# *************************************************************************** # * Copyright (c) 2023 Uwe Stöhr * # * * # * This file is part of the FreeCAD CAx development system. * # * * # * This program is free software; you can redistribute it and/or modify * # * it under the terms of the GNU Lesser General Public License (LGPL) * # * as published by the Free Software Foundation; either version 2 of * # * the License, or (at your option) any later version. * # * for detail see the LICENCE text file. * # * * # * This program is distributed in the hope that it will be useful, * # * but WITHOUT ANY WARRANTY; without even the implied warranty of * # * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * # * GNU Library General Public License for more details. * # * * # * You should have received a copy of the GNU Library General Public * # * License along with this program; if not, write to the Free Software * # * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 * # * USA * # * * # *************************************************************************** import sys import FreeCAD import Fem import ObjectsFem from BOPTools import SplitFeatures from BasicShapes import Shapes from . import manager from .manager import get_meshname from .manager import init_doc def get_information(): return { "name": "Magnetic Field Around Wire", "meshtype": "solid", "meshelement": "Tet10", "constraints": ["electrostatic potential", "magnetization"], "solvers": ["elmer"], "material": "solid", "equations": ["electromagnetic"] } def get_explanation(header=""): return header + """ To run the example from Python console use: from femexamples.equation_magnetodynamics_elmer import setup setup() Magnetodynamic equation - Elmer solver """ def setup(doc=None, solvertype="elmer"): # init FreeCAD document if doc is None: doc = init_doc() # explanation object # just keep the following line and change text string in get_explanation method manager.add_explanation_obj(doc, get_explanation(manager.get_header(get_information()))) # geometric objects # wire Wire = doc.addObject("Part::Cylinder", "Wire") Wire.Radius = "1 mm" Wire.Height = "10 mm" Wire.ViewObject.Visibility = False # air around wire Air = Shapes.addTube(doc, "Tube") Air.Label = "AirObject" Air.OuterRadius = "5 mm" Air.InnerRadius = "1 mm" Air.Height = "10 mm" Air.ViewObject.Visibility = False # BooleanFregments object to combine cut with rod BooleanFragments = SplitFeatures.makeBooleanFragments(name="BooleanFragments") BooleanFragments.Objects = [Wire, Air] # set view doc.recompute() if FreeCAD.GuiUp: BooleanFragments.ViewObject.Transparency = 75 BooleanFragments.ViewObject.Document.activeView().viewAxonometric() BooleanFragments.ViewObject.Document.activeView().fitAll() # analysis analysis = ObjectsFem.makeAnalysis(doc, "Analysis") if FreeCAD.GuiUp: import FemGui FemGui.setActiveAnalysis(analysis) # solver if solvertype == "elmer": solver_obj = ObjectsFem.makeSolverElmer(doc, "SolverElmer") eq_electrostatic = ObjectsFem.makeEquationMagnetodynamic(doc, solver_obj) eq_electrostatic.AngularFrequency = "100 kHz" eq_electrostatic.BiCGstablDegree = 4 eq_electrostatic.IsHarmonic = True eq_electrostatic.LinearIterativeMethod = "BiCGStabl" eq_electrostatic.LinearPreconditioning = "None" else: FreeCAD.Console.PrintWarning( "Unknown or unsupported solver type: {}. " "No solver object was created.\n".format(solvertype) ) analysis.addObject(solver_obj) # material # air around the wire material_obj = ObjectsFem.makeMaterialFluid(doc, "Air") mat = material_obj.Material mat["Name"] = "Air" mat["Density"] = "1.204 kg/m^3" mat["ThermalConductivity"] = "0.02587 W/m/K" mat["ThermalExpansionCoefficient"] = "3.43e-3 1/K" mat["SpecificHeat"] = "1.01 kJ/kg/K" mat["ElectricalConductivity"] = "1e-12 S/m" mat["RelativePermeability"] = "1.0" mat["RelativePermittivity"] = "1.00059" material_obj.Material = mat material_obj.References = [(BooleanFragments, "Solid2")] analysis.addObject(material_obj) # copper wire material_obj = ObjectsFem.makeMaterialSolid(doc, "Copper") mat = material_obj.Material mat["Name"] = "Copper Generic" mat["Density"] = "8960 kg/m^3" mat["PoissonRatio"] = "0.343" mat["ShearModulus"] = "46.0 GPa" mat["UltimateTensileStrength"] = "210 MPa" mat["YoungsModulus"] = "119 GPa" mat["ThermalConductivity"] = "398.0 W/m/K" mat["ThermalExpansionCoefficient"] = "16.5 µm/m/K" mat["SpecificHeat"] = "385.0 J/kg/K" mat["ElectricalConductivity"] = "59.59 MS/m" mat["RelativePermeability"] = "0.999994" material_obj.Material = mat material_obj.References = [(BooleanFragments, "Solid1")] analysis.addObject(material_obj) # axial field around the wire AxialField = ObjectsFem.makeConstraintElectrostaticPotential(doc, "AxialField") AxialField.References = [ (BooleanFragments, "Face4"), (BooleanFragments, "Face5"), (BooleanFragments, "Face6")] AxialField.PotentialEnabled = False AxialField.AV_im_1_Disabled = False AxialField.AV_im_2_Disabled = False AxialField.AV_re_1_Disabled = False AxialField.AV_re_2_Disabled = False analysis.addObject(AxialField) # voltage on one end Voltage = ObjectsFem.makeConstraintElectrostaticPotential(doc, "Voltage") Voltage.References = [(BooleanFragments, "Face3")] Voltage.Potential = "10.000 mV" Voltage.AV_im_1_Disabled = False Voltage.AV_im_2_Disabled = False Voltage.AV_re_1_Disabled = False Voltage.AV_re_2_Disabled = False analysis.addObject(Voltage) # ground on other end Ground = ObjectsFem.makeConstraintElectrostaticPotential(doc, "Ground") Ground.References = [(BooleanFragments, "Face2")] Ground.Potential = "0 V" Ground.AV_im_1_Disabled = False Ground.AV_im_2_Disabled = False Ground.AV_re_1_Disabled = False Ground.AV_re_2_Disabled = False analysis.addObject(Ground) # magnetization Magnetization = ObjectsFem.makeConstraintMagnetization(doc, "Magnetization") Magnetization.References = [(BooleanFragments, "Solid1")] Magnetization.Magnetization_re_1 = "7500.000 A/m" Magnetization.Magnetization_re_2 = "7500.000 A/m" Magnetization.Magnetization_re_3 = "7500.000 A/m" Magnetization.Magnetization_re_2_Disabled = False analysis.addObject(Magnetization) # mesh femmesh_obj = analysis.addObject(ObjectsFem.makeMeshGmsh(doc, get_meshname()))[0] femmesh_obj.Part = BooleanFragments femmesh_obj.ElementOrder = "1st" femmesh_obj.CharacteristicLengthMax = "0.5 mm" femmesh_obj.ViewObject.Visibility = False # mesh_region mesh_region = ObjectsFem.makeMeshRegion(doc, femmesh_obj, name="MeshRegion") mesh_region.CharacteristicLength = "0.15 mm" mesh_region.References = [(BooleanFragments, "Solid1")] mesh_region.ViewObject.Visibility = False # generate the mesh from femmesh import gmshtools gmsh_mesh = gmshtools.GmshTools(femmesh_obj, analysis) try: error = gmsh_mesh.create_mesh() except Exception: error = sys.exc_info()[1] FreeCAD.Console.PrintError( "Unexpected error when creating mesh: {}\n" .format(error) ) if error: # try to create from existing rough mesh from .meshes.mesh_capacitance_two_balls_tetra10 import create_nodes, create_elements fem_mesh = Fem.FemMesh() control = create_nodes(fem_mesh) if not control: FreeCAD.Console.PrintError("Error on creating nodes.\n") control = create_elements(fem_mesh) if not control: FreeCAD.Console.PrintError("Error on creating elements.\n") femmesh_obj.FemMesh = fem_mesh doc.recompute() return doc