Postprocess a modal mechanical simulation

This example shows how to postprocess a modal mechanical simulation to view different mode shapes.

Perform required imports

Perform required imports. This example uses a supplied file that you can get by importing the DPF examples package.

from ansys.dpf import post
from ansys.dpf.post import examples

Get Simulation object

Get the Simulation object that allows access to the result. The Simulation object must be instantiated with the path for the result file. For example, "C:/Users/user/my_result.rst" on Windows or "/home/user/my_result.rst" on Linux.

example_path = examples.download_modal_frame()
# to automatically detect the simulation type, use:
simulation = post.load_simulation(example_path)

# to enable auto-completion, use the equivalent:
simulation = post.ModalMechanicalSimulation(example_path)

View the frequency domain

To help pick the right modes, printing the time frequency support.

print(simulation.time_freq_support)

# set_ids returns the unique identifiers for the modes
print(simulation.set_ids)

DPF  Time/Freq Support:
  Number of sets: 6
Cumulative     Frequency (Hz) LoadStep       Substep
1              253.615690     1              1
2              317.918491     1              2
3              329.825709     1              3
4              575.619678     1              4
5              621.973976     1              5
6              667.364882     1              6

[1, 2, 3, 4, 5, 6]

Extract and view all mode shapes

Extract all mode shapes and view them one by one.

displacement_norm = simulation.displacement(all_sets=True, norm=True)
print(displacement_norm)

for set_id in simulation.set_ids:
    displacement_norm.plot(set_ids=set_id)

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 results   U_N (mm)
 set_ids          1          2          3          4          5          6
node_ids
     367 1.3730e+00 1.8709e+00 2.0199e+00 2.2695e+00 2.9911e+00 1.2970e+00
     509 1.9036e+00 2.5893e+00 2.5942e+00 3.0953e+00 4.0005e+00 1.2648e+00
     428 1.0166e+00 1.4147e+00 1.5069e+00 1.8534e+00 2.3165e+00 7.5843e-01
     510 1.0461e+00 1.4141e+00 1.4841e+00 1.8647e+00 2.2996e+00 8.1520e-01
    3442 1.6226e+00 2.2226e+00 2.2954e+00 2.6685e+00 3.4864e+00 1.2905e+00
    3755 1.4089e+00 1.9743e+00 1.9950e+00 2.4323e+00 3.1554e+00 9.2167e-01
     ...        ...        ...        ...        ...        ...        ...

Extract and view a selection of mode shapes

Extract and view a selection of mode shapes and view them one by one.

modes = [1, 2, 3]

displacement_norm = simulation.displacement(modes=modes, norm=True)
print(displacement_norm)

for set_id in modes:
    displacement_norm.plot(set_ids=set_id)

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 results   U_N (mm)
 set_ids          1          2          3
node_ids
     367 1.3730e+00 1.8709e+00 2.0199e+00
     509 1.9036e+00 2.5893e+00 2.5942e+00
     428 1.0166e+00 1.4147e+00 1.5069e+00
     510 1.0461e+00 1.4141e+00 1.4841e+00
    3442 1.6226e+00 2.2226e+00 2.2954e+00
    3755 1.4089e+00 1.9743e+00 1.9950e+00
     ...        ...        ...        ...