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INNOVATIONS IN HIGH-STRENGTH WHEEL TECHNOLOGY

Eduardo C. MikamiArvinMeritor Inc. – Wheels Systems

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The application of new design tools, materials and manufacturing technologies brought key features to the steel wheel, which combined have leveraged the steel wheel competitiveness in a so restrict market, and reducing the aluminum wheel penetration growth.

Some of the reasons for that are:

• High strength steels• Static and dynamic structural analyzes• Process stamping simulation• New Finishing• Sizing

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STEEL WHEELSDESIGN EVOLUTION

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In order to keep up with more restricts requirements from the OEM’s and final customers for lighter, larger and better looking wheels, a broad array of product and process simulations have been applied during the ordinary steel wheel development phase, and the development of new concepts as well.

Those new simulation capabilities has been the enabler for the industry to take advantages of the benefits that the new steel grades and process can offer.

STEEL WHEELSDESIGN EVOLUTION

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PRODUCT SIMULATIONTOOLS

Cornering Fatigue Test Simulation

Traditional Design Simulations Tools

Radial Fatigue Test Simulation

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PRODUCT SIMULATIONTOOLS

Advanced Design Simulations Tools

Stiffness of th Wheel

0

100.000

200.000

300.000

400.000

500.000

600.000

700.000

1 2 3 4 5 6 7 8

Wheel2

KN

.m/rd

"K" FEA

"K" Device

Wheel Stiffness Simulation

193 194305 302

510 520565 562

908 935

0

200

400

600

800

1000

1200

(Hz)

Frequency

Validate Model - Frequency

FEA Laboratory

Wheel Natural Frequency Analysis

Generic Algorithm for Disc Profile

brake

disc

brake

disc

Torque Simulation

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Stiffness of the Wheel

0

100,000

200,000

300,000

400,000

500,000

600,000

700,000

1 2 3 4 5 6 7 8

Wheel2

KN.m

/rd

"K" FEA

"K" Device

Wheel Stiffness Simulation• Method to determine the ideal values of wheel stiffness, to be used as requirement for new wheel development, in order to avoid handling and noise problems

PRODUCT SIMULATIONTOOLS

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193 194305 302

510 520565 562

908 935

0

200

400

600

800

1000

1200

(Hz)

Frequency

Validate Model - Frequency

FEA Laboratory

Wheel Natural Frequency Analysis• Method to simulate and investigate the different wheel’s resonance modes in order to improve NVH

PRODUCT SIMULATIONTOOLS

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PRODUCT SIMULATIONTOOLS

Generic Algorithm for Disc Profile

• Methodology to define the optimum disc profile, for a specific project, using a generic algorithm

• Reduces the stress levels on the disc

brake

disc

brake

disc

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PRODUCT SIMULATIONTOOLS

581.1 MPa566.5 MPa554.0 MPa541.0 MPa514.7 MPa486.9 MPa437.1 MPa417.0 MPa410.3 MPa398.9 MPa384.6 MPa378.5 MPa358.1 MPa581.1 MPa

358.1 MPa

Generic Algorithm for Disc Profile

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LoadLoad

Deflection

PRODUCT SIMULATIONTOOLS

Torque Simulation• Predict bolt hole deflection and nut/bolt torque

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PRODUCT SIMULATIONTOOLS

7

• Improves the quality of the wheel “A” surface

• Helps to reduce wheel development time

• Identifies wrinkles and cracks on the part before tooling design and construction start

Process Sequence and Stamping Analysis

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PROCESS SIMULATIONTOOLS

Process Sequence and Stamping Analysis• Ansys LS-Dyna

• Essential tool to work with High Strength Steels

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DESCRIPTIONTo utilize an integrated flow form process in order to produce the wheel rim with thickness variation consistent with the stress level.

OBJECTIVES/ BENEFITSReduction of weight Environment friendly

Approx. 1Kg saved per wheel in an actual program study and

Approx. 1kg saved per wheel in an actual program study - 16” x 7”

FLOW-FORMED RIMS

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PROCESSWelding of a ring with constant thickness.Cylindrical flow forming of the ring in order to obtain variable thickness.Normal rolling, assembly and welding.

49

Saved material

185

Preform strip for Flow Forming Process

Preform strip for traditional process

234

Flow formed strip for weight optimized rim

49

Saved material

185

Preform strip for Flow Forming Process

49

Saved material

4949

Saved material

185185

Preform strip for Flow Forming Process

Preform strip for traditional processPreform strip for traditional process

234

Flow formed strip for weight optimized rim

234234

Flow formed strip for weight optimized rim

FLOW-FORMED RIMS

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9

1 – SAPH38

(TS = 380 MPa)

2 – SAPH45

(TS = 450 MPa)

3 – SHA540B

(TS = 550 MPa)

4 – SHA590D

(TS = 600 MPa)

5 – 780 MPa Sumitomo Steel

6 – Trip Steel

(TS > 800 MPa) 0

100

200

300

400

500

600

700

800

900

1970 1980 1990 1995 2002 2008

Year

Stre

ngth

(min

. MPa

)

1

56

3 42

EvolutionEvolution

2004

Tensile Strength (MPa)

350 400 450 500 550 600 650 700 800

45

40

35

30

25

20El

onga

tion

(%)

780 MPa

Tensile Strength (MPa)

350 400 450 500 550 600 650 700 800

45

40

35

30

25

20El

onga

tion

(%)

Tensile Strength (MPa)

350 400 450 500 550 600 650 700 800

45

40

35

30

25

20El

onga

tion

(%)

780 MPa

SimilarSAPH 38

SimilarSAPH 45

SimilarSAPH 55

SimilarSAPH 60

STEEL APPLICATION

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Great Designs in Steel is Sponsored by:•AK Steel Corporation•Dofasco Inc.

•Severstal North America Inc.•United States Steel Corporation

•Mittal Steel Company•Nucor Corporation