# 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 LCCMaterialCost(om.ExplicitComponent):
"""
Computation of the raw material cost per aircraft, 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:geometry:cabin:pressurized",
val=0.0,
desc="Cabin pressurization; 0.0 for no pressurization, 1.0 for pressurization",
)
self.add_input(
"data:cost:cpi_2012",
val=np.nan,
desc="Consumer price index relative to the year 2012",
)
self.add_output(
"data:cost:production:material_cost_per_unit",
val=2.0e5,
units="USD",
desc="Development flight test adjusted cost per aircraft",
)
self.declare_partials("*", "*", 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 = 1.02
else:
f_flap = 1.0
outputs["data:cost:production:material_cost_per_unit"] = (
24.896
* inputs["data:weight:airframe:mass"] ** 0.689
* inputs["data:TLAR:v_max_sl"] ** 0.624
* inputs["data:cost:production:number_aircraft_5_years"] ** -0.208
* inputs["data:cost:cpi_2012"]
* f_flap
* (1.0 + 0.01 * inputs["data:geometry:cabin:pressurized"])
)
[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"]
cpi_2012 = inputs["data:cost:cpi_2012"]
num_5years = inputs["data:cost:production:number_aircraft_5_years"]
pressurized = inputs["data:geometry:cabin:pressurized"]
if inputs["data:geometry:flap_type"] != 0.0:
f_flap = 1.02
else:
f_flap = 1.0
partials["data:cost:production:material_cost_per_unit", "data:weight:airframe:mass"] = (
17.153344
* v_cruise**0.624
* num_5years**-0.208
* cpi_2012
* f_flap
* (1.0 + 0.01 * pressurized)
/ m_airframe**0.311
)
partials["data:cost:production:material_cost_per_unit", "data:TLAR:v_max_sl"] = (
15.535104
* m_airframe**0.689
* num_5years**-0.208
* cpi_2012
* f_flap
* (1.0 + 0.01 * pressurized)
/ v_cruise**0.376
)
partials[
"data:cost:production:material_cost_per_unit",
"data:cost:production:number_aircraft_5_years",
] = (
-5.178368
* m_airframe**0.689
* v_cruise**0.624
* cpi_2012
* f_flap
* (1.0 + 0.01 * pressurized)
/ num_5years**1.208
)
partials["data:cost:production:material_cost_per_unit", "data:cost:cpi_2012"] = (
24.896
* m_airframe**0.689
* v_cruise**0.624
* num_5years**-0.208
* f_flap
* (1.0 + 0.01 * pressurized)
)
partials[
"data:cost:production:material_cost_per_unit", "data:geometry:cabin:pressurized"
] = 0.24896 * m_airframe**0.689 * v_cruise**0.624 * num_5years**-0.208 * cpi_2012 * f_flap