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Thank you very much.
I have checked this solution and it also provides a result independent of the mesh density.
But why does the stiffness of E have to be so much higher if we are treating this part of the plate as elastic?
Why 100x more and not 10x or 1000x?

But why does the stiffness of E have to be so much higher if we are treating this part of the plate as elastic?
Why 100x more and not 10x or 1000x?

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Ask this to the new ChatBot we implemented in the forum:

I have a slab modeled as a shell. Its Young's modulus is E. I want to make a portion of that slab rigid. What alternatives to rigidLink do I have?

Here's the rationale behind it:

• I want to make a portion of a deformable slab (with Young's modulus E) rigid
• I should use kinematic constraints (rigidLink in this case) to enforce correctly the constraint
• Alternatively I can impose the constraint approximately using a penalty approach
• In the penalty approach I "penalize" the deformability of the stiff part using a stiffer material Estiff = alpha*E
• In theory, to obtain the correct result alpha should be INFINITY, but you can't due to numerical issues.
• Assume you are fine with a 1% error, you can make alpha = 100
• Likewise, if you want an error of 10%, alpha = 10

Dear STKO,
I wanted to return to the topic of the sensitivity of the result to the density of the MES mesh.
In my attached model, I have done all the instructions in this topic, regarding elastic shear and the connection of the slab to the column also as elastic. I performed the anlysis depending on the density of the mesh. And the smaller the mesh, my deflections differed. Now I don't know which result can be good? I noticed in the results that the value of stresses in the steel (over the columns) does not vary depending on the mesh. The same is the case with the damage d- of the compression concrete. The big difference I noticed is that the smaller the mesh, the damage d+ has a different range. But should it affect the result that much? Can you please advise how to choose a mesh in this type of situation ?
Best regards

Actually, this happens because the initial mesh is very coarse for this kind of problem.
The solution converges as you approach a mesh of 10 cm.