Plot the Von Mises stress

[Anonymous]

Hi,

I'm wondering if it is possible to plot the von mises stress along an entity (like an edge).

If I select "nodes", as I see, the only available choices are: displacement, rotation, spc and solid mesh error.

Instead, if I select "elements", the von mises stress is available to plot, but since it is referred to elements the graph is not so clear because it has too many values to plot, and it is difficult to read for the user.

Isn't it possible to plot something like in the annexed picture? (the handmade graph of the stress).

Thanks,

Luca

[AndrewSears · Accepted solution]

Hi Luca,

See if this gets you what you need.  It sounds like you might have tried this though so please let us know if you are getting different results.

In the plot dialog, use these settings below.  The Z in my image is the part Z direction.    

The Green box shows the elements ID's I selected.  You need to hold CTRL key when selecting multiple elements. This will add the element ID's to the list for plotting.  You can make a group if you plan to report more information along these elements.  

When I select to show the XY plot, here is what I get below.  This matches your picture but mine is reversed because we report based on the value and not the selection order.

Let us know if this is not what you are looking for.

Thanks,

Andy 

[Anonymous]

Hi Andy, yes you got what I meant. Unfortunately, as I see, there isn't the possibility to plot the Von Mises stress along an entity that you select. The multi-selection with CTRL is valid, but a little restrictive if you think to an edge with hundreds of elements. The plot along an entity could be very useful and I hope it could be an improvement for the next Nastran version. Thx Luca

[AndrewSears]

Luca,

Here is another idea.  It appears that you are not aware of plotting along the edge of a part and are concerned about how the data that is shown to you.  You said "it is not that clear because it has to many values to plot".  Do you mean the data is somewhat scattered when plotted, like this image below? 

For your reference, below are the settings to get the above plot.  

If your concern is with the data being somewhat hard to read, you could copy the information to Excel and add a higher order polynomial trendline to the data.  This trendline will not give you the exact values but should show something a little easier to read.  Below is what I get in Excel to make the data easier to read.  The trendline is orange to make it easier to see.

If this is not getting you to the solution you want, please let us know.

Hope this helps!  Please add more screen shots of the unclear data/plot as you see it.  I would like to know how it looks for you. 

Thanks,

Andy 

[Anonymous]

Yes Andy, you've centered the point. I meant that the Von Mises trend is somewhat scattered. I'll for sure use Excel. It's a good idea. Anyway let me say that if we could obtain this trend within the Nastran plot (without passing through another program), we could save a little bit of time. thx, Luca

[AndrewSears]

Luca,

Here is a little more info to get a smoother plot of the stress along an entity.

Reason for current results:

When plotting along an entity, In-CAD is reporting von Mises stress at the element centroid along the selected entity you are plotting results against.  This is why you are seeing this graph that appears to be scattered.  

Another Solution:

You can modify the bulk data file to have the results shown at the element nodes by changing the STRESS card to show GPSTRESS.  GPStress means Grid Point Stress where the grid points are the element nodes.  To change the output from STRESS to GPSTRESS, RMB on the Analysis node in the Browser and select Generate Nastran File.

This will switch the Browser from Model Tree to Nastran.

Double click on STRESS in the Nastran FIle and add [GP] to STRESS.  Hit OK.

Staying in the Nastran File, select the Run icon.  This will run a new analysis with the current settings.

When the results show up you can plot nodal data along the edge.  The plot is a lot cleaner.  We are looking into this though because this still appears to be reporting more info than just what is along the edge.

Hope this helps!

Let me know if you have other questions.

Thanks,

Andy 

[Anonymous]

I've just tryed the process you suggested and it works. The plot looks very good. I hope the programmers could succeed in this development. Thanks for the patience, Luca