Endlosfaser verstärkte Thermoplastmaterialien als ... · Endlosfaser verstärkte...

Folie 1 Werkstoff Kolloquium 2006 W. Dudenhausen27.11.2006

Endlosfaser verstärkte Thermoplastmaterialien alsAlternative in Hochleistungs-Leichtbaustrukturen

Werkstoff Kolloquium 2006

Dr.-Ing. Wolfgang Dudenhausen

DLR – Institut für Bauweisen- und Konstruktionsforschung (IBK), Stuttgart

Köln, 5. Dezember 2006


Content

• Department of Computer Supported Component Design

• Vacuum consolidation technique as basis for manufacturing large flat structures

• Vacuum moulding - a shaping process for complex geometry

• Application examples

• Further Application and Future prospects

• Conclusion


31 research institutes and scientific/technical facilities at

8 sites4 branchesGerman-Dutch Wind Tunnel DNW)European Transonic Wind Tunnel ETW)

Institute of Structures and Design, DLR - Stuttgart

DLR Locations


Computer Supported Component Design

Head of Department:

Dr.-Ing. Wolfgang Dudenhausen


Polymer CFRP Structure

TemperingPyrolysis

Si-Infiltration (LSI)

Mechanical Finishing e.g. withJetcut or Machine Tools

PolymerTechnology as

Basis of Structural

Design


Competence

CAD/CIMFE/MKS

Design and Engineering

Tool- and Manufacturing Development

Evaluation and designDevelopment of new and innovative high performance structuresMission depending design (UCAV)

Technology for manufacturing with thermoplastics and infusions processesJoining technique and tooling conceptsIntegrated QS

Provision of specified process sequences,Design for manufacturingConsulting of internal and external partners.

Transfer of Technology


Processing and Fabrication:•Rapid fabrication•No chemistry during processing•Manufacture complex parts in a single step•Integrated fabrication and assembly

Properties: (high performance thermoplastic composites)•High toughness and damage tolerance•Excellent solvent resistance and very low moisture absorption•Excellent high temperature properties •Outstanding fire resistance and very low smoke generation•Superior wear resistance

General:•Indefinite shelf life•Room temperature storage•Recyclable

Drawbacks:High manufacturing temperatureUpper material cost than thermosetLower Tg than thermoset

Benefits of Thermoplastic Composites

Source: Airbus Deutschland GmbH


Overview of Thermoplastic Polymer Matrices

Limited database in composite formExcellent environmental resistanceHigh toughnessLower process temperature than PEEK

340156PEKK

Extensive databaseExcellent environmental resistanceHigh toughnessHigh process temperature

390143PEEK

High TgEnvironmental resistance

330217PEI

Excellent environmental resistanceLow TgMicro cracking

32590PPS

CommentsTypical ProcessTemperature (°C)

Tg(°C)

Matrix

Source: Cytec Engineered Materials

PPS: Poly Phenylen Sulphide

PEI: Poly Ether Imide

PEEK: Poly Ether Ether Ketone

PEKK: Poly Ether Ketone Ketone


Comparison of Material Cost

Source: Institute of Structures and Design, DLR 2003

Reference: Flat Plate 1 m², 3 mm Thickness


Fibre Reinforced Thermoplastics Manufacturing Technologies

VacuumAtmospheric pressure

Insulation

Heated Table

Vacuum table

Heating / cooling

Heated Press

Heated table

Prepreg Pressure roller

Hand or robot lay up

Autoclave

VacuumPressure


Fibre Reinforced Thermoplastics Manufacturing Technologies

Limited area

over 1 Mio. €A

Limited area

over 1 Mio. €A

Extendable area

under 200.000 €A

Extendable area

over 1 Mio. €A


Content

Department of Computer Supported Component Design

Vacuum consolidation technique as basis for manufacturing large flat structures

Vacuum moulding - a shaping process for complex geometry

Application examples

Further Application and Future prospects

Conclusion


Vacuum Consolidation Techniques

VacuumAtmospheric pressure

Insulation

Heated TableVacuum table

General Characteristics:• Low investment cost • Adaptable work space through

modular set-up• Simple shaped plates can be

consolidated on heated table using vacuum down to 3 mbar

• Low porosity reachable (< 2%)


Pre cut with water jet

Vacuum Consolidation Technique

Fixing of prepreg layers with a soldering gun

Realization of tailored panels



Principle of vacuum consolidation



• Processing temperature up to400° C is possible

• Active cooling system is integrated in the table, usable media: gas and fluids

• Vacuum channels are integrated in the table surface

• Main dimensions of the table

– at present:3000 mm x 1200 mm

– in near future:4800 mm x 1200 mm

Manufacturing of simple shaped rib stiffened plates is possible

Main characteristics of IBK/DLR vacuum table facility


Content






Conclusion


Vacuum Molding as a Shaping Process

• Basis for shaping process is a vacuum consolidated plate

• Vacuum table can be completed by a positive mold

• Heating of the mold can be realized by the heated table itself; in case of unfavorable mold dimensions additional heating is necessary

Pre consolidated plate



• Mold and plate are covered with a vacuum bag

• Kapton vacuum bag consists of two foil parts glued together

• Additional heater mat assures constant temperature within the CFRP plate



• Due to manufacturing a spring in angel has to be taken into account

• Inner and outer surface have good quality

• C-Scan showed no significant failure in the shell

ca. 1000 mm


Content




Application examplesThermoplastic CF-PEEK rudderHybrid Fan Blade


Conclusion


Rudder with Fibre Reinforced Thermoplastics


Vacuum Consolidation Techniques


Vacuum Welding Method


Press Welding Method (Rib forming)

Welding device1 2 234 4 5

6 7 8

1. rudder skin2. L-Stringer3. rib to be welded4. compressor part

5. spring washer set6. bracket7. heating element8. insulating material


Bonding Techniques


Press Welding Method (Spar)


Comparison of Manufacturing CostRudder with Thermosetting or Thermoplastic Prepregs (APC 2)

Calculated by EADS


Content




Application examplesThermoplastic CF-PEEK rudderHybrid Fan Blade


Conclusion


Basic Concept

Titanium

CFRP

Joining Area

Reduction of structural weightResistance against erosion and FOD

by having a metal leading edgeReduced rotational blade energy with

view on a fan blade offIncreasing structural damping

Hybrid fan blade for BR700 engine family

Hybrid fan blade for NDV 4.5


Results of FE Modelling

HEX meshed blade Combined HEX / SHELL mesh

Different FE models showed good correspondence with respect to equivalent stress (v. Mises)

FE analysis showed reduction of stress within the Titanium part and an acceptable utilisation of CFRP material


Realised Compressor Blades

Hybrid fan blade for NDV

• Experimentalverification of joining technique and assessment of load carrying capacity

• Preparation of FE modelling technique for hybrid structures

• Demonstration of an material appropriate manufacturingtechnique

Hybrid fan blade for BR700 engines

Development status


Content






Conclusion


Generic Target Structure - Leading Edge

Typical leading edges:• Wing• Horizontal stabilizer• Vertical stabilizer

Outer shell

Rib flange

Rib

Leading edge made of thermoplastic CF-PEEK


Rib

Outer shell

Different link systems between a rib and an outer shell

Combination of Short and Continuous Fiber Reinforced Composites



Principle of over injection molding

Injection of short fiber reinforced CF-

PEEK

Embeddedcontinuous fiber

reinforced material

Transfer of experience

T-Pull specimen for verification of rib flange



Main intention of over injection molding for rib flanges:

• No separate shaping tool for every single rib with view on tapered leading edges necessary – last form giving step can be done by milling

• Simple high efficient flat plates can be used for every rib design• New options for welding technique due to unhindered plastic

deformation of short fiber reinforced flange material during welding • Use of well known and cost effective basic technology derived from

automotive industry • Avoiding of riveting within aircraft structures• Usage of high inherent strength of short fiber reinforced CF-PEEK



Achieved results:• Over injection molding in general

applicable for rib flanges• Quality extremely depends on process

parameters of injection • Procedure not applicable for prototype

structures due to costs of a single tooling• Process reliability not sufficient up to now

Laminate

Short fibre material

Micrograph of achievable quality

Decision: For manufacturing of generic leading edge structure an alternative

pressing technology was chosen



Basic structure: Pressed sandwich plate

Short fiber reinforced material

Continuous fiber reinforced material

Alternative: Local attached short fiber reinforced material

Generalized rib after milling

Caution: Combinationof mentioned material leads to high internal stresses ->

A process avoiding these stresses is still under development


J-Nose

Aileron Ribs

Engine Pylon PanelKeel Beam Ribs

Aileron Jack Fairings

The Future for Composites

Source: Airbus Deutschland GmbH


Application: J-Nose (Airbus)

Source: Ten Cate Advanced Composites


Manufacturing: Cost Reduction



Application: Ribs


Ribs are riveted (Hybrid structures)

Complete structures made of thermoplastic composites should be welded or bonded.


Manufacturing: Cost Reduction through New Thermoplastic Materials

Cost Evaluation Landing Flap Ribs Dornier 328


Rib press formed from a plate in one step.

Metal parts need more forming steps.


Application: Beams



Application:Flaps (moulded ribs, folded trailing edge)




The 777 Used Advanced Materialsfor Reliable and Economic Operation


Product:

• APC-2 / AS4

Application:

• Development `Pork Chop` Ribs

• Development Strut Access Door

Manufacturer:

• Boeing Commercial

Features:

• Press or stamp formed


Application: Boeing Commercial


Manufacturing: Boeing CommercialProduct:

• APC-2 / AS4Application:

• Development Wing RibsManufacturer:

• Boeing CommercialFeatures:

• Pressclave and Diaphragm forming• Integral ribs



Application: Dassault Rafale


Product:• APC-2 / AS4

Application:• Engine Tunnel

Manufacturer:• Dassault Aviation

Features:• Welding of stiffener to skin


Application: Lockheed Martin F - 22


Product:• APC-2 / IM 7

Application:• Weapons Bay Doors• Undercarriage Doors• Forward Fuselage Components

Manufacturer:• Lockheed Martin• Superform USA

Features:• Superplastic Diaphragm forming• Dual Resin Bonding


Application: Ruder (DLR)

Source: Institute of Structures and Design, DLR

Comparison of Manufacturing Cost: Thermoset (100 %) / Thermoplastic version (71,79 % )Manufacturing Technology for the Thermoplastic Version: Vacuum Consolidation Technique



Application: Augusta Westland EH 101

Product:• APC-2 / AS4

Application:• Floor Panels

Manufacturer:• Cytec Engineered

Materials / AugustaFeatures:

• Textured surfacemoulded onto upperpanels


Impact endangered area

• Access panel made out of continuous fibre reinforced thermoplastic (CF-PEEK).

• Lightweight construction and cost effective manufacturing.

• Fuel tightness after impact caused by a tyre burst in the integral fuel tank region (Impact).

Application: Impact endangered parts (DLR)

Source: Institute of Structures and Design, DLR


Application in Automotive: Door Frame

High performance, thin-walled door frame made out of glass fibre reinforced thermoplastic

BMW AG - DLR

Window frame and substructure door framefor a passenger car

Förderkennzeichen 03M 10444 8

Work share


Stamping of Sheet Thermoplastics

Temperature in the infra-red heating area: 160-500 °C

Heating time: 70-85 sec

Transportationtime: 2-3 sec

Temperature in the Mould: 60 -160 °C

Pressure: 5 bar

Forming time: 2-5 secTotal process time: 74-93 sec

Stamping time of sheet-thermoplastic comparable to process time of sheet-metal


Application in Automotive: Suspension Arm


Application in Automotive: Seat Back Rest

Combination of continuous fibre reinforced thermoplastics (stiffness and strengths) and short fibre reinforced thermoplastics

Advantage in PriceHigher stiffness and strengths than short fibre reinforced thermoplasticsProcessing from continuous fibre reinforced thermoplastics scrap

Over Injection Moulding


Content






Conclusion


Conclusion

Reduction of structural weight of aircraft

Improvement of durability of composite components

Reduction of manufacturing lead-times

No chemistry during processing

Manufacture complex parts in singe step

Integrate fabrication & assembly

Recycling of waste and parts of service

Despite higher material cost for thermoplastic materials, an economic manufacturing is possible.


Acknowledgement

For the support during the preparation of this lecture, we thankbelow people and companies:

Airbus Deutschland GmbH, Mr. Ch. Rückert

Ten Cate Advanced Composite, Mr. W.H.M. van Dreumel

Cytec Engineered Materials, Mr. D. Leach

After 37 years in developing of technologies for reinforced thermoplastic material, Mr. G. Kempe has gone into retirement at the end of September 2006.

I would like to thank him for his loyalty, his responsibility and his work during the last years at the Institute and in the department.


Thank you for your attention!Thanks to:

Frank Kocian, Günter Kempe, Rüdiger Keck, Thomas Hetzel et. al.

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