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Results for every node?

pdkoren
Newbie

Results for every node?

Just curious if there is a way to create a file of all the results for each node of an analysis?I have had agander at the files in the analysis directories, opening things with Notepad, butnothing looks like what I would like.Whathas me thinking of this is our typical fatigue analysis methodology. We have developed cyclic stress limit graphs for typical material we use. These are Max and Min Principal stress along the Y and X axis respectively with plotted lines for the various required cycles. We interogate our analysis results for max and min principal stress "(x,y)" points and if these points are below the required cycle line then we judge these as meeting the requirment. You can see how this could get a bit tedious, and how the potential to "miss" a failure would exist. My thinking is that IF somehow I could obtain a list of the max and min principal stress for each and every node, I could quickly evaluate them to their position relative to the required cyclic line and determine if the requirement is met. Maybe there is even a way to visually correlate the node number for display purposes. At the very least, this would seem to be a much more mistake proof processing of the results. One possible problem with this, might be in singularities, which would obviously show very high values and to discount them, you would need to identify them in the model. Maybe this would "spoil" my thinking...


Comments and suggestions welcomed... just thinking out loud a bit...

4 REPLIES 4

Results for every node?

Paul,

If you request ASCII output for your analysis (in the run settings), then you will get what you need. The format of the files is in the help documentation.

If you want to do fatigue analysis I would strongly recommend FESafe - www.safetechnology.com<">http://www.safetechnology.com>

Regards,

Rod


Rod Giles
Principal Engineer - Powertrain CAE
Triumph Designs Ltd

Results for every node?

Paul,

This should be possible. By default the Mechanica output is in binary
mode, but you can set it to be in ASCII in the Run Settings. From
memory, the Analysis\Analysis\*.s?? files contain the stress results. If
i'm not mistaken there is a document somewhere deep in the Knowledge
Base that describes the file structure of the result files.

Of course there is software available that will do this for you.
FE-SAFE is one that can read Mechanica result files, and I'm sure there
are many more. (Maybe even some freeware?). Advantage is that they have
implemented all sorts of tricks in their software (example: critical
plane analysis), that they are fast, have a nice GUI, and that they will
save you the effort of maintaining software code for each new release.
Downside is the expense of course.

It will be fun to build something, if you have the time to do it 🙂

Best regards,
Patrick Asselman

Re: Results for every node?

Paul,

I have made exactly this in Matlab and uploaded the *.m file here: https://www.ptcusercommunity.com/docs/DOC-6935

The matlab script extracts the max- and min- principal stress, and calculates the stress range for a series of load sets. In my case, I had a rotating load.

You need to request ASCII-output files ("Run-settings") . As it is now, it only extracts results for shell elements.

FYI I discovered a bug; according to PTC's support documentation, stresses in the "Analysis1.s01" files should be reported in a 9x6 matrix (tab delimited text).

As it happens, beam elements give a 7x6 matrix. I filed this to PTC Support, and that support case is now raised to an SPR (software performance report).

It took me some time to figure out what was wrong, but the matlab script now handles this. It identifies 7x6 stress martices and ignores those.

I hope this helps...

Best regards

/Mats Lindqvist

Re: Results for every node?

Hi Mats 

 

I don't seem to be able to access matlab file. The link you provided just takes me to the ptc comunity home page. 

 

Any change you could upload it again? 

 

Thanks, 

Martin 

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