ken karbon...ken karbon, september 24, 2008 2 1908-2008 general motors corp. (nyse: gm), the...

Ken KarbonGeneral Motors

Simulation and Visualization in Automotive Design

2Ken Karbon, September 24, 2008

1908-2008

General Motors Corp. (NYSE: GM), the world's largest

automaker, has been the annual global industry sales leader for

76 years. Founded in 1908, GM today employs about 284,000

people around the world.

www.gmnext.com


Who am I?

Ken Karbon, Energy Center,

Aerodynamics

Engineering Design

Product

Development

“Karbon footprint” = size 12

No “Karbon Kredits”

“Karbon Neutral”


GM Global Engineering Centers

Warren, MI, USA

Trollhä ttan, Sweden

Rü sselsheim, Germany

Seoul, South Korea

Sã o Paulo, Brazil

Toluca, Mexico

Bangalore, India

Port Elizabeth, South Africa

Shanghai, China

Melbourne, Australia

Oshawa, Canada

Millbrook, England

15 Countries - 12 Brands - 9 Time Zones - 28000+ Managed Workstations – 19 Engineering / Design Centers (and 181 plants)


Outline

GM Design Process

Visualization Methods

Styling

Simulation (aerodynamics, wind tunnels, CFD)

Design and Collaboration

EnSight Success Stories


24+

Mon

th V

DP

18-24

Mon

th V

DP

<18

Mon

th V

DP

Hardware Math

Concurrent, compressed hardware

Math used for synthesis/virtual build

Continuous, synthesis learning

Hardware to confirm and validate

Where We’ve Been

Where We Are

Where We Are Going!

Vehicle Development Process

Consecutive hardware learning

Math used to “check problems”


Math-Based Performance Integration

16 month vehicle development cycleV Series


Integrated Virtual Vehicle Development

MANUFACTURINGDESIGN

MARKETING

SALES

SERVICE

RE-USE

VEHICLE SPECIFICATION

STYLING

CONCEPT

VALIDATION

Focus on complete vehicle life cycle

Integrated

Vehicle

Data Base

TCAE / UG

Vehicle Simulation

http://carpoint.msn.com/vip/Nissan/Xterra


Outline

GM Design Process


Styling





Design Studio Visualization

Cintiq “Boards”

Sketches

GM's Global Design Intern Program

Paper


Animation and RenderingPower Walls

Immersive Caves

Visualization RoomsBuick Velite Concept

Trunk Study


Design Studio Clay Modeling

GM's Global Design Intern Program


Outline

GM Design Process


Styling





Why is Aerodynamics Important?

Comfort

• Windrush Noise

• Ventilation

• Gas Intrusion

Cooling

• Radiator

• Condenser

• Components

• Brakes

Performance

• Fuel Economy

• Range

• Emissions

• Top Speed

• Acceleration

Handling

• Cornering Capability

• Crosswind Response

• Directional Stability

• On-Center Handling

Visibility

• Glass Contamination

• Wiper Lift

Aero Drag is the primary factor

for Highway Fuel Economy and

accounts for 15%-25% of vehicle

energy use


Well-Executed Aero Can Look Good Too!

Chevrolet Corvette: CD = 0.286Best in segment

Chevrolet Tahoe Hybrid: CD = 0.348Best in segment


Front end airflow development

Supplement wind tunnel with drag development

Flow visualization, diagnosis

Detailed pressure and velocity loads on exterior

body components

Things that can’t be done in wind tunnel

GM Aerodynamics Laboratory

CFD

Aerodynamics Tools

Aerodynamic drag and lift development

Opened in 1980

World’s largest automotive wind tunnel


Wind Tunnel Visualization

Smoke wand

Yarn tufts

Ink

Traverse

Video


Noise & Vibration

Vehicle Dynamics

Control Systems

Manufacturing CAE & Dimensional Integration

Powertrain

Crash/Safety

Aerodynamics & Airflow

Energy, Drive Quality,& Environment

Structures

Optimization &Robust Engineering

Structural Durability

Harmony & Human Factors

Thermal

2000+ Simulation Load Cases

160 SoftwareSimulation

CFD

More legal/regulatory requirements

Higher fidelity simulations

DOE, DFSS


GM’s CFD Focus – 1990’s

Emerging CAE technology

Code evaluations – commercial vs. in-house

Capability demonstration

Aero, thermal, HVAC, wind noise, fuel, brakes,

contamination, water management, etc.


GM’s CFD Focus – 2000’s

Vehicle Development

Make decisions with CFD

Use the best tool (simulation or test)

Globalized Standard Work

Streamline software

Common simulation procedures

Part naming convention

Standard load cases

Correlation to physical tests

Increase Capacity

Meshing turn-around time

Process automators


Assemble CAD - Unigraphics Clean, Mesh, and Stitch

Watertight Surfaces - ANSA

1

43

2

Build Volume CFD Grid,

Boundary Conditions (Virtual

Wind Tunnel) - TGrid

Run Simulations and

Analyze – Fluent, EnSight

Rapid-modeling “wrappers”

reduce meshing from weeks to

days

Aero CFD Modeling

20+ million cells

Up to 700 cpu hr


OVAL Automation

In-house software wrapped around GM’s Fluent process

Automates volume meshing, BCs, solver setup, HPC submission,

post-processing, reporting (>50% throughput improvement)

Eliminates mistakes. Gives reliable, repeatable results.

Boss Kettering Award (GM’s highest technical achievement)

Allows batch EnSight to run after Fluent job for custom analysis

Courtesy of Silvestre Artiaga-Hahn, Nicolas Kruse, Frank

Werner, Adam Opel AG, Ruesselsheim, Germany


Front End Airflow

Saturn Vue Hybrid

Optimize grille openings, grille texture, seals, and airdam to meet powertrain cooling load cases

Complex hybrid powertrains present challenges

100% virtual development in CFD – fast design iterations and optimization

Volts Speed

kph

Heat Exchanger

Flow, CMM

12.5 Idle 48

12.5 50 53

12.5 90 63

Example Data


m/s

---- Sealing Improvement opportunities

FEAF Visualization


m/s

Flow Through 5 Heat Exchangers


Design For Six Sigma

Quality Initiative

Taguchi Method for

Robust Optimization

Large design arrays

solved with CFD

Output

Radiator/Condenser

Airflow

Unwanted Customer Outputs

Engine Overheat

Degraded AC performance

Noise Factors

Seal leakage

CRFM Aging

Control Factors

Lower grille texture

Lower Opening size

Ped Pro size

Airdam location

Condenser location

Upper grille texture

Upper opening size

CRFM

Front End Airflow

CFD Model

Signal

Vehicle speed


DFSS - Optimum Front End Airflow Design

-0.05

0

0.05

0.1

0.15

0.2

0.25

20 30 40 50 60 70 80 90 100

Initial

Optimal

Dynamic S/N Ratio

-32.0

-31.0

-30.0

-29.0

-28.0

-27.0

-26.0~ A1 A2 ~ B1 B2 B3 ~ C1 C2 C3 ~ D1 D2 D3 ~ E1 E2 E3 ~ F1 F2 F3 ~ G1 G2 G3

Factor & Level

S/N

Ra

tio

in

dB

0.130

0.132

0.134

0.136

0.138

0.140

0.142

0.144

0.146

0.148

0.150

~ A1 A2 ~ B1 B2 B3 ~ C1 C2 C3 ~ D1 D2 D3 ~ E1 E2 E3 ~ F1 F2 F3 ~ G1 G2 G3

Factor & Level

Slo

pe

(

)

dB Gain 4.05% efficiency increase 26.3


Wheel Aero PerformanceFlat wheel cover - baseline

Wheel Design 2Wheel Design 1

Convex wheel cover DCD CFD = +0.002

DCD CFD = +0.016DCD CFD = +0.015

DCD WT = +0.002

DCD WT = +0.010 DCD WT= ?

**No prototypes to test**


Flow Through Wheels

out

in

q net = 0.026 m3/s outflow

q net = 0.063 m3/s outflow

Virtual surfaces “case-mapped” to

existing solution to measure flow

ratesWheel Design 2

Wheel Design 1


Fog Lamp Pocket

DCD = -0.003

Rear Corner

Vortex

Wind Tunnel

Wind TunnelCFD

CFD

CFD Flow Visualization and Diagnosis


Animated GIF of

model morphing

and CFD drag

simulation

Morphing


Sunroof lift force at top speed Door pressure with crosswind

Aero Sims for Structural/Sealing Analysis

CFD FEA LoadsStress/Deflection


GM’s CFD Focus – Future?

More aero drag development

Fuel economy focus

Aggressive CD targets

Limited wind tunnel resources

Visualization, Communication, Collaboration

Less meshing, more design and analysis


Outline

GM Design Process


Styling





Siemens/UGS TeamCenter PLM Software

Unigraphics and TCAE

CAD Management and Design

TeamCenter Community

Workflow, secure data transfer, conferencing

Visualization Mockup

High-performance, lightweight, JT data format

Manage/view large assembly structures

Sections, measure, annotate, query, compare

JT 2 Go

Lightweight viewer

Embed into MS Office, etc.


TeamCenter Visualization Mockup


VisMockup Surface Comparison

Exterior Design 1

Exterior Design 2

Tri-Color Mapping

Blue = Common Surface


Goal: CFD to VisMockup

Need 3D, interactive CAE data

Eliminate numerous, static images, ppts

Common GM PLM environment

No additional software or learning

Compare CAD and simulation together seamlessly

Long term storage system

EnSight to jt?

ensight.to.vis jt2go demo


Outline

GM Design Process


Styling





Things We Like in EnSight Quality images, anti-aliasing

Fast dynamic viewing of large models

Compare multiple cases simultaneously

Calculator functions

Derived parts (iso-surfaces)

Case Map

CAD – import/export

Customized color palettes, legends

Query

Command files (same syntax in batch and GUI)

Context files (usually)

evo, EnVe

Case format used for in-house codes

Batch operation

Python, Quicktools (TBD)


Wiper Wind Noise Prediction

Allowable wiper packaging

to meet wind noise

requirements

Aero CFD Simulation

GM Wind Noise Model

1500 lines of EnSight command code

Using only While Loops!

Runs automatically after Fluent job

GM Intellectual Property

dB value

Standard center, zoom, vectors, particle

traces, contours, clips, annotations, etc

http://www.ensight.com/ensight-helps-reduce-wind-noise-in-general-motors-vehicles.html


Some Pitfalls with Automatic Post-

Processing

Full vehicle pics are

usually not informative

No details

Missed cutplanes

Vectors too big or too

small

Boring contours

Too many pics

Where’s the car?

Not enough contrast

Shadow surfaces

create problems


Improving Visual Communication

Zoomed and

highlighted surface Cutplane icon

Highlight the concerns

±Surface restrict

traces on outside only

Anti-aliasing (no stair

steps)

Contrasting colors

and vector size


Improving Pressure Pictures

Cp* Normal [x] indicates

drag contribution

Eliminate uninteresting middle scale


Isosurface of Ptotal = 0 (Flames)

CFD Model 1 with

crosswind

CFD Model 2 with

crosswind


Chevrolet Volt

40 miles range on electric charge

E-Flex generator system

Can use various fuels: Gas, E85, Diesel, Hydrogen Fuel Cell

Very open development. Target launch 2010.

Media event CFD movie

ken karbon...ken karbon, september 24, 2008 2 1908-2008 general motors corp. (nyse: gm), the...

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