How to treat a body as rigid?

[ANYS]

@ANYS

it can be read wrong

By read wrong I mean undervalue the importance of REF node position. (bad english from my side)
Rotations of the rigid body are done arround him.

[FEAnalyst]

@tatertots89

My work around is to treat all 3 links as deformable bodies and make the 2 “rigid” bodies have a very high high Youngs Modulus with a low Poissons Ratio. This works as I have low strain in the 2 links I wish to be rigid. The problem is now I have a long compute time as it’s computing the stresses in all 3 members.

I’ve tried selecting the entire link as a rigid body but the issue is it still requires me to assign a material to the body. If I assign a material and run the simulation it throws an error.

Can you share the file with your model so that we can try to make some improvements ?

[synt]

@synt

Since there are two member connected share the same common nodes, it is a convenient way using Remove in Equation. Some rotational DOF for beam and shell element model, translation in longitudinal axes for solid element model.

sorry i i missed at this. It seems not possible to remove some dof’s at node in continuous mesh, separation and connecting by MPC is required.,

[ANYS]

Hi,

I have been able to connect all three shell components but with many custom keywords. (The system is unstable and stability is far from its actual position. I have help the system to converge with some addition constrain but, anyway, that’s another matter).

In Prepomax it doesn’t seem to work even with some additional BC , and I think i see the reason.

Does Prepomax always create a new node number for the REF node?. I mean, I have selected as reference node an existing node which is part of a component. I know that’s possible. For some reason when I do that, Prepomax creates a new node at the selected position instead of using the selected node.That makes both parts disconnect.

Could that option have been added to Prepomax?

[Matej]

In PrePoMax, a new node is created as a reference node on the location of the selected point.