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Stress Gradient Extraction

Creator
Creator

Hi Everyone,

 

I am trying to use the charting tool to extract a gradient along a specified curve and plot the data vs distance along the curve. This is something we are able to do in PATRAN but I am having a hard time trying to figure out how to do it in FEMAP.

 

Essentially what I ultimately need to determine is how fast the stress is dropping off in a specified location on my part.

 

 

Thanks.

3 REPLIES

Re: Stress Gradient Extraction

Solution Partner Phenom Solution Partner Phenom
Solution Partner Phenom

Hello,

The FEMAP guys are rewritten all the postprocessing portion of FEMAP and when the POWER GRAPHICS will be finished then we will see great improvements in many aspect of postprocessing in FEMAP, one will be that "simply task" like generating an XYPlots of the vonMises Nodal Stress result along a curve, in the future I am sure that all you will need is pick the curve and all will be done, automatically.

 

But for now, well, this is a little tricky, a little complex for novice users, but once you understand the process you will realize the power of FEMAP. Here you are ONE-WAY (you can have others, this is the good of FEMAP) to make plots of results in curves:

 

  • Plot the vonMises nodal stress results in FEMAP (remember, nodal stress, not elemental stress results).
  • Open the Data Table (remember to Unlock the data table!!).
  • In the SELECTOR ENTITY chose NODE.
  • In the SELECTOR MODE activate SELECT MULTIPLE.
  • In the SELECTOR ACTIONS choose DIALOG, then you need to select all nodes where you want to generate the XYPLOT. Simply choose METHOD > ON CURVES and pick the curve or curves you like and FEMAP will select all nodes there (or alternatively enter a GROUP if you have a group of nodes created previously).
  • Press OK and you will have your DATA TABLE filled with plenty of results.

data-table1.png

 

  • Don't panic, all you need is "pair of results". Click to the right of the icon "SHOW/HIDE COLUMNS" and open the menu, select UPDATE MULTIPLE COLUMNS, you will see something like this, will all the names of active columns. Your target column is OUT-NODAL-CONTOUR, there you have the nodal vonMises stress value, the same that you have in the screen if you pick a node and ask for the nodal stress result using SHOW TOOLTIPS. This is exactly the value you want to plot in your XYPLOT chart, this should be your "Y" value of the chart.

data-table-out-nodal-countour.png

 

  • Then UNSELECT all results and select the PAIR of results you want to plot. For instance, in my case I want to order the X-axis of the XYPLOT using the global Z axis, ie, "Z-Def" (if you have created a local coordinate system, active it, and select the axis you want, for instance "Z_Act"):

data-table-out-nodal-countour-detail.png

 

  • Click OK and you will see in the DATA TABLE the data you were looking for: a PAIR of values with distance & vonMises stress, OK?.

data-table-out-nodal-countour-filterZ.png

 

  • Next click in the second icon of the DATA TABLE to perform a COPY TO CLIPBOARD.
  • Create a new functions using command MODEL > FUNCTIONS > NEW, and click in PASTE FROM CLIPBOARD and here you are your data, ready to plot. Fill the TITLE and SAVE WITH OK.

data-table-out-nodal-countour-function.png

 

And finally, in the MODEL INFO tree, under FUNCTIONS click with right mouse button (RMB) on top of the newly created function and select SHOW, you will see automatically your function plotted in the CHARTING window, OK?.

 

data-table-out-nodal-countour-charting.png

 

Enjoy!.

Best regards,

Blas.

Blas Molero Hidalgo, Ingeniero Industrial, Director
IBERISA • 48004 BILBAO (SPAIN)
WEB: http://www.iberisa.com
Blog Femap-NX Nastran: http://iberisa.wordpress.com/

Re: Stress Gradient Extraction

Creator
Creator

This is an amazing response thank you so much.

 

However, from what I understand, the only way to take the stresses is at each nodes? The reason why I am asking is because if my mesh has, lets say, a 0.3in element size and I need measurments every 0.1in would I have to remesh the area to get the correct distance?

 

 

Thank you again,

 

Angela

Re: Stress Gradient Extraction

Solution Partner Phenom Solution Partner Phenom
Solution Partner Phenom

Dear Angela,

In fact, using the above method means "one node, one result". But if you need to interpolate between two nodes using a straight line (not matter the mesh density!!), then the FEMAP Stress Linearization Tool is what you need, this tool was created by one of the developers genius of Femap, Mark Sherman, both are impressing!!. Visit the FEMAP Knowledge Base to download:

http://community.plm.automation.siemens.com/t5/Femap-Knowledge-Base/FEMAP-Stress-Linearization-Tool/...

 

femap-stress-linearization-tool.png

 

Best regards,

Blas.

Blas Molero Hidalgo, Ingeniero Industrial, Director
IBERISA • 48004 BILBAO (SPAIN)
WEB: http://www.iberisa.com
Blog Femap-NX Nastran: http://iberisa.wordpress.com/