Fixed acceleration in Marc

[jerez]

Hello,
I have problem with run the analysis with BC fixed acceleration, exactly rotational acceleration. The Marc talks to me that he warrning me that this condition hasn't DOF prescribed and he solves the problem without this BC. What I should to do to solve this problem??

Thanks for answers
Mat.

 

[zsp]

You need to make sure that the analysis type supports this boundary condition. Only dynamic analysis supports fixed acceleration.

zsp

 

[Elabbasi]

Also make sure that the nodes at which you apply the rotational acceleration have active rotational DOFs. You cannot apply them for example to nodes attached to only solid elements.

Nagi Elabbasi

http://www.veryst.com

 

[jerez]

Hi

I noticed this what you elabbasi wrote during try of solving this problems, so I used RBE2 to solve this problem connected to one node.
But I have the new question:
how (if this is possible) activate rotational dofs of nodes attached to for ex. solid elements?
The analysis type is dynamic transient.

thx for replay
Mat.

 

[Elabbasi]

You cannot active rotational DOFs at a node unless at least one of the attached elements uses them. RBE2 type connections provide a convenient way to rotate a solid part. It actually applies translations at the solid element nodes which are calculated from the master node rotations and its location relative to the slave node.


Nagi Elabbasi

http://www.veryst.com