please decide whether to use bonded or no saperation contact. You will get the modes accordingly. Further, You can also couple the DOF of the hole surfaces of the plates to make them move together. 

Thanks 

Regards

Shashidhar, PhD