Learning Forum

[fsvensen92]

Hi

I have a some solids which all have a face in the same YZ plane. I want apply a pulling force in the X direction to the faces and study the displacement. I have created a rigid remote point scoped to all the faces and applied a force to the point.

 

However I notice some rotation of the faces which I want to eliminate, the faces should only have translation in the X direction. What would be the correct approach to achieve this?

My ideas currently are:

- Apply a displacement to the faces directly, with only the X DOF free
- Apply a remote displacement to the remote point

Is there a difference between the two?

Thanks!

[mohan.urs]

Hey,

Applying a displacement directly to the faces with only the X DOF free would constrain the faces to move only in the X direction, without any rotation. This method directly restricts the movement of the nodes on the face to the specified DOF.

On the other hand, using a remote displacement involves defining a remote point and applying the displacement to this point. Remote points are particularly useful when you want to apply a displacement to the center of a face while allowing rotational freedom, or when you want to apply a force at a location away from the mesh without over-constraining the system.

In your case, since you want to eliminate rotation completely, applying a displacement directly to the faces with only the X DOF free might be the more straightforward approach. This would ensure that the faces are constrained to translate only in the X direction without any rotation.

If you need more insights on this, I would suggest that you explain the setup and your end goal with some snipshots.

Regards,
Mohan Urs

[fsvensen92]

Hi Mohan
Thanks for your reply. 

This is my base setup.
Fixed support on one end, remote force thorugh a rigid remote point on the other. I want to disallow rotation on the faces where the remote force is applied. 

I am also getting warnings about rigid body motion and the solver is adding weak springs, any idea what is causing this?

[mohan.urs]

Hey,

So the direct displacement should work for you. 
And regarding the warning you can check the weak spring forces that are being generated. If they are low it won't be a problem.
To check what is causing that error you can check out this course https://innovationspace.ansys.com/courses/courses/prevent-rigid-body-motion-in-contact/

Regards,
Mohan Urs

[fsvensen92]

Thank you!

I see these warnings - assume they are due to scoping the displacement and the remote point to the same nodes?

Would it make sense to change some of the DOFs for the remote point where I apply the force?