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PRESENTED BY Dean Tener, Technical Manager | Smithers Rapra Michael Stackpole, President | Stackpole Engineering

INSIGHTS ON PRODUCING A HIGH FIDELITY TIRE MODEL

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www.smithersrapra.com 2 www.stackpoleengineering.com

TODAY’S PRESENTERS

Dean Tener, Technical Manager, Smithers Rapra • 30+ years experience in tire research, design and testing • Previous positions at Honda, GM & Bridgestone/Firestone • Technical manager of Smithers Ravenna Laboratory which

specializes in whole tire testing /performance evaluations

Michael Stackpole, President, Stackpole Engineering • 30+ years experience in tire/vehicle simulation, testing and modeling • Previous positions at Goodyear and Firestone • Founder and president of Stackpole Engineering


TODAY’S AGENDA

1. Who Are We and What Do We Do?

2. Development of Purpose-Driven Tire Models.

3. Review of Typical Tire Models and Their Applications.

4. Overview of the SES/Smithers Integrated Approach to Tire Modeling.


Break Products o Endurance / Durability Testing

Dissect P roducts o C hemical and Physical Analysis o Forensic Analysis

Measure P erformance o S pring and Damping R ate o R olling R esistance o C ornering and Traction Forces o Treadwear

C haracterize P erformance o Tire Models

P UTTING YOUR P R ODUC TS TO THE TE S T WHAT DOES SMITHERS DO?


WHAT DOES STACKPOLE ENGINEERING DO?

o Vehicle Dynamics S ervices for both S ystem Design and Analys is

o Vehicle S imulation Analys is Utilizing C ommercial and C ustom Developed S olutions

o Vehicle Test Design, Data Acquis ition and R esult Analys is

o Mechanical Design and C AD S ervices

o E ngineering S oftware Development for both Data Management and Analys is

o Tire Testing, Tire Data Fitting and Advanced Tire Model Development

Our expert staff of vehicle dynamics and computer engineers provide technical services and products to the transportation and racing communities.

TIRE/VEHICLE SYSTEM ANALYSIS AND UNDERSTANDING


o An interface for computer s imulation

o Assis t / guide design process

o E liminate the need for high cost, long lead, trial-and-error methods

o E xtrapolate to s imulation conditions outs ide of costly physical testing

o Allows investigation on how tire choices influence your vehicle’s performance

o E valuate options which would be impractical to test

o S afe way of investigating design alternatives

REASONS FOR A TIRE MODEL


o S pecify an inventory of candidate tireso R equest Test according to generic procedureso R eceive a collection of raw data files with no actual tire “model” yet implementedo C ustomer must develop required tire model files or select third party fitter

THE CLASSIC PROCESS FOR GENERATING A TIRE MODEL

Classic Tire Modeling Process

•ExecuteTesting•GenerateRaw DataFiles

Test Facility

•ProcessInput Files•GenerateTire Model

Modeling Service

•ImplementModel•AnalyzeSimulations

End User


Characterization of Tire Performance from

Customized Testing

Data Fitting and Certification

Tire Model Generation

Customer Implementation and

Evaluation

Model Performance Evaluation

o Traditionally, tire models have been delivered as a singular product – delivered and done. We strive to implement a circular process.

o Utilizing the expertise of the simulation

and testing resources available within the S ES /S mithers teams, data collection is customized to each customer’s needs and end use.

o Tire models are developed and certified for goodness of fit within the design parameters of customer requested tire model.

o Direct feedback from customer on performance of models is utilized to tune test procedures to ensure progression in future testing.

THE SES/SMITHERS PROCESS FOR GENERATING A TIRE MODEL

A NEW APPROACH


Essentially the world of tire modeling can be broken into three classes: 1. Performance Based Models

o R ely on F&M testing w/o physical construction being characterized

o G enerally utilized for evaluation of vehicle handling characteris tics

2. C omponent Level Modelso Testing performed to quantify S tructure/P hys ical properties of tire

o Most commonly used for vehicle ride and durability analys is

3. F inite E lement Modelso R equires detailed knowledge of the tire’s component materials and internal

structure

o Most useful for tire manufacturers

o (outs ide of the scope of this discus s ion – will not be covered here)

TIRE MODEL OVERVIEW

Performance Based Models

CLASS 1 MODELS


A. Tables and Splines o Data is interpolated between measured points of F&M test

o S imulation program often dictates the methodology

o C an be the most accurate method

o C an not extrapolate outside bounds of tested data

o Fast

o Good for general handling simulations

o No applicability for ride simulations

B . P acejka® or MF ® Models o Equation fitted to F&M data

o Fast solution time with ability to extrapolate outside bounds of test data

o Ex: Pac 89, 94, 2002, MF-Tyre 5.1… 6.2

o Good for handling simulations

o Limited applicability for ride simulations

PERFORMANCE BASED MODELS


EXAMPLE: PACEJKA® OR MF ® HANDLING TIRE MODEL PROGRAM Smithers and SES work with you to set expectations for simulation and select the proper tire testing inventory. Handling models allow for scalability in testing based on simulation needs.

TIP: Most customers planning to utilize their tire model in a full vehicle simulation or simulator will require a model built utilizing the “Intermediate” specification. (Sometimes referred to as “Use Mode 14” in simulation jargon.)

BAS

IC

Free Rolling Cornering Zero Slip Drive/Brake Linear Spring Rates

INTE

RM

EDIA

TE

Contains All Data from Basic Spin Up Characterization Combined Loading Drive/Brake Linear Relaxation Behavior

ADVA

NC

ED

Contains All Data from Intermediate Pressure Dependency Advanced Transient Characteristics


WHAT IS REQUIRED TO PRODUCE A PACEJKA® OR MF® HANDLING TIRE MODEL

Proper parameterization of a USE MODE 14 model will require collection of the following: o G eneral P hysical C haracteristics

o Nominal S ize/Geometry S pecification o Measured Dimensions/Variations for S ample Tire Inventory R elative to Nominal S pecifications

o Force and Moment Testing

o Vertical S tiffness Testing o Evaluation of the vertical spring rate characteristics tires at test speed to be collected both

pre and post test. Provides insight into changes in tire stiffness with use. o Dynamic Loaded R adius

o Velocity R amp data is collected at several camber settings over a range of speeds. o C ornering

o Pure Lateral testing to be conducted at several camber settings at a range of vertical load settings o R elaxation Length Tests

o Lateral R elaxation Length Testing – zero (very slow) rolling speed at multiple vertical loads. o Drive/B rake

o Pure Traction testing to be conducted at 0° camber and 0° s lip for a range of vertical load settings o C ombined Traction testing to be conducted at several camber settings and a range of vertical loads.


HOW DO WE GENERATE THE DATA FOR YOUR PERFORMANCE TIRE MODEL? Flat Trac 3 F&M testing to Characterize: o C ornering Forceo Drive / B rake Forceo R olling R adiuso Thermal or Wear Effectso Lateral R elaxation Lengtho Inclination S tiffnesso Nordeen Functions, etc.

Flat S urface Tire Dynamics Machine to Identify: o S tatic S tiffness

o Lateral, Longitudinal and Vertical

o Performance on Flat S urfaces or Obstacles


SO I HAVE ALL THIS DATA … AND YOU GAVE ME ATIRE MODEL. DOES IT ACCURATELY REPRESENT MY TIRE?


WE PROVIDE YOU WITH ASSURANCE OF A “GOOD” MODEL SO YOU HAVE CONFIDENCE IN YOUR RESULTS:

The proprietary data analysis and fitting tools developed by SES require that all fit coefficients adhere to the model assumptions used to define the Pacejka/MF model.

o S tatistical analysis is performed to ensure goodness of fit between raw data and model coefficients. In addition, we adhere to all the functional constraints to ensure accurate model performance well outside bounds of the test data.

o Each model generated by S ES is delivered with a fit certification report illustrating the model’s performance relative to the defined model constraints.


HANDLING MODEL PROGRAM DELIVERABLES

o TYDEX formatted *.tir for use in Tire/Vehicle Handling simulations. File will be developed utilizing proprietary S ES data analysis and fitting tools

o Fit report describing correlation to measured data and all other valid model constraints

o TYDEX (IS O oriented) files containing test results

o All raw data collected for the generation of the tire model.

For Customers interested in visualizing their tire models outside of a simulation program, SES offers the “SES-TireAnalyzer” program. This proprietary tool allows users to investigate: o Inflation Pressure Trends

o Force/Moment C haracteristic P lotting

o Tire-to-tire C omparative Analysis

o Tire/Vehicle S ystem Level Analysis

Customers investing in a tire modeling program can expect the following:

Component Level Models

CLASS 2 MODELS


o Treats The Whole Tire As A S tructure With S pecified Properties

o R igid or flexible ring with stiffness damping

o Moderate C omplexity

o Appropriate For R ide And Durability

o S low, B ut R eal Time Versions Exist

o Examples:

o FTire

o MF-S wift 6.0, 6.1

o C D-Tire

COMPONENT LEVEL TIRE MODELS


TESTING TO PRODUCE A COMPONENT LEVEL MODEL SUCH AS FTIRE

The team at Smithers and SES have developed an efficient testing inventory for proper parameterization of a single pressure FTire model:

General Physical Characteristics o Mass: Total and Free

o Measured Inertial C haracteristics for Tire, Wheel and C omplete Test Assembly

o Dimensional analysis

o Tread Depth, Thickness and S hore A

o C ontact Patch Analysis

o Footprints at a multiple camber angles

S teady S tate Testing

o Lateral S tiffness at 0° camber

o Longitudinal S tiffness at 0° camber

o Vertical S tiffness on:

o Flat P late

o Longitudinal C leat

o Lateral C leat

o Oblique C leat

o Torsional S tiffness at 0° C amber


FTIRE TESTING (CONTINUED)

Dynamic Response

o Transverse cleat testing - determination of in-plane response. Testing conducted at a minimum of three speeds.

o Oblique cleat testing - characterization of out-of-plane response characteristics. Testing conducted at a minimum of three speeds.

Force And Moment C haracterization

o Dynamic Loaded R adius - Velocity ramps at multiple camber settings.

o C ornering - Pure lateral testing to be conducted at two camber angles, three loads minimum.

o Drive/B rake - Pure traction testing for a minimum of three load settings.


GENERATING AN FTIRE MODEL SES engineers have developed custom software for processing raw test data and generating the proper data to feed Cosin’s FTire/fit modeling program. The Ftire/fit parameterization tools enable SES engineers to tune and optimize the physical tire model for both static and dynamic performance. Because this is a physical model SES and Smithers have gone to great lengths to understand Smithers test equipment and to optimize test procedures to ensure accurate parameterization.


VALIDATING AN FTIRE MODEL SES engineers generate a fit report detailing not only the model itself, but also certification plots for the model’s performance:


DELIVERABLES FOR A FTIRE MODEL

Customers investing in a FTire modeling program can expect the following: o FTire formatted *.tir for use in Tire/Vehicle Handling simulations. File will be developed

utilizing a combination of C osin FTire/fit 2015-1 (or latest release), along proprietary S ES data analysis and fitting tools.

o FTire generated fit report describing correlation to measured data and all other model input settings and parameters.

o Inventory of TYDEX (IS O oriented) files summarizing processed test results

o All raw data collected for the generation of the tire model.


WHICH TIRE MODEL WILL BEST EQUIP YOUR TEAM TO GET THE ANSWERS YOU NEED?

Every tire modeling project with SES/Smithers begins with two questions: o With which tools you plan to use your model?

o What “answers” do you need from your model?

S E S specializes in delivering fully parameterized models for all commercially available s imulation software. S tandard formats available include: o Pacejka Tire model ('89, '94, '96, '02)

o MF-Tyre™ (all versions)

o FTire™

o If standard formats are insufficient solutions, SES has both the expertise and experience to modify most public domain models or we can create a custom model for your focused analysis.


WHY WOULD YOUR PROGRAM REQUIRE A CUSTOMIZED MODEL?

o C ommercially available tire models are created for generalized applications, and are typically adequate for most applications.

o S pecialized simulations or targeted analysis may require a custom tire model solution

o Off R oad, Military and Motorsports customers may need refined models for specialized tires.

o S ES can deliver completely customized models that integrate flawlessly with your commercial s imulations.

o Through the partnership between S mithers, S ES and the customer, all options can be discussed and the most appropriate tire model can be chosen for the application.

Optimized Tire Model Solution

SES Custom Model

Refinements

Program Requirements

Commercial Tire Model


Our respective teams are leaders in their fields. The first choice for many looking to explore new technologies, advanced modeling techniques and expanded accuracy in simulations.

Our combined experience and working relationship allows us to tailor both testing and modeling techniques to produce optimized solutions specific to your programs.

Working closely together and understanding our customer’s need, we regularly develop enhancements and implementations to expand your commercially available simulation tools.

PUT OUR EXPERTISE TO WORK FOR YOU!

QUESTIONS?

Michael Stackpole President, Stackpole Engineering 9149 Cleveland Ave North Canton, OH 44720 USA T 330.244.9110 E [email protected] www.stackpoleengineering.com

Dean Tener Technical Manager, Ravenna Laboratory 1150 N Freedom Street Ravenna, OH 44266 USA T 330.762.7441 E [email protected] www.smithersrapra.com

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