Composite Structures 303 (2023) 116323
Contents lists available at ScienceDirect
Composite Structures
journal homepage: www.elsevier.com/locate/compstruct
Numerical simulation and validation of MWCNT-CFRP hybrid composite
structure in lightweight satellite design
Shoaib Iqbal , Tariq Jamil *, Syed Murtuza Mehdi
Department of Mechanical Engineering, NED University of Engineering & Technology, Karachi 75270, Pakistan
A R T I C L E I N F O
A B S T R A C T
Keywords:
Electronic housing
Space avionics
Finite element analysis
Composite materials
Structure analysis
Aluminum alloy is generally used in electronic housings of satellites in space avionics due to its remarkable
mechanical, thermal, electrical, and radio-frequency shielding properties. This paper proposes a design for a
lightweight multi-functional electronic housing made from plastic containing multi-wall carbon nanotubes
(MWCNT) composite material. The structural design of housings was validated against a set of boundary con­
ditions and requirements of launch and space environments as prescribed by European Cooperation for Space
Standardization (ECSS) standards. The proposed concept for lightweight composite housing was designed with
special emphasis on reducing machining operations. The composite housing offers a mass saving of ~25 % over a
typical aluminum housing with similar mechanical performance in the three orthogonal directions. The modal
frequency is greater than 100 Hz qualifying the design requirement for satellite electronic housings. Under si­
nusoidal vibration loads, the structure shows no noticeable excitation in acceleration response graph, indicating
no resonance in low-range frequencies from 5 to 100 Hz. Maximum stresses obtained from Quasi-static and
random vibration loads are within the tensile strength limit in the three orthogonal directions. In addition,
maximum deflection observed in electronic printed circuit boards is within the 1 mm design requirement.
1. Introduction
Satellite development is among the most diverse research areas of
modern science, as it entails scientific research in materials,
manufacturing processes, vibrations, and numerous other engineering
aspects. Out of the many complex stages of satellite development, the
launch stage has continued to be the most challenging, particularly in
terms of cost overheads. Budgeting is among the most important factors
when carrying out a feasibility study for a space mission in view of the
high costs of launching a unit mass of payload into space. Presently, the
cost of launching a satellite into lower earth orbit varies between US$
4,600/kg and US$ 15,400/kg for medium-sized satellites, depending on
the launch vehicle and orbit distance from Earth [1]. Several researchers
have accomplished this by employing lightweight composite materials,
such as Carbon Fiber Reinforced Plastic (CFRP), in structural compo­
nents of satellites for mass optimization [2,3]. Electronic housings with a
focus on high thermal conductivity have also been developed using
monolithic composite laminates through autoclave manufacturing [4].
CFRP has also been used to develop composite structures with
embedded electronics to improve mass savings in satellites [5]. A
combination of pitch-based K1100 carbon fibers and Aluminum alloy
materials has been extensively used to design and test lightweight
housings with high thermal conductivity using numerical and experi­
mental methods [6–8]. Considerable mass savings by completely
replacing Aluminum alloy by CFRP in satellite housing enclosures have
also been discussed [9].
In general, electronic housings are made of aluminum alloys,
particularly AA-6061 and AA-7075, due to their low density, suitable
mechanical and thermal properties, low cost, manufacturability, and
availability. Although aluminum alloys have a high strength-to-weight
ratio compared to other readily available metals, there is still consid­
erable room for improvement in the selection of materials for spacecraft
structure applications, especially in housing enclosures for satellite
electronics. Several lightweight materials can substitute aluminum al­
loys for making electronics housings of satellites and spacecraft sub­
systems, but the selection procedure is easier said than done. Since the
housing enclosure carries a large portion of the weight of the entire
electronic unit, appropriate material and mechanical design is required
to optimize its mass without compromising structural requirements
[10].
* Corresponding author.
E-mail address: tariqjamil@neduet.edu.pk (T. Jamil).
https://doi.org/10.1016/j.compstruct.2022.116323
Received 13 March 2022; Received in revised form 25 July 2022; Accepted 7 October 2022
Available online 17 October 2022
0263-8223/© 2022 Elsevier Ltd. All rights reserved.
S. Iqbal et al.
Composite Structures 303 (2023) 116323
For the scope of this research work, a lightweight composite material
made of CFRP and MWCNT is used to replace aluminum in plates of the
electronics housing. CFRP is expansively used in numerous structural
components of satellites [11], particularly supporting structures for
imaging devices, antennas, and solar arrays, primarily because of its
exceptional mechanical properties and fatigue resistance [12], but pri­
marily a higher strength-to-weight ratio, which proposes potential mass
savings of up to 20 % compared to the Aluminum-alloy design [2–4,6].
This advantage, however, comes with several obstacles, such as low
thermal conductivity, machinability, and insufficient electromagnetic
radiation shielding properties of CFRP-based composites. While carbon
fibers possess high electrical and thermal conductivity due to their high
carbon content [3,7,13], an insulating medium is created due to the
presence of polymer-epoxy matrix that is used to hold the reinforcing
fibers in place in the CFRP form. The addition of MWCNTs into the
polymer-epoxy matrix addresses these issues to a sizable extent.
Experiments have shown that the addition of 0.25 wt% MWCNTs
increase the tensile strength of CFRP by 60 % [12]. MWCNTs added into
the polymer-epoxy matrix significantly increase the electrical conduc­
tivity of the composite laminates, thereby improving the electromag­
netic interference (EMI) shielding in CFRP and epoxy laminar
composites [2,14,29]. When used as matrix reinforcement, CNTs in­
crease the vibration damping characteristics of fiber-reinforced com­
posites [15,21]. The addition of MWCNTs into cured epoxy resin has
also tested to increase EMI shielding effectiveness and tensile strength
[16,20,25]. With the help of computational study, interconnected bun­
dles of nanotubes are shown to have a strong effect on the thermal
conductivity of CNT-based materials [17,35]. When used as multifunc­
tional nano-fillers, highly conductive CNTs are shown to improve the
thermal conductivity of polymer-resin based nanocomposites [18,19].
Although CFRP is acknowledged for high material stiffness, it lacks the
appropriate damping capacity due to the viscoelastic nature of carbon
fibers [22]. CNTs increase the interfacial adhesion between polymer
resin and carbon fibers [15]. Additionally, the damping effect is also
enhanced by the relative motion of MWCNTs against the surface of
polymer-epoxy resin. Since the surface area of CNTs is very high, the
extreme friction occurs when they come in contact with the epoxy sur­
face, resulting in large amounts of energy absorption that improves the
damping capability [23,24]. The primary objective of the research work
presented here was to design and validate a lightweight composite
housing for satellite electronics with respect to constraints of mass,
natural frequency, structural integrity, and thermal conductivity, using
a hybrid composite of MWCNT and CFRP.
2. Design methodology
2.1. Requirements of electronic housing
An electronics housing is designed to fulfil a set of basic re­
quirements, which include multiple interfaces for mounting of elec­
tronic printed circuit boards (PCBs) within the structure; support for
delicate internal components against mechanical loads during launch
and space phase, a suitable thermal pathway for channeling excessive
heat towards the satellite structure away from sensitive electronic
components; a minimum of 2 mm thick walls made of AA-6061 protect
the internal electronics against harmful radiations and EMI. Table 1
summarizes the key requirements of an electronic housing.
2.2. Work approach
The principal objective of this study is to propose a lightweight
composite design of electronic housing for satellite electronic sub sys­
tems. Typical electronics housing is made of aluminum AA-6061 alloy,
which provides the right mechanical, thermal, and electrical charac­
teristics required for satellite applications. A hybrid MWCNT-CFRP
composite was chosen for the proposed lightweight housing design
due to its multi-functional properties, particularly a high strength-toweight ratio. Two computer aided designs of electronics housing were
developed for this study, one using aluminum AA-6061 alloy and
another with MWCNT-CFRP laminates, using PTC Creo Parametric
software. The respective CAD models of the two housings are shown in
Fig. 1 and Fig. 3. The structure designs of both housings were validated
against static and dynamic loads as prescribed by European Cooperation
for Space Standardization (ECSS) testing standards for launch and space
environments. Multiple FEA numerical simulations in MSC Patran soft­
ware with MSC Nastran solver were performed. The results of stresses
Table 1
Requirements for a typical electronic housing for space applications.
Item
Requirements
Physical Interface
Accommodation of up to 4 PCBs and provision for electronic
connectors
>100 Hz
>0
Natural Frequency
Margin of Safety
(MoS)
Max Deflection
Radiation shielding
<1 mm
≥2 mm (Aluminum)
Fig. 1. (a) Typical AA-6061 Housing. (b) Arrangement of PCBs and D-sub connectors.
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and deflections obtained from the structural analyses and potential mass
saving between the two housings were compared.
in Fig. 2. These composite laminates make up the top plate, left plate,
right plate, front plate, and back plate of the structure of the lightweight
housing. The PCB frames are made of a combination of AA-6061 and
MWCNT-CFRP composite laminate for improving the stiffness as well as
heat dissipation. Other places where aluminum alloy is used are the
bottom plate, PCB guide rails and mounting lugs. Fig. 3(b) shows the
housing components made of MWCNT-CFRP in grey texture and AA6061 components in white color.
2.3. Aluminum housing
Fig. 1(a) shows the external view of a conventional electronics
housing made of Aluminum. The housing case consists of 6 plates made
of AA-6061 material which are held together with stainless steel fas­
teners. The top plate of the housing features cut-outs for electrical
interfacing of conventional D-sub connectors (DB-15 in this case).
On the right and left plates, a total of eight mounting lugs for the
housing are provided which are used to mount the housing on the sat­
ellite structure panels. The housing provides easy installation of four
PCBs of standard Eurocard 6U size (233.33 mm × 160 mm). With some
external plates hidden, Fig. 1(b) shows the internal organization of PCBs
and D-sub connectors. All PCB cards are fastened to metallic frames,
which are designed to provide optimum stiffness to PCBs and prevent
excessive elastic deformation under external loads acting on the housing
during launch and space environment.
The frame and PCB assemblies are held inside the housing with the
help of wedge-lock retainers that slide along the guide rails provided on
the inner side of Left and Right housing plates. In the scope of this
research project, each PCB is designed to hold a mass of up to 500 g,
which has been distributed over the entire surface using the nonstructural mass feature of MSC Patran software. The housing compo­
nents of the conventional housing, including plates and frames are made
of aluminum alloy AA-6061, whereas the PCB cards are made of Flame
Retardant FR-4 material. AA-6061 is an excellent material for space
applications, since it is both lightweight and has good structural and
thermal properties. FR-4 is a glass-reinforced epoxy laminate composite,
which is used as a standard for manufacturing of electronic circuit
boards.
2.4.1. Advantages of MWCNT-CFRP laminates
While CFRP characterizes outstanding properties on its own, studies
by multiple researchers have shown that adding MWCNTs into the
polymer matrix improves the mechanical, thermal, and electrical
properties of CFRP laminates by a large margin [13,27,30,34]. In one
study, researchers showed that the addition of 0.25 wt% MWCNTs into
the epoxy polymer matrix improved the tensile strength by 60 % [12].
While CFRP exhibits good stiffness, the poor viscoelastic nature of car­
bon fibers results in an overall low damping capacity. MWCNTs increase
the interfacial linkage between carbon fibers and resin, increasing
damping properties [15,20]. A damping coefficient of 1.5 % is used for
the numerical analyses in this study.
In another study, the electrical conductivity of neat CFRP and
MWCNT-CFRP laminates were compared and the surface resistivity of
MWCNT-CFRP laminate was found by experimentation to be signifi­
cantly lower than neat CFRP [2]. Low surface resistivity is equivalent to
a higher electrical conductivity, which is essential for satellite applica­
tions in order to fulfill electromagnetic interference (EMI) and electro­
magnetic compatibility (EMC) requirements. Electronic housings are
generally required to have appropriate shielding measures from outer
space radiations [2,4]. Generally, shielding equivalent to 2 mm thick
aluminum alloy is acceptable for satellite electronic housings. Due to the
polymer-epoxy matrix between carbon-fiber fabric sheets, neat CFRP is
ineffective for shielding, however, MWCNTs improve the shielding
properties of carbon-based composite laminates [2,16,28,31].
2.4. Lightweight composite housing
2.4.2. Heat transfer path
In satellites and spacecraft, a large amount of heat is generated by
electronic components mounted on the PCBs that is required to be
dissipated through a conductive path, since there is no medium for heat
convection in space. For this approach to work, the housing structure for
satellite electronics is required to be thermally conductive [3,7]. One of
the main advantages of introducing MWCNTs as nano-fillers into the
polymer resin matrix of CFRP is improvement in thermal conductivity
[2,16,28]. To ensure an uninterrupted heat transfer in the course of this
research work, housing components that make the primary heat transfer
path are designed with AA-6061, particularly the frames, PCB guide
rails, bottom plate, and lugs. In addition to providing optimum stiffness
to electronics, the four frames act as heat sinks to transfer excessive heat
away from the sensitive electronic components towards the PCB guide
rails and bottom plate, from where excessive heat will disperse into the
main satellite structure. Red arrows in Fig. 4 represent the heat transfer
path.
The lightweight housing design must also satisfy the design re­
quirements of natural frequency, MoS, maximum deflection, and most
importantly, the accommodation of four PCBs within the structure, as
mentioned in Table 1. The composite-based electronic housing presents
a similar interface for installation of four PCBs each of Eurocard 6U size
inside the structure as shown in Fig. 3(b).
CFRP is an excellent material for a range of applications thanks to its
lightweight characteristics, high strength-to-weight ratio, corrosion
resistance, and low coefficient of thermal expansion, which makes it an
attractive choice for space applications [11,12,14]. Mechanical prop­
erties of the composite material have been acquired from the experi­
mental work of Shifa et al. [2] and Tariq et al. [12], in which carbonwoven fabric (weave type: 5 Harness Satin, areal density 270 ± 5 g/
m2 and 0.4 ± 0.005 mm thickness) was used as carbon-fiber ply. A
combination of Bisphenol-A-based resin and Cycloaliphatic-amine
hardener was used in ratio of 10:3.5 (by weight) as the epoxy matrix.
The resin matrix was impregnated by 0.25 wt% MWCNTs with a
diameter range of 10–20 nm and length range of 10–30 µm.
A schematic of a typical MWCNT-CFRP composite laminate is shown
Fig. 2. Schematic of a typical MWCNT-CFRP composite laminate.
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Composite Structures 303 (2023) 116323
Fig. 3. Lightweight composite housing. (a) External CAD model view. (b) Exploded view.
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Composite Structures 303 (2023) 116323
Table 2
Mechanical properties of AA-6061 and FR-4 material.
Property
AA-6061
FR-4
Elastic Modulus (GPa)
Yield Strength (MPa)
Poisson Ratio
Density (g/cm3)
68.7
276
0.33
2.7
22.4
262
0.143
1.5
Table 3
Mechanical Properties of MWCNT-CFRP composite [2].
Property
MWCNT-CFRP
Elastic Modulus E11 (GPa)
Elastic Modulus E22 (GPa)
Shear Modulus G12 (GPa)
Poisson Ratio
Density (g/cm3)
65.1
65.1
5.0
0.1
1.6
Table 4
First ten natural frequency modes.
Mode
Fig. 4. Heat transfer path in composite housing (red). (For interpretation of the
references to color in this figure legend, the reader is referred to the web
version of this article.)
1st
2nd
3rd
4th
5th
6th
7th
8th
9th
10th
3. Results and discussion
3.1. Structure analysis
Spacecraft are subject to extreme acoustic noise during the launch
phase, which produce high-frequency vibrations in satellite structure
and internal electronic components. Additionally, events like the igni­
tion of propulsion systems, disengaging of flight control systems, and
transportation of satellite to the space launch facility have the tendency
to induce low-frequency vibrations with potentially large deflections.
The electronics housing are designed in such a way to prevent unwanted
environments from severely damaging the onboard electronics. Housing
is required to pass a series of structural analyses before its design is
validated for manufacturing. These include Modal analysis, Sinusoidal
vibration analysis, Quasi-static analysis, and Random vibration analysis
[32,33]. The mechanical loads for the aforementioned analyses have
been acquired from ECSS Testing Standard for Space Engineering (ECSSE-10-03A) [26]. Components of both housings were modeled using 2D
shell (plate) elements of order 1 using a mesh size of 3 mm. The FE
model of the aluminum housing design consisted of 54,520 elements and
184 RBE2 multi-point connections. For the lightweight composite
housing, 56,735 elements and 205 multi-point connections were used.
Mechanical properties of AA-6061 and FR4 materials are listed in
Table 2. The material properties of MWCNT-CFRP composite laminates
listed in Table 3 have been acquired from Shifa et al (2020) [2].
Aluminum Housing
Composite Housing
Frequency (Hz)
Mode Location
Frequency (Hz)
Mode Location
278.83
288.60
295.66
303.33
354.68
358.87
361.18
364.28
480.29
499.81
PCB 2
PCB 1
PCB 2
PCB 4
PCB 1
PCB 2
PCB 3
PCB 4
Top Plate
Front Plate
257.95
269.62
271.21
273.97
323.97
325.72
327.24
328.93
394.23
464.04
All PCBs
PCB 1
PCB 4
PCB 1
PCB 2
PCB 1
All PCBs
All PCBs
Top Plate
Top Plate
3.2. Modal analysis
Modal or Natural Frequency analysis involves the determination of
the fundamental frequency of satellite and its components. Launch
vehicle puts a lower limit on the fundamental frequency of a satellite and
all electronic housings must be designed above this limit to maintain
their mechanical integrity. If the fundamental frequency of the housing
is lower than the lower limit in any direction, the electronics can get
damaged due to resonance. The natural frequency of individual housings
of satellite payloads is required to be greater than 100 Hz to avoid
resonance [36]. The frequency and location of the first 10 natural fre­
quency modes of the two housings are listed in Table 4.
The first three mode shapes of the two housings in all three orthog­
onal axis directions are shown in Fig. 5 and Fig. 6. For the aluminum
housing, the first, second and third modes appear on the PCBs, which
appear to be bending. A similar pattern was shown in the results of
composite housing, where the PCBs appear to be bending in the initial
three modes.
Fig. 5. Mode shapes of aluminum housing. (a) 1st Mode. (b) 2nd Mode. (c) 3rd Mode.
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Fig. 6. Mode Shapes of composite housing. (a) 1st Mode. (b) 2nd Mode. (c) 3rd Mode.
3.3. Sinusoidal vibration analysis
Table 5
Load case of sinusoidal vibration.
Satellite and all of its components experience a low frequency vi­
bration environment (from 0 Hz to 100 Hz) due to various reasons, the
first and foremost of which is the excitation of Propulsion System of the
launch vehicle. Additional source of the sinusoidal vibration environ­
ment is the transportation of the satellite towards the launch site. Since
the mounting location of the housing is undecided, the same maximum
load is considered in all directions. The sinusoidal vibration loads pre­
sented in Table 5 are applied in all three directions.
Fig. 7 depicts the sinusoidal input profile and response accelerations
Frequency (Hz)
Sinusoidal Amplitude
(5–20) Hz
(21–60) Hz
(61–100) Hz
11 mm (0–peak)
20 g (0–peak)
6 g (0–peak)
of both the aluminum and composite housings in x, y, and z-directions.
Fig. 7(a) shows the input acceleration profile of sinusoidal vibration
loads along with responses of aluminum and Composite housing in xdirection. Since the fundamental frequency of both housing designs is
Fig. 7. Sinusoidal Input and Response Acceleration. (a) x-direction. (b) y-direction. (c) z-direction.
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Composite Structures 303 (2023) 116323
greater than 100 Hz, no excitation can be observed in the output
response graphs. Furthermore, the input and output response curves
virtually overlap each other throughout the entire frequency range,
ensuring that the housing design will not resonate in low-frequency
environments between 5 and 100 Hz.
In Fig. 7(b), a slight excitation in output response of both housings in
Y-direction is observed. The maximum acceleration transmissibility in
the aluminum housing is calculated to be 1.185 at 100 Hz, whereas the
value for the Composite housing is 1.26 at 100 Hz. Fig. 7(c) shows that
the response behavior of the aluminum and Composite housing in Zdirection follows the input acceleration load profile closely without any
noticeable excitation. The three graphs demonstrate that neither hous­
ing display substantial excitation in acceleration under sinusoidal loads,
which qualifies the housing designs for low frequency vibration
environment.
Table 6
Load case for Quasi-static analysis.
Direction
Inertial Load
All orthogonal directions (x, y, z)
13.5 g
Table 7
Von Mises Stress and Deflection.
Direction
X-axis
Y-axis
Z-axis
Von Mises Stress (MPa)
Deflection (mm)
Aluminum
Housing
Composite
Housing
Aluminum
Housing
Composite
Housing
5.96
10.9
5.08
23.5
22.5
6.98
0.00542
0.0546
0.0228
0.0151
0.0735
0.0275
static analysis is presented in Table 6, and the resulting Von Mises
stresses and deflections are listed in Table 7. The maximum Von Mises
stress and deflections are shown in Fig. 8 and Fig. 9 respectively.
The Von Mises stress generated in housings due to constant accel­
eration loads are significantly lower than the yield and tensile strength
of raw materials used. Maximum stress has been observed in y-direction
on the mounting lugs in both housings, which is due to the large number
of housing components perpendicular to the y-direction. Similarly, the
max deflection in PCBs caused by the static load is lower than 1 mm in
all three directions, which was the design requirement.
3.4. Quasi-static analysis
The Static loading occurs during the launch phase and it is caused by
the constant acceleration of the engines of launch vehicle and aero­
dynamic forces during the various phases of the vehicle flight. Static
analysis is performed to verify and validate the structure of satellite. The
maximum stresses on the components must not be greater than the yield
strength of the raw material to keep it in the elastic region. If the
generated stresses are greater than the yield limit, the respective ma­
terials will undergo plastic deformation, a phenomenon which is highly
unacceptable in space technology. In such a situation, appropriate
modifications are required to be made in the structure of the housing to
maintain maximum stress in the desired range. More precisely,
maximum stress must remain within some factor of safety of the yield
strength of the raw materials used.
The housing is constrained at mounting lugs and the static loading is
applied in the form of Inertial Load and. The load case for the Quasi-
3.5. Random vibration analysis
During the launch phase, a typical satellite experiences high fre­
quency vibration environment primarily caused by the excitation of
acoustic noise fluctuations generated by different engine operations of
the launch vehicle. In addition, engines generate high frequency thrust
Fig. 8. Von Mises Stress produced in the electronic housing. (a) Aluminum housing. (b) Composite housing.
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Fig. 9. Deflection produced in the electronic housing. (a) Aluminum housing. (b) Composite housing.
vibration simulations are presented in Table 9.
The random response GRMS of aluminum housing is used as static
inertial load to estimate Von Mises stresses and deflections generated in
the aluminum and lightweight composite housings under random vi­
bration loads in the three orthogonal directions, as shown in Table 9.
The resulting Von Mises stresses and deflections are tabulated in
Table 10. The maximum Von Mises stress and deflections in the two
housings are shown in Fig. 11 and Fig. 12 respectively.
Stress values of 242 MPa were observed around the mounting holes
of lugs due to stress concentration. Disregarding the abnormally high
values in these elements, the actual maximum stress obtained in the
composite housing is close to 189 MPa. Maximum Von Mises stress
obtained from equivalent random load in both housings is observed in ydirection. In aluminum housing, the stress is concentrated on mounting
lugs and fastener locations of housing plates as shown in Fig. 11(a). In
composite housing, the Von Mises stress is observed on the mounting
lugs and PCB frames as displayed in Fig. 11(b). Max PCB deflection in
either housing is obtained to be lower than 1 mm in all three directions
as shown in Fig. 12, which was the structure design requirement.
Table 8
Load case for random vibration analysis (M is mass of housing).
Frequency
Levels
GRMS
(20–100) Hz
(100–300) Hz
(300–2000) Hz
+3 dB/octave
PSD (M) = 0.12 g2/Hz × (M + 20)/(M + 1)
− 5 dB/octave
16.85 g
oscillations, which are translated into the body of the launch vehicle,
from where these random vibrations are transferred to the outer panels
of the satellite through the launch vehicle adapter.
The adapter transfers these vibrations to the structure panels of the
satellite, from where they are transferred to the housings of sub-system
units located inside the satellite [26]. The load case for the Random
vibration simulation is presented in Table 8. Since location of housing in
the satellite is unknown, the maximum random vibration loads ac­
cording to the ECSS standard is applied in all directions.
The GRMS of input random vibration load is calculated to be 16.85 g.
The comparisons of random vibration input and output random re­
sponses of both aluminum and composite housings in ×, y, and z-di­
rections are depicted in Fig. 10. The response graph in x-direction shows
that the aluminum housing excites at around 800 Hz, whereas the
composite housing shows a peak acceleration response at around 500
Hz. In y-direction, the aluminum housing first excites at around 300 Hz,
with subsequent excitations at 800 Hz and 1100 Hz, whereas the com­
posite housing shows an excitation slightly at slightly lower frequency of
250 Hz. In z-direction, the aluminum housing first excites at around 500
Hz with a higher peak at 700 Hz. For the composite housing, the first
excitation appears at 600 Hz, with a higher peak at around 1100 Hz. The
response GRMS values of the two housings obtained from random
4. Conclusion
The aim of this research study was to design a lightweight electronics
housing that satisfies the design requirements of electronic housings for
satellite applications. A composite housing was successfully designed for
satellite electronics using a combination of CFRP, MWCNTs and AA6061 materials with the following observations:
1. The lightweight composite housing offers a mass saving of 25 %
compared to a typical electronics housing made entirely of AA-6061,
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Fig. 10. Random input and response acceleration. (a) x-direction (b) y-direction (c) z-direction.
Table 9
Random response GRMS of electronic housings.
Direction
x-direction
y-direction
z-direction
Random Response GRMS
Aluminum Housing
Composite Housing
70.72 g
83.6 g
160.7 g
84.51 g
145.1 g
256.6 g
which was the primary objective. Table 11 shows the potential mass
difference between the two housings.
2. Results of Modal analysis show that the fundamental natural fre­
quencies of the composite housing in all three directions is greater
than the 100 Hz and, therefore, can easily evade resonance with the
primary structure of satellite and launch vehicle.
3. Acceleration response of the composite housing under sinusoidal
vibration loads in the three orthogonal directions does not indicate
any unwarranted excitation, validating the earlier results of natural
frequency analysis.
4. Results of stresses and deflections obtained from Quasi-static anal­
ysis validate the structure design of composite housing for constant
acceleration loads in all three directions.
5. Response of random vibration loads and resulting stresses obtained
from Random vibration analysis show that the lightweight composite
housing can safely hold the PCBs in place inside the housing without
any damage due to excessive vibrations during the launch phase.
Additionally, deflections obtained from Random vibration loads are
found to be under 1 mm in all directions, which was the design
requirement.
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Table 10
Von Mises stress (MPa) and deflection (mm).
Direction
x-axis
y-axis
z-axis
Table 11
Mass Saving in the electronic housing.
Von Mises Stress (MPa)
Deflection (mm)
Aluminum
Housing
Composite
Housing
Aluminum
Housing
Composite
Housing
31.0
67.7
60.5
147
189
132
0.0261
0.338
0.0314
0.0942
0.762
0.522
Housing
Mass (kg)
% Mass Saving
Conventional
MWCNT-CFRP Composite
2.95
2.23
~25 %
Fig. 11. Von Mises Stress generated in the electronic housing. (a) Aluminum housing. (b) Composite housing.
Fig. 12. Deflection generated in the electronic housing. (a) Aluminum housing. (b) Composite housing.
The above findings observations demonstrate that the composite
housing offers similar mechanical functionality as that of the aluminum
housing and satisfies all the structure design requirements for electronic
housings in satellite applications mentioned in Table 1.
and associated advantages. The thermal and electrical characteristics of
the composite material and housing itself have been briefly discussed in
Section 2.4.2, however, experimental tests can be performed to validate
the findings of the research work using a manufactured prototype. This
paper has opened several opportunities for researchers to explore and
experiment the thermal, electrical, and RF shielding properties of
MWCNT-CFRP composite laminates for demanding applications,
particularly in satellites and spacecraft structures.
5. Future work
This study mainly focused on the structural application of MWCNTCFRP composite laminates in lightweight satellite electronic housings
10
S. Iqbal et al.
Composite Structures 303 (2023) 116323
CRediT authorship contribution statement
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Shoaib Iqbal: Conceptualization, Methodology, Writing – original
draft, Data curation, Investigation, Software, Visualization. Tariq
Jamil: Resources, Supervision, Project administration, Writing – review
& editing, Validation. Syed Murtuza Mehdi: Formal analysis.
Declaration of Competing Interest
The authors declare that they have no known competing financial
interests or personal relationships that could have appeared to influence
the work reported in this paper.
Data availability
The raw/processed data required to reproduce these findings cannot
be shared at this time as the data also forms part of an ongoing study.
Acknowledgement
The authors wish to express their gratitude to S. M. Shahab Hussain,
Saeed-ur-Rehman, and M. Aurangzeb Khan for their valuable contribu­
tions. The authors also acknowledge NED University of Engineering and
Technology Karachi for providing computing resources to Dr. Tariq
Jamil. The authors declare that they have no known competing financial
interests or personal relationships that could have appeared to influence
the work reported in this paper.
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