Learning Forum

[deepesh.p.gurdasani]

Hi,

How to give bonded contact between 2D to 3D bodies so that 6 DOF effects from 2D are transferred to 3D body just like its done using Share Topology?

Thanks 

[Erik Kostson]

Hi

This post might be of help:

/forum/forums/topic/properly-model-contact-between-shell-and-solid/

Also search the forum and internet on this.

All the best

Erik

[deepesh.p.gurdasani]

Thanks for the reply Erik. 

When we give share topology, do the 3 rotational DOF from 2D get transferred to 3D body ? (Considering that 3 Translational DOF do get transffered but I want to know about 3 ROT DOFs in general) and if MPC is used, will it give similar effect to that of Share Topology ?

Thanks in advance

[deepesh.p.gurdasani]

Any help/guidance is much appreciated. 

Thanks

[deepesh.p.gurdasani]

Any information in this regard is much appreciated.

Thanks

[peteroznewman]

Deepesh, it would be helpful if you show your particular geometry.

If you use shared topology between a surface and a solid, the common face or edge will share nodes.  If the common edge is a straight line of the surface on the face or edge of a solid, there will be shared nodes along that line, but the solid elements have no rotational stiffness to support the shell elements. The model will have a hinge, also called a mechanism, which can often cause the Static Structural model to fail to solve. If you don't want a hinge you have two choices: 1) Use Bonded Contact and select an area on the solid to bond to the edge of the surface or 2) Extend the surface so that it shares an area on the face of the solid, which will provide a way to support the moment on the straight edge that was a hinge in the original Shared Topology configuration.

[deepesh.p.gurdasani]

Thanks for the reply.

1) Extending the surface changes the design, right? which can have effect on the solution output?

I do understand that solid elements don't have rotational stiffness but what I want to understand is:

2) Does shared topology transfer the effect of 3 ROT DOFs of Shell elements to solid ? Or does bonded contact provides the same? just want a clarification so that following this, I can ask the query related to bonded contact.

If possible, can you reply pointwise? it would be helpful in easy understanding of answer.

Thank you

[peteroznewman]

Read Erik's reply in this discussion which illustrates what I described above: a straight line of nodes along the edge of a surface that shares nodes with solid elements. A hinge is created which has a zero frequency first mode of vibration.

[deepesh.p.gurdasani]

Thanks for the link to the discussion.

1) Shouldn't the second image in the discussion be of shared topology? as in share topology the nodes are merged at the interface and the body acts as One. The hinge mechanism should have been in bonded contact, isnt it?

2) As Erik stated in the discussion that Rot DOF not being transferred as solid elements dont have those DOFs, there is no way to transfer Shell element's effect of ROT DOFs to Solid element? 

 

[peteroznewman]

1) The first image uses shared topology and creates a hinge in the mechanism.  The second image uses bonded contact between the face of the solid and the edge of the surface which eliminates the hinge becuase it uses the face of the solid so is no longer a line but an area that can support rotations.

2) In SpaceClaim, it is very easy to select the face of a solid and use Copy/Paste to create a surface from that face. If the Share button is used with this extra surface, that narrow surface will share nodes with both the solid and the long cantilevered surface which eliminates the hinge in the same way bonded contact between the solid and original surface does.