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Basic DPF-Core Usage with PyMAPDL#

This example is adapted from Basic DPF-Core Usage Example and it shows how to open a result file in DPF and do some basic postprocessing.

If you have Ansys 2021 R1 installed, starting DPF is quite easy as DPF-Core takes care of launching all the services that are required for postprocessing Ansys files.

First, import the DPF-Core module as dpf_core and import the included examples file.

import tempfile

from ansys.dpf import core as dpf

from ansys.mapdl.core import launch_mapdl
from ansys.mapdl.core.examples import vmfiles

Create model#

Running an example from the MAPDL verification manual

mapdl = launch_mapdl()

vm5 = vmfiles["vm5"]
output = mapdl.input(vm5)

print(output)

# If you are working locally, you don't need to perform the following steps
temp_directory = tempfile.gettempdir()

# Downloading RST file to the current folder
rst_path = mapdl.download_result(temp_directory)

Next, open the generated RST file and print out the Model object. The Model class helps to organize access methods for the result by keeping track of the operators and data sources used by the result file.

Printing the model displays:

  • Analysis type

  • Available results

  • Size of the mesh

  • Number of results

If you are working with a remote server, you might need to upload the RST file before working with it. Then you can create the DPF Model.

dpf.core.make_tmp_dir_server(dpf.SERVER)

if dpf.SERVER.local_server:
    model = dpf.Model(rst_path)
else:
    server_file_path = dpf.upload_file_in_tmp_folder(rst_path)
    model = dpf.Model(server_file_path)

print(model)

Model Metadata#

Specific metadata can be extracted from the model by referencing the model's metadata property. For example, to print only the result_info:

metadata = model.metadata
print(metadata.result_info)

To print the mesh region:

print(metadata.meshed_region)

To print the time or frequency of the results use time_freq_support:

print(metadata.time_freq_support)

Extracting Displacement Results#

All results of the model can be accessed through the Results property, which returns the ansys.dpf.core.results.Results class. This class contains the DPF result operators available to a specific result file, which are listed when printing the object with print(results).

Here, the displacement operator is connected with DataSources, which takes place automatically when running results.displacement(). By default, the displacement operator is connected to the first result set, which for this static result is the only result.

results = model.results
displacements = results.displacement()
fields = displacements.outputs.fields_container()

# Finally, extract the data of the displacement field:
disp = fields[0].data
disp

Plot displacements#

You can plot the previous displacement field using:

model.metadata.meshed_region.plot(fields, cpos="xy")

Or using

fields[0].plot(cpos="xy")

This way is particularly useful if you have used ansys.dpf.core.scoping.Scoping on the mesh or results.

Close session#

Stop MAPDL session.

mapdl.exit()