series-production automotive hood in integral cfrp design

27
© ika 2011 · All rights reserved 09.11.2011 Slide Nr. 1 #93090 · 11sd0038.pptx Institut für Kraftfahrzeuge RWTH Aachen University Series-Production Automotive Hood in Integral CFRP Design European HyperWorks Technology Conference 2011 Bonn, November 9 th 2011 Dipl.-Ing. Kristian Seidel, Univ.-Prof. Dr.-Ing. Lutz Eckstein

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Page 1: Series-Production Automotive Hood in Integral CFRP Design

© ika 2011 · All rights reserved 09.11.2011 Slide Nr. 1 #93090 · 11sd0038.pptx

Institut für Kraftfahrzeuge

RWTH Aachen University

Series-Production Automotive Hood in

Integral CFRP Design

European HyperWorks Technology Conference

2011

Bonn, November 9th 2011

Dipl.-Ing. Kristian Seidel, Univ.-Prof. Dr.-Ing. Lutz Eckstein

Page 2: Series-Production Automotive Hood in Integral CFRP Design

© ika 2011 · All rights reserved 09.11.2011 Slide Nr. 2 #93090 · 11sd0038.pptx

Agenda

Introduction

Motivation

Project Description

Requirements

Simulation and Design of CFRP

Summary

Page 3: Series-Production Automotive Hood in Integral CFRP Design

© ika 2011 · All rights reserved 09.11.2011 Slide Nr. 3 #93090 · 11sd0038.pptx

Introduction

FRP in Automotive Research at ika

Production

• Fibre manufacturing

• Semi-finished products

• Polymer processing

• Handling

Vehicle

• Full vehicle competence

• Functions & requirements

• Integration & assembly

• Testing & assessment Chassis

Body

Drivetrain E / E

Acoustics Driver

Assistance

Material

• Characterisation

• Simulation

• Optimisation

• Verification

Fib

re r

ein

forc

ed

pla

stics

in a

uto

mo

tive

en

gin

ee

rin

g

Page 4: Series-Production Automotive Hood in Integral CFRP Design

© ika 2011 · All rights reserved 09.11.2011 Slide Nr. 4 #93090 · 11sd0038.pptx

Agenda

Introduction

Motivation

Project Description

Requirements

Simulation and Design of CFRP

Summary

Page 5: Series-Production Automotive Hood in Integral CFRP Design

© ika 2011 · All rights reserved 09.11.2011 Slide Nr. 5 #93090 · 11sd0038.pptx

Motivation

Future Mobility

Energy costs will increase further in medium term

Fuel consumption and emissions will be strongly financially sanctioned in the future

Emissions gain major impact on mobility, e.g. in congested urban areas

„Harmonising the qualities efficiency,

safety and driving experience.“

Vehicle

Concepts

Architecture &

Functions

Materials

SAFETYDRIVING

PLEASUREDriving please despite ADAS

Vehicle

EFFICIENCY

Page 6: Series-Production Automotive Hood in Integral CFRP Design

© ika 2011 · All rights reserved 09.11.2011 Slide Nr. 6 #93090 · 11sd0038.pptx

Motivation

Potential of Fibre Reinforced Plastics

Stiffness and strength of fibre reinforced plastics (FRP) are strongly depending

on the direction (anisotropy)

Carbon fibre reinforced plastics (CFRP) have highest specific properties

Superior buckling stiffness and dent resistance of FRP e.g. outer panels

Particularly for structural parts fibres have to be aligned to the load to achieve

considerable weight reduction

103%

57%

60%

44%

105%

31%

5%

23%

9%

32%

88%

15%

41%

17%

91%

144%

14%

61%

19%

152%

365%

35%

96%

30%

436%

0%

20%

40%

60%

80%

100%

Steel (500 MPa) Aluminium (400 MPa)

CFRP uni-directional CFRP quasi-isotropic

GFRP uni-directional CFRP quasi-Gsotropic

Page 7: Series-Production Automotive Hood in Integral CFRP Design

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Prestige

Versatility / benefit

Price

Driving experience

Potential of FRPs in cars

Future vehicle development

1985: 9 Segments 2008: 40 Segments

Flexible and economic production for lower production volumes

[Source: Volkswagen AG]

Rising diversity of derivates

Decreasing production volume

Higher level of individualisation

Costs

/ u

nit

Production volume

Metal

current future

Economic FRP production

FRP current

FRP future

Lower fixed costs offer advantages for

lower production volumes

Exploitation of higher production volumes

by reducing variable costs

Flexible production by variable

manufacturing facilities

future EV

FRP future with EV

Versatility / benefit

Price

Driving experience

Prestige

Page 8: Series-Production Automotive Hood in Integral CFRP Design

© ika 2011 · All rights reserved 09.11.2011 Slide Nr. 8 #93090 · 11sd0038.pptx

Agenda

Introduction

Motivation

Project Description

Requirements

Simulation and Design of CFRP

Summary

Page 9: Series-Production Automotive Hood in Integral CFRP Design

© ika 2011 · All rights reserved 09.11.2011 Slide Nr. 9 #93090 · 11sd0038.pptx

Project goals:

Technological and economical potential analysis

Simulation of CFRP under static and dynamic loads

Load, material and production suited design

Enhancement of production concepts (gap impregnation)

regarding cycle times and class-A surface quality

Funding:

Ministerium für Innovation, Wissenschaft und Forschung

(MIWF) within funding call Hightech.NRW

Duration: 01/2010 – 12/2012

Partner:

Hightech.NRW

CFRP Body Panels

Technology demonstrator

Page 10: Series-Production Automotive Hood in Integral CFRP Design

© ika 2011 · All rights reserved 09.11.2011 Slide Nr. 10 #93090 · 11sd0038.pptx

Hightech.NRW - CFRP Body Panels

Production

Production scenario: 10,000 units p.a.

Gap impregnation

Fast impregnation

Low pressure

High level of automation

Low cycle times

Production process chain

Material supply

Trimming

Preform manufacturing

Gap impregnation

Finishing

Storage

Reduction of production costs

Gap

impregnation

TrimmingMaterial

supply

Preform

manufacuring

Storage

Finishing

Page 11: Series-Production Automotive Hood in Integral CFRP Design

© ika 2011 · All rights reserved 09.11.2011 Slide Nr. 11 #93090 · 11sd0038.pptx

Agenda

Introduction

Motivation

Project Description

Requirements

Simulation and Design of CFRP

Summary

Page 12: Series-Production Automotive Hood in Integral CFRP Design

© ika 2011 · All rights reserved 09.11.2011 Slide Nr. 12 #93090 · 11sd0038.pptx

Hightech.NRW - CFRP Body Panels

Benchmark

Design benchmark

Functional benchmark

Global stiffness

Torsion stiffness

Longitudinal stiffness

Lateral stiffness

Local stiffness

Buckling stiffness

Dent resistance

Acoustics

Noise intensity

Sound transition loss

Pedestrian protection

Euro NCAP head impact

0

50

100

150

200

250

300

0 2 4 6 8 10 12 14

Kra

ft [N

]

Deformation [mm]

Analyse Beulsteifigkeit Motorhaube VW Golf VI (MJ 2010) - Messpunkt BS1

10.01.2011

Ci = 77,2 N/mm

SOC

-12

-10

-8

-6

-4

-2

0

100 300 500 700 900 1100 1300

dB

[W

/m²·

N]

Terz [Hz]

Transferfunktion

Focus 2010

Auris

Prius

Volvo C30

Golf VI

Mittelwert

0

20

40

60

80

100

120

0 5 10 15 20 25 30 35 40 45

Kra

ft [N

]

Auslenkung [mm]

Torsionssteifigkeit

Ford Focus (MJ 2010)-Außenblech

Ford Focus (MJ 2010)-Strukturinnenblech

Toyota Auris (MJ 2010)-Außenblech

Toyota Auris (MJ 2010)-Strukturinnenblech

Toyota Prius (MJ 2010)-Außenblech

Toyota Prius (MJ 2010)-Strukturinnenblech

Volvo C30 (MJ 2010)-Außenblech

Volvo C30 (MJ 2010)-Strukturinnenblech

VW Golf VI (MJ 2010)-Außenblech

VW Golf VI (MJ 2010)-Strukturinnenblech

Ford Focus (MJ2011)-Außenblech

Ford Focus (MJ 2011)-Strukturinnenblech

0

10

20

30

40

50

60

70

80

90

100

110

120

130

140

0,000 0,005 0,010 0,015 0,020 0,025 0,030 0,035 0,040 0,045 0,050

Ac

ce

lera

tio

n [

g]

Time [s]

Beschleunigung-Zeit-Diagramm

resultierende Beschleunigung

Fußgängerschutzversuch 27.05.2011

Ford Focus Serienhaube Impaktpunkt 193090SK001

v = 39,641 km/hHIC_15 = 510,9

Page 13: Series-Production Automotive Hood in Integral CFRP Design

© ika 2011 · All rights reserved 09.11.2011 Slide Nr. 13 #93090 · 11sd0038.pptx

Hightech.NRW - CFRP Body Panels

Buckling Stiffness & Dent Resistance

Buckling Stiffness

Elastic buckling (e.g. polishing, oil canning)

Circular indentor (d = 50 mm)

Force up to 250 N

Dent Resistance

Plastic deformation (e.g. Hail, stone impact)

Spherical indentor (d = 25 mm)

Force up to 200 N

Solver: RADIOSS 10.0 (explicit)

0

50

100

150

200

250

300

0 2 4 6 8 10

Forc

e [N

]

Displacement [mm]

Buckling Stiffness / Dent Resistance

BS3 SimulationBS5 SimulationBF4 SimulationBF5 SimulationBS3 TestBS5 TestBF4 TestBF5 Test

Page 14: Series-Production Automotive Hood in Integral CFRP Design

© ika 2011 · All rights reserved 09.11.2011 Slide Nr. 14 #93090 · 11sd0038.pptx

Hightech.NRW - CFRP Body Panels

Pedestrian Protection

Euro NCAP Head Impact

40 km/h, 50°

Child head (3.5 kg)

Head Injury Criteria:

ΔHIC ≈ 3 %

1000)tt(t

t

dt)t(a)tt(

1maxHIC 12

5,22

112

Page 15: Series-Production Automotive Hood in Integral CFRP Design

© ika 2011 · All rights reserved 09.11.2011 Slide Nr. 15 #93090 · 11sd0038.pptx

Agenda

Introduction

Motivation

Project Description

Requirements

Simulation and Design of CFRP

Summary

Page 16: Series-Production Automotive Hood in Integral CFRP Design

© ika 2011 · All rights reserved 09.11.2011 Slide Nr. 16 #93090 · 11sd0038.pptx

Hightech.NRW - CFRP Body Panels

Degrees of Freedom for FRP Design

Standard Design

Shape

Material Thickness

FRP Design

Fibre

Material

Matrix

Material

Fibre

Orientation

Laminate

Layup

Volume

Content

Additional degrees of freedom when designing fibre reinforced plastics

Lack of experience and uncertainties require advanced CAE support

Intelligent optimisation procedures ensure utilisation of material properties

Reduction of development costs

Maximised weight saving Reduced part costs

Page 17: Series-Production Automotive Hood in Integral CFRP Design

© ika 2011 · All rights reserved 09.11.2011 Slide Nr. 17 #93090 · 11sd0038.pptx

Hightech.NRW - CFRP Body Panels

CFRP Optimisation

Free-shape / free-size optimisation

(OptiStruct 10.0.5)

Combined optimisation strategy

Topography of inner panel (free-shape)

Load adapted laminate layup (free-size)

Fibre orientation outer panel (discrete size)

Considered load cases:

Torsion

Longitudinal, lateral bending

Buckling stiffness

Design concept

Shape change Shape change

Design refinement

•Review of node set for

free-shape optimisation

• Interpretation of design concept

•Consideration of package requirements

•Generation of final mesh

Final design

Page 18: Series-Production Automotive Hood in Integral CFRP Design

© ika 2011 · All rights reserved 09.11.2011 Slide Nr. 18 #93090 · 11sd0038.pptx

Free-size / Composite size / shuffling optimisation

(OptiStruct 10.0.5)

Hightech.NRW - CFRP Body Panels

CFRP Optimisation

Ply book concept (free-size)

Fibre orientation outer panel (discrete size)

Ply book concept

Shell thickness

0.5-1.75 mm

Ply thickness

• Interpretation of free-size results

•Definition of patches

Final ply book (reduced number of plies)

Fibre orientation & thickness inner panel

(discrete & composite size)

Stacking sequence (composite shuffling)

Final ply book

Thickness

0.5 mm < t < 1.5 mm

2 full plies

12 local plies

Δm ~ 65%

Page 19: Series-Production Automotive Hood in Integral CFRP Design

© ika 2011 · All rights reserved 09.11.2011 Slide Nr. 19 #93090 · 11sd0038.pptx

Hightech.NRW - CFRP Body Panels

Material characterisation

Tensile test DIN EN ISO 527 – 4 (non-unidirectional)

Tensile test DIN EN ISO 527 – 5 (unidirectional)

Compression test DIN EN ISO 14126 (non- / unidirectional)

Tensile shear test DIN EN ISO 14129 (in plane shear)

Shear test DIN EN ISO 14130 (interlaminar shear)

Dynamic tensile and shear tests

Tension / shear

Lf = 150 mm (0° / 90° / +45°)

Compression

Lf = 10 mm (0° / 90°)

Shear (interlaminar)

10x20 mm (0° / 90°)

Tension / shear (dynamic)

Lf = 75 mm (0° / 90° / +45°)

[BA

SF

]

Page 20: Series-Production Automotive Hood in Integral CFRP Design

© ika 2011 · All rights reserved 09.11.2011 Slide Nr. 20 #93090 · 11sd0038.pptx

Hightech.NRW - CFRP Body Panels

CRASURV Model

CRASURV material model (RADIOSS /MAT/COMPSH)

Anisotropic, visco-elasto-plastic, strain rate dependant material behaviour

Damage and failure in tension, compression and shear based on plastic work

Advanced Tsai-Wu failure model

Initial Tsai-Wu is shifted to account for hardening and softening

σmax

σres

σ

WpWp2Wp1

maximum

stress

residual

stress

elasticity

plasticity

failure

erosion [Altair]

2: Tsai-Wu after hardening

and softening in some directions

1: Tsai-Wu after hardening

0: Initial Tsai-Wu

3: Residual Tsai-Wu

σ1

σ2

[Altair]

Welastic

Wplastic

Page 21: Series-Production Automotive Hood in Integral CFRP Design

© ika 2011 · All rights reserved 09.11.2011 Slide Nr. 21 #93090 · 11sd0038.pptx

Hightech.NRW - CFRP Body Panels

Material modelling of CFRP

Layered Shell Method (RADIOSS /SH_SANDW or /SH_COMP)

Laminate layers are represented as integration points

within one shell element

Good trade-off between calculation time and accuracy for crash simulation

0

200

400

600

800

0,0 0,5 1,0 1,5

Spannung [M

pa]

Dehnung [%]

Zugversuch

Simulation

Versuch

020406080

100120140

0 5 10 15 20 25 30 35

Spannung [M

pa]

Dehnung [%]

Schubversuch

Simulation

Versuch

0

200

400

600

800

0,0 0,5 1,0 1,5 2,0 2,5

Spannung [M

pa]

Dehnung [%]

Druckversuch

Simulation

Versuch

tension

str

ess [

MP

a]

strain [%]

simulation

test

simulation

test

compression

str

ess [

MP

a]

strain [%]

simulation

test

shear

str

ess [

MP

a]

strain [%]

Composite panel: 2 layers FEM Model: 5 layers

Z

X, Y 1-2 integration points per layer

(material and orientation)

Shell element on mid-surface

[Altair]

CRASURV material model (RADIOSS /MAT/COMPSH)

Comparison of test and simulation

Page 22: Series-Production Automotive Hood in Integral CFRP Design

© ika 2011 · All rights reserved 09.11.2011 Slide Nr. 22 #93090 · 11sd0038.pptx

0,0

1,0

2,0

3,0

0 50 100

Kra

ft [k

N]

Weg [mm]

CFK monolithisch 1 mm

FK002Simulation

Hightech.NRW - CFRP Body Panels

Drop tower test

Monolithic CFRP plate (1x400x400 mm)

Hemispherical impactor (Ø 114 mm)

Impactor velocity up to 30 km/h

Impactor mass: 9 kg

Solver: RADIOSS 11.0 (explicit)

Drop tower test CFRP

Forc

e [kN

]

Displacement [mm]

CFRP Monolithic 1 mm

Page 23: Series-Production Automotive Hood in Integral CFRP Design

© ika 2011 · All rights reserved 09.11.2011 Slide Nr. 23 #93090 · 11sd0038.pptx

Hightech.NRW - CFRP Body Panels

Pedestrian Protection with CFRP

Deceleration of the head is determined by a combination of mass inertia and

stiffness/strength of the hood

Short pulse induced by mass inertia results in a short HIC window and low HIC

values for steel hood

Missing pulse due to mass reduction (e.g. CFRP) has to be compensated by

stiffness/strength which results in a wider HIC window

Acceleration is distributed over a

longer time period which results

in higher intrusions

0

500

1.000

1.500

0

50

100

150

0 10 20 30

HIC

[ ]

acce

lera

tio

n [g

],

dis

pla

ce

me

nt [m

m]

time [ms]

Steel - acceleration CFRP - accelerationSteel - displacement CFRP - displacementSteel - HIC CFRP - HIC

Inertia dominated

Page 24: Series-Production Automotive Hood in Integral CFRP Design

© ika 2011 · All rights reserved 09.11.2011 Slide Nr. 24 #93090 · 11sd0038.pptx

Agenda

Introduction

Motivation

Project Description

Requirements

Simulation and Design of CFRP

Summary

Page 25: Series-Production Automotive Hood in Integral CFRP Design

© ika 2011 · All rights reserved 09.11.2011 Slide Nr. 25 #93090 · 11sd0038.pptx

Hightech.NRW - CFRP Body Panels

Summary

Pedestrian protection

Manufacturing

Paint process

... 100% 40% 50%

Reference Hood

CFRP Hood (stiffness)

CFRP Hood

Weig

ht

[kg]

-65 % ?

Increased need for lightweight design and improved production processes

offer potential for CFRP applications also for higher volumes

Potential of CFRP can only be utilised with load adapted fibre orientation

Additional degrees of freedom in FRP design require advanced CAE support

(Appropriate simulation models, optimisation tools, …)

Expected lightweight potential for CFRP hood of -50 to -60 %

Hightech.NRW technology demonstrator at the end of 2012

40 -

50 % 35 %

Page 26: Series-Production Automotive Hood in Integral CFRP Design

© ika 2011 · All rights reserved 09.11.2011 Slide Nr. 26 #93090 · 11sd0038.pptx

Thank you for your attention!

Page 27: Series-Production Automotive Hood in Integral CFRP Design

© ika 2011 · All rights reserved 09.11.2011 Slide Nr. 27 #93090 · 11sd0038.pptx

Institut für Kraftfahrzeuge

RWTH Aachen University

Steinbachstraße 7

52074 Aachen

Germany

Phone

Fax

Email

Internet www.ika.rwth-aachen.de

Contact

Dipl.-Ing. Kristian Seidel

+49 241 80 25641

+49 241 80 22147

[email protected]