linear static with contacts
Altair EmployeeI am carrying out a linear static loading of helical spring, which is interfaced between two plates and have defined slide contact between the spring and the plates. Upon applying the load to the top plate i obtained the spcf forces on the bottom plate nodes. However, I am obtaining unexpectedly high loads at the contacts (100 times higher than the loading force~1000). Am i doing something wrong in setting up the contacts?
I am attaching pictures of result, setup and contact surfaces for clarity
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Answers
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Can you share the model file please?
use the dropbox link in my signature below to share the model file.
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@Prakash Pagadala I have shared the model files with you.
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still havent figured it out. can anybody help?
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Hi Rahul,
Sorry for a late reply.
Why did you choose to run Linear static with contacts?
Linear static with non linear contacts may not provide right results.
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Thanks for your reply. I have now carried out non linear analysis and now the results make sense.
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Hi Rahul,
Thank you for the update
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While carrying out the non linear analysis I am unable to obtain a force balance (between contact force and reaction force) on the plates. I tried defining different conditions of contact (slide and stick) however in both the cases i am unable to obtain a force balance. Something seems to be wrong.
I can transfer the file if needed.
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Hi Rahul,
Isn't it the reaction force equals to applied force?
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I am carrying out a fixed displacement analysis. The reaction force on the bottom plate should be equal and opposite to the contact force experienced by the plate.
But when i obtain the nodal reactions and nodal contact forces they are not balancing each other
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Hi Rahul,
I think we are confusing each other
Contact force is a measure of force to prevent penetration.
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Lets take a simple example for explanations sake.
If a plate is pushed onto another plate (such that the two plates are in contact). How can i find the force transferred at the contact regions?
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Hi prakash,
Hope you doing well
Here i am need reaction force at constrained location but i unable to get the force it showing zero i defined all the parameters. Can you please check the model once for me .
And please give feedback. Thanks for your time. i have attached the model as shown below.
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hi Prakash,
Hope you doing well. i am trying to do analysis on enforced displacement with friction contact between the contacts. but the top component is penetrating i have changed the parameters but i unable to get the solution. Please take a look once to the file.
thanks for you support.
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Hi Ajay,
Instead of linear static analysis try with NLSTAT analysis type.
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Hi Prakash,
Could you please let me know NLSTAT and Non linear Quasi static analysis are same ?
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Hi,
Yes, NLSTAT again has large displacement and small displacement analysis types.
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I have tried a static analysis in Optistrct and i m facing two issues.
1)
2) Contact is not working in Quasi static also. Could you please help me out
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Hi,
Can you share the files, please?
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Please find the attached file and let me know your comments
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Hi,
I see the load is applied to a point/node and not distributed to an entire top surface of load component, is that correct?
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Actually i have created a load bar that is connected with the RBE2 elements. So i have applied the load at the RBE2 element so that the load will be distributed through the load bar part.The things is the contact between the Load bar and part is working and the contact between the bottom support and the part is not working.
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OK, I will update and check the run.
meanwhile what about units?
I see element size in the order of 0.3 and height of the component is 15 approx...
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I have used the B units (ton,mm,s)
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Hi @Prakash Pagadala Do you have any update on this model ?
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Hi,
Can you add EXPRTNL>>CNTSTB
The analysis is still ON on my machine. But I see the difference in the .out file.
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Hi Prakash,
Where can i find this option ?
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In ControlCards>> PARAM>> EXPRTNL>> CNTSTB
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Analysis is done at my end,
If you still face the problem, let me know
I will share the updated file.
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Hi Prakash,
The analysis is proper now. Thanks for your support.
During the analysis i have faced the convergence issue but automatically i has rectified. How the convergence factor works here in optistrct since generally in Ls-dyna implicit analysis once the convergence error comes it is very difficult to get the solution right. so how does the convergence in optistrct differ from the ls dyna convergence ?
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Hi,
To understand better, I would suggest you go through the non-linear quasi-static section on OptiStruct help which provides details about criteria details, D
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