MES Problem

[jmcternan]

I cannot get the analysis to compete for a simple hinged valve model.  The model is too large to attach.  Is there a log file or somethng else I could attach?  It is a simple hinge that revovles around a pin and bushing.  The analysis will run, but will stop after about an hour, giving no resulsts.  Any help with is will be appreciated.  I am new to MES so it is probably an error in my setup.

[John_Holtz]

Hi,

You can view the log file from the Report environment. It is listed in the browser. But unless there is a warning or error message, the log file by itself will not be enough to determine what's going wrong. If there is a message about "Reached autotm limit", this page in the Help has some things to check in the model: Help > Autodesk Simulation > Setting Up and Performing the Analysis > Set Up Analyses Part 3 > Perform Analyses - Run Simulation > Perform Nonlinear Analyses

If possible, simplify the model down to the parts that are absolutely necessary. For example, the part with the load and anything attached (welded, bonded) to it. You may need to add some additional constraints to simulate other parts of the model. Will this simplified model run? If not, you have narrowed the problem down, and maybe the problem will be easier to find.

Otherwise, please read this message about sending models:

Create, Post, or Provide an Archive of your model

[jmcternan]

Thanks for help with the file size - it is now attached.  It may be that my computer cannot handle the model.  I am running windows xp 32 bit Quad core with 4 GB or ram.  I will also try shrinking the model as you suggested.

[zhuangs]

You can also try to run the model from command line.  And after the running is done, you can open the .fem file to check the results.

Shoubing

[jmcternan]

I did try to run from the command line, but did not have any success.

[zhuangs]

If like this, the current size of the model might be too large for you machine.

Shoubing

[jmcternan]

I think I may have stumbled on one of problems.  In my modle I have bushings between the pin and hinge.  This bushing are "floating" and have no constraints on them.  I modified the model so that the bushings are larger and are connected to the hinge frame.  I am currently running this model and it has progressed to step 3.  It does appear that my bushings are moving through the hinge frame though.  Maybe this is a contact error?

[zhuangs]

I had a look at your model (valve 3.zip)  that you posted.  It seems that some constraints were missing.  I provided the following changes:

(1) Adding two Load and Constraint Groups: 4, 5.   These two constraints prevent Y-direction motion of Part 3 and Part 4.  Note that the frictionless contact between each of them and Part 1, Part 2 and Part 5 cannot provide constraints aong Y-direction.

(2) Setting surface-surface contact rather than Part-Part contact.  Note that this can provide better performance.

(3) Modifying some contact settings.

The log file are posted.  The size of the modified model is too large to be posted.  If you can post your email, I can send the modified model to you.  You can rerun to check the two extra constraint groups.

Shoubing

[jmcternan]

Thanks so much for the help.  Here is my email:

jmcternan@cecoenviro.com

[zhuangs]

The model was sent to your email.  Let me know if there is any more question.

Shoubing

[jmcternan]

Thanks, I am running your model and it seems to be working perfectly.  I do have a question about some of the advanced settings that were changed in the surface contact menu.  I noticed that the contact stiffness and tolerance were changed.  I understand what these options are, but I am curios as to why you changed them and how you decided what values they should be.

[zhuangs · Accepted solution]

For your model, the other changes might be more significant.

The following tips might be helpful to adjust some advanced settings:

(1) Large stiffness -> small penetration, but maybe bad convergence; Small stiffness -> maybe large penetration, but good convergence.

(2) For a reasonable stiffness CS, CS*0.1 and CS*10 might have no apparent difference on the results.

Shoubing

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@jmcternan wrote:

Thanks, I am running your model and it seems to be working perfectly.  I do have a question about some of the advanced settings that were changed in the surface contact menu.  I noticed that the contact stiffness and tolerance were changed.  I understand what these options are, but I am curios as to why you changed them and how you decided what values they should be.

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