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Estimating Secondary Mass Changes in Vehicle Design with

Application to the

Design Advisor

Donald E. Malen

University of Michigan

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Cost

GHG

Secondary

mass

Sensitivity

Analysis

Graphic Dash

Board

Design Advisor

Design Advisor- Excel Workbook to support material selection decisions

Component

benchmarking

and scaling

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Material selection decisions often occur early in the design process

Product

Planning Detail Validation Production

Context for Design Advisor

Stamped Steel,10 kg

Cast Magnesium, 6 kg

advise the

decision

Design

Advisor

limited

available

information

Vehicle

•Mass

•Cost

•LC GHG

Sedan/Hatchback

5 passenger

100 kg cargo

Powertrain Gas-IC

4.7 m

1.8 m

Configuration

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Design Advisor Solution Map

Sensitivity

analysis

5-

Sensitivity

analysis

Cost savings

for resized

subsystems

Cost for part

Vehicle mass

savings

Environment

impact

Material

Use

Recycle

4-Vehicle

comparison

summary

Compare

vehicles

3-Resize

nominal

vehicle for

competitor

component

Resize nominal

vehicle for

component

change

3a-Input

component

and part data

3b-Scale

component for

nominal

vehicle

Component

technology

1-Define

nominal

vehicle

2-Size

powertrain for

nominal

vehicle

Define

nominal

vehicle

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Marginal trade off ratios

stacked bar chart

shows relative

performance

Total

LCA for

each

vehicle

Example: Summary output

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$27.37 performance worse

for resized vehicle

performance better

for resized vehicle

performance better

for resized vehicle

relative component cost

relative subsystem cost

relative fuel savings -$18.75

-1.89

net cost difference $25.48 worse

for resized when only product cost

is considered

net cost difference $6.73

worse for resized when fuel

savings is considered

0

- $1.89

$18.75

- $6.73

Summary Output - Graphs

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relative mass

reduction for

resized

relative cost

reduction for

resized

both metrics are better for resized vehicle

both metrics are worse for resized vehicle

one metric is better, one worse for resized vehicle

Trade-off ratio significant

= -2.61

Summary Output- Trade off ratios

T.O.R.= D product cost

D mass

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difference

607.12 worse for

resized vehicle

Summary Output- Life Cycle GHG

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Body loads

reduced

Chassis

loads

reduced

fuel tank

capacity reduced

Aachener Karosserietage 2012 (VW AG)

Engine power reduced

for same performance

Primary and Secondary Mass Change

Secondary

mass

change

due to

resizing

other

subsystems

0.519

0.342

0.406

0.684

Simple Compounded

Secondary mass change

1kg primary mass change

Regression method

Analytical method

SAE 2013-01-0655

Steel10 kg Mag. 6 kg

Primary mass

change

- 8 kg

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Vehicle type: Hatchback

L=4.2 m

W=1.750 m

100 kg cargo

New architecture

Internal Combustion-gasoline

Powertrain is fixed and will not change 6. liter/100 km (HYZEM schedule)

Life time range =155,000 km

Original

Component

AHSS

Stamped

14.66 kg

Competitor

Component

Aluminum-wrought

Stamped

11.00 kg

hood area, A=1.5 m2

Component: Hood Plans for 20xx vehicle

Area=2 m2 Area=2 m2

Case Study 2- Hood

Lightweight Vehicle Consortium

J. Dahmus and R. Roth, 2008

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Case Study 2- Hood (Alum vs. Steel) Benchmarking and Scaling

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We have mass information on

a hood from a previous study

The nominal vehicle has

different hood size

How should we scale this mass

data to represent the mass of a

hood for the nominal vehicle?

mHOOD=14.66 kg mHOOD=?

A=2.0 m2 A=1.5 m2

Scaling Component Mass

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Subsystem

Attributes

system

Attributes

Component

Interaction

Mass Drivers determined by statistical significance

Aluminum

SteelConv.m Aream

00.1

65.1)(28.4ˆ 24.12

0

10

20

benchmarking-130 hoods

24.1

ˆ

ˆ

B

A

B

A

Area

Area

m

mresulting scaling equation

Hood

frame

mass

kg 5

15

25

0 1 2 3

Area m2

Scaling Component Mass

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door

frame

hood

frame

deck lid

frame

lift gate

frame

hatch

frame

wheel

knuckle

front seat

frame

instrument

panel beam

bumper

beam

body

shell

exhaust

Lower

control arm

599.02438.0 ),(),(418.3ˆ mAreakgGVMm

Closures Chassis Body

24.12 )(28.4ˆ m Aream

SLA

McPhersonkgFGAMm

00.1

571.0),(343.0ˆ 478.0

Scaling Component Mass

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Case Study 2- Hood (Alum vs. Steel) Summary Results (Same powertrain size)

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Case Study 2- Hood (Alum vs. Steel) Summary Results (Powertrain resized)

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What is fuel consumption for

resized vehicle?

•MNOMINAL

•Fuel consumptionNOMINAL

Resized vehicle

MRESIZED=MNONMINAL + DM

Fuel consumptionRESIZED=?

DM

Fuel Consumption Mass Sensitivity

MNOMINAL

Fuel consumption=6.2 l/100 km

Nominal vehicle

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Fuel Consumption (l/100km)

0

5 10 15

m=

2195 kg m=

1655 kg 235 kW

4.5 liter

183 kW 0-60 mph

acceleration

time (s)

Powertrain displacement fixed

0.190 l/100 km/100 kg

US combined, IC-Gasoline

fka, Schulte-Corne, Claus, et al., Determination of weight influence on the energy consumption

Fuel Consumption Mass Sensitivity

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US combined, IC-Gasoline

Fuel Consumption (l/100km)

Acceleration fixed (engine downsized)

0

5 10 15

235 kW

4.5 liter

183 kW 0-60 mph

acceleration

time (s)

0.415 l/100 km/100 kg

m=

2195 kg m=

1655 kg

Fuel Consumption Mass Sensitivity

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HYZEM NEDC

Comp Mid SUV

US comb 0.45 resize PT

20 mi

range

40 mi

range

A

Class

C

Class

0 no resize

1) reduced

sensitivity to

mass change

2) reduced

sensitivity to

powertrain

resizing

1000 2000

vehicle mass kg

Fuel Consumption Mass Sensitivity liters/100 km/100 kg

Internal

combustion

Parallel

Hybrid

Fuel

Cell

Plug-in

Hybrid

Electric

Battery

Electric

Gas

Diesel

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Material Primary

Process

Total

Mass

(kg)

Steel-AHSS Hydroform 7.81

Aluminum Stamping 6.77

All hatchbacks have surface area=1.0 m2

Case Study 3- Hatchback closure

Lightweight Vehicle Consortium

J. Dahmus and R. Roth, September 11, 2008

Results Summary – Hatchback

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Case Study 3- Hatchback closure

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100,000 parts

$0

$20

$40

$60

$80

AHSS Steel Aluminum SMC Composite

20.43 26.31

59.88

D.A. Rigorous

Part

Cost

D.A. Rigorous D.A. Rigorous

28.99

67.85

30.83

Case Study 3- Hatchback closure Shaping Cost Estimation

Lightweight Vehicle Consortium

J. Dahmus and R. Roth

Assembly Cost

Part Production Cost

Material Cost

Other

Labor

Equipment

Tooling

More

information

required to

estimate these

than is input to

Design Advisor

w w w . a u t o s t e e l . o r g CES Process Selection Software, 2011

First Order Part Shaping Cost Model

Steel Stamping

Steel Tailor Welded Blank Stamping

Steel Hot Stamping

Steel Open Roll Form

Steel Tubular Hydroforming

Steel Forging

Iron Casting

Composite Sheet Molding

Compound

Composite Resin Transfer

NonFerrous Stamping

NonFerrous Forging

NonFerrous Extrusion

NonFerrous Die Casting

WO

CTM

tL

C

n

n

C

f

Cm C

1

1

material

cost

tooling

cost

equipment

cost

part mass (kg)

0

2 4 6

10 20

106$ 106$

part mass (kg) 0

1 2

3

10 20 3.16 4.94

($/kg) Al Mg

NonFerrous

Stamping

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255 213

1975

328

Contemporary

steel mix

AHSS Alum Sedan

5 passengers

100 kg cargo

L=4938 mm

W=1831

IC gasoline

HYZEM

life time range 155,000km

ability to resize all

subsystems including

powertrain

GVM

used to size

component

1600

164

Carbon

fiber

1600 1600

Component: Body structure 2011 Honda Accord

Body

structure

mass (kg)

Case Study 4- Body Material

, H. Singh

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curb 1534.43→1471 kg

HYZEM 7.2→7.0 l/100km

Case Study 4- Body Material (Conv. Steel vs. AHSS)

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curb 1534.43→1411 kg

HYZEM7.2 →6.84 l/100km

Case Study 4- Body Material (Conv. Steel vs. Alum)

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curb 1534.43→1341 kg

HYZEM 7.2 →6.64 l/100km

Case Study 4- Body Material (Conv. Steel vs. Carbon fiber)

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fuel consumption material production shaping

process

fuel production

recycling

C

O2

Material Production Stage

SCO

2

Life Cycle Assessment of

Green House Gas

C

O2

C

O2

C

O2

C

O2

Use Stage End of life LCA

Design Advisor uses models and parameters from UCSB GHG Model, R. Geyer, 2013

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Material Production and

Recycling GHG

1 kg

Finishing

material in

vehicle

prompt

scrap

CO2 Produced

Material Production Part Forming

to secondary

production

which offsets

primary

production

recycled from mfg process

recycled from vehicle

used in primary

production

Primary

production

Secondary

production

Material Production Recycling

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• Multiple Metrics

Mass including subsystem resizing

Cost

Life Cycle GHG

• Use information available during preliminary design

5 pieces of info about each component

7 pieces of info about vehicle

Parameters for models are pre-loaded

• Very quick analysis time

<5 minutes data entry

<30 seconds for computations

• Accuracy sufficient for A-B comparison

Uses rigorous analytical models

• Graphic display to promote What-if studies and

understanding of trade-offs

Summary: Design Advisor for Preliminary

Material Selection Decisions

B>A

-Length, Width

-passengers, cargo

-Powertrain type

-Fuel type

-component mass

-material

-manufacturing

component vehicle

mass

cost GHG

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Estimation of Secondary Mass Effects in Vehicle Design white paper

Design Advisor workshop: June 7

SMDI Offices, Southfield

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