# This file is part of FAST-OAD_CS23-HE : A framework for rapid Overall Aircraft Design of Hybrid
# Electric Aircraft.
# Copyright (C) 2025 ISAE-SUPAERO
import numpy as np
import openmdao.api as om
[docs]
class LCCManufacturingManHours(om.ExplicitComponent):
"""
Compute the number of man-hours required in manufacturing, obtained from
:cite:`gudmundsson:2013`.
"""
[docs]
def setup(self):
self.add_input("data:weight:airframe:mass", units="kg", val=np.nan)
self.add_input("data:TLAR:v_max_sl", units="kn", val=np.nan)
self.add_input("data:geometry:flap_type", val=np.nan)
self.add_input(
"data:cost:production:number_aircraft_5_years",
val=np.nan,
desc="Number of planned aircraft to be produced over a 5-year period or 60 months",
)
self.add_input(
"data:cost:production:composite_fraction",
val=0.0,
desc="Fraction of airframe made of composite, range from 0.0 to 1.0",
)
self.add_output(
"data:cost:production:manufacturing_man_hours_5_years",
val=2.0e5,
units="h",
desc="Number of engineering man-hours required per aircraft",
)
self.declare_partials(of="*", wrt="*", method="exact")
self.declare_partials("*", "data:geometry:flap_type", method="fd")
[docs]
def compute(self, inputs, outputs, discrete_inputs=None, discrete_outputs=None):
if inputs["data:geometry:flap_type"] != 0.0:
f_flap = 1.01
else:
f_flap = 1.0
outputs["data:cost:production:manufacturing_man_hours_5_years"] = (
9.6613
* inputs["data:weight:airframe:mass"] ** 0.74
* inputs["data:TLAR:v_max_sl"] ** 0.543
* inputs["data:cost:production:number_aircraft_5_years"] ** -0.476
* f_flap
* (1.0 + 0.25 * inputs["data:cost:production:composite_fraction"])
)
[docs]
def compute_partials(self, inputs, partials, discrete_inputs=None):
m_airframe = inputs["data:weight:airframe:mass"]
v_cruise = inputs["data:TLAR:v_max_sl"]
num_5years = inputs["data:cost:production:number_aircraft_5_years"]
f_composite = inputs["data:cost:production:composite_fraction"]
if inputs["data:geometry:flap_type"] != 0.0:
f_flap = 1.01
else:
f_flap = 1.0
partials[
"data:cost:production:manufacturing_man_hours_5_years",
"data:weight:airframe:mass",
] = (
7.149362 * v_cruise**0.543 * num_5years**-0.476 * f_flap * (1.0 + 0.25 * f_composite)
) / m_airframe**0.26
partials[
"data:cost:production:manufacturing_man_hours_5_years",
"data:TLAR:v_max_sl",
] = (
5.2460859
* m_airframe**0.74
* num_5years**-0.476
* f_flap
* (1.0 + 0.25 * f_composite)
/ v_cruise**0.457
)
partials[
"data:cost:production:manufacturing_man_hours_5_years",
"data:cost:production:number_aircraft_5_years",
] = (
-4.5987788 * m_airframe**0.74 * v_cruise**0.543 * f_flap * (1.0 + 0.25 * f_composite)
) / num_5years**1.476
partials[
"data:cost:production:manufacturing_man_hours_5_years",
"data:cost:production:composite_fraction",
] = 2.415325 * m_airframe**0.74 * v_cruise**0.543 * num_5years**-0.476 * f_flap