The topic of rolling friction is addressed in most mechanical engineering texts and handbooks; however, much of the data provided therein is dated and not relevant to tires. In general, friction in bearings and wheels refers to the energy loss retarding the rolling motion of cylindrical objects traveling over a flat or curved surface. For the specific case of tires, we often refer to such energy dissipation using various units of measurement—viz., power loss, energy consumption, or more commonly, rolling resistance. The investigation of tire rolling resistance, and its impact on vehicle fuel consumption, came to the fore during the

Abstract

This research deals with finite element analysis (FEA) predictions of coastdown rolling resistance as outlined by the SAE J2452 test procedure. The proposed method employs a phenomenological formulation of hysteresis which considers the effects of strain, strain rate, and temperature. Through specifically designed test conditions, material parameters are established for typical tire rubber components. The strain and strain rate histories at the cross section integration points are obtained from a static FEA of a loaded tire for one tire revolution and the desired speed. In subsequent postprocessing, the locations of the octahedral shear strain reversal in tire volume are found, and then rolling resistance is calculated by assuming an isothermal analysis. The simulation sensitivity to modeling considerations, including geometry accuracy and FE mesh resolution, on predicted rolling losses is pointed out. The applicability of the present approach to daily product engineering is discussed through benchmark studies of a variety of tires of different sizes, constructions, tread materials, and test conditions. Correlation studies demonstrate that this is a robust and easily implemented technique for rolling resistance analysis. A steady-state temperature solution, obtained from the hysteretic loss results, is used to predict the temperature field in the tire and to investigate its influence on the rolling resistance calculation.

Abstract

Vehicle dynamics packages can be used to simulate handling or braking maneuvers that would otherwise need to be performed outdoors. Many of the parameters for these types of vehicle models are determined through kinematics and compliance (K&C) measurements. Machines that perform these measurements apply various forces or moments and measure the response of the vehicle. The rate that these forces or moments are applied can be quasistatic or dynamic. Machines that are capable of performing dynamic tests are more expensive due to the need for inertia compensation, sensors that can acquire data at higher rates, and larger actuators or hydraulic power supplies. However, it is possible that measurements of dynamic vehicle response may increase the fidelity of parameter identification, compared to the sole use of quasistatic tests. One reason that parameter identification may be more accurate is the rate of force and moment application in dynamic tests is more like those in the actual maneuvers that are desirable to simulate.

A study was performed to determine where the advantages of performing dynamic K&C testing lie. Quasistatic K&C tests, along with dynamic tests performed at several frequencies up to 3.0 Hz, were performed on the front axle of a front-wheel drive compact sedan, using an MTS Systems High-Rate K&C Machine. Assessment of any advantages of dynamic K&C testing has been made through correlations of the vehicle response between dynamic and quasistatic tests.

Abstract

Finite element methods are well established for the mechanical analysis of tires in industry. For stationary rolling contact analysis a relative kinematics description based on a mixed spatial–material description provides a suitable framework for efficient computations of quite detailed tire models. Despite these advantages, special effort is necessary for the reliable treatment of tractive rolling with friction, or even when inelastic material properties have to be considered. An additional challenge is the simulation of high-frequency response for comfort analysis, for example.

This paper focuses mainly on the latter aspect, namely, the transient dynamics response with respect to rolling noise prediction. The theoretical basics have been outlined in prior publications; this presentation concentrates on a systematic analysis of the transient dynamic behavior of rolling tires based on a modal analysis first. Based on computed eigenvectors, a partial modal energy criterion is introduced to judge the influence of different assembly parts on the dynamics of rolling tires. The capability of the suggested approach will be outlined in a second part, where the transient dynamic response due to the excitation from different road surface textures and bridge connection constructions are discussed. The sensitivity of these computations with regard to the excitation mechanism will be shown, from which a much higher potential in road construction regarding traffic noise reduction is concluded.

The presented results are the partial outcome of research project “Leiser Straßenverkehr 2,” funded by the Federal Ministry of Economics and Technology (BMWi) and organized by the Federal Highway Research Institute (BAST). This research was performed in close cooperation between tire manufacturers, road construction companies, and universities.

Comparison Between Tire Rolling Resistance Measurements on a Flat Track and a Test Drum Under Non-Steady-State Conditions

Lisa Ydrefors,

Mattias Hjort,

Sogol Kharrazi,

Jenny Jerrelind, and

Annika Stensson Trigell

IN MEMORIAM: DIETERICH J. SCHURING (1922–2006)

Accuracy, Sensitivity, and Correlation of FEA-Computed Coastdown Rolling Resistance ³

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Vehicle Suspension Measurements: Evaluation of the Benefits of Dynamic over Quasistatic Kinematics and Compliance Testing ³

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Computational Investigations on the Dynamics of Tires Rolling on Rough Roads ³

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Comparison Between Tire Rolling Resistance Measurements on a Flat Track and a Test Drum Under Non-Steady-State Conditions

Critical Plane Analysis of Surface-Proximal Fields for the Simulation of Thermo-Mechanical Wear

Enhancing Tire Model Parameterization for Rollover Simulation: A Validated Approach

Research on Fast and Efficient Virtual Sample Delivery Method of Tire Mechanical Characteristics

Prediction of the Frictional Power Distribution in the Tire Contact Patch Based on an Empirical Tire Model and an Artificial Neural Network