lecture 9, global lightweighting

BY

Dr. M. Nasim [email protected]

734 546 0450

Lecture IXMarch 13, 2014

Introduction to Vehicle Design: Materials &

Manufacturing I

Forces Acting On a Two-Axle Vehicle

Normal Loads on Axles

Normal Load on Front Axle, Wr

Wf = (Wl2cos Raha haw/g Rdhd whsin)/L

The negative sign for the term whsin vehicle is climbing

up!

Normal Load on Rear Axle, Wr

Wr = (Wl1cos + Raha+ haw/g + Rdhd whsin)/L

The positive sign for the term whsin vehicle is climbing

up!

Material Percentage of vehicle weight Major areas of application

Steel 55 Body structure, body panels, engine and transmission components,

suspension components, driveline

components

Cast iron 9 Engine components, brakes, suspension

Aluminum 9 Body Panels, Engine block, wheel

Copper 1.5 Wiring, electrical components

Polymers (plastics)

and polymer matrix

composites

9 Interior components, electrical and

electronic components, under-the

hood components, fuel line

components

Elastomers 4 Tires, trims, gaskets

Glass 3 Glazing

Other 10 Carpets, fluids, lubricants, etc.

Material Distributions in Typical Automobiles

Lightweighting Strategy

Outline

OE Customer FocusEfficient Fundamentals

Vehicles

Camaro Z28Opel AdamSilveradoCadillac ATSChevrolet SSCadillac CTSCorvette

Technologies

SteelAluminumCarbon Fiber CompositesMagnesiumShape Memory AlloysJoining

Lightweighting Strategy

Efficient Fundamentals Premium Matls & Mfg Processes

Body Lightweighting Strategy

CostUp CFRP + Aluminum +

Baseline5%0%

Regression Line

CostDown

(Applied Independent of Material

type to Minimize Mass & Cost)

PHS + Aluminum

AHSS/UHSS/PHS

Magnesium

MaterialMaterial Utilization

Customer Selection

Requirements

10% 20% 30% 40%

Percent Below Industry

Customer Focus

Customer Focus

Means understand what the customer is expects.

Delivering a vehicle that exceeds expectations

Vehicle must be priced / sized consistent with competition

Camaro Z28

Understanding the Customer

To increase speed, Chevrolet jettisoned just about everythingthat added weight but wasn't critical. That includes carpeting in

the trunk, insulation and every speaker but one.

Vehicle mass reduced by 140 kg.

Efficient Fundamentals

Efficient Fundamentals

Overall right sizing

Topology Optimization

Material Selection

Gage Selection

Material Utilization

Independent of material type vehicle platform



CostUp

AHSS/UHSS/PHS

Baseline5%0%

Regression Line

CostDown



AHSS/UHSS/


Customer Selection

Requirements

10% 20% 30% 40%


Opel ADAM

56,3 %16,5 % 16,5 %

% %

Opel Adam Materials Mild SteelsBH &

HSS DP

PHS

AL

8,4 1,6

HS

Opel

HB3

Adam Materials

AdamCorsa

1.7 MM PHS 1.3 MM P

1.0 MM

PATCH

PHS

WEIGHT = 2.9KG

WEIGHT = 4.3KG

Zinc-coatedPHS Rear Rails

CORSA HB3CR340

t=2,2mm / 5,72kg

WEIGHT = 5.72KGADAM

PHS

t =1,9mm

3,42kg WEIGHT = 4.4KG

DP800

t=1,7mm

0,98kg

Silverado

ATS Materials Strategy

Cadillac Steel Strength Trend

Tensile strength (average MPa)

429371

337

2003 Predecessor 2008 Predecessor 2013 ATS

el

ATS Material Utilization

2.8 kgiminated

Patch Laminated Dash


Body LightweightingStrategy

CostUp

Baseline5%0%

Regression Line

CostDown



PHS + Aluminum


Customer Selection

Requirements

10% 20% 30% 40%


Aluminum

Chevy SS

CTS Door-in-White

General Motors first aluminum doorstructure, saving ~18kg/vehiclefrom the most mass efficient steeldoor systems in the industry, and~25kg/vehicle from the Gen 2 CTS

Includes additional noise absorptioncontent to achieve Library Quietperformance

12.0

8.0

0.60 0.65 0.70 0

Cadillac CTS Door Benchmarking

24.0

R = 0.6196

InfinitEff

More Efficient

Efficiency: 0.73.75 0.80 0.85 0.90 0.95 1.00 1.05

DIW

Sp

ecif

icM

ass

(kg

)

Front DIW Mass Prediction

22.0

20.0

18.0

16.0

14.0

Less Efficient y = 17.658x + 3.5464

y = 18.803x + 0.8224R = 0.8657

5.0 kg below Mass Efficient Steel

Prediction

BMW 7 Series: 11.0 kgEfficiency: 0.71

InfinitEff

i M45: 11.0 kgiciency: 0.73

More Effici

CTS: 10.7 kgEfficiency: 0.68

10.0

BMW535iL: 10.8 kg

~Surface Area Below Belt (m^2)

ATS Aluminum HPDC Shock Towers

Corvette Stingray

Aluminum Frame



Aluminum + CFRP +CostUp


Magnesium

Baseline5%0%

Regression Line

CostDown




Customer Selection

Requirements

10% 20% 30% 40%


Carbon Fiber Composites

Leader on panel volumeGM Carbon Fiber Leadership

Industry Not purely mass driven executions Design is not optimized for CF; Material substitution for SMC

Z06 Z07Fenders

Hood

Roof Outer Panel

Fascia Splitter

Rocker Panels

Floor Pan Assemblies

ZR1Fenders

Hood

Roof Outer Panel (exposed)

Fascia Splitter (exposed)Fenders

Rocker Panels (exposed)

Roof Bow Cover (exposed)Wheel House Outer Panel

Corvette Stingray Carbon Fiber Hood

Magnesium

Magnesiumon Corvette

Steering Column Support Seats

Magnesium Sheet Prototypes at GM

Hot ToolForm Press Cleaning Robot

Form Tool Opera

Statio

Ergono

Destack Robot

Exit

Convey

Cooling Fixture

Location

Press Automation

Blank Pre-Heater

Blank Presentation

Fixture

Blank Stack

ance

tor n& mics

GMs QPF Process

Hot blow forming at automotive volumes

Blank Stack

Blank Presentation

Fixture

Blank Pre-Heater

Press Automation

Cooling Fixture

Location

Exit

Conveyance

Destack Robot

Operator Station &

Ergonomics

Form Tool

Form PressHot Tool

Cleaning Robot

QPF Aluminum

Prototype Magnesium Intensive Door

(Inner, STAR panel, Beltline reinforcement)

Magnesium SUV Door Inner and Liftgate Inner

Magnesium Hood Inner and Outer

GM Hood Assembly

54

Decklid for Cadillac STS

AluminumOuter panelAluminum

Hinge reinf .

Magnesium

AluminumLatch reinf .

CAE Predictions

Peak stress locations

Overslam deflection

Al MgAZ31

Inner panel thickness 1.6 mm

(% of max allowed) 86.00 84.00


(% of max allowed) 92.00 102.00

Peak von Mises Stress

Al MgAZ31


(max stress as a fraction of

yield strength)1.16 0.98


(max stress as a fraction of

yield strength)1.16 1.04

As-Formed Panels

Trimmed Inner Panel(Die Trimmed)

3.6 kg in 1.6 mm AA5083 Al sheet2.4 kg in 1.6 mm AZ31B Mg sheet

Assembly Cell with Coated Inner Panel

Joining

Rivet reinforcements to inners instead of clinch

Assembled Panels with Mg Inners

Drop Tower Testing of Mg Decklid

Before After

Hem Corrosion Protection Details

(Sheared Edge Preparation Patent Pending)

Rounding of the cut edge is key to achieving uniform coating thickness

and good corrosion resistance.

AZ31

Powder coating

Uniform powder coating thickness on rounded edge

Thin coating at sharp corner onsheared edge

Additional Lightweight Technology

Developments

Aluminum Spot Welding

Shape Memory Alloys

GM Al RSW ApplicationHistory

GM Electric Vehicle, EV1 (1996) Manually weld bonded structure with

coating

GMT800 SUV high volume Al liftgate (1999) MaleCap High volume conventional MFDC RSW using

Ford-style male cap

QPF mule structure (2001-2002) Prototype structures built with grit blasted

electrodes (U.S. #6,861,609)

UniversalElectrode

MRD Electrode Arlington GMT920 liftgate (2008) 1st application of MRD electrode (U.S.

#8,222,560)

CTS-V Hood (2008) 2nd application of MRD electrode

Corvette Welding

Y1XX Corvette StructuralComponents (2013)

Heavy sheet, extrusions, andcastings

General Motors

MRD Electrode

SMA Potential Aero Applications

Air dam

Louver

Active Air Dam

Summary

GM has a comprehensive lightweighting strategy thatfocuses on a combination of efficient designfundamentals and the strategic use of premiummaterials including AHSS, PHS, Aluminum, CarbonFiber Composites, and Magnesium.

Numerous recent technology demonstrations have provided excellent opportunities to demonstrate elements of GMs strategy.

lecture 9, global lightweighting

Documents

vehicle mass

material distributions

engine components

vehicle design

expectations vehicle

term whsin vehicle

electronic components

hood components