Design and analysis of
conformal composite LH2 fuel
tanks for hypersonic aircrafts
Background
The need for more detailed investigations on liquid
hydrogen tanks in future airliners is urgent in hypersonic
aviation. The propellant tank technologies are critical for
the vehicle operations, cost and safety. New materials and
design concepts are required, such as fibre composites, in
order to reduce the tank weight and to increase the
structural performance. This is particularly important if the
tank has load carrying functions.
PhD Candidate: Ilias Tapeinos
Department: ASM
Section: Structural Integrity & Composites
Supervisor: S. Koussios
Promoter: R. Benedictus
Start date: 01-2-2013
Funding: TU Delft
Cooperations: DLR-SICOMP-FOI-ULB-ECM-ELTE-CENAEROGDL-ORB
Several design concepts will be considered for a proof-ofconcept demonstrator cryogenic tank.
• Classical shaped
• Multi-bubble shaped (quadri-spherical)
• Conical shaped
[2]
CHATT Project
The main focus is to reduce tank weight and increase
structural performance of cryogenic tanks. New materials
(Carbon Fiber Reinforced plastic-CFRP) and design
concepts need to be explored [1].
To minimize the weight, ‘iso-tensoid’ structures provide the
lightest solutions. Fibre reinforced materials are structurally
the most efficient material for pressure vessels due to their
high specific strength, stiffness and because there is the
possibility to direct the right amount of fibers according to
the orientation and the magnitude of the principal stresses.
Multi-bubble concept of cryogenic tanks for LH2 storage
B) Cryogenic Tank Structure Modeling
(a) Permeability tests for various polymer liners – Helium
(b) Thermo-mechanical tests (TMA) for various polymer liners
and composite materials
D) Testing Procedures
• Permeability tests for various polymer liners – Helium at
a) room and b) cryogenic temperatures
SpaceLiner hypersonic passenger transport with a nonintegral cryogenic tank with cryogenic propellant
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Cryogenic environment
Long duration flights
Tank geometry and size
Fuel permeation
Tank wall & Liner material selection
Hydrogen embrittlement
Aim of my research
The aim of the research would be the design, prototyping
and testing of composite tanks -that deviate from classic
shape- for cryogenic fuel containment.
The challenge in my research is to preserve structural
optimality, select suitable materials, design the tank within
the limitations posed by manufacturing, maintenance and
operation, manufacture proof-of-concept tanks and employ
various testing methods.
Research methodology
A) Design Procedures
Flight duration time affects significantly tank architecture.
• Micro-cracking tests on representative of reinforced
candidate materials (LCP & toughened epoxy) at a) room
temperature and at b) –55oC
• Run comparative tests on load concentration between
experimental and FE Model
• Classical Lamination Theory (CLT) for laminate analysis
• Progressive Failure Analysis (PFA) for definition of
material degradation
• Failure criteria application to tank structure components
• Evaluation methods for structural analysis (FE analysis)
Progress
C) Manufacturing Methods
Composite Pressure Vessel
Liner requirements: (H2 permeation resistance, thermal
expansion compatibility with composite, low density &
good resistance to thermo-mechanical loads)
Evaluate the use of different pressure vessel manufacturing
methods for the multi-bubble, conical concept (filament
winding, fiber placement)
Liner length (L)
Liner diameter (Ø)
Liner surface
Input
Output
Lay-up
Filament Winding
Number of Plies
Thickness distribution
Ply thickness
Laminate stacking
sequence
function
Laminate structural
performance
A small deal of progress was obtained to my own
judgment, since I’ve started working on CHATT project
only recently (2 months). Results can be seen below:
Definition of liner materials demands and selection
200
0,30
Tensile Strength
Thermal Conductivity
180
0,25
160
140
0,20
120
100
0,15
80
0,10
60
40
0,05
Thermal Conductivity (W/m*k)
Cryogenic LH2 Tanks Key Challenges
Internal pressure in spherical and cylindrical
pressure vessels in thin-walled analysis
• Thermo-mechanical tests (TMA) for various polymer
liners and composite materials for linear thermal expansion
coefficient (CTE) calculation
Tensile Strength (MPa)
Aerospace Engineering
• Built-up of parametric pressure vessel generator (FE
analysis)
• Thin-walled and thick-walled pressure vessel analysis
• Definition of load environment
20
0
0,00
LCP
DCPD
PET
PFA
FEP
Liner Material (-)
Correlation of tensile strength and thermal conductivity
for various polymer liner material candidates
Definition of
requirements
permeability
testing
apparatus
setup
Fiber orientation
Tank weight
Stress environment
Design challenges:
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Integration or no-integration at aircraft
Volume efficiency
Tank weight minimization
Optimum distribution of thermo-mechanical loads
Liner
Structural Configurations
Evaluate the use of different liner manufacturing methods
for the multi-bubble, conical concept (rotational/ injection/
blow moulding).
Permeability experimental set-up for volumetric
determination method [3]
Publications
- M. Sippel, A. Kopp, K. Sinkó, D. Mattsson, (2012) “ Advanced Hypersonic Cryo-Tanks Research in CHATT’’, 18th AIAA International Space Planes and Hypersonic Systems and Technologies
Conference
- S. Choi, B.V. Sankar, (2008) “Gas permeability of various graphite/epoxy composite laminates for cryogenic storage systems ’’, Composites Part B: Engineering 39, pp 782–791
- ASTM D1434-82, (2009) “ Standard test method for determining gas permeability characteristics of plastic film and sheeting’’