src/Mod/Fem/femexamples/ccx_buckling_flexuralbuckling.py

# ***************************************************************************
# *   Copyright (c) 2021 Tobias Vaara <t@vaara.se>                          *
# *   Copyright (c) 2021 Bernd Hahnebach <bernd@bimstatik.org>              *
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# *   This file is part of the FreeCAD CAx development system.              *
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import FreeCAD

import Fem
import ObjectsFem

from . import manager
from .manager import get_meshname
from .manager import init_doc


def get_information():
    return {
        "name": "Flexural Buckling",
        "meshtype": "solid",
        "meshelement": "Hexa8",
        "constraints": ["fixed", "force"],
        "solvers": ["ccxtools"],
        "material": "solid",
        "equations": ["buckling"],
    }


def get_explanation(header=""):
    return (
        header
        + """

To run the example from Python console use:
from femexamples.ccx_buckling_flexuralbuckling import setup
setup()


See forum topic post:
https://forum.freecad.org/viewtopic.php?f=18&t=20217&start=80#p488666

This example is based on a CalculiX verification example.
http://www.feacluster.com/CalculiX/ccx_2.13/doc/ccx/input_deck_viewer.php?input_deck=beam8b.inp

"""
    )


def setup(doc=None, solvertype="ccxtools"):

    # 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 object
    geom_obj = doc.addObject("Part::Box", "Beam")
    geom_obj.Length = 1
    geom_obj.Width = 1.5
    geom_obj.Height = 8
    doc.recompute()
    if FreeCAD.GuiUp:
        geom_obj.ViewObject.Document.activeView().viewAxonometric()
        geom_obj.ViewObject.Document.activeView().fitAll()

    # analysis
    analysis = ObjectsFem.makeAnalysis(doc, "Analysis")

    # solver,
    if solvertype == "ccxtools":
        solver_obj = ObjectsFem.makeSolverCalculiXCcxTools(doc, "CalculiXCcxTools")
        solver_obj.WorkingDir = ""
    else:
        FreeCAD.Console.PrintWarning(
            "Unknown or unsupported solver type: {}. "
            "No solver object was created.\n".format(solvertype)
        )
    if solvertype == "ccxtools":
        solver_obj.SplitInputWriter = False
        solver_obj.AnalysisType = "buckling"
        solver_obj.BucklingFactors = 10
        solver_obj.GeometricalNonlinearity = "linear"
        solver_obj.ThermoMechSteadyState = False
        solver_obj.MatrixSolverType = "default"
        solver_obj.IterationsControlParameterTimeUse = False
    analysis.addObject(solver_obj)

    # material
    material_obj = ObjectsFem.makeMaterialSolid(doc, "MechanicalMaterial")
    mat = material_obj.Material
    mat["Name"] = "CalculiX-Steel"
    mat["YoungsModulus"] = "210000 MPa"
    mat["PoissonRatio"] = "0.30"
    material_obj.Material = mat
    analysis.addObject(material_obj)

    # constraint fixed
    con_fixed = ObjectsFem.makeConstraintFixed(doc, "ConstraintFixed")
    con_fixed.References = [(geom_obj, "Face5")]
    analysis.addObject(con_fixed)

    # constraint force
    con_force = ObjectsFem.makeConstraintForce(doc, "ConstraintForce")
    con_force.References = [(geom_obj, "Face6")]
    con_force.Force = "21 N"
    con_force.Reversed = True
    analysis.addObject(con_force)

    # mesh
    from .meshes.mesh_flexural_buckling 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(ObjectsFem.makeMeshGmsh(doc, get_meshname()))[0]
    femmesh_obj.FemMesh = fem_mesh
    femmesh_obj.Shape = geom_obj

    doc.recompute()
    return doc