# *************************************************************************** # * 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 from FreeCAD import Vector import Draft import ObjectsFem import Part from BOPTools import SplitFeatures from . import manager from .manager import get_meshname from .manager import init_doc def get_information(): return { "name": "Magnetostatic - Elmer 2D", "meshtype": "solid", "meshelement": "Tet10", "constraints": ["magnetization"], "solvers": ["elmer"], "material": "solid", "equations": ["magnetostatic"] } def get_explanation(header=""): return header + """ To run the example from Python console use: from femexamples.equation_magnetostatics_2D_elmer import setup setup() Magnetodynamic2D 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 defining the lower horse shoe end p1 = Vector(0.0, -200.0, 0.0) p2 = Vector(200.0, -200.0, 0.0) p3 = Vector(200.0, -100.0, 0.0) p4 = Vector(0.0, -100.0, 0.0) Horseshoe_lower = Draft.make_wire([p1, p2, p3, p4], closed=True) Horseshoe_lower.Label = "Lower_End" Horseshoe_lower.ViewObject.Visibility = False # wire defining the upper horse shoe end p1 = Vector(0.0, 100.0, 0.0) p2 = Vector(200.0, 100.0, 0.0) p3 = Vector(200.0, 200.0, 0.0) p4 = Vector(0.0, 200.0, 0.0) Horseshoe_upper = Draft.make_wire([p1, p2, p3, p4], closed=True) Horseshoe_upper.Label = "Upper_End" Horseshoe_upper.ViewObject.Visibility = False # the U-part of the horse shoe # credits: https://forum.freecad.org/viewtopic.php?p=663051#p663051 vpairs = [[Vector(340.0, 200.0, 0.0), Vector(200.0, 200.0, 0.0)], [Vector(200.0, 200.0, 0.0), Vector(200.0, 100.0, 0.0)], [Vector(200.0, 100.0, 0.0), Vector(325.0, 100.0, 0.0)], [Vector(325.0, 100.0, 0.0), Vector(325.0, -100.0, 0.0)], [Vector(325.0, -100.0, 0.0), Vector(200.0, -100.0, 0.0)], [Vector(200.0, -100.0, 0.0), Vector(200.0, -200.0, 0.0)], [Vector(200.0, -200.0, 0.0), Vector(340.0, -200.0, 0.0)], [Vector(340.0, 200.0, 0.0), Vector(340.0, -200.0, 0.0)]] typeId = ['Part::GeomLine', 'Part::GeomLine', 'Part::GeomLine', 'Part::GeomBSplineCurve', 'Part::GeomLine', 'Part::GeomLine', 'Part::GeomLine', 'Part::GeomBSplineCurve'] e3Poles = [Vector(325.0, 100.0, 0.0), Vector(400.0, 100.0, 0.0), Vector(400.0, 0.0, 0.0), Vector(400.0, -100.0, 0.0), Vector(325.0, -100.0, 0.0)] e3Knots = [0.0, 0.5, 1.0] e3Mults = [4, 1, 4] e3Degree = 3 e7Poles = [Vector(340.0, 200.0, 0.0), Vector(500.0, 200.0, 0.0), Vector(500.0, 0.0, 0.0), Vector(500.0, -200.0, 0.0), Vector(340.0, -200.0, 0.0)] e7Knots = [0.0, 0.5, 1.0] e7Mults = [4, 1, 4] e7Degree = 3 c3 = Part.BSplineCurve() c3.buildFromPolesMultsKnots(e3Poles, e3Mults, e3Knots, False, e3Degree) c7 = Part.BSplineCurve() c7.buildFromPolesMultsKnots(e7Poles, e7Mults, e7Knots, False, e7Degree) edges = [c3.toShape(), c7.toShape()] for i in range(len(typeId)): if typeId[i] == 'Part::GeomLine': edges.append(Part.makeLine(*vpairs[i])) sedges = Part.__sortEdges__(edges) Horseshoe_U = doc.addObject("Part::Feature", "Horseshoe_U") Horseshoe_U.Shape = Part.Face(Part.Wire(sedges)) # a circle defining later the air volume Air_Circle = doc.addObject("Part::Feature", "Air_Circle") Air_Circle.Shape = Part.Face(Part.Wire(Part.makeCircle(1500.0))) # a link of the Horseshoe_lower Horseshoe_lowerLink = doc.addObject("App::Link", "Link_Lower_End") Horseshoe_lowerLink.LinkTransform = True Horseshoe_lowerLink.LinkedObject = Horseshoe_lower Horseshoe_lowerLink.ViewObject.Visibility = False # a link of the Horseshoe_upper Horseshoe_upperLink = doc.addObject("App::Link", "Link_Upper_End") Horseshoe_upperLink.LinkTransform = True Horseshoe_upperLink.LinkedObject = Horseshoe_upper Horseshoe_upperLink.ViewObject.Visibility = False # a link of the Horseshoe_U Horseshoe_ULink = doc.addObject("App::Link", "Link_Horseshoe_U") Horseshoe_ULink.LinkTransform = True Horseshoe_ULink.LinkedObject = Horseshoe_U Horseshoe_ULink.ViewObject.Visibility = False # fusion of all links Fusion = doc.addObject("Part::MultiFuse", "Fusion") Fusion.Shapes = [Horseshoe_lowerLink, Horseshoe_upperLink, Horseshoe_ULink] Fusion.ViewObject.Visibility = False # cut all objects from Air wire to get volume of fluid Cut = doc.addObject("Part::Cut", "Cut_Air") Cut.Base = Air_Circle Cut.Tool = Fusion Cut.ViewObject.Visibility = False # BooleanFregments object to combine cut with rod BooleanFragments = SplitFeatures.makeBooleanFragments(name="BooleanFragments") BooleanFragments.Objects = [Horseshoe_lower, Horseshoe_upper, Horseshoe_U, Cut] # set view doc.recompute() if FreeCAD.GuiUp: BooleanFragments.ViewObject.Document.activeView().viewTop() 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") solver_obj.CoordinateSystem = "Cartesian 2D" equation_magnetodynamic2D = ObjectsFem.makeEquationMagnetodynamic2D(doc, solver_obj) equation_magnetodynamic2D.CalculateMagneticFieldStrength = True else: FreeCAD.Console.PrintWarning( "Unknown or unsupported solver type: {}. " "No solver object was created.\n".format(solvertype) ) return doc analysis.addObject(solver_obj) # materials # air around the horse shoe 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, "Face4")] analysis.addObject(material_obj) # iron of the horse shoe material_obj = ObjectsFem.makeMaterialSolid(doc, "Iron") mat = material_obj.Material mat["Name"] = "Iron Generic" mat["ElectricalConductivity"] = "10.3 MS/m" mat["RelativePermeability"] = "5000.0" material_obj.Material = mat material_obj.References = [ (BooleanFragments, "Face1"), (BooleanFragments, "Face2"), (BooleanFragments, "Face3")] analysis.addObject(material_obj) # magnetization lower Magnetization_lower = ObjectsFem.makeConstraintMagnetization(doc, "Magnetization_Lower_End") Magnetization_lower.References = [(BooleanFragments, "Face1")] Magnetization_lower.Magnetization_re_1 = "-7500.0 A/m" Magnetization_lower.Magnetization_re_1_Disabled = False analysis.addObject(Magnetization_lower) # magnetization upper Magnetization_upper = ObjectsFem.makeConstraintMagnetization(doc, "Magnetization_Upper_End") Magnetization_upper.References = [(BooleanFragments, "Face2")] Magnetization_upper.Magnetization_re_1 = "7500.0 A/m" Magnetization_upper.Magnetization_re_1_Disabled = False analysis.addObject(Magnetization_upper) # mesh femmesh_obj = analysis.addObject(ObjectsFem.makeMeshGmsh(doc, get_meshname()))[0] femmesh_obj.Part = BooleanFragments femmesh_obj.CharacteristicLengthMax = "100.0 mm" femmesh_obj.ViewObject.Visibility = False # mesh_region mesh_region = ObjectsFem.makeMeshRegion(doc, femmesh_obj, name="MeshRegion") mesh_region.CharacteristicLength = "6.5 mm" mesh_region.References = [ (BooleanFragments, "Face1"), (BooleanFragments, "Face2"), (BooleanFragments, "Face3")] 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) ) doc.recompute() return doc