Help for a project "Cantilever Snap Fit Design"

[atanas_kuzev]

Hello everyone,
I am working on a project “Cantilever Snap Fit Design” from “The “Solve it with SimScale” Project”. My results don’t match with the experimental data presented in the paper. For details see the project’s comment.
I would appreciate any suggestions you have!.

Cantilever Snap Fit Design-Nonlinear Structural Analysis

[vsriv90]

@atanas_kuzev

My results don’t match with the experimental data presented in the paper

Hi @atanas_kuzev,

The project looks awesome! Here are a few suggestions-

1. Use finer mesh on the snap. This shall definitely cause the simulation to run for a longer period of time, but the results should be much closer to the experimentally validated results.

2. The penetration between the snap and the fixed block is too high. This can be avoided in two ways- either use Augmented Lagrangian contacts (which are not as stable as penalty, but do not allow any penetration) or increase the penalty coefficient (by 10-100x)

3. The displacement is not sufficient, and hence the final “snap” is not occurring. Please provide a higher displacement to the body (in the positive x-direction)

4. I am not sure about the fillet radius. Please check on that once again, as the fillet radius (especially at the neck of the snap) can cause a big variation in the results.

Hope this helps!

Regards,
Vikrant Srivastava

[atanas_kuzev]

Hi @vsriv90,
Thanks for your reply.

@vsriv90

The penetration between the snap and the fixed block is too high. This can be avoided in two ways- either use Augmented Lagrangian contacts (which are not as stable as penalty, but do not allow any penetration) or increase the penalty coefficient (by 10-100x)

I tried to use Augmented Lagrangian contacts, but I got this message:

What’s wrong with my settings?

[vsriv90]

Hey @atanas_kuzev,

I once again had a look at your simulation: as you are using a symmetry, the nodes common between the “symmetry” boundary condition and the “Augmented Lagrangian” contacts have two very separate conditions acting on them. Hence, they cause a singularity and result in this error.

What you can do with Augmented Lagrangian is use a complete body. But in case of this simulation, I would suggest using a Penalty contact formulation - they are much more stable, and a high value of the penalty coefficient shall ensure that there is no penetration.

Regards,
Vikrant Srivastava

[atanas_kuzev]

Hi @vsriv90,

1. I used higher values for penalty coefficients, but the simulations took a long time to run (from my point of view - many core hours used without results) and I canceled them.

2. How can I set up mesh refinement using an edge/ a point?