src/Mod/Fem/femsolver/calculix/write_femelement_material.py

# ***************************************************************************
# *   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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__title__ = "FreeCAD FEM calculix write inpfile materials"
__author__ = "Bernd Hahnebach"
__url__ = "https://www.freecad.org"


import FreeCAD
from femtools import constants


def write_femelement_material(f, ccxwriter):

    # floats read from ccx should use {:.13G}, see comment in writer module
    # see unit comment in writer module

    def is_density_needed():
        if ccxwriter.analysis_type == "frequency":
            return True
        if (
            ccxwriter.analysis_type == "thermomech"
            and not ccxwriter.solver_obj.ThermoMechSteadyState
        ):
            return True
        if ccxwriter.member.cons_centrif:
            return True
        if ccxwriter.member.cons_selfweight:
            return True
        return False

    f.write("\n** Physical constants for SI(mm) unit system with Kelvins\n")
    f.write("*PHYSICAL CONSTANTS, ABSOLUTE ZERO=0, STEFAN BOLTZMANN=5.670374419e-11\n")

    f.write("\n{}\n".format(59 * "*"))
    f.write("** Materials\n")
    f.write("** see information about units at file end\n")
    for femobj in ccxwriter.member.mats_linear:
        # femobj --> dict, FreeCAD document object is femobj["Object"]
        mat_obj = femobj["Object"]
        mat_info_name = mat_obj.Material["Name"]
        mat_name = mat_obj.Name
        mat_label = mat_obj.Label

        # get material properties of solid material, Currently in SI units: M/kg/s/Kelvin
        if mat_obj.Category == "Solid":
            YM = FreeCAD.Units.Quantity(mat_obj.Material["YoungsModulus"])
            YM_in_MPa = YM.getValueAs("MPa").Value
            PR = float(mat_obj.Material["PoissonRatio"])
        if is_density_needed() is True:
            density = FreeCAD.Units.Quantity(mat_obj.Material["Density"])
            density_in_tonne_per_mm3 = density.getValueAs("t/mm^3").Value
        if ccxwriter.analysis_type == "thermomech":
            TC = FreeCAD.Units.Quantity(mat_obj.Material["ThermalConductivity"])
            # SvdW: Add factor to force units to results base units
            # of t/mm/s/K - W/m/K results in no factor needed
            TC_in_WmK = TC.getValueAs("W/m/K").Value
            SH = FreeCAD.Units.Quantity(mat_obj.Material["SpecificHeat"])
            # SvdW: Add factor to force units to results base units of t/mm/s/K
            # FIXME: why not get it directly in the units needed ?
            SH_in_JkgK = SH.getValueAs("J/kg/K").Value * 1e06
            if mat_obj.Category == "Solid":
                TEC = FreeCAD.Units.Quantity(mat_obj.Material["ThermalExpansionCoefficient"])
                TEC_in_mmK = TEC.getValueAs("mm/mm/K").Value
                if "ThermalExpansionReferenceTemperature" in mat_obj.Material:
                    RT = FreeCAD.Units.Quantity(
                        mat_obj.Material["ThermalExpansionReferenceTemperature"]
                    )
                else:
                    RT = FreeCAD.Units.Quantity("0 K")
                RT_in_K = RT.getValueAs("K").Value
            elif mat_obj.Category == "Fluid":
                KV = FreeCAD.Units.Quantity(mat_obj.Material["KinematicViscosity"])
                KV_in_mm2s = KV.getValueAs("mm^2/s").Value
                DV_in_tmms = KV_in_mm2s * density_in_tonne_per_mm3
        if ccxwriter.analysis_type == "static":
            if mat_obj.Category == "Solid":
                if "ThermalExpansionCoefficient" in mat_obj.Material:
                    TEC = FreeCAD.Units.Quantity(mat_obj.Material["ThermalExpansionCoefficient"])
                    TEC_in_mmK = TEC.getValueAs("mm/mm/K").Value
                else:
                    TEC_in_mmK = 0.0
                if "ThermalExpansionReferenceTemperature" in mat_obj.Material:
                    RT = FreeCAD.Units.Quantity(
                        mat_obj.Material["ThermalExpansionReferenceTemperature"]
                    )
                else:
                    RT = FreeCAD.Units.Quantity("0 K")
                RT_in_K = RT.getValueAs("K").Value
        if (
            ccxwriter.analysis_type == "electromagnetic"
            and ccxwriter.solver_obj.ElectromagneticMode == "electrostatic"
        ):
            rel_perm = FreeCAD.Units.Quantity(mat_obj.Material["RelativePermittivity"]).Value
            vacuum_perm = FreeCAD.Units.Quantity(constants.vacuum_permittivity())
            abs_perm = vacuum_perm.getValueAs("C/(mV*mm)").Value * rel_perm
        # write material properties
        f.write(f"** FreeCAD material name: {mat_info_name}\n")
        f.write(f"** {mat_label}\n")
        f.write(f"*MATERIAL, NAME={mat_name}\n")
        if mat_obj.Category == "Solid":
            f.write("*ELASTIC\n")
            f.write(f"{YM_in_MPa:.13G},{PR:.13G}\n")
        if is_density_needed() is True:
            f.write("*DENSITY\n")
            f.write(f"{density_in_tonne_per_mm3:.13G}\n")
        if ccxwriter.analysis_type == "thermomech":
            if mat_obj.Category == "Solid":
                f.write("*CONDUCTIVITY\n")
                f.write(f"{TC_in_WmK:.13G}\n")
                f.write(f"*EXPANSION, ZERO={RT_in_K:.13G}\n")
                f.write(f"{TEC_in_mmK:.13G}\n")
                f.write("*SPECIFIC HEAT\n")
                f.write(f"{SH_in_JkgK:.13G}\n")
            elif mat_obj.Category == "Fluid":
                f.write("*FLUID CONSTANTS\n")
                f.write(f"{SH_in_JkgK:.13G},{DV_in_tmms:.13G}\n")
        if ccxwriter.analysis_type == "static":
            if mat_obj.Category == "Solid":
                f.write(f"*EXPANSION, ZERO={RT_in_K:.13G}\n")
                f.write(f"{TEC_in_mmK:.13G}\n")
        if (
            ccxwriter.analysis_type == "electromagnetic"
            and ccxwriter.solver_obj.ElectromagneticMode == "electrostatic"
        ):
            f.write("*CONDUCTIVITY\n")
            f.write(f"{abs_perm:.13G}\n")

        # nonlinear material properties
        if ccxwriter.solver_obj.MaterialNonlinearity == "nonlinear":

            for nlfemobj in ccxwriter.member.mats_nonlinear:
                # femobj --> dict, FreeCAD document object is nlfemobj["Object"]
                nl_mat_obj = nlfemobj["Object"]
                if nl_mat_obj.LinearBaseMaterial == mat_obj:
                    if nl_mat_obj.MaterialModelNonlinearity == "isotropic hardening":
                        f.write("*PLASTIC\n")
                    else:
                        f.write("*PLASTIC, HARDENING=KINEMATIC\n")
                    for yield_point in nl_mat_obj.YieldPoints:
                        f.write(f"{yield_point}\n")
                f.write("\n")