PyVista Mesh Integration#

Run a modal analysis on a mesh generated from pyvista within MAPDL.

import os
import tempfile

from ansys.mapdl.reader import save_as_archive
import pyvista as pv

from ansys.mapdl.core import launch_mapdl

# launch MAPDL as a service
mapdl = launch_mapdl(loglevel="ERROR")

# Create a simple plane mesh centered at (0, 0, 0) on the XY plane
mesh = pv.Plane(i_resolution=100, j_resolution=100)
mesh.plot(color="w", show_edges=True)
pyvista mesh

Write the mesh to a temporary file

archive_filename = os.path.join(tempfile.gettempdir(), "tmp.cdb")
save_as_archive(archive_filename, mesh)

# Read in the archive file
response = mapdl.cdread("db", archive_filename)
mapdl.prep7()
print(mapdl.shpp("SUMM"))

# specify shell thickness
mapdl.sectype(1, "shell")
mapdl.secdata(0.01)
mapdl.emodif("ALL", "SECNUM", 1)

# specify material properties
# using aprox values for AISI 5000 Series Steel
# http://www.matweb.com/search/datasheet.aspx?matguid=89d4b891eece40fbbe6b71f028b64e9e
mapdl.units("SI")  # not necessary, but helpful for book keeping
mapdl.mp("EX", 1, 200e9)  # Elastic moduli in Pa (kg/(m*s**2))
mapdl.mp("DENS", 1, 7800)  # Density in kg/m3
mapdl.mp("NUXY", 1, 0.3)  # Poissons Ratio
mapdl.emodif("ALL", "MAT", 1)

# Run an unconstrained modal analysis
# for the first 20 modes above 1 Hz
mapdl.modal_analysis(nmode=20, freqb=1)

# you could have also run:
# mapdl.run('/SOLU')
# mapdl.antype('MODAL')  # default NEW
# mapdl.modopt('LANB', 20, 1)
# mapdl.solve()
SUMMARIZE SHAPE TESTING FOR ALL SELECTED ELEMENTS

 ------------------------------------------------------------------------------
            <<<<<<          SHAPE TESTING SUMMARY           >>>>>>
            <<<<<<        FOR ALL SELECTED ELEMENTS         >>>>>>
 ------------------------------------------------------------------------------
                    --------------------------------------
                    |  Element count     10000 SHELL181  |
                    --------------------------------------

  Test                Number tested  Warning count  Error count    Warn+Err %
  ----                -------------  -------------  -----------    ----------
  Aspect Ratio              10000              0             0         0.00 %
  Parallel Deviation        10000              0             0         0.00 %
  Maximum Angle             10000              0             0         0.00 %
  Jacobian Ratio            10000              0             0         0.00 %
  Warping Factor            10000              0             0         0.00 %

  Any                       10000              0             0         0.00 %
 ------------------------------------------------------------------------------

*****  MAPDL SOLVE    COMMAND  *****

 *** NOTE ***                            CP =       0.000   TIME= 00:00:00
 There is no title defined for this analysis.

 *** SELECTION OF ELEMENT TECHNOLOGIES FOR APPLICABLE ELEMENTS ***
                ---GIVE SUGGESTIONS ONLY---

 ELEMENT TYPE         4 IS SHELL181. IT IS ASSOCIATED WITH ELASTOPLASTIC
 MATERIALS ONLY. KEYOPT(8)=2 IS SUGGESTED AND KEYOPT(3)=2 IS SUGGESTED FOR
 HIGHER ACCURACY OF MEMBRANE STRESSES; OTHERWISE, KEYOPT(3)=0 IS SUGGESTED.


   *****MAPDL VERIFICATION RUN ONLY*****
     DO NOT USE RESULTS FOR PRODUCTION

                       S O L U T I O N   O P T I O N S

   PROBLEM DIMENSIONALITY. . . . . . . . . . . . .3-D
   DEGREES OF FREEDOM. . . . . . UX   UY   UZ   ROTX ROTY ROTZ
   ANALYSIS TYPE . . . . . . . . . . . . . . . . .MODAL
      EXTRACTION METHOD. . . . . . . . . . . . . .BLOCK LANCZOS
   NUMBER OF MODES TO EXTRACT. . . . . . . . . . .    20
   SHIFT POINT . . . . . . . . . . . . . . . . . .  1.0000
   GLOBALLY ASSEMBLED MATRIX . . . . . . . . . . .SYMMETRIC

 *** WARNING ***                         CP =       0.000   TIME= 00:00:00
 No constraints have been defined using the D command.

 *** NOTE ***                            CP =       0.000   TIME= 00:00:00
 The step data was checked and warning messages were found.
  Please review output or errors file ( ) for these warning messages.

 *** NOTE ***                            CP =       0.000   TIME= 00:00:00
 The conditions for direct assembly have been met.  No .emat or .erot
 files will be produced.



     D I S T R I B U T E D   D O M A I N   D E C O M P O S E R

  ...Number of elements: 10000
  ...Number of nodes:    10201
  ...Decompose to 0 CPU domains
  ...Element load balance ratio =     0.000


                      L O A D   S T E P   O P T I O N S

   LOAD STEP NUMBER. . . . . . . . . . . . . . . .     1
   THERMAL STRAINS INCLUDED IN THE LOAD VECTOR . .   YES



                         ***********  PRECISE MASS SUMMARY  ***********

   TOTAL RIGID BODY MASS MATRIX ABOUT ORIGIN
               Translational mass               |   Coupled translational/rotational mass
         78.000        0.0000        0.0000     |     0.0000        0.0000      -0.93259E-14
         0.0000        78.000        0.0000     |     0.0000        0.0000      -0.35527E-14
         0.0000        0.0000        78.000     |    0.93259E-14   0.17764E-14    0.0000
     ------------------------------------------ | ------------------------------------------
                                                |         Rotational mass (inertia)
                                                |     6.5006      -0.63664E-15    0.0000
                                                |   -0.26108E-15    6.5006        0.0000
                                                |     0.0000        0.0000        12.999

   TOTAL MASS =  78.000
     The mass principal axes coincide with the global Cartesian axes

   CENTER OF MASS (X,Y,Z)=  -0.45548E-16   0.11956E-15    0.0000

   TOTAL INERTIA ABOUT CENTER OF MASS
         6.5006      -0.63664E-15    0.0000
       -0.63664E-15    6.5006        0.0000
         0.0000        0.0000        12.999
     The inertia principal axes coincide with the global Cartesian axes


  *** MASS SUMMARY BY ELEMENT TYPE ***

  TYPE      MASS
     4   78.0000

 Range of element maximum matrix coefficients in global coordinates
 Maximum = 749504998 at element 0.
 Minimum = 749503915 at element 0.

   *** ELEMENT MATRIX FORMULATION TIMES
     TYPE    NUMBER   ENAME      TOTAL CP  AVE CP

        4     10000  SHELL181      0.000   0.000000
 Time at end of element matrix formulation CP = 0.

  BLOCK LANCZOS CALCULATION OF UP TO    20 EIGENVECTORS.
  NUMBER OF EQUATIONS              =        61206
  MAXIMUM WAVEFRONT                =            0
  MAXIMUM MODES STORED             =           20
  MINIMUM EIGENVALUE               =  0.10000E+01
  MAXIMUM EIGENVALUE               =  0.10000E+31

  Memory available (MB) =    0.0    ,  Memory required (MB) =    0.0

   *****MAPDL VERIFICATION RUN ONLY*****
     DO NOT USE RESULTS FOR PRODUCTION

 *** FREQUENCIES FROM BLOCK LANCZOS ITERATION ***

  MODE    FREQUENCY (HERTZ)


   FREQUENCY RANGE REQUESTED=   20 MODES ABOVE   1.00000     HERTZ

    1     32.74664192961
    2     47.77804288724
    3     59.17108298322
    4     84.60790505095
    5     84.60790505219
    6     148.8927748644
    7     148.8927748650
    8     154.6519861743
    9     168.3840411458
   10     187.7790667334
   11     255.9751634906
   12     255.9751634914
   13     285.2444050786
   14     298.2943388376
   15     319.8023401629
   16     319.8023401636
   17     370.6023621793
   18     391.8457651365
   19     409.1039880841
   20     482.6516135508

Load the result file within pyansys and plot the 8th mode.

result = mapdl.result
print(result)

result.plot_nodal_displacement(7, show_displacement=True, displacement_factor=0.4)
pyvista mesh
PyMAPDL Result
Units       : User Defined
Version     : 24.1
Cyclic      : False
Result Sets : 20
Nodes       : 10201
Elements    : 10000


Available Results:
NSL : Nodal displacements

plot the 1st mode using contours

result.plot_nodal_displacement(
    0, show_displacement=True, displacement_factor=0.4, n_colors=10
)
pyvista mesh

Animate a high frequency mode

Get a smoother plot by disabling movie_filename and increasing n_frames. Enable a continuous plot looping with `loop=True`.

result.animate_nodal_displacement(
    18,
    loop=False,
    add_text=False,
    n_frames=30,
    displacement_factor=0.4,
    show_axes=False,
    background="w",
    movie_filename="plane_vib.gif",
)
pyvista mesh
[(1.5773502691896262, 1.5773502691896262, 1.5773502691896262),
 (0.0, 0.0, 0.0),
 (0.0, 0.0, 1.0)]

Stop mapdl#

mapdl.exit()

Total running time of the script: (0 minutes 7.665 seconds)