SimScale CAE Forum

Physical Contact between moving objects


#1

To whom it may concern

I am writing to request your kindly assistance to teach me run following simulation?

https://www.simscale.com/projects/exceedemand/test1/

I am new to simscale but used Ansoft for years. Aforementioned model is to learn about the replace stress to different pattern, e.g. square and hexagon.

Thanks in advance.


#2

Hi @exceedemand and excuse me for the delayed response.

I assume you want to move both objects across the plate and see the resulting stresses as mentioned, right?

Some tips on your setup:

  • Create a physical contact between the components and your plate (you can vary the coulomb coefficient in the created connection)

  • You can fix the plate from below by just picking the lower surface

  • You apply the force on both components in one step. I would rather apply the forces smoothly over time by defining a function looking like this: 0.01*t [m] (you can also place both components more at the other side of the plate to have more frames to observe the behavior


Once you fixed these issues you can give the project a quick spin to see if everything works. @cjquijano & @ggiraldo, let us know if you have any additional thoughts on this case.

Best,

Jousef


#3

Hi @exceedemand,

I would be happy to help you out. Can you provide a little more information about what you are trying to solve for? I looked at your model and I saw three parts and all three parts have a face that is fixed. So, what you are trying to solve for.

Thanks!
Chrisotpher


#4

Thanks Chrisotpher,
I attempt to simulate stress occur to thermal grown glass (silicon oxide) in either square or Hexagon pattern on a silicon wafer, when the silicon wafer is bended like a bow. The model in my mind is that hexagon with rounded corner performs better, but it is first time for me to use this tool. Thanks a lot.
BR, Jin


#5

Hi Jousef

Many appreciate your response. I attempt to simulate stress occur to thermal grown glass (silicon oxide) in either square or hexagon pattern on a silicon wafer, when the silicon wafer is bended like a bow.

You are absolutely correct that transient (time domain) simulation will be interesting. Static analysis is to give me initial impression,

The tutorial named “Linear Static Stress Analysis” < https://www.youtube.com/watch?v=5uyY3eUJAOU > does not go through the entire setting, please forgive my stupidness even though it is the first time for me to use this tool. Cheers.

Thanks a lot.

BR, Jin


#6

Hi @exceedemand,

I was able to get you model to run with the following changes.

I had to remesh the model with the Allow Quadrangles turned off.

I added gravity to the model. Not sure if you wanted it.

I added an elastic support to the two parts to help stabilize the model.

Once I made those changes the model was able to run. Here is a link to the project.

https://www.simscale.com/workbench/?pid=3881217561386163795&mi=spec%3Aa4302959-a311-498b-a991-66d3dc14b8d6%2Cservice%3ASIMULATION%2Cstrategy%3A2&ps=analysis%2FStaticAnalysis--oneOf%2FsimulationControl

Please let me know if this helps.
Christopher


#7

Hello Christopher

Thank you so much for prompt support and thorough explanation! The problem has been resolved after 9 fails and please feel free to check the result in the 10th run. Your expert advice will be highly appreciated.

  1. Learning that you have also run a number of simulations, I wonder how to tweak the simulation fails, i.e. diagnose the cause of convergence / fails in the solver log? I have a brief look into the solver log text but was unable to find where ‘error’ occurs.

  2. How does elastic support stabilize the model? Does it hamper the stress formation (which subsequently reduce convergence)?

  3. Is there any method to mirror the plot after simulation? To accelerate the calculation, I am going to re-draw the symmetric structure into half or quarter but wonder, if it is possible to retrofit the contour plot. Please feel free to recommend any tutorial video to modify the result & plot.

Thank you very much!

Best regards,
Jin


#8

Hi @exceedemand,

The elastic support help to stabilize parts . I use them quite a bit when I have physical contacts. They are basically springs from the part to ground, if there value is too high they can negatively affect the results. Since you switched to a bonded contact you don’t need the soft springs anymore.

For mirroring the part after simulation and other advanced post-processing please check out the following thread.

Please let me know if you have additional questions.

Christopher