1. TC-SKAR
Thermoplastic Composite – Square
Kilometer Array Reflector
R.Bakker – Airborne Technology Centre

2. Content
• SKA Introduction
• TC SKAR
– Concept
– Design
– Analysis
– Prototype
– Conclusions

3. • Aus
• afrika

4. SKA Project timeline

5. TC SKAR
Radical new design for automated
production of a thermoplastic reflector
• >3000 reflectors in total
• Rate of 2 per day in total
• Sub assemblies possible as locations
up to 3000 km apart
• Low cost production

6. TC SKAR
• Press forming
• Material tests
• Induction welding
• Reflector tests &
consultancy
• Consortium
lead
• Design
• Consolidation
• Cost analysis

7. Design concept baseline
• Single reflector skin
• Automated fibre placement of UD-
tape, press-forming into shape
• Modular design
• Standard skin sections and stiffeners
• Induction welding of all parts into 1
reflector
• Symmetric shape

8. Material choice
• Thermoplastic carbon composite
• Thermoplastic
– Robust
– Machinable
– Joining by welding
– Easy to form
• Industrial grade – low cost
• Carbon
– High stiffness
– Low CTE
– Low weight

9. Baseline design
Overview
• Diameter of 15 [m]
• Focal ratio of 0.42 [-]
• Total mass appr. 1586 kg (excl. QP &
feed)
• 5 skin panels per pie section
• Rib and ring components for
integrated support structure

10. Baseline design
Tangential stiffeners
• Mid-ring: low, non-critical blade stiffener in
the center
• Center: Critical blade stiffener, reflector is
mounted on this ring to the pedestal
• Ring 1: non-critical blade stiffener
• Outer ring: Semi-critical blade stiffener
Radial stiffeners
• Radial mid-ring: low, non-critical blade
stiffener in the center
• Quadrapod stiffeners section 1: Critical and
relative heavy T-stiffener
• Non-quadrapod stiffener section 1: semi-
critical T-stiffener
• Quadrapod stiffeners section 2: Critical and
relative heavy T-stiffener
• Non-quadrapod stiffener section 2: semi-
critical blade-stiffener

11. Structural analysis
rms results
• Gravity 90 degree elevation:
• Wind load:
• Thermal load:
• 90 degrees elevation
+ 12 [m/s] wind
+ low temperature:
• Manufacturing:
• Total:
0.44 [mm]
0.06 [mm]
0.04 [mm]
0.41 [mm]
0.50 [mm]
0.61 [mm]

12. Reflectivity
• Reflectivity carbon composite
insufficient
• Addition of metallic mesh
• Embedded in the composite resin
• Contribution to noise insignificant
compared to bare metal mesh

13. Welding
• All joints can be welded
• Induction welding
• Automated process
• No addition of material

14. Reflector prototype test
Representative of the production process chain
when manufacturing Westerbork panel
• Testen van gehele paneel in bedrijf
2 meter
1,5meter

15. Demonstrator panels Westerbork

16. Westerbork
• Press formed beam
(untrimmed in photo’s)

17. Conclusions
• Fully integrated composite design
possible
– Stiffness, CTE, reflectivity and other
requirements
• Automated processes can be utilized
for series production
– Skin, stiffeners, strips and other
reinforcements
• Rate of 1 per 2 days possible with
current processes
• Material durability further tested on-
site