Thermoplastic composites for primary aircraft structuresNew trends in composite materials

20001990 2010

A380 wing fixed

leading edges

First large scale

assembly:Welded fixed

wing leading edges A340

Glass/PPS

First welded

assembly:MUC door

Fo50

Carbon/PPS

First primary

structure: bonded

GV pressure

floors

Ca/PEKKPrimary stiffened skin UD

based structure

First series production:

press-formed Dornier ribs

Carbon/PEI

First co-consolidated

torsion box, AW169

Carbon/PPS

First Induction welded

control surfaces,

G650

Co-consoli-dated floor

beam

Carbon/PEKK

Workshop at the University of Girona, 17-09-2019

Bas Tijs, Bas Veldman, Arnt Offringa

GKN Aerospace: Fokker

GKN Aerospace: FokkerOur history is aircraft

1911 - Fokker ‘Spider’ 1924 - Fokker F.VII 1986 – Fokker 100

200019901980197019601950194019301920 2010 202019101900

1996- Super Specialist

Anthony FokkerAviation Pioneer

1890 - 19391911Anthony Fokker’s

first flight in his

home-built

‘Spider’

1996• Acquisition by Stork.

• Aircraft production ceased

1940Destruction of

Dutch facilities

1945Return from the

ashes

2010Fokker

Technologies,

new company name

of the 4 Fokker

Business Units

1919Dutch Fokker

Company founded

1950-90’sMajor player in 50-

100 seats segment,

Fokker 50, 70, 100

1920’sLargest Aircraft

manufacturer in

the USA

2015 - NowAcquisition by GKN

200019901980 2010

Integrated Systems• Wiring & Sensors• Complex assemblies• Industry 4.0 & HRM

Thermoplastics• Welding & AFP• Complex Concepts

Material & Manufacturing• Freeform and Blown

Powder AM• Welding and Machining• Automation

Design & Analysis• Advanced Concepts• Materials technology• Engineering workbench

AM• Powder Bed (EBM /LPB)• Composites• AM Integration (all)

Thermoset• Dry Fibre• Complex Concepts• Anti-Ice Systems

AM• Freeform – Airframe

Metallics• Metallic Forming• Spinning • Complex Ti machining• Transparencies/

Coatings

Composites• Thermoplastic Technologies• Filament winding• Thick walled composites

GKN Technology

Centre

(Bristol, UK)

GKN Technology

Centre (Hoogeveen, Netherlands)

GKN Technology

Centre (Trollhättan,

Sweden)

GKN Technology

Centre (ORNL, USA)

GlobalEco-

System

GKN Aerospace Global Technology CentresWorld Class Centres for Development of Technology and Capability

�Reduce cost

�Reduce weight

�High-move rates

�Improved repair and maintenance

�Green materials and processes

Aerospace OEM objectivesStrong focus on reduction of costs and high-move rates

Thermoplastic compositesMeeting objects through application of thermoplastic composites

Ho

urs

Total costs

€/kg labour

€/kg material+processing

• Out-of-autoclave technology

• Robot technology

• No freezers, less logistics

• No preforming for stiffeners

• Simple layup through

preforms

• Co-consolidation

• Welding

• High kg/hr lay-down rate for

fiber placement

• No pre-compacting

• Short co-consolidation cycle

Thermoplastic compositesAerospace grade thermoplastics at the top of the pyramid

(Figure from Arkema, introduction Kepstan PEKK, 2015)

Developments focussed on:

- Polyetherketoneketone (PEKK)

- Polyphenylene sulfide (PPS)

Available in many forms:

Powders, flakes, pellets, extrusions, (fiber)

reinforced compounds, fabrics, tapes, etc…

Within polymer family many different grades available with different;

- Processing temperatures

- Viscosity and processability

- Crystallization rates

- Strength and ductility

20001990 2010

A380 wing fixed

leading edges

First large scale

assembly:Welded fixed

wing leading edges A340

Glass/PPS

First welded

assembly:MUC door

Fo50

Carbon/PPS

First primary

structure: bonded

GV pressure

floors

Ca/PEKKPrimary stiffened skin UD

based structure

First series production:

press-formed Dornier ribs

Carbon/PEI

First co-consolidated

torsion box, AW169

Carbon/PPS

First Induction welded

control surfaces,

G650

Co-consoli-dated floor

beam

Carbon/PEKK

Thermoplastics road map towards primary stiffened structuresTechnology development at GKN Aerospace: Fokker

bulkhead floor panel

�>4000 panels/year

�panels with thermo-folded edges, welded inserts

�also: primary structure ‘pressure floor panels’ with press-formed edge reinforcements

Gulfstream 550 and 650 thermoplastic floor panelsThermo-folding, ultrasonic welding and press-forming

Gulfstream 550 and 650 floor panelsUltrasonic welding of inserts

Taking advantage of formability thermoplastics:• Cost reduction 50%• From sheet material to part

Gulfstream 550 and 650 thermoplastic trailing edgeThermo-folding of rudder trailing edge

photo courtesy Airbus

Press

• >800 ribs & stiffeners per aircraft

• Automated stamp forming

– preheated tools

– automated handling

• Automatic trimming cellE-glass

Reinforced

Fortron PPS

Airbus A380 thermoplastic leading edge ‘J-nose’Stamp forming and resistance welding

automatic resistance welding => elimination of rivets & shimming

spar or rib+

-

skin

welding

strip

Airbus A380 thermoplastic leading edge ‘J-nose’Stamp forming and resistance welding

Thermoplastic control surfaces Gulfstream G650Press-forming, thermo-folding and induction welding

• Post-buckled multirib design makes for low weight:• large number of ribs but

• a thin skin that may buckle

• Thermoplastics makes for low cost:• welding => low cost assembly• no freezers needed, easier logistics => lower capital

investments• press-forming of ribs, folding of trailing edge, fast lay-up

and short consolidation cycles => low cost parts

10% lighter than previous epoxy composite sandwich panel version

20% lower cost

Thermoplastic control surfaces Gulfstream / DassaultPress-forming, thermo-folding and induction welding

Generated

heat

Alternating

current in C/PPS

laminate

Induction coil

C/PPS

laminate

Magnetic field induces alternating current in laminate

Temperature generated within carbon fabric due to joule heating

Thermoplastic control surfaces Gulfstream / DassaultPress-forming, thermo-folding and induction welding

Thermoplastic control surfaces Gulfstream / DassaultRecycling: access panel from recycled carbon/PPS

Fabrics + PPS

UD PEKK tape

Products become:

• larger• more highly loaded

• at higher move rates

hand lay-up

AutomaticFibre Placement

Out-of-Autoclave

Co-consolidation

Welding

New design concepts

Evolution of thermoplastic composite material and technologyTowards high volume production of highly-loaded primary structures

STUNNING PROJECT - CleanSky 2

“SmarT mUlti-fuNctioNal and INtegrated TP fuselaGe”

Development of a multifunctional thermoplastic fuselage demonstrator

• Automated assembly processes

• Integration of multiple system functionalities

• Application of thermoplastic material and manufacturing processes

• Fastener free design: Thermoplastic welded joints

• Advanced simulation techniques: Virtual Testing & Manufacturing

Skin-stiffener welding Skin-stiffener-frame welding Frame-Floor beam welding

Evolution of thermoplastic composite material and technologyTowards high volume production of highly-loaded primary structures

Evolution of thermoplastic composite material and technologyOut-of-Autoclave manufacturing of parts

Final part

Welded frames &

zero bolts

Thermoplastic composite enabled new design conceptsFuselage frames welded on thermoplastic butt-joint stiffened orthogrid

Butt-joint concept

Flat pre-forms

(laminates)

Short-fiber

reinforced filler

Autoclave

Co-consolidation

Reduced peel forces due

to elimination of clips

Analysis and Testing of a Thermoplastic Composite Stiffened Panel Under Compression, Kevin S. van Dooren, Edgars Labans, Bas H.A.H. Tijs,

Jan E.A. Waleson and Chiara Bisagni, Proceedings of the 22nd International Conference of Composite Materials, Melbourne, Australia, 2019

Thermoplastic composite enabled new design conceptsAnalysis and testing of thermoplastic composites and stiffened structures

Artificial crack

Taking advantage of high fracture toughness.

Capability for post-buckling with large damage.Numerical

Experimental (DIC)

Development of advanced simulation techniquesPredicting manufacturability and performance

Virtual Testing Virtual Manufacturing

Stress

Manufacturing

MaterialAFP Forming

Part

Welding

Consolidation

Detail

(Sub)Component

FLOW OF INFORMATION

Requirements

Geometry

Loads

Design Cost

Optimization

Important next stepsLinking the flow of information from design and manufacturing to performance

Thank you for your attention