"""
Python module for fuselage volume calculation, part of the fuselage geometry.
"""
# This file is part of FAST-OAD_CS23 : A framework for rapid Overall Aircraft Design
# Copyright (C) 2025 ONERA & ISAE-SUPAERO
# FAST is free software: you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
# 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 General Public License for more details.
# You should have received a copy of the GNU General Public License
# along with this program. If not, see <https://www.gnu.org/licenses/>.
import numpy as np
import openmdao.api as om
import fastoad.api as oad
from ..constants import SERVICE_FUSELAGE_VOLUME, SUBMODEL_FUSELAGE_VOLUME_LEGACY
oad.RegisterSubmodel.active_models[SERVICE_FUSELAGE_VOLUME] = SUBMODEL_FUSELAGE_VOLUME_LEGACY
[docs]@oad.RegisterSubmodel(SERVICE_FUSELAGE_VOLUME, SUBMODEL_FUSELAGE_VOLUME_LEGACY)
class ComputeFuselageVolume(om.ExplicitComponent):
"""
Fuselage volume computation. Based on geometric consideration assuming the fuselage is
cylindrical at the center section and conical at the front and back.
"""
# pylint: disable=missing-function-docstring
# Overriding OpenMDAO setup
[docs] def setup(self):
self.add_input("data:geometry:fuselage:maximum_width", val=np.nan, units="m")
self.add_input("data:geometry:fuselage:maximum_height", val=np.nan, units="m")
self.add_input("data:geometry:cabin:length", val=np.nan, units="m")
self.add_input("data:geometry:fuselage:front_length", val=np.nan, units="m")
self.add_input("data:geometry:fuselage:rear_length", val=np.nan, units="m")
self.add_output(
"data:geometry:fuselage:volume",
units="m**3",
desc="Volume of the fuselage",
)
self.declare_partials("*", "*", method="exact")
# pylint: disable=missing-function-docstring, unused-argument
# Overriding OpenMDAO compute, not all arguments are used
[docs] def compute(self, inputs, outputs, discrete_inputs=None, discrete_outputs=None):
b_f = inputs["data:geometry:fuselage:maximum_width"]
h_f = inputs["data:geometry:fuselage:maximum_height"]
l_c = inputs["data:geometry:cabin:length"]
lar = inputs["data:geometry:fuselage:rear_length"]
lav = inputs["data:geometry:fuselage:front_length"]
l_f = np.sqrt(b_f * h_f)
# estimation of fuselage volume
volume_fus = np.pi * l_f**2.0 / 4.0 * (0.7 * lav + 0.5 * lar + l_c)
outputs["data:geometry:fuselage:volume"] = volume_fus
# pylint: disable=missing-function-docstring, unused-argument
# Overriding OpenMDAO compute_partials, not all arguments are used
[docs] def compute_partials(self, inputs, partials, discrete_inputs=None):
b_f = inputs["data:geometry:fuselage:maximum_width"]
h_f = inputs["data:geometry:fuselage:maximum_height"]
l_c = inputs["data:geometry:cabin:length"]
lar = inputs["data:geometry:fuselage:rear_length"]
lav = inputs["data:geometry:fuselage:front_length"]
partials["data:geometry:fuselage:volume", "data:geometry:fuselage:maximum_width"] = (
np.pi * h_f / 4.0 * (0.7 * lav + 0.5 * lar + l_c)
)
partials["data:geometry:fuselage:volume", "data:geometry:fuselage:maximum_height"] = (
np.pi * b_f / 4.0 * (0.7 * lav + 0.5 * lar + l_c)
)
partials["data:geometry:fuselage:volume", "data:geometry:cabin:length"] = (
np.pi * b_f * h_f / 4.0
)
partials["data:geometry:fuselage:volume", "data:geometry:fuselage:rear_length"] = (
0.5 * np.pi * b_f * h_f / 4.0
)
partials["data:geometry:fuselage:volume", "data:geometry:fuselage:front_length"] = (
0.7 * np.pi * b_f * h_f / 4.0
)