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---

Lorentz actuator

This example uses PyAEDT to set up a Lorentz actuator and solve it using the Maxwell 2D transient solver.

Keywords: Maxwell2D, transient, translational motion, mechanical transient

Perform imports and define constantss

Perform required imports.

import os
import tempfile
import time

import ansys.aedt.core

Define constants.

AEDT_VERSION = "2024.2"
NUM_CORES = 4
NG_MODE = False  # Open AEDT UI when it is launched.

Create temporary directory

Create a temporary directory where downloaded data or dumped data can be stored. If you’d like to retrieve the project data for subsequent use, the temporary folder name is given by temp_folder.name.

temp_folder = tempfile.TemporaryDirectory(suffix=".ansys")

Initialize dictionaries

Initialize the following:

• Electric and geometric parameters for the actuator

• Simulation specifications

• Materials for the actuator component

dimensions = {
    "Core_outer_x": "100mm",
    "Core_outer_y": "80mm",
    "Core_thickness": "10mm",
    "Magnet_thickness": "10mm",
    "Coil_width": "30mm",
    "Coil_thickness": "5mm",
    "Coil_inner_diameter": "20mm",
    "Coil_magnet_distance": "5mm",
    "Coil_start_position": "3mm",
    "Band_clearance": "1mm",
}

coil_specifications = {
    "Winding_current": "5A",
    "No_of_turns": "100",
    "Coil_mass": "0.2kg",
}

simulation_specifications = {
    "Mesh_bands": "0.5mm",
    "Mesh_other_objects": "2mm",
    "Stop_time": "10ms",
    "Time_step": "0.5ms",
    "Save_fields_interval": "1",
}

materials = {
    "Coil_material": "copper",
    "Core_material": "steel_1008",
    "Magnet_material": "NdFe30",
}

Launch AEDT and Maxwell 2D

Launch AEDT and Maxwell 2D after first setting up the project name. The following code also creates an instance of the Maxwell2d class named m2d by providing the project name, the design name, the solver, the version, and the graphical mode.

project_name = os.path.join(temp_folder.name, "Lorentz_actuator.aedt")
m2d = ansys.aedt.core.Maxwell2d(
    project=project_name,
    design="1 transient 2D",
    solution_type="TransientXY",
    version=AEDT_VERSION,
    non_graphical=NG_MODE,
)

PyAEDT INFO: Python version 3.10.11 (tags/v3.10.11:7d4cc5a, Apr  5 2023, 00:38:17) [MSC v.1929 64 bit (AMD64)]
PyAEDT INFO: PyAEDT version 0.12.dev0.
PyAEDT INFO: Initializing new Desktop session.
PyAEDT INFO: Log on console is enabled.
PyAEDT INFO: Log on file C:\Users\ansys\AppData\Local\Temp\pyaedt_ansys_dab0fde8-c5c7-44d8-95c4-dc5d5fd16851.log is enabled.
PyAEDT INFO: Log on AEDT is enabled.
PyAEDT INFO: Debug logger is disabled. PyAEDT methods will not be logged.
PyAEDT INFO: Launching PyAEDT with gRPC plugin.
PyAEDT INFO: New AEDT session is starting on gRPC port 53092
PyAEDT INFO: AEDT installation Path C:\Program Files\AnsysEM\v242\Win64
PyAEDT INFO: Ansoft.ElectronicsDesktop.2024.2 version started with process ID 4600.
PyAEDT INFO: Project Lorentz_actuator has been created.
PyAEDT INFO: Added design '1 transient 2D' of type Maxwell 2D.
PyAEDT INFO: Aedt Objects correctly read

Define variables from dictionaries

Define design variables from the created dictionaries.

m2d.variable_manager.set_variable(name="Dimensions")
for k, v in dimensions.items():
    m2d[k] = v

m2d.variable_manager.set_variable(name="Winding data")
for k, v in coil_specifications.items():
    m2d[k] = v

m2d.variable_manager.set_variable(name="Simulation data")
for k, v in simulation_specifications.items():
    m2d[k] = v

Definem materials.

m2d.variable_manager.set_variable(name="Material data")
m2d.logger.clear_messages()
for i, key in enumerate(materials.keys()):
    if key == "Coil_material":
        coil_mat_index = i
    elif key == "Core_material":
        core_mat_index = i
    elif key == "Magnet_material":
        magnet_mat_index = i
material_array = []
for k, v in materials.items():
    material_array.append('"' + v + '"')
s = ", ".join(material_array)
m2d["Materials"] = "[{}]".format(s)

Create geometry

Create magnetic core, coils, and magnets. Assign materials and create a coordinate system to define the magnet orientation.

core_id = m2d.modeler.create_rectangle(
    origin=[0, 0, 0],
    sizes=["Core_outer_x", "Core_outer_y"],
    name="Core",
    material="Materials[" + str(core_mat_index) + "]",
)

PyAEDT INFO: Modeler2D class has been initialized!
PyAEDT INFO: Modeler class has been initialized! Elapsed time: 0m 1sec
PyAEDT INFO: Materials class has been initialized! Elapsed time: 0m 0sec

hole_id = m2d.modeler.create_rectangle(
    origin=["Core_thickness", "Core_thickness", 0],
    sizes=["Core_outer_x-2*Core_thickness", "Core_outer_y-2*Core_thickness"],
    name="hole",
)
m2d.modeler.subtract(blank_list=[core_id], tool_list=[hole_id])

True

magnet_n_id = m2d.modeler.create_rectangle(
    origin=["Core_thickness", "Core_outer_y-2*Core_thickness", 0],
    sizes=["Core_outer_x-2*Core_thickness", "Magnet_thickness"],
    name="magnet_n",
    material="Materials[" + str(magnet_mat_index) + "]",
)
magnet_s_id = m2d.modeler.create_rectangle(
    origin=["Core_thickness", "Core_thickness", 0],
    sizes=["Core_outer_x-2*Core_thickness", "Magnet_thickness"],
    name="magnet_s",
    material="Materials[" + str(magnet_mat_index) + "]",
)

m2d.modeler.create_coordinate_system(
    origin=[0, 0, 0], x_pointing=[0, 1, 0], y_pointing=[1, 0, 0], name="cs_x_positive"
)
m2d.modeler.create_coordinate_system(
    origin=[0, 0, 0], x_pointing=[0, -1, 0], y_pointing=[1, 0, 0], name="cs_x_negative"
)
magnet_s_id.part_coordinate_system = "cs_x_positive"
magnet_n_id.part_coordinate_system = "cs_x_negative"
m2d.modeler.set_working_coordinate_system("Global")

True

Assign current

Create coil terminals with 100 turns and winding with 5A current.

coil_in_id = m2d.modeler.create_rectangle(
    origin=[
        "Core_thickness+Coil_start_position",
        "Core_thickness+Magnet_thickness+Coil_magnet_distance",
        0,
    ],
    sizes=["Coil_width", "Coil_thickness"],
    name="coil_in",
    material="Materials[" + str(coil_mat_index) + "]",
)
coil_out_id = m2d.modeler.create_rectangle(
    origin=[
        "Core_thickness+Coil_start_position",
        "Core_thickness+Magnet_thickness+Coil_magnet_distance+Coil_inner_diameter+Coil_thickness",
        0,
    ],
    sizes=["Coil_width", "Coil_thickness"],
    name="coil_out",
    material="Materials[" + str(coil_mat_index) + "]",
)

m2d.assign_coil(
    assignment=[coil_in_id],
    conductors_number="No_of_turns",
    name="coil_terminal_in",
    polarity="Negative",
)
m2d.assign_coil(
    assignment=[coil_out_id],
    conductors_number="No_of_turns",
    name="coil_terminal_out",
    polarity="Positive",
)
m2d.assign_winding(is_solid=False, current="Winding_current", name="Winding1")
m2d.add_winding_coils(
    assignment="Winding1", coils=["coil_terminal_in", "coil_terminal_out"]
)

True

Assign motion

Create band objects. All the objects within the band move. The inner band ensures that the mesh is good, and additionally it is required when there is more than one moving object. Assign linear motion with mechanical transient.

band_id = m2d.modeler.create_rectangle(
    origin=[
        "Core_thickness + Band_clearance",
        "Core_thickness+Magnet_thickness+Band_clearance",
        0,
    ],
    sizes=[
        "Core_outer_x-2*(Core_thickness+Band_clearance)",
        "Core_outer_y-2*(Core_thickness+Band_clearance+Magnet_thickness)",
    ],
    name="Motion_band",
)
inner_band_id = m2d.modeler.create_rectangle(
    origin=[
        "Core_thickness+Coil_start_position-Band_clearance",
        "Core_thickness+Magnet_thickness+Coil_magnet_distance-Band_clearance",
        0,
    ],
    sizes=[
        "Coil_width + 2*Band_clearance",
        "Coil_inner_diameter+2*(Coil_thickness+Band_clearance)",
    ],
    name="Motion_band_inner",
)
motion_limit = "Core_outer_x-2*(Core_thickness+Band_clearance)-(Coil_width + 2*Band_clearance)-2*Band_clearance"
m2d.assign_translate_motion(
    assignment="Motion_band",
    axis="X",
    periodic_translate=None,
    mechanical_transient=True,
    mass="Coil_mass",
    start_position=0,
    negative_limit=0,
    positive_limit=motion_limit,
)

<ansys.aedt.core.modules.boundary.BoundaryObject at 0x1a8e3b82f20>

Create simulation domain

Create a region and assign zero vector potential on the region edges.

region_id = m2d.modeler.create_region(pad_percent=2)
m2d.assign_vector_potential(assignment=region_id.edges, boundary="VectorPotential1")

<ansys.aedt.core.modules.boundary.BoundaryObject at 0x1a8e3b82f80>

Assign mesh operations

The transient solver does not have adaptive mesh refinement, so the mesh operations must be assigned.

m2d.mesh.assign_length_mesh(
    assignment=[band_id, inner_band_id],
    maximum_length="Mesh_bands",
    maximum_elements=None,
    name="Bands",
)
m2d.mesh.assign_length_mesh(
    assignment=[coil_in_id, coil_in_id, core_id, magnet_n_id, magnet_s_id, region_id],
    maximum_length="Mesh_other_objects",
    maximum_elements=None,
    name="Coils_core_magnets",
)

PyAEDT INFO: Mesh class has been initialized! Elapsed time: 0m 0sec
PyAEDT INFO: Mesh class has been initialized! Elapsed time: 0m 0sec

<ansys.aedt.core.modules.mesh.MeshOperation at 0x1a8f72091e0>

Turn on eddy effects

Assign eddy effects to the magnets.

m2d.eddy_effects_on(assignment=["magnet_n", "magnet_s"])

True

Turn on core loss

Enable core loss for the core.

m2d.set_core_losses(assignment="Core")

True

Create simulation setup

setup = m2d.create_setup(name="Setup1")
setup.props["StopTime"] = "Stop_time"
setup.props["TimeStep"] = "Time_step"
setup.props["SaveFieldsType"] = "Every N Steps"
setup.props["N Steps"] = "Save_fields_interval"
setup.props["Steps From"] = "0ms"
setup.props["Steps To"] = "Stop_time"

Create report

Create an XY-report with force on the coil, the position of the coil on the Y axis, and time on the X axis.

m2d.post.create_report(
    expressions=["Moving1.Force_x", "Moving1.Position"],
    plot_name="Force on Coil and Position of Coil",
    primary_sweep_variable="Time",
)

PyAEDT INFO: Parsing C:/Users/ansys/AppData/Local/Temp/tmpqq4lecgm.ansys/Lorentz_actuator.aedt.
PyAEDT INFO: File C:/Users/ansys/AppData/Local/Temp/tmpqq4lecgm.ansys/Lorentz_actuator.aedt correctly loaded. Elapsed time: 0m 0sec
PyAEDT INFO: aedt file load time 0.015631437301635742
PyAEDT INFO: PostProcessor class has been initialized! Elapsed time: 0m 0sec
PyAEDT INFO: Post class has been initialized! Elapsed time: 0m 0sec

<ansys.aedt.core.visualization.report.standard.Standard at 0x1a8f7bf5b70>

Analyze project

setup.analyze(cores=NUM_CORES, use_auto_settings=False)

PyAEDT INFO: Key Desktop/ActiveDSOConfigurations/Maxwell 2D correctly changed.
PyAEDT INFO: Solving design setup Setup1
PyAEDT INFO: Key Desktop/ActiveDSOConfigurations/Maxwell 2D correctly changed.
PyAEDT INFO: Design setup Setup1 solved correctly in 0.0h 6.0m 32.0s

Release AEDT

m2d.save_project()
m2d.release_desktop()
# Wait 3 seconds to allow AEDT to shut down before cleaning the temporary directory.
time.sleep(3)

PyAEDT INFO: Project Lorentz_actuator Saved correctly
PyAEDT INFO: Desktop has been released and closed.

Clean up

All project files are saved in the folder temp_dir.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()

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Download this example as a Jupyter Notebook or as a Python script.