Tire modeling for an outstanding grip on vehicle dynamics · • Tire behavior dominates vehicle performance aspects • Essential to use fit-for-purpose tire modelling methodologies

Unrestricted © Siemens AG 2019

siemens.comUnrestricted © Siemens AG 2019

Tire modeling for an outstanding grip on vehicle dynamics


The influence of tires on vehicle performance properties

* Vieweg Handbuch Kraftfahrzeugtechnik, 8. Auflage, S. Pischinger, U. Seiffert, ISBN 978-3-658-09527-7

*Comfort

Mechanical Acoustic Steering precision

Driving stability

Aquaplaning

Road Tires Vehicle

+Water

+Snow

&Ice

Driving behavior Driving safety

Influence of Road, Tires and Vehicle on functional properties

FrictionWet Winter

Fuel consumption

Pass-by noise

Wear(tires)

EfficiencyEnvironment

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Automotive industry trends and engineering challenges

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Diversification

Autonomous driving

Gra

ms

CO2

per k

m

Eco driving

Digitalization throughout the

vehicle design processPage 3 Siemens PLM Software

Source: ICCT

Passenger car CO2 emissions historical trend and future targets

Renault-Nissan Common Module Family

Addressing these challenges requires an integral tire modelling approach

Page 4

Digitally representing tire behavior throughout the complete development process with integrated fit-for-purpose modelling methodologies

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Unrestricted © Siemens AG 2019Siemens PLM Software


Tire modelling applications

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Aerodynamics NVHVehicle

dynamics & durability

Page 5 Siemens PLM Software


Vehicle dynamics & durability

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Tire modeling for vehicle dynamics Customer challenge

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Tire testing SimulationParameter identification



Tire modeling for vehicle dynamics Customer challenge

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Tire testing Parameter identification Simulation

Cost Virtual prototyping

‘Savings’

Quality of individual steps determines final accuracy,efficiency reduces costs



Tire modeling for vehicle dynamics Solution

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Rigid ring (6 DOF)

Enveloping model with elliptical cams

Effective road plane

Sidewall stiffness& dampingRim

Residualstiffness &damping

Slip model

Cleat

Effective road surface

Contact patch dimens oi ns

throughout all steps of the V-CycleModel applicability from handling to durability…


Provide in- and intercompany standardization


Tire modeling for vehicle dynamics Integral modelling approach

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SimulationIdentificationMeasurement

Def

ine

proc

ess

Vehicle ranges Tire sizes + LI

Manoeuvre types + evaluation criteria

Model parts (theory) parameters to

identify

Measurement protocol

estimations

Measurement execution Fitting procedure End users

start

end

Integral modelling approach to optimize accuracy and efficiency


Def

ine

requ

irem

ents


• A simplified ABS control loop

Tire modeling for vehicle dynamics Example: ABS braking

06/04/2019

• Control loop of a single wheel • Linearized around an operating point • Useful to study parameter sensitivity

𝑊 =1

𝑠 𝐼𝑦 + −𝐾𝑠𝑡 𝐻(𝑠)

Tire steady-state gain

Tire transientresponse

C 𝜅𝑟 𝑒𝜅 𝑀𝑐

Ω

𝜅𝑒

-+

Wheel inertiamoment

Ω

𝑀𝑡

𝑀𝑦

+

+ 𝑀𝑐

Wheel



Proven that accurate ABS braking simulations can be accomplished, making use of:• Steady state slip characteristics based on Tire Test Trailer tests:

• The non-linear transient modelling method:


Dependency of the dynamic response on local slip stiffness

Difference in local gradient

06/04/2019Page 12 Siemens PLM SoftwareReference: ATZ worldwide, June 2017, Volume 119, Issue 6, pp 16–21

Unrestricted © Siemens AG 201906/04/2019Page 13

11 different ABS settings tested with:• Full measurements (closed proving ground)• Full vehicle simulation

Observations:• Influence of ABS settions on braking distance are

predicted well in simulation

• Difference between simulations and measurements fall within test repeatability

• Effect of ABS settings on braking distance (e.g. ABS appl. 2 and 9) are predicted by the simulation model

ABS appl. 11 Measurement

Simulation

ABS appl. 9

ABS appl. 8

ABS appl. 7

ABS appl. 6

ABS appl. 5

ABS appl. 4

ABS appl. 3

ABS appl. 2

ABS appl. 1

ABS appl. 10

0mBraking Distance

Wh

eel

Sp

eed

Time To Standstill

FL

FR

RL

RR

0 % 100 %

100 %

20 %

40 %

60 %

80 %

0%

Measurement

Time To Standstill

FL

FR

RL

RR

0 % 100 %

Simulation


Siemens PLM SoftwareReference: ATZ worldwide, June 2017, Volume 119, Issue 6, pp 16–21


Tire modeling for vehicle dynamics Example: Road load prediction for durability

• Magic Formula extended with:• Enveloping model for more detailed tire road contact modelling• Rigid Ring for representing primary tire eigenmodes

• Matching application domain and tire testing effort

• Tire model parameter estimation functionality:

Rigid ring (6 DOF)

Enveloping model with elliptical cams

Effective road plane

Sidewall stiffness& dampingRim

Residualstiffness &damping

Slip model

Cleat

Effective road surface

Contact patch dimens oi ns

Siemens PLM Software

Unrestricted © Siemens AG 2019Siemens PLM Software06/04/2019Page 15

Tire modeling for vehicle dynamics Example: Road load prediction for durability

• Validation: front left shock absorber force

• Methodology also successfully tested for impact of:• Different tire sizes• Different damper settings

SAE paper 2011-01-0190


Aerodynamics

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NVHVehicle


Aerodynamics



AerodynamicsCustomer challenge

• Worldwide Harmonized Light Vehicle Test Procedure:• increased importance of aerodynamics• reporting of every individual vehicle configuration

• Up to hundreds of aerodynamic vehicle configurations

• Digitalization required for:• Product development • Virtual certification

• Tires & wheels determine up to 25% of vehicle drag

Simulation effort to grow exponentially


Hucho, Aerodynamik des Automobils, Springer, 2013


AerodynamicsSolution

• Numerical method combines:• Fully automated volume meshing• Steady and transient solvers and related turbulence

modelling (RANS and DES / LES) • Different motion modelling approaches

• Steady state simulations proven to predict deltas between vehicle configurations

• Combined modelling methods to find optimal balance between fidelity and overall ‘costs’



Wheel AerodynamicsValidation Case

• Measuring tire wakes in wind tunnel facility• Fully treaded, deformed, rotating tire in ground contact• Measuring wheel drag• Capturing the wheel wake with a traverse-mounted twelve-hole

pressure probe in different test sections

Schnepf et al., 2013



Wheel AerodynamicsValidation Case


Simulation setup• Fully transient simulation (DES) with

real mesh motion• Tire rotation rate 119 rad/s

Averaged CFDExperiment


NVH

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Tire modelling in full-vehicle NVHCustomer Challenges

Electrification: increasing importance of road noise

CAE-driven design for early stage assessment

Market trends – challenges

Improving the full-vehicle NVH performance in an

early stage of the design

Accurate representation of a tire for road noise

Customer need



Tire modelling in full-vehicle NVHSolution

Tire ModelTest or CAE based

dynamic representation

Vehicle ModelTest or CAE based

body and suspension

NVH PerformanceRoad synthesis,

Transfer Path Analysis, …

Design improvementComponent and full-vehicle

level NVH design

+ =



Tire modelling in full-vehicle NVHIndustry hot-topics

Component based approachTargets at component level

in early stages of the design process

System operational phenomenaRelevance of operating

vs typical laboratory conditions

Mode- tracking

Static condition Operating condition

Body

Peak Shifting

Shifts in structural dynamics

Tire modal behavior



Tire modelling in full-vehicle NVHApplication case

How to optimize body

and chassis for NVH

performance?

SuspensionFEM assembly FRFs

Trimmed bodyMeasured or CAE FRFs

Tire/wheelMeasured FRFs

ParametersBushing stiffness

FBS

Optimization

Road displacementLoad Identification

Full Vehicle

Forcedresponse

Target evaluation

Customer requirementRoad noise reduction

Technical approachBushing design optimization

Project outcome• Process workflow• Optimized bushing set• 3 dB noise reduction

Road Noise Evaluation

3rd octave levels

FRRI microphone

25 31.5 40 50 63 80 100

125

160

200

250

315

3rd octave band

SPL [

Pa (d

B-A)

] Base

Modified



Tire modelling applications

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Non-Integrated development approaches


• Heterogeneous tools

• Inefficient workflow

• Limited data management

Lack of integration limits program performance


Aerodynamics

Noise Vibration & Harshness

Tire to full vehicleengineering solution

Optimal balance costs vs. fidelity

Integral tiremodelling method


Integrated development approach



Aerodynamics

Noise Vibration & Harshness

Integrated

Development

Solution

Tire to full vehicleengineering solution

Optimal balance costs vs. fidelity

Integral tiremodelling method

• Integral tooling

• Scalability of simulation

• Exchange of results

Integration boosts individual and overall performance


• Tire behavior dominates vehicle performance aspects

• Essential to use fit-for-purpose tire modelling methodologies

• Siemens provides industry validated tire modelling solutions:• Integral tire modelling methodology for vehicle dynamics & durability• Powerful and versatile CFD solutions for aerodynamics• Complete tire to full vehicle NVH methodologies from tire to full vehicle

• Supported by Siemens to supply integrated development approach

• Webinar “Tire testing and model parameterization for Vehicle Dynamics” in October 2019

Summarizing


Documents

Tire modeling for an outstanding grip on vehicle dynamics · • Tire behavior dominates vehicle performance aspects • Essential to use fit-for-purpose tire modelling methodologies