body-in-white technology in the new: saturn outlook …/media/files/autosteel/great designs in...

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Body-in-White technology in the new:

Saturn OutlookGMC Acadia &Buick Enclave

Terry Swartzell and Don KolisGeneral Motors North America

March 7, 2007

Swartzell


• Vehicle architecture

• High level body-in-white strategy

• Underbody steel strategy

• Uppers steel strategy

• Construction

• Performance

• Questions

Outline

Swartzell


Outlook, Acadia & Enclave architecture

• All new BFI crossover utility platform for GM.

• Spacious accommodations for 7 or 8 passenger.

• 3.6L transverse V6 and six- speed transmission.

• Offered in both AWD and FWD versions.

• Built in new Delta Township plant near Lansing, Michigan.

• EPA estimated 26 MPG highway (FWD).

Swartzell


Chev SuburbanFord ExpeditionNissan Armada

Chev TahoeToyota Sequoia

Outlook & AcadiaDodge Durango

Mercedes GLHyundai VeracruzChrysler Pacifica

Audi Q7Chev Trailblazer

06 Acura MDXMazda CX-9Honda Pilot

BMW X5Ford Freesytle

VW TouregCadillac SRX

Ford EdgeChevrolet Equinox

04 Lexus RXNissan Murano

HighlanderMazda CX-7

BMW X3Saturn VUE

Honda ElementFord Escape

07 Hyundai Sante07 Honda CR-VJeep Compass

06 Toyota RAV 4

Body-Frame-Integral (BFI) crossovers

Body-on-Frame (BOF) sport utilities

Market trends(selected vehicles)

Increasing Vehicle

size

Saturn Outlook, GMC Acadia & Buick Enclave

• Market is demanding larger BFI crossover vehicles with accommodations similar to full size BOF SUV’s.

• Steel technology remains key in satisfying the performance requirements of the larger BFI entries at a competitive mass.

SwartzellOAL x OAW x OAH


BIW high level strategy

World class BIW performance across platform bandwidth.

Develop enablers to achieve world class quality: - gap and flushness of fits- “jewel effect” features on panels- secondary surfaces appearance

Maximize re-use for future variants.

Enable competitive mass with effective geometry, steel selection and optimization.

Configure BIW to achieve best-in- class interior spaciousness

Aggressively leverage AHSS, UHSS & HSLA’s in cost effective applications.

Advance GM common product and process strategies.

Swartzell


BIW structure features

Open front end facilitates vehicle assembly.

Straight rails tuned for high crush efficiency.

Sub-assembly of structure surrounding lift-gate provides high torsional stiffness.

Cost effective usage of martensitic, D-P, and HSLA steels in primary load paths.

Layered framing allows welding prior to outer panels closing section.

Laminated steel plenum.

Pumpable foam acoustic cavity treatments.

Rear HVAC duct integrated inside section.

UHSS straight C/C tube manages side impact load.

Swartzell


Mild steel

Steel specification strategy

Bake hardenable

HSLA

Dual Phase

Martensitic

Steel selection strategy

Low Carbon

180-210-300

340-410-550

DP600 DP800

DP1000

Grade 9 Grade 13

Large underbody closeout panels, highest quality outer panels.

Stiffness dominant parts and formability restricted parts.

Strength dominant parts with minimal energy absorption.

Strength dominant energy absorption parts and high strain parts.

Parts requiring highest ultimate strength.

Grades used Typical usages

Tensile Strength

(mPa)

900 - 1300

440 - 650

590 - 980

300 - 390

260 - 270

Swartzell


Steel grade usagepercent by mass

Bake Hardenable 26%

Dual Phase 7%

HSLA 34%

Martensitic 7%

Low Carbon 26%

180B - 210B - 300B

340 - 410 - 550

600 - 800 - 1000

Grade 9 – Grade 13

Swartzell


• Used where maximum strength is required for crash (rockers and cross-members).

• Constant sections provide structural continuity and allows roll form processing .

• Both Grade 9 and Grade 13 used based on optimum weldability.

Underbody steel applications Steel grade usage(underbody)

Dual PhaseMartensitic HSLA Bake

Martensite applications

Rocker Inner panels

Cross-car tube

F.O.C.

Mild

Swartzell


Dual Phase

• Used in crush zones for improved energy absorption.

• Also used in high strain areas.

• Use DP 600 and DP 800 grades in underbody based on manufacturability.

Underbody steel applications

Martensitic

Dual-Phase applications

HSLA Bake

Steel grade usage(underbody)

F.O.C.

Mild

Swartzell


HSLA

• Used as complement to Dual Phase to facilitate weldability.

• Used where high yield strength is required but with minimal energy absorption need.

• Use 340, 410 and 550 grades based on formability.


HSLA applicationsF.O.C.

Dual PhaseMartensitic Bake Mild

Swartzell


Bake

• Used in stiffness dominant parts and formability restricted parts.

• 180, 210 and 300 grades of bake hardenable used.


Bake Hardenable applications

F.O.C.

HSLADual PhaseMartensitic Mild

Swartzell


Bake

Low Carbon applications

HSLADual PhaseMartensitic Mild

F.O.C.

Steel grade usage(underbody)

• Used to close out underbody.

• Not treated as primary load path.

• Thickness minimized for mass and cost efficiency.

Swartzell


• Used in rocker outer as well as underbody.

• Creates fully closed martensitic rocker section.

• Section stabilized with bulkheads.

• Maximizes structural efficiency for front, rear and side crash events.

Upper structure steel applicationsSteel grade usage(upper structure)

Martensite applications

Rocker Outer panels

F.O.C.

Dual PhaseMartensitic HSLA Bake Mild

Kolis


Dual-Phase applicationsF.O.C.

Steel grade usage(upper structure)

• Used in “B” pillar for side impact and roof crush loading events.

• DP 800 and DP 1000 grades used.

Dual PhaseMartensitic Bake MildHSLA

Kolis


HSLA

• Used selectively for reinforcements.

HSLA applicationsF.O.C.

Dual PhaseMartensitic Bake Mild


Kolis


Upper structure steel applications

Bake Hardenable applications

F.O.C.


• Used in stiffness dominant parts and formability restricted parts.

• 180, 210 and 300 grades of bake hardenable used.

• Grades specified based on manufacturability and strength balance.

BakeHSLADual PhaseMartensitic Mild

Kolis



Low carbon applications

• Used in one-piece body side outer panel and roof.

• Selected to enable crisp features in styled panels for highest possible quality.

• Mild steel panels not treated as load carrying primary structure.

BakeHSLADual PhaseMartensitic Mild

Kolis


Dual Phase considerations

Kolis

• Develop part geometry with features to control spring back and side wall curl.

• Provide greater open wall angles for spring-back compensation.

• Provide constant section height to maximize shape set & strain.

• Shorten overall part length to minimize twist end to end.

• Plan for additional binder tonnage and try-out time to compensate die for spring back.

• Reduced trim and pierce angles and use hardened/coated tool steels.

• Flanging possible in non work hardened areas from draw or form dies.

• Develop part to minimize compression and stretch flanges and edge splitting

• Develop robust processes for weld verification.


BOP framing sequence / construction strategyLayered framing facilitates weld access

1) Inner panels loaded. 3) Outer panels loaded.2) Inner panels welded to underbody with full access.

Benefits:- reduced need to weld through access holes.

- has demonstrated high dimensional capability.

- allows optimal welding for improved mass efficiency.

Kolis


Stiff back body opening built as sub-assembly

GM Framing Process

Sub-assembled back body buildTraditional back body build

Benefits:- structural continuity through corners.- effective corner reinforcement.

- allows integration of HVAC duct which maximizes enclosed area of section.

Results: - 25.9 N-m / deg torsional stiffness.- 24 hz first bending mode (fully trimmed)- 28 hz first torsion mode (fully trimmed)

HVAC duct integrated

inside welded section

Kolis


0.00 2.00 4.00 6.00 8.00 10.00

1

2

3

4

5

6

Lightweight design coefficient*

Lightweight design

coefficient

Body-in-white mass (kg)

Area (m2) x Torsional stiffness (N-m/deg)=

Lightweight design coefficient used to evaluate construction and joint efficiency

Projected Area

Benchmark vehicle #5





Outlook, Acadia & Enclave

Results vs benchmark crossover’s

More efficient

* Described in SAE paper 2006 - 01-1405Kolis


BIW noise strategy

Pumpable foam acoustic cavity treatments provide robust noise barrier and sealing.

Liquid applied sound deadener tuned for optimum performance

Laminated steel plenum reduces structure borne noise

Sealing strategy achieved aggressive body leakage targets

Extensive mobility development at isolated chassis interfaces

Best practices executed to minimize wind noise at source

Kolis


Crash Performance

Overall crash performance: Competitive!

Kolis


Driver Passenger

Frontal Crash

Driver Passenger

Side Crash

Not yet released Not yet released

Crash Test Results*

* Source: National Highway Traffic Safety Administration


Questions & Answers:

Acknowledgements: Andy White, Bushan Dandekar, Marcel Cannon, Curt Horvath, Gary Telleck, Greg Warden

body-in-white technology in the new: saturn outlook …/media/files/autosteel/great designs in...

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