"""
Estimation of fuselage weight
"""
# This file is part of FAST-OAD : A framework for rapid Overall Aircraft Design
# Copyright (C) 2021 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
[docs]class FuselageWeight(om.ExplicitComponent):
"""
Fuselage weight estimation
Based on a statistical analysis. See :cite:`supaero:2014`, mass contribution A2
"""
[docs] def setup(self):
self.add_input("data:geometry:fuselage:wetted_area", val=np.nan, units="m**2")
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:mission:sizing:cs25:sizing_load_1", val=np.nan, units="kg")
self.add_input("tuning:weight:airframe:fuselage:mass:k", val=1.0)
self.add_input("tuning:weight:airframe:fuselage:mass:offset", val=0.0, units="kg")
self.add_input("settings:weight:airframe:fuselage:mass:k_lg", val=1.05)
self.add_input("settings:weight:airframe:fuselage:mass:k_fus", val=1.0)
self.add_output("data:weight:airframe:fuselage:mass", units="kg")
[docs] def setup_partials(self):
self.declare_partials("*", "*", method="fd")
[docs] def compute(self, inputs, outputs, discrete_inputs=None, discrete_outputs=None):
fuselage_wet_area = inputs["data:geometry:fuselage:wetted_area"]
width_max = inputs["data:geometry:fuselage:maximum_width"]
height_max = inputs["data:geometry:fuselage:maximum_height"]
n1m1 = inputs["data:mission:sizing:cs25:sizing_load_1"]
k_a2 = inputs["tuning:weight:airframe:fuselage:mass:k"]
offset_a2 = inputs["tuning:weight:airframe:fuselage:mass:offset"]
k_lg = inputs["settings:weight:airframe:fuselage:mass:k_lg"]
k_fus = inputs["settings:weight:airframe:fuselage:mass:k_fus"]
temp_a2 = (
fuselage_wet_area
* (10 + 1.2 * np.sqrt(width_max * height_max) + 0.00019 * n1m1 / height_max ** 1.7)
* k_lg
* k_fus
)
outputs["data:weight:airframe:fuselage:mass"] = k_a2 * temp_a2 + offset_a2