| # *************************************************************************** | |
| # * Copyright (c) 2020 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. * | |
| # * * | |
| # * 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 * | |
| # * * | |
| # *************************************************************************** | |
| """Collection of natural constants for the Fem module. | |
| This module contains natural constants for the Fem module. | |
| All constants are in SI units. | |
| """ | |
| __title__ = "FEM collection of natural constants" | |
| __author__ = "Bernd Hahnebach" | |
| __url__ = "https://www.freecad.org" | |
| def gravity(): | |
| # https://en.wikipedia.org/wiki/Gravitational_acceleration | |
| return "9.80665 m/s^2" | |
| def stefan_boltzmann(): | |
| # https://en.wikipedia.org/wiki/Stefan-Boltzmann_constant | |
| return "5.67037e-8 W/(m^2*K^4)" | |
| def vacuum_permeability(): | |
| # https://en.wikipedia.org/wiki/Vacuum_permeability | |
| return "1.256637e-6 N/A^2" | |
| def vacuum_permittivity(): | |
| # https://forum.freecad.org/viewtopic.php?f=18&p=400959#p400959 | |
| # https://en.wikipedia.org/wiki/Permittivity#Vacuum_permittivity | |
| return "8.85419e-12 F/m" | |
| def boltzmann_constant(): | |
| # https://en.wikipedia.org/wiki/Boltzmann_constant | |
| return "1.38065e-23 J/K" | |
| """ | |
| from FreeCAD import Units | |
| from femtools import constants | |
| Units.Quantity(constants.gravity()).getValueAs("mm/s^2") | |
| """ | |
| # TODO: a unit test to be sure these values are returned! | |