SimScale CAE Forum

Rigid solid constraint


How can I give rigid body properties to a body? That is, it can move with the assembly to which it is welded but does not have the capacity to deform.


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Hi @MaikelLamb

I think a high Young modulus can model what you want. As to how big I would say ~10x the value of other parts, but you have to test dependence of results against variations in this value.

Do not exaggerate the value as this would cause numerical instabilities. Also, bear in mind there will be stress concentration points, so be careful when interpreting results.

Hope this helped, happy simulation!


Thank you @ggiraldo ! I will try this :slight_smile:

Hello. I followed the advice in the series of posts. The portion that I have circled in the picture below is the part that needs to be rigid:

As you can see, I overlaid the deformed shape and the undeformed shape (the opaque volume is the undeformed shape and the transparent shape is the deformed shape). You must note that the scaling for the deformed shape is 1:1, meaning it is the “true value”.

As you can see, the shape that I wanted to be rigid has deformed significantly. Should I just add to the Young’s Modulus until the deformation stops, or are there other factors at play here?

Thank you!

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Hi @jlogsdon,

If you want that portion of the model to be rigid, why not just fix the bottom of the head tube? Seems like that would give you what you are looking for.


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Hello @cjquijano,

The reason why I wanted that part to be rigid is that there is going to be a torque, acting through the motorcycle front fork (this is the part I wanted to be rigid), that will cause a lot of stress where the steering neck meets the frame.

I was hoping that I could try and account for it with the FEA

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Hey @jlogsdon

You can model a rigid body using the boundary condition as “Fixed value” on the body’s faces. Take a look:


You can use isovolume to verify the rigid body condition:

Simulation link:




Thank you so much for your help @paulosantos !!

I’ve got a question for you: How did you overlay the deformed frame over the undeformed shape? Did you do that in SimScale’s online viewer or did you have to do it in Paraview? The only way that I could pull it off was in Paraview.


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I’m not sure if it is possible to overlay the images using SimScale. I did it manually, using an image editor. It’s not a smart way of doing the job, but it works well if you make sure the scale is okay.