FEAT: Magnet collector (#429)

Author: gmalinve

examples/low_frequency/magnetic/_static/BH.png

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+# # Magnetic behavior of a magnet-collector system
+#
+# This example shows how to use PyAEDT to understand the magnetic behavior of a simplified
+# magnet-collector system when the magnet position changes.
+# The example shows how to setup the model, an optimetrics analysis to sweep the magnet position
+# and the post-processing of the results, from report creation to field plotting using PyVista.
+#
+# Keywords: **Maxwell 3D**, **Magnetostatic**, **Magnetic**, **Optimetrics**.
+
+# ## Perform imports and define constants
+#
+# Perform required imports.
+
+# +
+import os
+import tempfile
+import time
+
+import ansys.aedt.core  # Interface to Ansys Electronics Desktop
+from ansys.aedt.core.generic.constants import Axis
+
+# -
+
+# ## Define constants
+#
+# Constants help ensure consistency and avoid repetition throughout the example.
+
+AEDT_VERSION = "2025.2"
+NUM_CORES = 4
+NG_MODE = False  # Open AEDT UI when it is launched.
+
+# ## Create temporary directory
+#
+# Create a temporary working directory.
+# The name of the working folder is stored in ``temp_folder.name``.
+#
+# > **Note:** The final cell in the notebook cleans up the temporary folder. If you want to
+# > retrieve the AEDT project and data, do so before executing the final cell in the notebook.
+
+temp_folder = tempfile.TemporaryDirectory(suffix=".ansys")
+
+# ## Launch Maxwell 3d
+#
+# Create an instance of
+# the ``Maxwell3d`` class. The Ansys Electronics Desktop will be launched
+# with an active Maxwell3D design. The ``m3d`` object is subsequently
+# used to create and simulate the model.
+
+m3d = ansys.aedt.core.Maxwell3d(
+    project="magnet_collector",
+    solution_type="Magnetostatic",
+    version=AEDT_VERSION,
+    non_graphical=NG_MODE,
+    new_desktop=True,
+)
+
+# ## Define variables
+#
+# Later on we want to see how the magnetic behavior of the system changes with the position of the magnet.
+
+m3d["magnet_radius"] = "2mm"
+m3d["magnet_height"] = "15mm"
+m3d["magnet_z_pos"] = "0mm"
+
+# ## Add materials
+#
+# Create custom material ``"Aimant"``.
+
+mat = m3d.materials.add_material("Aimant")
+mat.permeability = "1.1"
+mat.set_magnetic_coercivity(value=2005600, x=1, y=1, z=0)
+mat.update()
+
+# ## Create non-linear magnetic material with single valued BH curve
+#
+# Create list with  BH curve data
+
+bh_curve = [
+    [0.0, 0.0],
+    [0.032, 0.5],
+    [0.049, 0.8],
+    [0.065, 1],
+    [0.081, 1.13],
+    [0.17, 1.52],
+    [0.32, 1.59],
+    [0.65, 1.62],
+    [0.81, 1.65],
+    [1.61, 1.7],
+    [3.19, 1.75],
+    [4.78, 1.79],
+    [6.34, 1.83],
+    [7.96, 1.86],
+    [15.89, 1.99],
+    [31.77, 2.1],
+    [63.53, 2.2],
+    [158.77, 2.41],
+    [317.48, 2.65],
+    [635, 3.1],
+]
+
+# ## Create custom material "Fer" and assign the BH curve to the permeability value
+
+mat = m3d.materials.add_material("Fer")
+mat.permeability.value = bh_curve
+mat.set_magnetic_coercivity(value=0, x=1, y=0, z=0)
+mat.update()
+
+# ## Create the collector
+#
+# Create a simple geometry to model the collector and assign a material to it.
+
+# +
+collector = m3d.modeler.create_cylinder(
+    orientation=ansys.aedt.core.constants.AXIS.Z,
+    origin=[12, 13, 25],
+    height="3mm",
+    radius="9.5mm",
+    axisdir="Z",
+    name="collector",
+)
+cylinder2 = m3d.modeler.create_cylinder(
+    orientation=ansys.aedt.core.constants.AXIS.Z,
+    origin=[12, 13, 25],
+    height="3mm",
+    radius="8mm",
+    axisdir="Z",
+    name="cyl2",
+)
+
+m3d.modeler.subtract(
+    blank_list=[collector], tool_list=[cylinder2], keep_originals=False
+)
+
+cylinder3 = m3d.modeler.create_cylinder(
+    orientation=ansys.aedt.core.constants.AXIS.Z,
+    origin=[12, 13, 28],
+    height="3mm",
+    radius="8.7mm",
+    axisdir="Z",
+    name="cyl3",
+)
+cylinder4 = m3d.modeler.create_cylinder(
+    orientation=ansys.aedt.core.constants.AXIS.Z,
+    origin=[12, 13, 28],
+    height="3mm",
+    radius="2mm",
+    axisdir="Z",
+    name="cyl4",
+)
+
+m3d.modeler.subtract(
+    blank_list=[cylinder3], tool_list=[cylinder4], keep_originals=False
+)
+m3d.modeler.unite(assignment=[collector, cylinder3], keep_originals=False)
+
+collector.material_name = "Fer"
+# -
+
+# ## Create magnet
+#
+# Create a cylinder and assign a material to it.
+
+magnet = m3d.modeler.create_cylinder(
+    orientation=Axis.Z,
+    origin=[0, 0, "magnet_z_pos"],
+    radius="magnet_radius",
+    height="magnet_height",
+    num_sides=0,
+    name="magnet",
+    material="Aimant",
+)
+
+# ## Create a polyline
+#
+# Create a polyline to plot the field onto.
+# The polyline is placed in the center of the collector so to capture the magnetic flux density.
+
+line = m3d.modeler.create_polyline(points=[[12, 13, 0], [12, 13, "32mm"]], name="line")
+
+# ## Create a vacuum region to enclose all objects
+
+region = m3d.modeler.create_region(
+    pad_value=50, pad_type="Percentage Offset", name="Region"
+)
+
+# ## Create the collector cross-section on the XZ plane
+
+collector_relative_cs = m3d.modeler.create_coordinate_system(
+    origin=[12, 13, 28], name="collector_cs"
+)
+section = m3d.modeler.create_rectangle(
+    orientation="XZ",
+    position=[-25, 0, -35],
+    dimension_list=["50mm", "50mm"],
+    name="section",
+)
+m3d.modeler.set_working_coordinate_system("Global")
+
+# ## Create a dummy geometry for mesh operations
+#
+# Create a cylinder that encloses the polyline to force the mesh to be finer on the polyline.
+
+dummy_cylinder = m3d.modeler.create_cylinder(
+    orientation=Axis.Z,
+    origin=[12, 13, 0],
+    radius="1mm",
+    height="32mm",
+    num_sides=6,
+    name="dummy_cylinder",
+)
+
+# ## Create a custom named expression
+#
+# Create a custom named expression to calculate relative permeability of the ferromagnetic material.
+# This expression is used to see how the relative permeability of the collector changes with magnet position.
+
+mu_r = {
+    "name": "mu_r",
+    "description": "Relative permeability of the ferromagnetic material",
+    "design_type": ["Maxwell 3D"],
+    "fields_type": ["Fields"],
+    "primary_sweep": "Time",
+    "assignment": "",
+    "assignment_type": [""],
+    "operations": [
+        "NameOfExpression('Mag_B')",
+        "NameOfExpression('Mag_H')",
+        "Scalar_Constant(1.25664e-06)",
+        "Operation('*')",
+        "Operation('/')",
+    ],
+    "report": ["Field_3D"],
+}
+m3d.post.fields_calculator.add_expression(mu_r, None)
+
+# ## Set mesh operations
+#
+# Assign mesh operations to the dummy cylinder and the collector.
+
+poly_mesh = m3d.mesh.assign_length_mesh(
+    assignment=[dummy_cylinder], maximum_length="1mm", name="polyline"
+)
+collector_mesh = m3d.mesh.assign_length_mesh(
+    assignment=[collector],
+    inside_selection=False,
+    maximum_length="3.8mm",
+    name="collector",
+)
+
+# ## Create simulation setup
+
+setup = m3d.create_setup()
+setup.props["MaximumPasses"] = 10
+setup.props["PercentRefinement"] = 30
+setup.props["PercentError"] = 2
+setup.props["MinimumPasses"] = 2
+setup.props["NonlinearResidual"] = 1e-3
+
+# ## Add parametric sweep
+#
+# Create a linear count sweep where the parameter to sweep is ``"magnet_z_pos"``.
+# The magnet position is changed at each step to see how the magnetic behavior of the system changes.
+# Enable the saving fields option.
+
+# +
+param_sweep = m3d.parametrics.add(
+    variable="magnet_z_pos",
+    start_point=m3d["magnet_z_pos"],
+    end_point="25mm",
+    step=5,
+    variation_type="LinearCount",
+)
+
+param_sweep.props["ProdOptiSetupDataV2"]["SaveFields"] = True
+# -
+
+# ## Analyze parametric sweep
+
+param_sweep.analyze(cores=NUM_CORES)
+
+# ## Create reports
+#
+# Create rectangular and data plots on the polyline for different magnet positions.
+
+# +
+data_table = m3d.post.create_report(
+    expressions="Mag_B",
+    report_category="Fields",
+    plot_type="Data Table",
+    plot_name="Mag_B",
+    variations={"magnet_z_pos": "All"},
+    context=line.name,
+    polyline_points=101,
+)
+
+rectangular_plot = m3d.post.create_report(
+    expressions="Mag_B",
+    report_category="Fields",
+    plot_type="Rectangular Plot",
+    plot_name="Mag_B",
+    variations={"magnet_z_pos": "All"},
+    context=line.name,
+    polyline_points=101,
+)
+# -
+
+# ## Create field plots
+#
+# Create field plots over the collector cross-section and on
+# the collector surface to see how the magnetic flux density (B),
+# the vector B field, the magnetic field strength (H) and the permeability
+# of the ferromagnetic material (μ) change.
+
+mag_b = m3d.post.create_fieldplot_surface(
+    assignment=[section.name], quantity="Mag_B", plot_name="Mag_B", field_type="Fields"
+)
+vector_b = m3d.post.create_fieldplot_volume(
+    assignment=[collector.name],
+    quantity="B_Vector",
+    plot_name="B_Vector",
+    field_type="Fields",
+)
+mag_h = m3d.post.create_fieldplot_surface(
+    assignment=[section.name], quantity="Mag_H", plot_name="Mag_H", field_type="Fields"
+)
+mu_r = m3d.post.create_fieldplot_surface(
+    assignment=[collector.name], quantity="mu_r", plot_name="mu_r", field_type="Fields"
+)
+
+# ## Export field
+#
+# Export magnetic flux density B on the collector cross-section in a .fld file.
+
+fld_filename = os.path.join(temp_folder.name, "Mag_B.fld")
+m3d.post.export_field_file(
+    quantity="Mag_B",
+    output_file=fld_filename,
+    assignment=section.name,
+    objects_type="Surf",
+)
+
+# ## Overlay fields using PyVista
+#
+# Plot electric field using PyVista and save to an image file.
+# Plot the relative permeability on the collector surface at a given magnet position.
+# Change argument ``"show"`` to ``True`` see the permeability plot.
+
+m3d["magnet_z_pos"] = "18.75mm"
+
+py_vista_plot = m3d.post.plot_field(
+    quantity="mu_r", assignment=collector.name, plot_cad_objs=True, show=False
+)
+py_vista_plot.isometric_view = True
+py_vista_plot.plot(
+    export_image_path=os.path.join(temp_folder.name, "mu_r.jpg"), show=True
+)
+
+# ## BH curve of the ferromagnetic material
+#
+# From the plot exported in the previous section, we can see the trend of the relative permeability
+# when the magnet gets close to the collector.
+# Looking at the scale of the relative permeability, we can see that the collector is far from saturation.
+# With a permeability peak value around 1.3E+7, the collector is still in the linear region of the BH curve.
+# ![BH curve and relative permeability of the ferromagnetic material](_static/BH.png)
+# ![Zoom in on the relative permeability of the ferromagnetic material](_static/BH_zoom_in.png)
+
+# ## Release AEDT
+
+m3d.save_project()
+m3d.release_desktop()
+# Wait 3 seconds to allow AEDT to shut down before cleaning the temporary directory.
+time.sleep(3)
+
+# ## Clean up
+#
+# All project files are saved in the folder ``temp_folder.name``.
+# If you've run this example as a Jupyter notebook, you
+# can retrieve those project files. The following cell
+# removes all temporary files, including the project folder.
+
+temp_folder.cleanup()