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Training / Education

The Tire as a Vehicle Component

The principal functions of the pneumatic tire are to generate driving, braking, and cornering forces while safely carrying the vehicle load and providing adequate levels of ride comfort. This seminar explains how tire forces and moments are generated under different operating and service conditions and, in turn, demonstrates how these forces and moments influence various vehicle responses such as braking, handling, ride, and high-speed performance. The content focuses on the fundamentals of tire behavior in automobiles, trucks, and farm tractors, but also includes experimental and empirical results, when necessary.
Training / Education

Tire and Wheel Safety Issues

One of the most important safety critical components on cars, trucks, and aircraft is the pneumatic tire. Vehicle tires primarily control stopping distances on wet and dry roads or runways and strongly influence over-steer/under-steer behavior in handling maneuvers of cars and trucks. The inflated tire-wheel assembly also acts as a pressure vessel that releases a large amount of energy when catastrophically deflated. The tire can also serve as a fulcrum, both directly and indirectly, in contributing to vehicle rollover. This seminar covers these facets of tire safety phenomena.
Training / Education

Basic Tire Mechanics and Applications

This course introduces basic tire mechanics, including tire construction components based on application type, required sidewall stamping in accordance with DoT/ECE regulations, tread patterns, regulatory and research testing on quality, tire inspections and basic tire failure identification. The course will provide you with information that you can use immediately on-the-job and apply to your own vehicle. This course is practical in nature and supplemented with samples and hands-on activities. It serves as a good primer for the in-depth SAE Tire Forensic Analysis course.
Training / Education

Tire Forensic Analysis

This course provides a detailed description of tire failure modes, their potential causes, identification, and the sometimes-subtle nuances that go along with determination of tire failure. In addition, proper inspection techniques of tires will be discussed and samples will be available to reinforce the concepts learned. The course is helpful for investigators and individuals who need to  explore and explain tire failures and point out the failure contributing factors. The course will help to clarify failure root cause between tire production process deviation, tire design, and service application.
Standard

Test Method for Catalytic Carbon Brake Disk Oxidation

2013-12-04
WIP
AS6289
The scope of the test method is to provide stakeholders including fluid manufacturers, brake manufacturers, aircraft constructors, aircraft operators and airworthiness authorities with a relative assessment of the effect of deicing chemicals on carbon oxidation. This test is designed to assess the relative effects of runway deicing chemicals by measuring mass change of contaminated and bare carbon samples tested under the same conditions.
Standard

Missionized Wear Testing

2019-01-02
WIP
ARP6979
Publicize Aircraft Recommended Practice for Missionized Wear Testing on Wright Patterson’s Landing Gear Test Facility’s 168i dynamometer.
Standard

Landing Gear Based Weight and Balance Systems

2019-04-18
WIP
AIR6941
This document outlines historical systems which have used the landing gear as a sensor or installation point for full aircraft weight and balance systems. A number of systems have been developed, installed, certified, and placed in service but few systems remain in regular use. The document will capture the history of these systems, reasons (where known) for their withdrawal from service, and lessons learned.
Standard

Nitrogen Absorption/Desorption (Gas Dissolution) in Aircraft Shock Absorbers

2019-04-18
WIP
AIR6942
This document outlines the current state of the art in the understanding of gas in solution in shock absorber oils in unseperated shock absorbers. A literature review, overview of Henry's law, Henry's law coefficients for known gas and oil couples, in-service operational problems, lessons learned, and potential future work will be discussed in the document.
Standard

Composite Secondary and Tertiary Structure for Landing Gear

2019-04-29
WIP
AIR6827
This document will contain guidance and considerations for the use of composite materials on non-primary structure for landing gear systems. Content to include design considerations, conditions and applications where composites are feasible/beneficial, high-level descriptions of various manufacturing processes, and certification/validation considerations.
Technical Paper

Integration of SEA Tire Model with Vehicle Model

1999-05-17
1999-01-1700
Statistical energy analysis (SEA) has recently emerged as an effective tool for design assessment in the automotive industry. Automotive OEM companies develop vehicle models to aid design of body and chassis systems. The tire and wheel suppliers develop and supply component models to OEM companies in the engineering stage. In the model development process, some information on the vehicle side or component side is necessary for model development and correlation. A suitable termination representation of the vehicle characteristics on the tire/wheel model is required. This termination should account for the dissipation of energy on vehicle body and chassis side, otherwise the component model will overestimate the vibration responses and energy levels. On the vehicle model side, a representative simplified tire/wheel model may be sufficient for full vehicle road noise simulation.
Technical Paper

Experimental Determination of the Noise Emitting Parts of a Rotating Tire in the European Research Project TINO

1999-05-17
1999-01-1732
One of the objectives in the European Research project TINO is to identify, in detail, the surfaces of a rotating tire which actually generate the radiated noise. The approach is completely experimental and is based upon the ASQ (Airborne Sound Quantification) technique. The quantification of the contribution of the different tire surfaces to the sound pressure measured under defined conditions is carried out through a process of near-field measurements during rotation of the tire and static acoustic transfer function measurements. The ASQ method is further developed and tested when focussing at the applications. In first instance, the procedure has been validated and fine-tuned under well-controlled boundary conditions at a tire chassis dynamometer. The results of this first investigation served also as a “reference” set of data which has been used for verification and validation of numerical tire models.
Technical Paper

Tire/Road Interface Airborne Noise Characteristics Generation

1999-05-17
1999-01-1731
In recent years there has been much interest in problems involving the noise prediction and reduction inside and outside the vehicle. Tire/road exterior noise has been considered to be the major vehicle exterior noise source. However, this paper describes an investigation into the characteristics of the air pumping noise mechanism in terms of source locations and directionality. Some rubber tire/road air pumping noise measurements are presented, whereas some predicted results are computed based on the boundary element method (BEM) to display some parameters which are found to be difficult to be obtained experimentally.
Technical Paper

Tire/Pavement Interaction Noise Source Identification Using Multi-Planar Nearfield Acoustical Holography

1999-05-17
1999-01-1733
In this study, multi-planar Nearfield Acoustical Holography (NAH) is used to investigate noise radiated from the front, side and rear areas of single tires on a two-wheel trailer. Contributions to the radiated noise from the leading edge, trailing edge, and sidewall of the tire are identified. Two tires - an experimental monopitch tire and a production passenger car tire - are evaluated on a smooth asphalt pavement at 58 km/hr. From the measured complex pressure, acoustic intensity is reconstructed on three planes surrounding the tire using modified NAH procedures. Additionally, sound power levels are presented in tabulated and spectra forms. Tire noise generating mechanisms are inferred based on the results.
Technical Paper

A Non-Averaging Method of Determining the Rheological Properties of Traction Fluids

1999-05-03
1999-01-1518
Traction machines have been frequently used to study the rheological properties of lubricants in elasto-hydrodynamic lubrication (EHL) contacts. Fundamental properties are inferred from EHL traction measurements based on the average pressures and temperatures in the contact. This average approach leads to uncertainty in the accuracy of the results due to the highly nonlinear response of fluid rheological behavior to both pressure and temperature. A non-averaging method is developed in this paper to determine the elastic and plastic properties of traction fluids operating in EHL contacts at small slide-to-roll ratios. A precision line-contact traction rig is used to measure the EHL traction at a given oil temperature and Hertz pressure. By choosing a sensible pressure-property expression, the parameters of the expression can be determined through the initial slope and peak traction coefficient of the traction measurements.
Technical Paper

The Effect of Tire Stiffness Parameters on Medium-Duty Truck Handling

2000-05-01
2000-01-1645
This paper presents the results of a sensitivity study on the effect of tire stiffness parameters on selected handling performance metrics of a medium-duty truck. The tire stiffness parameters considered in the study are radial stiffness, longitudinal or braking stiffness, and cornering stiffness. An ADAMS model of a medium-duty truck was developed to simulate vehicle handling maneuvers. Two handling scenarios were considered: a combined braking and cornering scenario and a split-μ, straight-line braking scenario. The results of the study indicate that all three tire stiffness parameters are important in accurately predicting vehicle handling performance. Furthermore, when conducting design studies on suspension and steering system design variables other than tire stiffness parameters, the choice of specific values used for the tire stiffness parameters can significantly influence the results of the design studies.
Technical Paper

Fundamental Physics Behind New Suspension Concept for Automobiles

2000-05-01
2000-01-1647
The Transverse Leaf suspension with Superior Roll Axis is a new suspension concept for automobiles. It enables the load transfer during a turn to be more evenly redistributed between the two wheels on the same axle thus optimizing its tires lateral force capabilities. The TLSRA concept is made up of a single transverse leaf spring linking the middle of the sprung mass to the outer end of 2 transverse suspension arms per axle. Those transverse arms are mounted close to the middle of the sprung mass with their attachment points located above the mass centroïd. Each wheel assembly is mounted directly onto the free end of its respective suspension arm. Because body roll is now counteracting vertical load transfer during transient and permanent operating conditions, this suspension enables designers to keep spring stiffness low without compromising road handling.
Technical Paper

Using μ Feedforward for Vehicle Stability Enhancement

2000-05-01
2000-01-1634
Vehicle stability augmentation has been refined over many years, and currently there are commercial systems that control right/left braking and throttle to create vehicles that remain controlled when road conditions are very poor. These systems typically use yaw rate and lateral acceleration in their control philosophy. The tire/road friction coefficient, μ, has a significant role in vehicle longitudinal and lateral control, and there has been associated efforts to measure or estimate the road surface condition to provide additional information for the stability augmentation system. In this paper, a differential braking control strategy using yaw rate feedback, coupled with μ feedforward is introduced for a vehicle cornering on different μ roads. A nonlinear 4-wheel car model is developed. A desired yaw rate is calculated from the reference model based on the driver steering input.
Technical Paper

A New Method for Determining Tire Traction on Ice

2000-05-01
2000-01-1640
The development of tires traction models is very important for tire mechanics and automobile dynamics. Based on principle of thermal balance and theory of frictional melting, a new method for determining tire traction on an iced highway was presented. It was shown that the computed results could compare with the available test results. The advantages of a car with CTI-DS travelling on ice or compact snow were demonstrated in theory and in experiment. It was recommended that an automobile be operating at lower inflation pressures to increase tire traction force on the above highways.
Technical Paper

MRA Vehicle Dynamics Simulation-Matlab®/Simulink®

2000-05-01
2000-01-1624
Milliken Research Associates has developed a new simulation tool, named Vehicle Dynamics Simulation-Matlab/Simulink (VD-M/S). Produced for the government's Variable Dynamic Testbed Vehicle (VDTV), VD-M/S is an 18 degree-of-freedom simulation programmed in the Matlab/Simulink environment. It contains a detailed non-linear tire model, kinematic and compliance effects, aerodynamic loadings, etc. as do MRA's other simulation programs. Unique to VD-M/S is its development from Day One as a simulation catered to the inclusion and exploration of active systems within the vehicle.
Technical Paper

Vehicle and Tire Modeling for DynamicAnalysis and Real-Time Simulation

2000-05-01
2000-01-1620
This paper reviews the development and application of a computer simulation for simulating ground vehicle dynamics including steady state tire behavior. The models have been developed over the last decade, and include treatment of sprung and unsprung masses, suspension characteristics and composite road plane tire forces. The models have been applied to single unit passenger cars, trucks and buses, and articulated tractor/trailer vehicles. The vehicle model uses composite parameters that are relatively easy to measure. The tire model responds to normal load, camber angle and composite tire patch slip, and its longitudinal and lateral forces interact with an equivalent friction ellipse formulation. The tire model can represent behavior on both paved and off-road surfaces. Tire model parameters can be automatically identified given tire force and moment test data.
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