Connecting RBE3 over a spring to SPC

Felix-Th

Hello,

 

in order to get a smooth stress distribution with no spikes, my plan is to constrain a surface with RBE3-Elements to an SPC. Since it is not possible to directly connect the dependent nodes of the RBE3 to the SPC I thought I could use a spring (cbush) between the RBE3 and the SPC. As long as K1 and K4 of the pbush property of the spring are rigid my simulation runs. But obviously the spring will be deformed when K2, K3 K5 and K6 are zero. Nevertheless I get a smooth stress distribution. Making all six Ks rigid gives me an error. Using an RBE2 directly connected to an SPC gives me spikes.

 

So my questions are:

- how can all 6 Ks of the pbush be rigid without getting an error?

- how can I connect an RBE3 to an SPC (is there a better way than using a rigid spring)?

 

The attached screen shot shows the problem.

 

Thank you in advance.

Felix

 

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Altair Forum User

Hi Felix-Th,

 

could you please let us know what the error is?

 

I have tried with a PBUSH will all Ks rigid and referenced a local coordinate system in CBUSH card and it went through without any error.

 

can you try the same?

 

1) create a local coordinate system (could be same as global system)

2) card edit CBUSH element and reference the the local system in CBUSH>>CID

3) Run the model and check if you get any error message.