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The LX BIW StructureA

Great “Steel” DesignThomas N. Seel

DaimlerChrysler

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LX BIW StructureA

Great “Steel” Design

Co-Authors/ AcknowledgementsShan Haq CAE

Mike Mihelich BIWPaul Belanger & J. P Singh MaterialsPamela Larson Vehicle Development

Subhas Shetty CAEChristie Brusha Manufacturing

Larry Brookes BIWLX BIW Engineering Department

DaimlerChrysler

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What Defines a “Great BIW Design”

• Looks (Styling)• Light Weight (materials/construction)• Structural Performance• Flexible Manufacturing Process• Low Cost ($)

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What Defines a “Great BIW Design”

• Looks (Styling)• Light Weight (materials/construction)• Structural Performance• Flexible Manufacturing Process• Low Cost ($)

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Looks (Styling) : The all new Chrysler 300

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Looks (Styling) : The all new Chrysler 300

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• Looks (Styling)

A new Classic Proportion for Chrysler

1955 C300 2005 300C50 years

300 C 5.7L Hemi V8 (340hp) 300 Touring 3.5L V6300 2.7L V6Start of Production: February 2004, in showroom: April 2004

Looks (Styling) : The all new Chrysler 300

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What Defines a “Great BIW Design”

• Looks (Styling)• Light Weight (Materials/Construction)• Structural Performance• Flexible Manufacturing Process• Low Cost ($)

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What Defines a “Great BIW Design”

• Light Weight (Materials/ Construction)– HSS Steel

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• Near Double Parts with High Strength Steel (HSS)– ’98 20% HSS– ’05 37% HSS

• Dual Phase Steel for Front Rails

0%10%20%30%40%50%60%70%80%90%

100%

'98300M

'05300C

>= 550Mpa>= 340Mpa>= 280Mpa

Light Weight : Materials / Construction

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05 LX HSS Part <= 280 MPa Yield

Light Weight : Materials / Construction

0%10%20%30%40%50%60%70%80%90%

100%

'98300M

'05300C

>= 550Mpa>= 340Mpa>= 280Mpa

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Light Weight : Materials / Construction

05 LX HSS Parts >= 340 MPa Yield

0%10%20%30%40%50%60%70%80%90%

100%

'98300M

'05300C

>= 550Mpa>= 340Mpa>= 280Mpa

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Light Weight : Materials / Construction

0%10%20%30%40%50%60%70%80%90%

100%

'98300M

'05300C

>= 550Mpa>= 340Mpa>= 280Mpa

05 LX HSS Parts >= 550 MPa Yield

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What Defines a “Great BIW Design”

Light Weight (Materials/ Construction)– HSS Steel– Construction : Section Design

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Delta %Ip1: 7.2%Ip2: 8.0 %A: 8.0%

NominalIp1:2.299 X106 mm4

Ip2:1.351 X106 mm4

A :888 mm2

EffectiveIp1: 2.132 X106 mm4

Ip2:1.243 X106 mm4

A: 817 mm2

ASPPCARS/GAS

Light Weight : Materials / Construction

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Variable Section Kick-Up C/M

Octagon Shape Front Rail

Double C-Section Rear Rails

Light Weight : Materials / Construction

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Light Weight : Materials / Construction

Load BearingRoof Bow

3 Layer Body Side Sections

Constant Moment B-Pillar Internal Shear Plate Sill

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What Defines a “Great BIW Design”

• Light Weight (Materials/ Construction)– HSS Steel– Construction : Section Design– New Technology

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05LX Headlamp Mounting Crossmember (HMC)

Metal / Plastic HybridWeight = 16 lbs. savings

Variable cost neutralInvestment = $6.8M savingsImproved Build Tolerances

Light Weight : Materials / Construction

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What Defines a “Great BIW Design”

• Light Weight (Materials/ Construction)– Bottom line ?

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LX 300C vs LH 300M

DE

D

EXTERIOR Chrysler ChryslerHARD PTS mm (in) 300C 300MLength. . . . . . . . . . 5,001 (196.9) 5,023 (197.8)Width . . . . . . . . . . 1,881 (74.1) 1,892 (74.5)Height . . . . . . . . . . 1,483 (58.4) 1,422 (56.0)Wheel Base . . . . . . 3,048 (120.0) 2,870 (113.0)Frt Track . . . . . . . . 1,600 (63.0) 1,573 (61.9)Rr Track . . . . . . . . 1,603 (63.1) 1,565 (61.6)Frt Over Hang . . . . . 876 (34.5) 1,054 (41.5)Rr Over Hang . . . . 1,078 (42.4) 1,100 (43.3)

Light Weight : Materials / Construction

7” longer WB1.5” wider trackRWD vs. FWDImproved Safety CageUpgraded NVH

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7.57.77.7Weight/Interior Volume

110114.8118.8Interior Volume ft^3

829.0880.0914.8Body Shell Weight lbs.

Benchmark#2 FWD

Benchmark#1 RWD

LX

Light Weight : Materials / Construction

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What Defines a “Great BIW Design”

• Looks (Styling)• Light Weight (Materials/Construction)• Structural Performance

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What Defines a "great BIW Design”

• Structural Performance– Torsional Stiffness

w w w . a u t o s t e e l . o r g Gregory M. Goetchius, A. Akanda APC/NVH LABApril 4, 2000

0

2000

4000

6000

8000

10000

12000

14000

16000

18000

20000

22000

400 500 600 700 800 900 1000 1100 1200 1300

Mass (lbs)

Ct/M = 35 Ct/M = 25 Ct/M = 17

Ct/M = 11

Ct/M = 494 Accord*

JA

ULSAB

BMW 5 Series

93LH

98 Accord*

JR

98LH

LX

E-Class

*Estimated BIW Mass

14000 lb-ft/deg

830 lbs

Proposed LX Target Zone

LX Sedan 13,200 ft. lbs/degLH Sedan 12,500 ft. lbs/deg12% Increased stiffness

Structural Performance: Torsional Stiffness

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What Defines a "great BIW Design”

• Structural Performance– Torsional Stiffness– React Chassis Inputs

w w w . a u t o s t e e l . o r gStu Eddy

Design Tools•FEA: Finite Element Analysis•Lab & Shaker Testing: Components & Assembly tests•Proving Grounds: On Road Testing•RTS: Road Test Simulation

Structural Performance: React Chassis Inputs

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What Defines a "great BIW Design”

• Structural Performance– Torsional Stiffness– React Chassis Inputs– Noise Attenuation / Shake Control

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Front Floor AssemblyRail Extensions

Front Rail AssemblyBulk heads

Chris Kennedy

Structural Performance: NVH

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Double ShearSuspension Attachments

Tuned Exhaust Attachments

Structural Performance: NVH

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0

20

40

60

80

100

120

140

Vehi

cle

Spee

d, m

ph

0 5 10 15 20 25 30 35 40 45 50

Frequency, HzHigh Speed

Fan #2(43.7 hz)

High SpeedFan #1

(39.7 hz)

Low SpeedFan #2

(23.3 hz)

0

200

400

600

800

1000

1200

1400

Engi

ne S

peed

, rpm

V-8 WarmIdle Range4th Order

500-650 rpm

1st Order17” Tire

1.5 Order (V6)500-650 rpm

(12.5-16.25 hz)

V-6 WarmIdle Range3rd Order

500-650 rpm

1st AcousticCavity Mode

(48.3 hz)

Low SpeedFan #1

(19.8 hz)La

t = (3

3.8H

z

Driv

er =

16.

8Hz

Vert

= (3

6.4H

z

P as s

= 1

5.7 H

z

5.7L four cylinder mode

2nd order excitation

Mode Shape Test Pre-Test CAEFrequency Prediction Mode Shape

Global Torsion 40.1 Hz 40.0 Hz 91%

Global Bending 48.8 Hz 49.2 Hz 84%

Structural Performance: NVH

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CAE Optimization for Low Frequency NVH Performance

• Four Bolt Bumper Attachment• Radiator Xmbr • HMC to Rail & Load Beam Joints• Bulk heads in the Toe board Xmbr• IP Center Stack

• Shelf Panels• Shelf Gussets• Beading of the Rear Floor Pan & battery Tray design

Structural Performance: NVH

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What Defines a “Great BIW Design”

• Structural Performance– Torsional Stiffness React Chassis Inputs– React Chassis Inputs– Noise Attenuation / Shake / Control– Superior Occupant Safety Cage

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Safety Cage: Enginebox•Dual phase DP 590 octagon shape front rails with defined crush zones•Dash panel toe-board crossmember, end rail extensions and rail extension to sill to limit intrusion

Structural Performance: Safety Cage

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35 mph Flat FrontalRail Tip Multiple fold / crushLow Intrusion

Structural Performance: Safety Cage

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40 mph Front OffsetMid Rail Body/Chassis CrushLow Intrusion

Structural Performance: Safety Cage

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Safety Cage: Body Sides- Cross car load bearing roof bow- C pillar reinforcement rear occupant protection - A pillar reinforcement for structural integrity for offset events - Occupant friendly B pillar deformation zones

Structural Performance: Safety Cage

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Structural Performance: Safety Cage

38.5 mph Crabbed SideSill / B pillar EngagementLow Intrusion

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Safety Cage : Rear Underbody• Double C section rear rail crush zones balance to rear cradle• Rear tire tub with designed crush zones

Structural Performance: Safety Cage

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Structural Performance: Safety Cage

50 mph Rear OffsetMultiple Crush ZonesProtected Zone

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What Defines a “Great BIW Design”

• Looks (Styling)• Light Weight (Materials/Construction)• Structural Performance• Flexible Manufacturing Process

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Assembly Plant Welds 2592Purchase Sub Welds 1685

Total Spot Welds 4277Adhesive C(mm) 22366Drawn Arc Studs 23Projection Weld 7

LX BIW Process

Flexible Manufacturing Process

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2000

3000

4000

5000

6000

7000

Spot Welds

LX#1#2

Underbody – 3 Sub AssembliesBody Sides – Robot Framed

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What Defines a “Great BIW Design”

• Looks (Styling)• Light Weight (materials/construction)• Structural Performance• Flexible Manufacturing Process• Low Cost ($)

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• 15% reduction in equalized variable costs

• 40 % reduction in capital tooling

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0.2

0 .4

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0 .8

1

1 .2

1 .4

1 .6

1 .8

'98 300M '05 300C

Variable Investment

Low Cost $

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What Defines a “Great BIW Design”

• Looks (Styling)– Wow!

• Light Weight (materials/construction)– Increased HSS Utilization/ Efficient

Design Engineering • Structural Performance

– Stiffer / Stronger /Safe• Flexible Manufacturing Process

– Strategic use of sub-assemblies• Low Cost ($)

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The LX Sedan BIW StructureJust The Beginning!