SimScale CAE Forum

Remote Displacement


#1

Hi everyone,
I learn to model and simulate (already a little higher level) in simscale. I have some troubles with documentation, everything is briefly described but missing drawings showing the instruction. Simscale has great modeling capabilities but it’s hard to understand when and what to apply.
I now have a problem with Remote Displacement - well described but difficult to understand - it’s mainly about rotation such as pin - what point to give. Such examples are in public and very cool but there is a small sketch out there to understand why such a point was used. I can read coordinate values but I do not know where they are on the model. Maybe someone will help, small sketch with a brief explanation.
Thank you very much
Greg


FE Static analysis with imposed displacement
#3

Hi Greg (@gkondracki)!

Thanks a lot for the feedback! Maybe my colleague @rszoeke could explain this in a bit more detail?

Cheers and all the best!

Jousef


#4

Hi @gkondracki,
first lets try with the easiest part - visualization of point coordinates. If you see a remote point in a simulation you can visualize its location by creating a geometry primitive of type point:

I guess you read the part about the remote displacement constraint in our documentation. Let me describe the concept of it a little more descriptive with an example.

The basic idea is that for the remote displacement constraint the translational and rotational behavior for a specific point in space is defined (for example “free to rotate around z-axis”). Then this point is connected via “multi-point constraints” to a face or edge of the model (either allowing a deformation of the connected areas or not).

As an example, imagine you want to model a pinned constraint, as seen below without actually needing to model the pin and the contact:

What you should do is:

  • choose as remote point the center of the pin
  • fix all degrees of freedom but the rotation around the axis of the pin
  • assign it to the cylindrical pin surfaces

In a sketch this looks like this (dashed lines represent MPCs), remote point in the COG of the pin:

Be aware that this constraint only works correctly under the assumption of small deformations and rotations (<~5°) .

Resulting displacement compared to a modelization using a modeled pin and sliding contact:


Left: Result using remote constraint Right: Pin modled and sliding contact between pin and bar

You can check out the actual project related to the example above from here: https://www.simscale.com/projects/rszoeke/pinned_bar_example/

I hope this helps understanding the remote constraint a little.
Best,
Richard


How to set up bolt joints properly
#5

Hi Richard
I now understand everything. You very well explained this, I just understood this problem. I have a request to include this information in the documentation - this will help a lot of other users.
I am very thankful.
Best
Grzegorz (Greg) Kondracki


#6

Hi Richard,
I did some work on your model today. I once again thank you for your help. I made other contacts on your model - penalty and Lagrange. The model works very well with different types of contacts.
Lagrange

Penalty


Best
Gregory (Greg)