Plot displacement with a nodes/elements

[peluho]

Dear all,

I'm quite new using python, I have a large model of a building.

I'm able to plot displacements through the following piece of code:

result = mapdl.result
result.plot_nodal_displacement(0,'UZ')

However, as it is a large building I'm only interested in some parts of it... when I try to do through a previous selection as:

mapdl.nsle('s','node',vmin=14807,vmax=28010)
mapdl.esel('S','elem',vmin=15596,vmax=28627)

the plotting is still for the whole building, I'm doing something wrong? is there that capability using mapdl?

I've tried the following code (selected_nodes)

result = mapdl.result
mask = mapdl.post_processing.selected_nodes.nonzero()[0]+1
result.plot_nodal_displacement(0,'UZ')_

and this version

result = mapdl.result
mask = mapdl.post_processing.selected_nodes
result.plot_nodal_displacement(0,'UZ')

but neither of them work at all.

Thank you for your help,

david

[germa89]

Hi @peluho

Unfortunately, PyMAPDL at the moments only support plotting of the full entity (nodes, or elements) sets.

I will plan accordingly to have that feature implemented in the future.

Thank you for bringing this up and sorry about the trouble!

[peluho]

au contraire. Thank you for all the efforts.

I was trying to do it by several means, but I was not able that's why i decided to write.

Thanks again,

dP

[mikerife]

Hi @peluho & @germa89 Peluho the "result" method is using the PyMAPDL Reader which is a stand-alone program. That is also included in PyMAPDL. It is meant to be used outside of MAPDL so it does not respect MAPDL commands...since it is stand alone. Please see the following PyMAPDL example model that shows how to post process part of a model using the "post_processing" method:

https://mapdl.docs.pyansys.com/examples/gallery_examples/00-mapdl-examples/lathe_cutter.html#sphx-glr-examples-gallery-examples-00-mapdl-examples-lathe-cutter-py

If you want to stick with the Reader then you can create Components in the MAPDL model prior to solving and those components will be included as definitions in the result file. You can then use those components with the result plotting command:

That "result" command can be found about 2/3rd of the was down this documentation page:
https://reader.docs.pyansys.com/api/rst.html

Mike

[germa89]

Thank you @mikerife , you are totally right... the result module allows you selection!

[peluho]

Thank you for your support.

@mikerife to use the plot_nodal_displacement (components) I found out that with ANSYS v18.0 it does not work. I did try with v2020 R1 and it worked perfectly, however I'm stuck at work witht v18.0 for other reasons.

I try to analyze and run the example you drop me, however I got an error at the step 3. Thank you again

https://mapdl.docs.pyansys.com/examples/gallery_examples/00-mapdl-examples/lathe_cutter.html#sphx-glr-examples-gallery-examples-00-mapdl-examples-lathe-cutter-py

Step 3: Coordinate system and load

mapdl.cskp(11, 0, 2, 1, 13)
mapdl.csys(1)
mapdl.view(1, -1, 1, 1)
mapdl.psymb("CS", 1)
mapdl.vplot(
    color_areas=True,
    show_lines=True,
    cpos=[-1, 1, 1],
    smooth_shading=True,
)

---------------------------------------------------------------------------
IndexError                                Traceback (most recent call last)
~\AppData\Local\Temp/ipykernel_33692/1707561685.py in <module>
      7     show_lines=True,
      8     cpos=[-1, 1, 1],
----> 9     smooth_shading=True,
     10 )

c:\users\perezd\appdata\local\programs\python\python37\lib\site-packages\ansys\mapdl\core\mapdl.py in vplot(self, nv1, nv2, ninc, degen, scale, vtk, quality, show_area_numbering, show_line_numbering, color_areas, show_lines, **kwargs)
   1415                 show_line_numbering=show_line_numbering,
   1416                 show_lines=show_lines,
-> 1417                 **kwargs,
   1418             )
   1419             self.cmsel("S", cm_name, "AREA", mute=True)

c:\users\perezd\appdata\local\programs\python\python37\lib\site-packages\ansys\mapdl\core\mapdl.py in aplot(self, na1, na2, ninc, degen, scale, vtk, quality, show_area_numbering, show_line_numbering, color_areas, show_lines, **kwargs)
   1538             if quality < 1:
   1539                 quality = 1
-> 1540             surf = self.geometry.generate_surface(11 - quality, na1, na2, ninc)
   1541             meshes = []
   1542             labels = []

c:\users\perezd\appdata\local\programs\python\python37\lib\site-packages\ansys\mapdl\core\misc.py in wrapper(*args, **kwargs)
    373             mapdl._set_log_level("CRITICAL")
    374 
--> 375         out = func(*args, **kwargs)
    376 
    377         if prior_log_level != "CRITICAL":

c:\users\perezd\appdata\local\programs\python\python37\lib\site-packages\ansys\mapdl\core\misc.py in wrapper(*args, **kwargs)
    395             mapdl.prep7()
    396 
--> 397         out = func(*args, **kwargs)
    398 
    399         if prior_processor == "Begin level":

c:\users\perezd\appdata\local\programs\python\python37\lib\site-packages\ansys\mapdl\core\mapdl_geometry.py in generate_surface(self, density, amin, amax, ninc)
    321                 # have to use original area numbering here as the
    322                 # duplicated areas numbers are inaccurate
--> 323                 entity_num[i : i + nelem] = orig_anum[index]
    324                 i += nelem
    325         else:

IndexError: index 0 is out of bounds for axis 0 with size 0

[germa89]

mapdl.post_processing.plot_nodal_displacement("norm", lighting=False, show_edges=True)

Did you correctly load the geometry? Can you see the elements if you do mapdl.eplot??

[peluho]

hi there,

The geometry seems to be alright, I created a png showing the geometry.