"""
Estimation of wing 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 WingWeight(om.ExplicitComponent):
"""
Wing weight estimation
This is done by summing following estimations:
- mass from sizing to flexion forces
- mass from sizing to shear forces
- mass of ribs
- mass of reinforcements
- mass of secondary parts
Based on :cite:`supaero:2014`, mass contribution A1
"""
[docs] def setup(self):
self.add_input("data:geometry:wing:root:thickness_ratio", val=np.nan)
self.add_input("data:geometry:wing:kink:thickness_ratio", val=np.nan)
self.add_input("data:geometry:wing:tip:thickness_ratio", val=np.nan)
self.add_input("data:geometry:wing:area", val=np.nan, units="m**2")
self.add_input("data:geometry:wing:span", val=np.nan, units="m")
self.add_input("data:geometry:wing:root:chord", val=np.nan, units="m")
self.add_input("data:geometry:wing:sweep_25", val=np.nan, units="rad")
self.add_input("data:geometry:wing:outer_area", val=np.nan, units="m**2")
self.add_input("data:weight:aircraft:MTOW", val=np.nan, units="kg")
self.add_input("data:weight:aircraft:MLW", val=np.nan, units="kg")
self.add_input("data:mission:sizing:cs25:sizing_load_1", val=np.nan, units="kg")
self.add_input("data:mission:sizing:cs25:sizing_load_2", val=np.nan, units="kg")
self.add_input("tuning:weight:airframe:wing:mass:k", val=1.0)
self.add_input("tuning:weight:airframe:wing:mass:offset", val=0.0, units="kg")
self.add_input("tuning:weight:airframe:wing:bending_sizing:mass:k", val=1.0)
self.add_input(
"tuning:weight:airframe:wing:bending_sizing:mass:offset", val=0.0, units="kg"
)
self.add_input("tuning:weight:airframe:wing:shear_sizing:mass:k", val=1.0)
self.add_input("tuning:weight:airframe:wing:shear_sizing:mass:offset", val=0.0, units="kg")
self.add_input("tuning:weight:airframe:wing:ribs:mass:k", val=1.0)
self.add_input("tuning:weight:airframe:wing:ribs:mass:offset", val=0.0, units="kg")
self.add_input("tuning:weight:airframe:wing:reinforcements:mass:k", val=1.0)
self.add_input(
"tuning:weight:airframe:wing:reinforcements:mass:offset", val=0.0, units="kg"
)
self.add_input("tuning:weight:airframe:wing:secondary_parts:mass:k", val=1.0)
self.add_input(
"tuning:weight:airframe:wing:secondary_parts:mass:offset", val=0.0, units="kg"
)
self.add_input("settings:weight:airframe:wing:mass:k_voil", val=1.0)
self.add_input("settings:weight:airframe:wing:mass:k_mvo", val=1.39)
self.add_output("data:weight:airframe:wing: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):
toc_root = inputs["data:geometry:wing:root:thickness_ratio"]
toc_kink = inputs["data:geometry:wing:kink:thickness_ratio"]
toc_tip = inputs["data:geometry:wing:tip:thickness_ratio"]
wing_area = inputs["data:geometry:wing:area"]
span = inputs["data:geometry:wing:span"]
l2_wing = inputs["data:geometry:wing:root:chord"]
sweep_25 = inputs["data:geometry:wing:sweep_25"]
cantilevered_area = inputs["data:geometry:wing:outer_area"]
mtow = inputs["data:weight:aircraft:MTOW"]
mlw = inputs["data:weight:aircraft:MLW"]
max_nm = max(
inputs["data:mission:sizing:cs25:sizing_load_1"],
inputs["data:mission:sizing:cs25:sizing_load_2"],
)
# K factors
k_a1 = inputs["tuning:weight:airframe:wing:mass:k"]
offset_a1 = inputs["tuning:weight:airframe:wing:mass:offset"]
k_a11 = inputs["tuning:weight:airframe:wing:bending_sizing:mass:k"]
offset_a11 = inputs["tuning:weight:airframe:wing:bending_sizing:mass:offset"]
k_a12 = inputs["tuning:weight:airframe:wing:shear_sizing:mass:k"]
offset_a12 = inputs["tuning:weight:airframe:wing:shear_sizing:mass:offset"]
k_a13 = inputs["tuning:weight:airframe:wing:ribs:mass:k"]
offset_a13 = inputs["tuning:weight:airframe:wing:ribs:mass:offset"]
k_a14 = inputs["tuning:weight:airframe:wing:reinforcements:mass:k"]
offset_a14 = inputs["tuning:weight:airframe:wing:reinforcements:mass:offset"]
k_a15 = inputs["tuning:weight:airframe:wing:secondary_parts:mass:k"]
offset_a15 = inputs["tuning:weight:airframe:wing:secondary_parts:mass:offset"]
k_voil = inputs["settings:weight:airframe:wing:mass:k_voil"]
k_mvo = inputs["settings:weight:airframe:wing:mass:k_mvo"]
toc_mean = (3 * toc_root + 2 * toc_kink + toc_tip) / 6
# A11=Mass of the wing due to flexion
temp_a11 = (
5.922e-5
* k_voil
* ((max_nm / (l2_wing * toc_mean)) * (span / np.cos(sweep_25)) ** 2.0) ** 0.9
)
weight_a11 = k_a11 * temp_a11 + offset_a11
# A12=Mass of the wing due to shear
temp_a12 = 5.184e-4 * k_voil * (max_nm * span / np.cos(sweep_25)) ** 0.9
weight_a12 = k_a12 * temp_a12 + offset_a12
# A13=Mass of the wing due to the ribs
temp_a13 = k_voil * (1.7009 * wing_area + 10 ** (-3) * max_nm)
weight_a13 = k_a13 * temp_a13 + offset_a13
# A14=Mass of the wing due to reinforcements
temp_a14 = 4.4e-3 * k_voil * mlw ** 1.0169
weight_a14 = k_a14 * temp_a14 + offset_a14
# A15=Mass of the wing due to secondary parts
temp_a15 = 0.3285 * k_voil * mtow ** 0.35 * cantilevered_area * k_mvo
weight_a15 = k_a15 * temp_a15 + offset_a15
temp_a1 = weight_a11 + weight_a12 + weight_a13 + weight_a14 + weight_a15
outputs["data:weight:airframe:wing:mass"] = k_a1 * temp_a1 + offset_a1