N.Z. Borba

Natascha Z. Borba

USE OF CFRP COMPOSITES AND NEW JOINING PROCESSES IN AIRCRAFT FUSELAGE

Solid State Joining Processes – WMPMaterials MechanicsInstitute of Materials Research

Composites Europe - Stuttgart – 08.11.2018

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Trend in aircraft design: rational mixture of metal and composites to reduce costs and cope with legislation (ACARE Flightpath 2050- Environmental goals)

INTRODUCTIONHybrid Metal-Polymer Structures in Aircraft Applications

[1]

[1] Airbus FAST57, 2016

Time

Perf

orm

ance

Metallic

structures

Composite

structures

€

Performancekg

Airbus A320

↓ CO2 emissions by 75% per passenger/km

71%

6%10%

Composite

53%

Ti

14%

Al/Al-Li

19%

Composite not yet at

„saturation level“

Airbus A350-XWB

Air vehicles more recyclableSustainable and commercially

viable alternative fuel

Steel

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INTRODUCTIONHybrid Metal-Polymer Structures in Aircraft Applications

Adhesive Bonding

Mechanical Fastening

Riveting, screwing, bolting,

clinching, collar joining

FricRiveting

ICJ

Welding-based Technologies

Ultrasonic

Induction

Resistance

Laser

Friction

Hybrid Technologies

RivbondingWeldingbond

Injection over Molding

Direct Assembly

(Co-Bonding/-Curing)

[*] S.T. Amancio-Filho, J.F. dos Santos, Polym. Eng. Sci., 2008

o Reduced maintenance

o Improved performance

o Cost effective and sustainable joining techniques

Metallic structures:

Friction Stir Welding Refill Friction Stir Spot

Welding Friction Surfacing

Metal-composite structures:

Friction Stir Welding Friction Spot Joining

Requirements: development of new designs and concepts for hybrid structures

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FRICTION-BASED JOINING PROCESSESWMP Demonstrator

Section of fuselage integrating seven innovative joining technologies which aimed to overcome drawbacks of conventional methods for dissimilar materials

Requirements: Materials:

Skin: CF-PEEK, AA2024 (3.1 mm)

Stringer: AA7050

Frame: AA7075

Short

joining

cycles

Defect free

Low

distortion

Improved

mechanical

performance

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FRICTION-BASED JOINING PROCESSESWMP Demonstrator

Friction-based welding processes for aluminum alloys components

Refill Friction Stir Spot Welding

Friction Surfacing

[3] Suhuddin, U. et al, Applied Physics Letters, 2014

[4] Ehrich, J. et al, MSE, 2018

Stationary Shoulder Friction Stir Welding

Bobbin Tool Friction Stir Welding

[1] Barbini, A., PhD Thesis, 2018

[2] Göbel, J., PhD Thesis, 2018

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FRICTION-BASED JOINING PROCESSESWMP Demonstrator

Friction-based joining processes for metal-composite hybrid components

Friction Spot Joining

[1] Manente, N., PhD Thesis, 2018

FSpJFricRiveting

FricRiveting

Frame Stringer Doubler

Friction Riveting

[2] Borba, N.Z., PhD Thesis, 2018

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FRICTION RIVETINGGeneral Aspects

Patented in 2007 by Amancio et al. (EP 1 790 462 B1; US 7 525 149 B2 )

Based on mechanical fastening and friction welding

Prize-winning joining technology

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FRICTION RIVETINGPrinciples of the Process

HZG patent: EP 1 790 462 B1; US 7,575,149 B2

(Amancio-Filho et al.)

Positioning of the joining parts

Rotating rivet insertion &

Polymer melting

Plasticizing of the rivet & Forging

Anchoring &Joint

consolidation

Time

CFRP

CFRP

Metallic rivet

Joining mechanisms: General aspects:

Joining cycles (0.5 to 12.0 s)

No surface preparation

Single side accessibility

Minimum thickness required

Permanent joint[1] Mechanical Anchoring (macro and micro)

[2] Adhesion Forces

5 mm

5 mm[1]

[1]

[2]

5 mm

squeezed material

[2]

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FRICTION RIVETINGIndustrial Transferability of Friction Riveting

Dev

elo

pm

ent

Time

Coupon

Sub-component

Component

Full-scaleScaling-up challenges

[1]

[2]

TRL 5

Engineering challenges

Knowledge gaps:

Joint design Fatigue analysis Joint durability Damage tolerance

TRL 4

5 mm

Case study: Ti6Al4V/ CF-PEEK friction-riveted joints

[1] Eastlake et al., Embry-Riddle Aeronautical University, National Transportation Safety Board, Boeing

[2] Airbus FAST57, 2016

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FRICTION RIVETING - SELECTED RESULTSMechanical Behavior and Damage evolution

Quasi-static mechanical performance

Comparison with reference bolted joints

Fracture micro-mechanisms: definition of failure criteria

135 mm

36

mm

36 mm

Loading direction

5 mm

36

mm

135 mm

Loading direction

30 mm

I.

II.III.

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FRICTION RIVETING - SELECTED RESULTSMechanical Behavior and Damage evolution

Fatigue life

Parameters (STP723/ASTM): R = 0.1, 5 Hz, room temperature, two-parameter Weibull distribution

[2] Bolted and bonded hybrid joints

[1] Aircraft industry requirement

66%

50%

35%

[1] Fatigue & Damage Tolerance Course, AeroStruct (2017)[2] G.Kelly, Composite Structures 72 (2006) 119-129

[2]

[1]

6.2 ± 0.3 kN 5.9 ± 0.3 kN

R-Sq = 89%

After 106 cyclesQuasi-static

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FINAL REMARKS

Concept of metal-composite hybrid aircraft fuselage joined by innovative friction-based joining processes was proven through the WMP demonstrator

Friction Riveting is an alternative, prize-winning joining technique for metal-composite multi-material structures

Similar-to-improved quasi-static and cyclic mechanical performance of friction-riveted joints compared to the stat-of-the-art bolted joints showing potential for future aircraft structural application

N.Z. Borba

Thank you! (Hall 9, C78)

FOR PEOPLE AND THEIRFUTURE ENVIRONMENT

Natascha Z. Borba

Helmholtz-Zentrum Geesthacht

Natascha.zocoller@hzg.de

+49 04152 87-2608

Max-Planck Str. 1

21502 Geesthacht

Acknowledgment