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Unrestricted © Siemens AG 2019
siemens.comUnrestricted © Siemens AG 2019
Tire modeling for an outstanding grip on vehicle dynamics
Unrestricted © Siemens AG 2019
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
06/04/2019Page 2 Siemens PLM Software
Unrestricted © Siemens AG 2019
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
06/04/2019
Unrestricted © Siemens AG 2019Siemens PLM Software
Unrestricted © Siemens AG 2019
Tire modelling applications
06/04/2019
Aerodynamics NVHVehicle
dynamics & durability
Page 5 Siemens PLM Software
Unrestricted © Siemens AG 2019
Vehicle dynamics & durability
06/04/2019
Aerodynamics NVHVehicle
dynamics & durability
Page 6 Siemens PLM Software
Unrestricted © Siemens AG 2019
Tire modeling for vehicle dynamics Customer challenge
06/04/2019
Tire testing SimulationParameter identification
Page 7 Siemens PLM Software
Unrestricted © Siemens AG 2019
Tire modeling for vehicle dynamics Customer challenge
06/04/2019
Tire testing Parameter identification Simulation
Cost Virtual prototyping
‘Savings’
Quality of individual steps determines final accuracy,efficiency reduces costs
Page 8 Siemens PLM Software
Unrestricted © Siemens AG 2019
Tire modeling for vehicle dynamics Solution
06/04/2019
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…
Page 9 Siemens PLM Software
Provide in- and intercompany standardization
Unrestricted © Siemens AG 2019
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
Page 10 Siemens PLM Software
Def
ine
requ
irem
ents
Unrestricted © Siemens AG 2019
• 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
Page 11 Siemens PLM Software
Unrestricted © Siemens AG 2019
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:
Tire modeling for vehicle dynamics Example: ABS braking
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
Tire modeling for vehicle dynamics Example: ABS braking
Siemens PLM SoftwareReference: ATZ worldwide, June 2017, Volume 119, Issue 6, pp 16–21
Unrestricted © Siemens AG 201906/04/2019Page 14
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
Unrestricted © Siemens AG 2019
Aerodynamics
06/04/2019
NVHVehicle
dynamics & durability
Aerodynamics
Page 16 Siemens PLM Software
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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
Siemens PLM Software
Hucho, Aerodynamik des Automobils, Springer, 2013
Unrestricted © Siemens AG 201906/04/2019Page 18
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’
Siemens PLM Software
Unrestricted © Siemens AG 201906/04/2019Page 19
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
Siemens PLM Software
Unrestricted © Siemens AG 201906/04/2019Page 20
Wheel AerodynamicsValidation Case
Siemens PLM Software
Simulation setup• Fully transient simulation (DES) with
real mesh motion• Tire rotation rate 119 rad/s
Averaged CFDExperiment
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NVH
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Aerodynamics NVHVehicle
dynamics & durability
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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
Siemens PLM Software
Unrestricted © Siemens AG 201906/04/2019Page 23
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
+ =
Siemens PLM Software
Unrestricted © Siemens AG 201906/04/2019Page 24
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
Siemens PLM Software
Unrestricted © Siemens AG 201906/04/2019Page 25
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
Siemens PLM Software
Unrestricted © Siemens AG 2019
Tire modelling applications
06/04/2019
Aerodynamics NVHVehicle
dynamics & durability
Page 26 Siemens PLM Software
Unrestricted © Siemens AG 2019
Non-Integrated development approaches
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• Heterogeneous tools
• Inefficient workflow
• Limited data management
Lack of integration limits program performance
Vehicle dynamics & durability
Aerodynamics
Noise Vibration & Harshness
Tire to full vehicleengineering solution
Optimal balance costs vs. fidelity
Integral tiremodelling method
Unrestricted © Siemens AG 2019
Integrated development approach
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Vehicle dynamics & durability
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
Unrestricted © Siemens AG 2019
• 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
06/04/2019Page 29 Siemens PLM Software