CAE in Automotive Body Final

8/10/2019 CAE in Automotive Body Final

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2011 ANSYS, Inc. All rights reserved. 1 ANSYS, Inc. Proprietary


Vehicle Body

Sandeep Sovani,

ANSYS, Detroit, USAAugust 26, 2011


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Outline

Vehicle Design & Development Process

Driven by CAE Simulation

Automotive Industry Challenges

ANSYS for Automotive Body Simulation Case Studies

Upfront Aerodynamics Optimization

Simulating Body-In-White

Reducing Vehicle Noise

Summary


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Product Knowledge

0%

50%

100%

Product Design & Development Production

Degree of Freedom for

Decisions

CONCEPT DESIGN PERFECTION PREP.

Cost Responsibility

Vehicle Design & Development

Process

[1]

[1] Ref. NAFEMS Autosim White Paper 2008


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CONCEPT

Specifications

DESIGN PERFECTION

Styling

Design

Parameters

Packaging

PRODUCTION

CAE

UseC

AE

to

decidedesign

specs

ReducedN

o.ofPrototypes

Physical Testing

CAE Simulations


Process Driven by CAE Simulations



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Product Knowledge

0%

50%

100%


Product Knowledge

Degree of Freedom for

Decisions

CONCEPT DESIGN PERFECTION PREP.

Cost Responsibility


Process Driven by CAE Simulations

[1] Ref. NAFEMS Autosim White Paper 2008

[1]


7/31 2011 ANSYS, Inc. All rights reserved. 7 ANSYS, Inc. Proprietary

Environmental Protection Reducing CO2 Emission

Improving Fuel Economy

Efficient Thermal Systems

Occupant/Pedestrian Safety Fuel Leaks

Crashworthiness

Comfort, Handling &Aesthetics Noise & Vibration comfort

Vehicle Dynamics

Vehicle Styling

Alternative Propulsion Hybrid Electric Vehicles /

Alternative Fuel Vehicles

Fuel Cell Vehicles / ElectricVehicles

Automotive Industry Challenges :Regulations, Customer/Market Demands



Market Demands

Fuel Economy

Aerodynamic shape

Weight Reduction

Safety

Rollover/ Impact

Crash worthiness

Comfort, Handling &

Aesthetics

Noise & Vibration Comfort

Vehicle Styling

Manufacturability

ANSYS Solutions

External Aerodynamics

BIW Structural Modeling Virtual Rollover/ Impact /

Crash Modeling

Aero/ Vibro Acoustics

Vehicle Soiling Modeling

Vehicle Painting Process

Simulations

Vehicle Body

.

.

.

ANSYS for Automotive Body

Simulation



External Aerodynamics

1. Drag, Lift & Side

Forces

2. Front End Flow

3. Dirt accumulation /

water splashing Body-In-White

1. Static/Dynamic Analysis

2. Component Mode

Synthesis (Sub-structuring)

3. Spot Weld, Riveting etc

4. Fatigue & Design Life

Vehicle NVH

1. Wind Noise

2. Structural Vibrations

3. Road Noise

4. Noise Propagation

5. Modal Analysis / FRF

ANSYS for Automotive Body

Simulation



Upfront Aerodynamics

More Degrees of Freedom to Vehicle Shape

Exploration During Early Stages of Design Process

Key Requirements of Upfront VehicleAerodynamics

Fast, Automated & Reliable Pre-processing

Fast & Accurate Solver

Mesh Morphing Technology Inbuilt in Solver

Design Exploration & Optimization Tools

Automated Work Flow Management

Case Study #1

Upfront Aerodynamics Optimization



Fast, Automated & Reliable

Preprocessing

SAE Paper 2009-01-0335

Fast, Automated &Reliable Preprocessing ANSYS Meshing

TGrid 13.0

ICEM 13.0

Cleaned CAD to Solution

Time Statistics(1) Ford Taurus (26 M)

Total Time for CleanedCAD to Solution = 7.5 Hours(2) Second Vehicle (31 M)

Total Time for CleanedCAD to Solution = 8.5 Hours

(3) Third Vehicle (36 M)

Total Time for CleanedCAD to Solution = 9.0 Hours



Fast & Accurate Solver

Model Exp. DDES DES LES

Drag (SCx) 0.70 0.71 0.75 0.69

Courtesy

DDESDES

Near-Linear

Speedup

Till 1000

Cores



Upfront Aerodynamics Example

(SAE Paper 2011-01-0170)

Study effect of various vehicle shapeparameters on drag force

Shape parameters are defined using

mesh morphing technology in ANSYS

Fluent

ANSYS WB & DX are used to drive the

shape parameters, create DOE &

perform goal driven optimization

ANSYS WB makes the process

automatic



Define shape parameters UsingMesh Morpher in FLUENT Solver

Setup Baseline CFD model inFLUENT solver

Access Shape Parameters in WB

Generate & Solve DOE

Generate Response Surface &Perform Goal Driven Optimization

2

3

4

5

6

1

ANSYS Work Bench Automated

Work Flow Management Framework

ANSYS D i X l



ANSYS Design Xplorer :Generate DOE, Study Design Space &

Perform Optimization



Design Space Point:-- Baseline Design

(Velocity Contours on x=0)



Design Space Point:-- Worst Design




Design Space Point:-- Optimized Design




Rain Water Management, Soiling & Water

Wading

Contours of volume fraction of liquid forBMW air-scoop

Rainwater management

Driving through water puddle

Water ingestion

Water films on body

Soil Deposition

Water wading


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Fast & Reliable Structural

Preprocessing

Efficient Mid surfacing, Automatic Contact Detection



Automated Spot Welds & Contact

Modeling

Nonlinear Analysis of Door Frame

using Spot Welds

Mesh Independent Spot Welds


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Hood Model

Node Number : 16048

Element Number : 16611

Door Model

Node Number : 11419


Component Mode Synthesis

Efficient Simulation of Substructures

Car Body ModelNode Number : 87680



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Component Mode Synthesis

Efficient Simulation of Substructures

0 500 1000 1500 2000 2500 3000

CMS- FULL

FEM- FULL

FEM- FULL

CMS- FULL

(S)

1. Huge Speed up using

CMS for BIW withoutloss of accuracy

2. Full FEM & CMS Results

match within 1 %


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Design Life & Fatigue Analysis of

Body In White


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Case Study #3 Reducing Vehicle

Noise

[2]

[2] J. Plunt , Finding and fixing NVH problems with transfer path analysis, Sound and Vibrations, 2005

Vehicle NVH Sound Sources Vehicle NVH : Sound Transfer Paths

Frequency

RangeDominant Sound Source

Low Frequency

(0- 100 Hz)

Mostly structure-borne noise

(Exception Buffeting)

Mid Frequency

(100 250 Hz)

Structure and Air borne noise

High Frequency

(> 250 Hz)

Airborne

Key Requirements for Vehicle Noise Modeling

Accurate modeling of air borne noise source

Accurate modeling of propagation of noise source from source location to receiver

Propagation of noise within fluid or solid medium

Structural and Acoustics Coupling (FSI)


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Side View Mirror

Door Gaps

Rain Gutter

Wipers

Sunroof

Courtesy: Opel

Accurate Modeling of Air borne

Noise Sources


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Accurate Noise Propagation

Modeling

Far Field Noise Propagation Ffowcs Williams Hawkings (FWH)

Model

Validated & First in Commercial

CFD Solver

ANSYS CFD & FFT Actran coupling

AIAA 2008-2906


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ANSYS Acoustics Structures

From Harmonic Vibrations to Noise Estimates


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Summary

Industry leading solutions from ANSYS

Automated Work-Flow Management

Advanced & Easy to Use Modeling Techniques

Fast Solver Algorithms (CFD & Mechanical Solvers)

Efficient High Performance Computing

Simulation Best Practices for Automotive Industry

ANSYS Provides Comprehensive Solutions forVehicle Body Simulation


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Thank You !

CAE in Automotive Body Final

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