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The mixed Material Concept of thenew BMW X5

Markus PfestorfBMW Group

BMWGroup

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ContentBMWGroup

• Technical Features• Stiffness• Passive Safety• Materials• Components• Driving Performance• Conclusion

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Technical FeaturesDimension of the Car

BMWGroup

Wheelbase 2933mm/115.5in (+ 113/+4.5)

Total length 4854mm/191.1in (+ 187/+7.4)

Trac

k w

idth

1644

mm

/64.

7in

(+ 6

1/+2

,4)

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Technical FeaturesUnique Chasis Technology

BMWGroup

50 %

50 %

Excellent handling and roadholding capabilitiesand a comfortable ride without compromiseHandles like a true BMW

Double wishbonefront axle

Integral IV rear axle

Variable steeringratio

Low centreof gravity

Wide track

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Technical FeaturesIntelligent Light Weight Contruction

BMWGroup

15 per cent higher torsional stiffness ~27.000 Nm/°Almost the same weight in spite of enlarged dimensionsInnovative technologies for optimum active and passive safety

Runflat tyres 4th generation fitted as standard

Cast aluminium front strut tower

Intelligent use of ultra high strength steel

Aluminium engine hood

Magnesium carrier for instrument panel

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A

StiffnessTorsional Stiffness

BMWGroup

Tors

iona

lStif

fnes

sc T

cT

L = mGer

Ct x A[ x 10³ ]Kg

Nm/° x m²

L Lightweight coefficientmGer. Weight of body in white

(without doors and closures)ct Static torsion

(including screens)A Area (wheel base x track width)

23.50027.000

3,7 3,3

0

5.000

10.000

15.000

20.000

25.000

30.000

Nm/°

40.000

Previous X5 New X5Li

ghtw

eigh

tCoe

ffici

entL

0

0,5

1,0

1,5

2,0

2,5

3,0

4,0

3,5

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StiffnessDesign Solutions

BMWGroup

Stiff Rear End due to the Torsion Ring

Stiff Front End byDiagonal Strut(Aluminium)

Additional Stiffness bybracing the trunk lid

between the D-pillars(Weight Saving: 6 kg)

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Passive SafetyMost Important Crash Tests

BMWGroup

Side Impact:– EU-NCAP Side: 950 kg Barrier, 50 km/h– EU-NCAP Side Pole: 29km/h to Pole– US IIHS Side: 1500 kg Barrier, 50 km/h

Front Impact:– EU-NCAP: 64 km/h, 40% overlap, deformable Barrier– US-NCAP 0°: 35mph, 100% overlap, undeformable Barrier– US IIHS 40%: 64 km/h, 40% overlap, special Barrier

Others:– AZT Frontcrash: 15 km/h, 10°, 40% overlapp,

undeformable Barrier– AZT Rear-Crash: 1000 kg Barriere, 15 km/h, 10°,

40% overlapp, undeformable Barrier– Roll Over

Rear Impact:– FMVSS 301: 80 km/h, 70% overlapp, undeformable Barrier

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Passive SafetyLoadpath for Front Crash

BMWGroup

Distribution of induced Forces Deformation after the Euro-NCAP

Minimum Yield Strength

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Passive SafetyEU-NCAP Front Crash

BMWGroup

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Body in White MaterialsOverview of Materials

BMWGroup

PlasticsThermoplastic Resin

AluminumAlMg3AlMg4,5Mn0,4AlSi9Cu3(Fe)AlMgSiAlMg0,4Si1,2AlSi10MgMn

Steel Grades (min. yield Strength)CR4 (DDQ) HD, CR4 (DDQ) HDG, CR4 (DDQ) HSDG, CR5 (EDDQ) HDCR 180B HD, CR 180B HDG, CR 180A HD, CR 180AT HDCR 210B HD, CR 210B HDG, CR 210AT HDCR 250B HD, CR 250B HDG, CR 250 A HD, CR 250 AT HDCR 280B HD, CR 280B HDGCR 380X (HSLA) HDCR 420X (HSLA) HD, CR 420X (HSLA) HDGCR 950DL (Dual Phase), HD 680C22MnB5

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Body in White MaterialsPercentage of Steel Grade

BMWGroup

Deep Drawing Steel25%

180 MPa11%

200 -220 MPa6%

260 MPa6%

300-340 MPa13%

380-450 MPa21%

600-700 MPa6%

> 900 MPa3%

AlMg Alloy1%

AlMgSi Alloy2%

Others4%Thermoplatic2%

AlMg Alloy(1%)

Deep Drawing Steel(25%)

Bake Hardening Steel(24%)

IF-Steel(13%)

Microalloyed Steel20%

Complex Phase Steel(4%)

Boron Steel(3%)

Thermoplastic(2%)

Others(4%)

AlMgSi Alloy(2%)

Dual Phase Steel(2%)

Minimum Yield Strength Steel Grade

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Body in White MaterialsAverage minimum Yieled Strength

BMWGroup

3´seriesSedan5´series

7´series

1´series

3´series Sedan

7´series 5´series

5´seriesSports Wagon

3´seriesSports Wagon

5´seriesSports Wagon

3´series Sports W. 3´series Coupé

3´seriesCompact

Z4´Coupé

6´series Coupé

3´seriesCoupé

Z4

3´seriesConvertible

6´series Convertible

150

200

250

300

350

400

MPa475

500

1994 1996 1998 2000 2002 2004 2006 2008 20102008Start of Production

Ave

rage

min

. Yie

led

Stre

ngth

Rp0

,2

previous X5

New X5?

n number of partsm weight of the partRp0,2 min. yield strength

n

Rp0,2 =Rp0,2 i * m i

m i

i = 1

i = 1

n

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Body in White MaterialsAverage Gauge

BMWGroup

7´series

5´series

previous X5

3´series Convertible

Z4

7´series

6´series Convertible

6´series Coupé

5´series Sports Wagon

1´series

3´series Sports Wagon

0,9

1,0

1,1

1,2

1,3

1,4

1,5

mm

1,7

1992 1994 1996 1998 2000 2002 2004 2006 2008 2010

Start of Production

Ave

rage

Gau

ge

New X5

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ComponentsMax. Styling Freedom in Front End

BMWGroup

Washer fluid container

Front Head Lights

Benefits:• Flexible Design• Less Gaps / reduced Gap Dimensions• Weight Saving• Pedestrian Safety (ACEA, Japan, Europe)

Fender (PP-EPDM)

Pedestrian Safety

Bonnet (Aluminum)

Front End

Passive Safety / Stiffness

Crash BeamRelocatedcooler

Fog light

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ComponentsCast Aluminum Front Strut Tower

BMWGroup

Benefits:• Weight Saving (-50% compared to Steel Sheet)• Optimized Package• Increased Stiffness

Mechanical Values:Yield Strength Rp0,2: 120 - 140 MPaTensile Strength Rm: 200 - 240 MPa

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ComponentsSimulation of the Forming Process

BMWGroup

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BMWGroup

s = 1.2

s = 1.4

s = 2.2

s = 1.6

s = 1.2

Weight Saving: 2 kg/Side(compared to a hot stamped Part with a constant Thickness)

Thickness s

ComponentsThe B-Pillar Reinforcement

Mechanical Values:Yield Strength Rp0,2: > 950 MPaTensile Strength Rm: > 1300 MPa

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ComponentsManufacturing of the B-Pillar Reinf.

BMWGroup

2. Direct Hot Stamping

Tailored rolled Sheet

22MnB5

Heating> 900°C

Hot Stamping + rapid Cooling

trimming• By Laser• By Tool

Scale remocal

Source: Mubea

Roll gapControl

Correc-tion Longitudinal

profile check

varyingthickness

1. Manufacturing of tailored rolled blanks

Advantages of a tailored rolled BlankCompared to a tailored welded Blank– With many different thicknesses: Cost Benefit– Now weekening of strength level by a weld seem– Notch free transition at varying thickness

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Driving PerformanceRacetrack Nuerburgring Nordschleife

BMWGroup

Length of the RacetrackNuerburgring Nordschleife: 20,8 km

Power to weight ratio

[kg/HP]

time taken

[s]Previous X5 9,3 9,07

New X5 9,9 8,54

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ConclusionBMWGroup

– Higher functional Requirements in the new BMW X5 are met by a consequent Implementation of innovative Light-Weight Design

– Process-suitable Design of structural Components allow for the use of Multi Phase Steels, hot formed Materials and Aluminum Castings

– Due to new Design of Carrier Structure Torsional Stiffness raised from 23500 Nm/° to 27000 Nm/°