Novel Deployable Membrane and Shell

Structures for Space

Prof.Dr. Omer Soykasap,

Afyon Kocatepe University,

Faculty of Engineering

Department of Material Science and Engineering

ANS Campus, 03200 Afyonkarahisar TURKEY

E-mail: soykasap@aku.edu.tr

Web: www2.aku.edu.tr/~soykasap

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Research Topics related to COST action

Strategic Research Cluster 1: new applications of structural skins and new

concepts

• Innovative concepts, adaptable structures, shell structures with textile reinforcement

• material developments and prototyping of lightweight structures

• Deployable structures: reflector antennas, synthetic aperture radar, booms, solar array

Strategic Research Cluster 4: materials and analysis

• Material characterization and analysis, material testing, Advanced numerical simulation,

Predictive material models, Finite element analysis

• Textile composite materials, carbon, glass, kevlar reinforced plastics,

• Advanced modelling and simulations for mechanical, thermal and electrical loads

• Optimization: Ant colony optimization, Particle swarm optimization Genetic algorithm,

etc.

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Lightweight deployable SAR membrane antenna

• Leipold et al. used technology developed for solar

sails to SAR membrane antenna.

• 12m 3m membrane structure is reinforced by X-form

CFRP

• It is designed for L- band. Areal density is 2 kg/m²

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Membrane Reflectors

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SMART reflector

• Developed by Munich Technical University.

• Carbon fiber reinforced silicon is used.

• 6-12 m diameter is possible, it can used for L or Ku-

Band antennas, surface accuracy is 0.5-1 mm RMS,

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Membrane Reflectors

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Concept design for large space application of

deployable antenna

• Zheng et al. studied new concept for deployable large

space antennas. Inflatable elements and rigid parts.

• Diameter 60 m, 520 kg, 3.1 m 1.9 m

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Membrane Reflectors

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Precipitation radar antenna

• ILC Dover developed JPL radar antenna, inflatable

edge support, membrane surface.

• Dimensions 5m 5m for Ku/Ka-band frequency

surface accuracy 0.17 mmr, areal density 2 kg/m2. 29-05-2014

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Membrane Reflectors

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Rapid deployable antenna, URDA

•Developed by ESA for telcomunication satellite. Refletor

surface is made of carbon fiber reinforced silicon

membrane.

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Membrane Reflectors

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CRTS, ESTEC/Cambridge University (1.5 m diameter

model)

•Pellegrino et al. Developed a deployable membrane

reflector concept. F/D=0.8, 5 m diameter, surface

accuracy 1.2 mm’dir. Reflective surface is made of

kapton (polyimide film) coated by aluminium. 29-05-2014

Membrane Reflectors

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Deployable reflector for small satellites, CTD

• Developed by Composite Technology Development

(CTD). Ku-Band D=4m, F=2.4 m

• Rigid central part and foldable outer part

• Folded dimensions: 1.4m 2m

.

29-05-2014

Membrane Reflectors

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Shell surface reflector, CTD

•Deployed dimension: 4 m 2.5 m,

•Developed by Composite Technology Development

• Surface made of CFRP, RMS 0.27 mm

29-05-2014

Shell Reflectors

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Deployable Stiffened Spring Back Reflector, 2004-2008

Spring back reflector,

Hughes Space and

Communication Company,

Launched in1996 for

MSAT. Monolithic,

foldable

Stiffened Spring back

reflector, TAHARA

project, University of

Cambridge, British Council

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Thin shell panel reflector by Astrium

•D=3 m, 30 CFRP panels.

•Mass= 10 kg, areal density 1.4 kg/m2

29-05-2014

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Shell Reflectors

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Large tape spring antenna

•Soykasap et al. developed P-band antenna for biomass

measurement from space

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Kabuk Yüzeyli Reflektörler

Shell Reflectors

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NKS Raumfahrt, Dr. Adrian klein

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Ultra-thin Shell, Compactly folding and Self-Deploying

Reflector Antenna (2010-2012)

• AKU design and analysis new foldable and space

deployable reflector antenna for Ku-band

telecommunication

• 6m diameter, made of carbon/epoxy, ultra thin shell, self

deployable, low mass and low cost

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Springback reflector by Afyon Kocatepe University

• Soykasap et al. developed springback reflector,

•D=6m, CFRP shell structure

•1.5 m scaled model, 6.8 Hz fundamental frequency and 0.42

mm RMS surface accuracy

29-05-2014

Shell Reflectors

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Deployable Solar Array, 2004-2005

University of Cambridge-SSTL project

Development of solar panel hinges,

Simulation and testing of solar array

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Deployable Solar Array: deployment simulation

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Development of Tape Spring Hinges

(2005-2007)

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Deployable Composite boom, CFRP, R=20 mm

t=0.36 mm, three plies (45)3 (2005-2007)

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New Deployable Reflector Concept

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Requirements for the reflector

Total mass of reflector system < 110 kg.

Geometry: packaged for ROKOT launcher

Stowed freq. > 40 Hz, deployed freq. > 0.1 Hz

Deployment: must not damage itself or the spacecraft

Surface error budget: 6 mm

Parabolic shape and area defined (3.2 m by 7.9 m)

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Structural Concept

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Structural Concept

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Design for folding

Connections

• must be strong and

flexible

• L- and T-connection

• 3M 79 woven glass

tape

Elastic hinge lines

• required for folding

• flexible

• careful design

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Design for folding

Sizing of cut-outs in side walls

• the width of the cut-out

w pRmin

• the length of the cut-out

L 2pRmin+ pt

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Design of Reflector Structure

Scale

– Full-scale structure for the flight loading environment

– Half-scale demonstrator structure under 1-g loading

conditions

Structural analysis of deployed reflector

– Design parameters: width, depth, taper, thickness

– Material: T300 carbon/epoxy woven composite

– FE model in ABAQUS

– Optimise the structure on the basis of lightweight,

high stiffness and strength.

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Design of Reflector Structure

Full-scale structure

– Designed for the flight loading environment

– Optimised structure has

• a wall thickness of 0.3 mm

• symmetric side walls with end heights of 2 m

• a mass of 33 kg (2.5 times lighter than that of

previous technology)

• first natural frequency of 3.3 Hz.

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Design of Reflector Structure

0.6 m

1 m

1.6 m

RF surface

Back structure

Half-scale demonstrator structure

– Scale the optimised structure

but use the same thickness

– More stiffeners added to

prevent buckling

– The demonstrator has

• a mass of 7.2 kg

• first natural frequency of 6.8 Hz

g

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Design of Reflector Structure

Gravity-induced displacement magnitudes (mm)

First vibration mode (frequency=6.8 Hz)

First buckling mode (factor of safety=1.9)

Tsai-Wu material failure criterion

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Testing of Demonstrator

Measurement of Stiffness

– Displacement at the tip of reflector measured by a laser

displacement sensor LK 081, Keyence Co.

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Testing of Demonstrator

Measurement of Surface Accuracy

– Used a Photogrammetry software PhotoModeler Pro 4.0

3.8 mm RMS error

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Testing of Demonstrator

Measurement of Surface Accuracy

– Precision: obtained by RMS marking residuals and

tightness within the sofware; 90% of data had a precision

of 1:3225 (1 part in 3225).

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Packaging and Deployment of the Demonstrator

Packaging: consists of first flattening (first stage) and then

longitudinal Z-type folds (second stage)