FEM: fem exapmles, add nonlinear material example to show peeq strain

src/Mod/Fem/CMakeLists.txt

@@ -38,6 +38,7 @@ SET(FemExamples_SRCS
     femexamples/boxanalysis.py
     femexamples/ccx_cantilever_std.py
     femexamples/manager.py
+    femexamples/material_nl_platewithhole.py
     femexamples/multimaterial_twoboxes.py
     femexamples/rc_wall_2d.py
     femexamples/thermomech_flow1d.py
@@ -50,6 +51,7 @@ SET(FemExampleMeshes_SRCS
     femexamples/meshes/mesh_canticcx_tetra10.py
     femexamples/meshes/mesh_rc_wall_2d_tria6.py
     femexamples/meshes/mesh_multimaterial_twoboxes.py
+    femexamples/meshes/mesh_platewithhole.py
     femexamples/meshes/mesh_thermomech_flow1d.py
     femexamples/meshes/mesh_thermomech_spine.py
 )

src/Mod/Fem/femexamples/manager.py

@@ -79,6 +79,7 @@ def run_all():
     run_ccx_cantileverfaceload()
     run_ccx_cantilevernodeload()
     run_ccx_cantileverprescribeddisplacement()
+    run_material_nl_platewithhole()
     run_multimaterial_twoboxes()
     run_rcwall2d()
     run_thermomech_flow1d()
@@ -155,6 +156,20 @@ def run_ccx_cantileverprescribeddisplacement(solver=None, base_name=None):
     return doc
 
 
+def run_material_nl_platewithhole(solver=None, base_name=None):
+
+    from .material_nl_platewithhole import setup
+    doc = setup()
+
+    if base_name is None:
+        base_name = "Nonlinear_material_plate_with_hole"
+        if solver is not None:
+            base_name += "_" + solver
+    run_analysis(doc, base_name)
+
+    return doc
+
+
 def run_multimaterial_twoboxes(solver=None, base_name=None):
 
     from .multimaterial_twoboxes import setup
@@ -221,6 +236,7 @@ doc = run_boxanalysisfrequency()
 doc = run_ccx_cantileverfaceload()
 doc = run_ccx_cantilevernodeload()
 doc = run_ccx_cantileverprescribeddisplacement()
+doc = run_material_nl_platewithhole()
 doc = run_multimaterial_twoboxes()
 doc = run_rcwall2d()
 doc = run_thermomech_flow1d()

src/Mod/Fem/femexamples/material_nl_platewithhole.py

@@ -0,0 +1,163 @@
+# ***************************************************************************
+# *   Copyright (c) 2019 Bernd Hahnebach <bernd@bimstatik.org>              *
+# *                                                                         *
+# *   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.                                 *
+# *                                                                         *
+# *   FreeCAD 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 FreeCAD; if not, write to the Free Software        *
+# *   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  *
+# *   USA                                                                   *
+# *                                                                         *
+# ***************************************************************************
+
+
+import FreeCAD
+import ObjectsFem
+import Fem
+
+
+mesh_name = "Mesh"  # needs to be Mesh to work with unit tests
+
+
+def init_doc(doc=None):
+    if doc is None:
+        doc = FreeCAD.newDocument()
+    return doc
+
+
+def setup(doc=None, solvertype="ccxtools"):
+    """ Nonlinear material example, plate with hole.
+
+    https://forum.freecadweb.org/viewtopic.php?f=24&t=31997&start=30
+    https://forum.freecadweb.org/viewtopic.php?t=33974&start=90
+    https://forum.freecadweb.org/viewtopic.php?t=35893
+
+    plate: 400x200x10 mm
+    hole: diameter 100 mm (half cross section)
+    load: 130 MPa tension
+    linear material: Steel, E = 210000 MPa, my = 0.3
+    nonlinear material: '240.0, 0.0' to '270.0, 0.025'
+    TODO nonlinear material: give more information, use values from harry
+    TODO compare results with example from HarryvL
+
+    """
+
+    if doc is None:
+        doc = init_doc()
+
+    # part
+    import Part
+    from FreeCAD import Vector as vec
+    from Part import makeLine as ln
+    from Part import makeCircle as ci
+
+    v1 = vec(-200, -100, 0)
+    v2 = vec(200, -100, 0)
+    v3 = vec(200, 100, 0)
+    v4 = vec(-200, 100, 0)
+    l1 = ln(v1, v2)
+    l2 = ln(v2, v3)
+    l3 = ln(v3, v4)
+    l4 = ln(v4, v1)
+    v5 = vec(0, 0, 0)
+    c1 = ci(50, v5)
+    face = Part.makeFace([Part.Wire([l1, l2, l3, l4]), c1], "Part::FaceMakerBullseye")
+    partfem = doc.addObject("Part::Feature", "Hole_Plate")
+    partfem.Shape = face.extrude(vec(0, 0, 10))
+    doc.recompute()
+
+    if FreeCAD.GuiUp:
+        import FreeCADGui
+        FreeCADGui.ActiveDocument.activeView().viewAxonometric()
+        FreeCADGui.SendMsgToActiveView("ViewFit")
+
+    # analysis
+    analysis = ObjectsFem.makeAnalysis(doc, "Analysis")
+
+    # solver
+    # TODO How to pass multiple solver for one analysis in one doc
+    if solvertype == "calculix":
+        solver = analysis.addObject(
+            ObjectsFem.makeSolverCalculix(doc, "SolverCalculiX")
+        )[0]
+    elif solvertype == "ccxtools":
+        solver = analysis.addObject(
+            ObjectsFem.makeSolverCalculixCcxTools(doc, "CalculiXccxTools")
+        )[0]
+        solver.WorkingDir = u""
+    if solvertype == "calculix" or solvertype == "ccxtools":
+        solver.AnalysisType = "static"
+        solver.GeometricalNonlinearity = "linear"
+        solver.ThermoMechSteadyState = False
+        solver.MatrixSolverType = "default"
+        solver.IterationsControlParameterTimeUse = False
+        solver.GeometricalNonlinearity = 'nonlinear'
+        solver.MaterialNonlinearity = 'nonlinear'
+
+    # linear material
+    matprop = {}
+    matprop["Name"] = "CalculiX-Steel"
+    matprop["YoungsModulus"] = "210000 MPa"
+    matprop["PoissonRatio"] = "0.30"
+    matprop["Density"] = "7900 kg/m^3"
+    material = analysis.addObject(
+        ObjectsFem.makeMaterialSolid(doc, "Material_lin")
+    )[0]
+    material.Material = matprop
+
+    # nonlinear material
+    nonlinear_material = analysis.addObject(
+        ObjectsFem.makeMaterialMechanicalNonlinear(doc, material, "Material_nonlin")
+    )[0]
+    nonlinear_material.YieldPoint1 = '240.0, 0.0'
+    nonlinear_material.YieldPoint2 = '270.0, 0.025'
+    # check solver attributes, Nonlinearity needs to be set to nonlinear
+
+    # fixed_constraint
+    fixed_constraint = analysis.addObject(
+        ObjectsFem.makeConstraintFixed(doc, "ConstraintFixed")
+    )[0]
+    fixed_constraint.References = [(partfem, "Face4")]
+
+    # force constraint
+    pressure_constraint = doc.Analysis.addObject(
+        ObjectsFem.makeConstraintPressure(doc, "ConstraintPressure")
+    )[0]
+    pressure_constraint.References = [(partfem, "Face2")]
+    pressure_constraint.Pressure = 130.0
+    pressure_constraint.Reversed = True
+
+    # mesh
+    from .meshes.mesh_platewithhole 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 = analysis.addObject(
+        doc.addObject("Fem::FemMeshObject", mesh_name)
+    )[0]
+    femmesh_obj.FemMesh = fem_mesh
+
+    doc.recompute()
+    return doc
+
+
+"""
+from femexamples import material_nl_platewithhole as nlmat
+nlmat.setup()
+
+"""