bluuebunny/crossref_metadata_2025 huggingface dataset:
Torsional Crack Growth Test to Simulate Belt Edge Deformation
Authors: Fleischman T. S. , Kerchman V. , Ebbott T. G.
Published: June 2006

The study of fatigue crack growth resistance for tire belt compounds is motivated by the high deformation cycles inherent in the belt edge region of radial tires. To improve the understanding of fatigue in this region, a test has been developed to simulate crack growth in shear (mode III). A rubber disk with a circumferential pre-crack is tested in cyclic torsion to simulate belt edge interlaminar shear cycles. Theoretical, numerical [finite element analysis (FEA)] and experimental methods have been employed to investigate and quantify the response. A recent improvement to the analysis considers nonlinear elastic material behavior which is characteristic of carbon black-filled tire compounds. The best agreement between torsional test results and results from typical thin sheet geometries was found for lightly reinforced compounds; crack branching often complicates results for more highly reinforced compounds. Fracture surfaces are examined for evidence of non-planar crack growth to help interpret the results.
Application of the Finite Element Method in Screening of Body Turn up Heights for Radial Truck Tires
Authors: Yan X.
Published: June 2006

A method is described to predict relative body turn up endurance of radial truck tires using the finite element method. The elastomers in the tire were simulated by incompressible elements for which the nonlinear mechanical properties were described by the Mooney-Rivlin model. The belt, carcass, and bead were modeled by an equivalent orthotropic material model. The contact constraint of a radial tire structure with a flat foundation and rigid rim was treated using the variable constraint method. Three groups of tires with different body turn up heights under inflation and static footprint loading were analyzed by using the finite element method. Based on the detail analysis for stress analysis parameters in the critical regions in the tires, the relative body turn up edge endurance was predicted.
Analysis of Contact Stresses on the Tread Rubber Blocks with Slip
Authors: Kim D-M. , Park I-J.
Published: June 2006

The tread rubber block of tire in contact with the roadway plays an important role of holding the frictional forces between the tire and the road in driving and braking. In this paper, a theoretical study based on the energy method is presented on the contact pressure of the tread block under the compressive forces with the slip between the tread block and the contact surfaces, by using a 2-D model of tread rubber block. Then, the slip-starting position is obtained by the theoretical analysis together with experimental results for the compressive force and deflection, which depends on the contact surface conditions. The experimental studies are conducted to verify the predicted results. Good agreement is obtained between these theoretical and experimental results for contact pressure and slip-starting position of the tread rubber block.
Optimization for Motorcycle Tire Using Explicit FEM
Authors: Koide M. , Heguri H. , Kamegawa T. , Nakajima Y. , Ogawa H.
Published: June 2006

A new procedure of the crown contour design for the motorcycle tire is proposed in this paper. The explicit finite element method (FEM) combined with the neural network has been utilized to optimize the cornering property of the motorcycle tire. For the motorcycle tire, the camber thrust is one of the most important cornering characteristics. The explicit FEM has been utilized for the camber thrust prediction to avoid poor numerical stability that will be caused by the implicit FEM. The prediction of the camber thrust that the results of finite element analyses (FEA) were in good agreement with the experimental results has been verified. For the approximation of the design space in the optimization, the neural network has been utilized to circumvent the multipeak and huge CPU time problems. The objective functions of the optimization were both the linearity of camber thrust and the uniformity of pressure distribution in the contact area. The design variable was the crown contour expressed by three variables, and the number of variables was defined in consideration of decreasing the number of FEA. The procedure has been applied to the practical development of a motorcycle tire and verified to be an effective method to improve the handling performance at the proving ground.
Application of a Shell-Spring Model for the Optimization of Radial Tire Contour Using a Genetic Algorithm
Authors: Unnithan G. , KrishnaKumar R. , Prasad A.
Published: June 2006

Optimization gives a new facet to design and development of tires. A new approach to the tire profile optimization is proposed in this study. The optimization procedure is integrated with a simple shell-spring finite element model for faster evaluation. In the shell-spring model, the shell elements represent the tire carcass, whereas the tread is represented by the spring elements. This is applied for the optimization of the tire contour for better maneuverability. The genetic algorithm, an evolutionary optimization procedure that is robust and efficient in solving complex optimization problems, is chosen. A new tire contour is obtained that improves tire maneuverability by increasing the sidewall belt tension.
Transient Finite Element Analysis of Tire Dynamic Behavior
Authors: Rao K. , Kumar R. , Bohara P.
Published: June 2006

Dynamic behavior of a pneumatic tire is simulated by use of an explicit finite element (FE) code. Different parts of the tire and their corresponding material properties are taken into account in the FE model because they play a significant role in tire dynamics. The work presented in this study discusses simulation of cornering behavior, braking behavior, and combined cornering-cum-braking behavior. The effects of camber angle and grooved tread on tire cornering behavior are discussed. ABAQUS/Explicit, a general non-linear FE code, was used for these simulations. To predict the Magic Formula characteristics over a complete range, various simulations are performed at different normal loads and operating conditions. Predicted Magic Formula curves from the simulation results for various dynamic conditions closely follow the experimental data curves. Even though these simulations demand huge computational resources, the predicted Magic Formula curves can be directly used as input in the complete study of vehicle dynamics. Thus, this proposed approach minimizes the costly experiments needed to determine the Magic Formula characteristics and thereby forms a viable tool in the design and the development of tires.
Prediction of Snow/Tire Interaction Using Explicit FEM and FVM
Authors: Seta E. , Kamegawa T. , Nakajima Y.
Published: June 2006

A three-dimensional prediction model has been developed in which the interaction between snow and a rolling tire with tread pattern is considered. An explicit finite element method (FEM) and a finite volume method (FVM) are used to model tire and snow respectively. Snow deformation is calculated by the Eulerian formulation to solve the complex interaction between snow and tire tread pattern. Coupling between a tire and snow is automatically computed by the coupling element. Numerical modeling of snow is essential to the tire performance prediction on snow. In this study, snow is assumed to be homogeneous and considered to be an elasto-plastic material. The Mohr-Coulomb yield model, in which the yield stress is a single function of pressure, is adopted. This function is investigated by tire traction tests under a wide range of tire contact pressures using several tires with different inflation pressures and patterns. The predicted results using the Mohr-Coulomb yield model are compared with those using the Capped Drucker-Pragger and the Cam-Clay yield models. Snow traction of a tire featuring different tread patterns is simulated by this technology. Results are shown to be in good qualitative agreement with experimental data.
Tread Discontinuities as Source of Vibration/Noise — Transient Dynamics of Rolling Tire
Authors: Liu H. H.
Published: June 2006

Tire vibrations supply energy for noise generation. Tread band features, such as grooves and blade cuts, affect noise signatures since they impart vibrations to a rolling tire. Finite element transient dynamics simulations have been performed with ABAQUS/Explicit on a rolling passenger tire to examine the vibrations induced by the entrance of tread pattern discontinuities into the contact patch. The loaded tire rolls on a 3.05 m (10 ft) diameter drum at terminal speeds of 4.3 km/h (2.7 mph) and 34.4 km/h (21.4 mph). Three models with augmented discontinuities in the circumferential ribs have been examined: 1) continuous (control); 2) angled lateral grooves; and 3) transverse grooves. They are ordered in increasing severity of rib discontinuity. The induced rolling vibrations are evaluated by identifying the ‘perturbed’ dynamic responses of (2) and (3) from (1). The results indicate that any discontinuity or abruptness in tread patterns can induce vibrations, which are similar in nature, for the two speeds studied. The higher rolling speed changes only the amplitudes, but not the frequencies of the induced oscillations at the free spindle. The ‘perturbed’ vibrations for both speeds manifest at the spindle as translational (vertical) and rotational (axial) oscillations of 29 and 44 Hz, respectively, for the tire studied.
Obstacle Impact Simulation of an ATV Using an Efficient Tire Model
Authors: Mousseau R. , Markale G.
Published: June 2006

When a vehicle travels over a large obstacle at a significant speed, dynamic loads are created that are severe enough to cause damage to its components. Prediction of these impact loads early in the design can greatly aid the vehicle development process. Thus, automobile manufactures have devoted considerable effort developing computer models to simulate durability events. An important part of any durability simulation is the tire model. This paper focuses on the problem of efficiently predicting dynamic loads that occur when an all terrain vehicle (ATV) impacts obstacle impact. An ATV simulation model that uses an efficient and simple tire model to represent the enveloping behavior and dynamic response was developed with the AUTOSIM multibody dynamics program. This program, using Kane's Method and symbolic algebra to automatically generate fully parametric simulations that are both efficient and easy to use, was used to model both the tire and ATV rigid body dynamics. This paper describes the combined ATV multi-body vehicle dynamics and tire simulation. To demonstrate the effectiveness of tire simulation, results from the efficient tire model isolated from the vehicle are compared to output from a nonlinear finite element model. Also, the paper compares results from the full vehicle ATV simulation and a field test.
A Prototype Instrument to Evaluate Fatigue Damage in the Sidewalls of Steel-Belted Radial Truck Tires
Authors: dos Reis H. L. M. , Golko P. J.
Published: June 2006

Using the acousto-ultrasonic approach, a prototype instrument capable of detecting and evaluating ply cord fatigue damage, which is a likely cause of the zipper mode of failure in radial steel belted truck tires, has been developed. The instrument has the potential to be production oriented and capable of being used for on-line inspection of new or used tires. The instrument is capable of producing color-coded scans, thereby reducing the possibility of operator error that could result in damaged tires being placed in service. Results for two tires, one with seeded defects and the other with field fatigue damage, are presented and discussed.
Tire Bead Overheating in Urban Buses and Trucks Using Drum Brake Systems
Authors: Costa A. L. A. , Natalini M. , Inglese M. F. , Xavier O. A. M.
Published: June 2006

Because the structural integrity of brake systems and tires can be related to the temperature, this work proposes a transient heat transfer finite element analysis (FEA) model to study the overheating in drum brake systems used in trucks and urban buses. To understand the mechanics of overheating, some constructive variants have been modeled regarding the assemblage: brake, rims, and tires. The model simultaneously studies the thermal energy generated by brakes and tires and how the heat is transferred and dissipated by conduction, convection, and radiation. The simulated FEA data and the experimental temperature profiles measured with thermocouples have been compared giving good correlation.
Transient Dynamics of a Tire Rolling over Small Obstacles — A Finite Element Approach with PAM-SHOCK
Authors: Kamoulakos A. , Kao B. G.
Published: June 2006

The capability of PAM-SHOCK, for studying the transient dynamic responses of a rolling tire impacting a road imperfection (“bump”) is presented. An industrial test case, that is, a tire rolling on a spinning drum that contains a cleat, was simulated using PAM-SHOCK. The simulation includes pressurization of the tire, loading the tire against the drum and progressive rotating of the drum until the tire model reached a steady state rotation speed corresponding to 30 mph spindle velocity, and, finally, impacting of the tire with the cleat. The excess vertical and horizontal spindle force histories extracted from this simulation were studied and compared against experimental measurements. The similarities between them were identified. The simulation was further extended for six more repeated impacts corresponding to 21 tire revolutions to demonstrate the reliability of the program in providing a stable solution to the tire impact problem. The results are contrasted against the equivalent unstable calculation results.
A Material Model for Simulating the Hysteretic Behavior of Filled Rubber for Rolling Tires
Authors: Becker A. , Dorsch V. , Kaliske M. , Rothert H.
Published: June 2006

The hysteretic behavior of tire rubber compounds was investigated by tension/compression tests at different strains and strain rates, dynamic tests with varying frequencies and amplitudes, and tests with small cycle loading and unloading. According to these effects, a material model was developed that considers the complex frequency dependent (viscoelastic) as well as the rate independent (elastoplastic) inelastic behavior of filled rubber. This model combines different rheological elements representing viscous and plastic effects. The approach is valid for large strains.

The hysteretic model has been implemented in an in-house FE code to analyze tire behavior assuming a constant driving velocity. The numerical algorithm is robust and shows excellent convergence, making it suitable even for large tire models. In computations for rolling tires, the consideration of the hysteresis yields a direct calculation of rolling resistance and energy dissipation, thus the new material law should prove useful in simulations of wear and durability.
Structure-Borne Vibration Transmission in a Tire and Wheel Assembly
Authors: Lee J. J. , Pham H. Q. , Moore J. A.
Published: June 2006

Vibration transmission through tires due to forces generated by the road-tire interaction during rolling over a rough road surface is an important source of noise in the vehicle interior over a wide frequency range. Vibration transmission along the tire tread and across the sidewalls to the rim was measured by striking the tread with an impact hammer in generating transfer functions for comparison with results from an SEA model of the wheel. The effects of tire and rim resonances are noted. Transfer functions to acoustic levels in the tire cavity were also measured.
Influence of Wheel Alignment and Tire Characteristics on Vehicle Drift
Authors: Yamazaki S. , Fujikawa T. , Suzuki T. , Yamaguchi I.
Published: June 2006

Tire properties are some of the most important factors causing vehicle drift. In this paper, the influences of wheel alignment and tire properties on vehicle drift are discussed. The relationship between the wheel alignment of a vehicle and vehicle drift are examined. Also analyzed is the relationship between vehicle drift and front tire torque by using a four-wheel model while considering tire characteristics. The calculated front tire torque is compared with vehicle drift.
Effects of Carbon Black and Process Oil on Viscoelastic Properties and Tire Wet Skid Resistance
Authors: Takino H. , Takahashi H. , Yamano K. , Kohjiya S.
Published: June 2006

Wet skid resistance for rubbers with a wide range of carbon black loadings and process oil loadings was investigated from the viewpoints of viscoelastic properties and abrasion properties. An analysis of wet skid resistance by the factors of Tα and BPST abrasion, which was effectively performed on a wide range of polymers in a previous report, gave a poor correlation this time. In the case of a wide range of carbon black loadings and oil loadings, the factors of tan δ and BPST abrasion had a good relationship with wet skid resistance. In this study, tan δ at 7°C was found to be a suitable factor corresponding to adhesion loss and hysteresis loss in rubber friction. By the evaluation of abrasions, BPST abrasion and PICO abrasion were estimated to be governed by different mechanisms.
Application of a Neural Network for the Optimization of Tire Design
Authors: Nakajima Y. , Kadowaki H. , Kamegawa T. , Ueno K.
Published: June 2006

When there are multiple peaks in the design space, it is difficult to obtain the global optimum by mathematical programming. The procedure to obtain the pseudo-global optimum in the multiple-peak problem is to select the best solution from many local optimums starting from different initial values. However, this approach requires large computer resources and has difficulty in obtaining the pseudo-optimum in a problem with many peaks, due to the complicated design space.

We propose more efficient and robust optimization procedures for the multiple-peak problem. In this approach, a neural network is applied for the approximation of the design space by learning the data when design variables are systematically changed, by employing a design of experiments. Since the neural network can approximate the nonlinear space, it can be applied for the approximation of the complicated design space. Moreover, since the number of analyses is determined by the design of experiments, it is much smaller than that of the mathematical programming. Hence the CPU time for optimization can be decreased by the proposed method. The proposed method is applied to the optimization of tire contact performance and is verified to be effective to improve the handling and wear of a tire.
Effect of Suspension Alignment and Modest Cornering on the Footprint Behavior of Performance Tires and Heavy Duty Radial Tires
Authors: Pottinger M. G. , McIntyre J. E.
Published: June 2006

Typical uneven wear originates from energy intensity differentials occurring in ordinary tire usage at moderate operational conditions. In this paper the footprint behavior of a typical performance tire and of typical heavy-duty radial tires are compared and contrasted with the intent of shedding light on the study of uneven wear. The examination is extended to modest lateral acceleration conditions, less than 0.3 g, with the greatest emphasis being on the behavior of the performance tire. Examples of very detailed information on the normal stress, lateral stress, longitudinal stress, lateral displacement, and longitudinal displacement fields within contact are examined. The concept of “virtual wear,” based on the use of shear energy intensity, is introduced as a way to predict uneven wear propensity in any number of different tests from the results of a single, nondestructive, indoor experiment.
An Analytical Model for the Transient Rolling Resistance Behavior of Tires
Authors: Mars W. V. , Luchini J. R.
Published: June 2006

The rolling resistance of tires has received increased attention as automakers and consumers seek to improve fuel economy. Standard rolling resistance tests are currently performed to characterize steady state rolling resistance. The transient rolling resistance behavior is also of interest, but requires more elaborate and more expensive testing.

This paper presents a theory to predict the transient response of rolling resistance to changes in velocity, from empirical data generated at steady state. The current model neglects the effect of changes in inflation pressure. A general relationship is derived for an arbitrary velocity history. The special case for instantaneous velocity histories is investigated. The model is then compared with experimental results. Finally, we use the model to predict transient rolling resistance results for coast down testing, and a simulated urban driving cycle.

The model provides a simple and effective way to determine transient tire rolling resistance from steady state test results. This may reduce the need for transient testing in the future.
A New Methodology to Get Reliable Input Data for Handling Simulations
Authors: Mancosu F. , Speziari D. , Ceresa M. , Sbarbati P.
Published: June 2006

This paper presents a methodology to obtain tire and vehicle parameters suitable for handling simulations, describing the experimental activity needed, a vehicle model, and an appropriate identification algorithm. The vehicle model has four degrees of freedom and takes into account roll movements, load transfers among the four tires, and lateral tire forces, described by the Magic Formula with transient behavior. The resulting system has 10 state variables.

A vehicle was equipped with standard sensors used by vehicle manufacturers in handling maneuvers and wheel vector transducers that measure the displacements and angles of the four hubs with respect to the chassis. Handling tests were performed, and some of the results were used to identify the tire Magic Formula coefficients and part of the vehicle parameters, using an Extended Kalman filter. The remaining tests were used for the validation: the results showed good agreement between simulations and measurements, confirming the validity of the model and the accuracy of the parameters' estimation.
Standardization in Tire Modeling and Tire Testing — TYDEX Workgroup, TIME Project
Authors: van Oosten J. J. M. , Unrau H.-J. , Riedel A. , Bakker E.
Published: June 2006

As a result of the 1st International Colloquium on Tire Models for Vehicle Dynamics Analysis in 1991, the international TYDEX Workshop working group was established. This workshop concentrated on the standardization of the exchange of tire measurement data and the interface between tire and vehicle models in order to improve the communications between vehicle manufacturers, suppliers, and research organizations. The development and knowledge of tire behavior is of great importance to both the tire and vehicle industries and will be intensified. Therefore the TYDEX Workshop received great interest from all parties to come to some kind of standardization.

In the two expert groups, one of which focused on Tire Measurements — Tire Modeling and the other on Tire Modeling — Vehicle Modeling, the TYDEX-Format and the standard tire interface have been developed, which will be explained in this paper.

Furthermore, a short overview of the European TIME project aiming at a standard tire testing procedure will be given, which is reliable and consistent with realistic driving conditions. Standard testing procedures are some of the important consequences of the TYDEX Workshop.
A Laboratory Device to Measure the Interfacial Phenomena between Rubber and Rough Surfaces
Authors: Garro L. , Gurnari G. , Nicoletto G. , Serra A.
Published: June 2006

The interfacial phenomena between tread rubber compounds and rough surfaces are responsible for most of the behavior of a tire on the road. A new device was developed for the investigation of these phenomena in the laboratory. The device consists of a fully instrumented road wheel on which a simple geometry specimen is driven. The possibilities offered by this device are to perform tests at constant slip or at constant torque on both wet and dry surfaces, with complex cycles. The machine allows the measurement of slip, tangential forces, and temperature on the specimen, and computer software adds the possibility of applying Fourier analyses on force, road wheel speed, and specimen speed data. Other possibilities offered by the road wheel are to change the road surface, the load on the specimen, and the water rate. The description of a complete experiment is detailed in the paper showing the correlation of data with actual tire performances.
A Finite Element Model for the Rolling Loss Prediction and Fracture Analysis of Radial Tires
Authors: Wei Y.-T. , Tian Z.-H. , Du X. W.
Published: June 2006

With the development of tire mechanics and computer technology, tire deformation, rolling resistance, and temperature distribution under rolling conditions may be predicted accurately through finite element analysis (FEA). Deep knowledge of tire fracture and failure behavior may also be obtained by FEA. During the past years, an in-house finite element program has been developed in our research laboratory which can analyze the tire deformation, stress, and strain under the static inflation and footprint load conditions and can predict the tire rolling resistance and temperature distribution as well. This paper gives a brief description of the mathematical and mechanical foundations of the developed FEA code and the computing procedures, emphasizing the tire material loss model and the calculation procedure of strain energy release rate in tire fracture analysis. Two characteristics of the presented model compared with the published literature are the three-dimensional anisotropic properties included in the loss model of cord-rubber materials and a new VCCT (Virtual Crack Closure Technique), which is simple and physically direct, saves on the amount of computation, and is developed to compute the fields of strain energy release rates (Serrs) in the crack front to analyze tire fracture behavior.
Contact Pressure Distribution of Radial Tire in Motion With Camber Angle
Authors: Kim S. , Kondo K. , Akasaka T.
Published: June 2006

Theoretical and experimental study is conducted on the contact pressure distribution of a radial tire in motion under various camber angles. Tire construction is modeled by a spring bedded elastic ring, consisted of sidewall springs and a composite belt ring. The contact area is assumed to be a trapezoidal shape, varying with camber angles and weighted load. The basic equation in a quasi-static form is derived for the deformation of a running belt with a constant velocity by the aid of Lagrange-Euler transformation.

Galerkin's method and stepwise calculation are applied for solving the basic equation and the mechanical boundary condition along both sides of the contact belt part subjected to shearing forces transmitted from the sidewall spring. Experimental results on the contact pressure, measured by pressure sensors embedded in the surface of the drum tester, correspond well with the calculated ones for the test tire under various camber angles, running velocities, and weighted loads. These results indicate that a buckling phenomenon of the contact belt in the widthwise direction occurs due to the effect of camber angle.
Effects of the Number of Siping Edges in a Tire Tread Block on Friction Property and Contact With an Icy Road
Authors: Yamazaki S. , Yamaguchi M. , Hiroki E. , Suzuki T.
Published: June 2006

Friction coefficients between tires and an icy road were measured at various temperatures and slip velocities using an inside-drum type testing machine. The tire contact with the icy road was observed during sliding. Effects of the number of sipes in a tread blocks on the friction coefficient were examined.
A New Tire Model to Predict Vibration Emission of Counterbalance Trucks
Authors: Lemerle P. , Mistrot P.
Published: June 2006

Counterbalance trucks are machines in widespread use in every industrial sector. Unlike cars, they are not designed with suspension systems. Consequently, they are considered to be high vibrating vehicles. Nevertheless, like suspension seats, tires can be selected as suspension parts. This paper presents a new numerical model for the analysis of the vibratory behavior of counterbalance truck tires. This model was intended to be a part of a fork lift truck model, including axles, chassis, and cabin. All the results reported here show a close agreement between measurements and numerical simulations. Thus, it can predict the vibration emission values at the driving position and is used to compare the efficiency of solid tires with pneumatic tires in terms of transmitted vibration levels.
Analysis of Tire Performance on Sand
Authors: Ataka H. , Yamashita F.
Published: June 2006

Recently, vehicles on sand have been operated at higher speeds with diversified usage, and requests for the development of radial tires, applicable to both pavements and sandy areas have emerged. Although a large number of studies and analyses of tire performance on paved surfaces have been reported, few reports are available for tire performance on sandy surfaces. This study deals with the behavior of radial tires on the sand.

A simple theoretical equation was derived in which the sand traction performance could be expressed as the difference between the propulsive force and the driving resistance on sand. The theoretical equation was found to be highly related to the empirical equation derived from previous work. Sand samples from typical deserts were used for analyses of shearing stress and compressive breaking force of sand through unique measuring techniques, resulting in modification of the theoretical equation to give more precise prediction of the tire performance on sand for most areas in the world.
One-Dimensional Contact Pressure Distribution of Radial Tires in Motion
Authors: Shiobara H. , Akasaka T. , Kagami S. , Tsutsumi S.
Published: June 2006

The contact pressure distribution and the rolling resistance of a running radial tire under load are fundamental properties of the tire construction, important to the steering performance of automobiles, as is well known. Many theoretical and experimental studies have been previously published on these tire properties. However, the relationships between tire performances in service and tire structural properties have not been clarified sufficiently due to analytical and experimental difficulties. In this paper, establishing a spring support ring model made of a composite belt ring and a Voigt type viscoelastic spring system of the sidewall and the tread rubber, we analyze the one-dimensional contact pressure distribution of a running tire at speeds of up to 60 km/h. The predicted distribution of the contact pressure under appropriate values of damping coefficients of rubber is shown to be in good agreement with experimental results. It is confirmed by this study that increasing velocity causes the pressure to rise at the leading edge of the contact patch, accompanied by the lowered pressure at the trailing edge, and further a slight movement of the contact area in the forward direction.
Millipolar Theory for Twisted Cord-Reinforced Composites
Authors: Padovan J. , Ma J. , Parris H.
Published: June 2006

Based on the torque-axial load coupling properties of twisted cord, a new unipolar composite theory is developed. Overall, the full complement of the so-called micropolar stress/moment-strain/rotation gradient coupling is accommodated. This includes the handling of the skew-symmetric stress to relative matrix wind-up interaction which is a central feature of continuous twisted cord-reinforced composites. To establish various interaction effects, both analytical and finite element models of unit cell behavior are employed. Due to the mixed tensor-vector properties of the constitutive formulation, a specially anisotropic polar formulation is developed. To illustrate the millimeter level importance of polarity, i.e., millipolarity, the results of several case study problems are also presented for cord-reinforced elastomeric composites. These include both square and alternating (triangular) packing morphologies. To generalize the results, the investigations include a wide range of packing densities.
Total Tire Energy Loss Comparison by the Whole Tire Hysteresis and the Rolling Resistance Methods
Authors: Pillai P. S.
Published: June 2006

Energy loss per hour in a tire traveling at 80 km/h was obtained for a number of tires of different sizes and makes from the respective whole tire hysteresis loss of each tire. This loss value was then compared to the corresponding rolling loss obtained from the 1.7 m dynamometer rolling resistance method. The two methods agreed, indicating that the basic premise of the rolling resistance hysteresis ratio relation is valid.
Application of a Technical Documentation System for Developing New Belt Constructions for Truck Tires
Authors: Németh T. , Nándori F. , Sárközi L. , Szabó T.
Published: June 2006

The highly challenging activity of designing tires can be supported by different types of software. An IBM compatible PC based technical documentation system has been worked out to help with both the design and manufacturing of four belted truck tires. It has the capability for construction of tire section geometry, for processing of pattern and general assembly drawings, etc. From the basic geometrical information pre-processing can be done by using an interface module for an in-house finite element analysis program. Examples are shown how the belt construction has been modified for a given TOP type tire.
Computational Models for Multilayered Composite Shells with Application to Tires
Authors: Kulikov G. M.
Published: June 2006

This paper focuses on four tire computational models based on two-dimensional shear deformation theories, namely, the first-order Timoshenko-type theory, the higher-order Timoshenko-type theory, the first-order discrete-layer theory, and the higher-order discrete-layer theory. The joint influence of anisotropy, geometrical nonlinearity, and laminated material response on the tire stress-strain fields is examined. The comparative analysis of stresses and strains of the cord-rubber tire on the basis of these four shell computational models is given. Results show that neglecting the effect of anisotropy leads to an incorrect description of the stress-strain fields even in bias-ply tires.
Pass-by Noise Measurement with a Noise-Isolated Car
Authors: Buschmann J.
Published: June 2006

To attain good tire performance in pass-by noise under acceleration (as requested in Europe by 92/97/EEC), tires have to be tested with a noise-isolated vehicle. The tire/road noise under acceleration can be evaluated without disturbance from engine noise. In a pass-by noise program (with simultaneous measurements of sound pressure level, torque, and slip) tires with different tread compounds and patterns were chosen to study the influence of both on pass-by noise. Due to the noise isolation of the test vehicle, the rolling noise and the tire/road pass-by noise under acceleration can be evaluated. Test results were compared to laboratory noise tests where a driven tire runs on a drum.
Dynamic Simulation of the Tire Curing Process
Authors: Han I-S. , Chung C-B. , Kim J-H. , Kim S-J. , Chung H-C. , Cho C-T. , Oh S-C.
Published: June 2006

The curing process is the final step in tire manufacturing where curing reactions of rubber compounds take place under elevated pressures and temperatures in a press. A simulator for the tire curing processes was developed, which implements numerical algorithms based on a finite element method to solve the rigorous model equations governing transient heat transfer and curing reactions. Extensive simulation has been carried out ranging from simple heat conduction problems to actual tire curing processes. The results have been verified through comparison with analytical solutions or actual thermocouple measurements. The simulator successfully describes the trends in temperature and the state of cure during the tire curing process. It also serves as the core module of an optimization algorithm, which is being developed for the curing processes.
Predictive Model for Reversion-Type Cures
Authors: Rimondi G. , Toth W. J. , Kounavis J.
Published: June 2006

Tire manufacturers exploit the use of cure kinetics models in the FEA for setting optimum cure cycles. The following cure process assures production of superior tire compound properties in a cost competitive manner.

It is well known that overcure of many tire compounds results in reversion. This effect is directly observed as a decrease in modulus relative to the optimum value. Reversion is directly observed on rheometric isothermal torque-time profiles which pass through a maximum torque value. Reversion usually implies a deleterious effect on vulcanizate properties.

We are not aware of any cure models, given in the literature, which adequately account for reversion. Such models cannot be used to accurately optimize cure cycles in those cases where the extent of reversion is significant.

This paper presents a cure kinetics model that accounts for reversion. Also, the model does not need to use an “induction time.” Rather, the model predicts a continuous torque-time trace, initially rising slowly but eventually rising sharply. The predicted and observed torque-time traces, as shown in this paper, exhibit excellent agreement over the entire rheometric time scale. Furthermore, the constants of the model can be interpreted as indicators of the basic mechanism of the curing process, i.e., rate constants for creation and loss rates of different types of cross-links, therefore enabling a prediction of the extent of reversion during a cure cycle.
Analytical Comments on Radial Tire Nonuniformity
Authors: Koutny F.
Published: June 2006

A circular eccentric serves as a useful model for simulating radial nonuniformities in tires. A belt model for radial tires has been utilized to study the dynamic responses to such nonuniformities. For direct experimental verifications, a special tire was made, with variable belt stiffnesses in the circumferential direction. The analysis presented in this paper is confined to only the most important radial nonuniformities. Force run-out formulas are given and related topics are discussed. Statistical views are applied in processing the experimental uniformity samples. It can be concluded that radial nonuniformities are mutually correlated while the others are not. A power transform is suggested to attain normality in simultaneous and marginal sample distributions.
Indoor Simulation of Tire Wear: Some Case Studies
Authors: Stalnaker D. , Turner J. , Parekh D. , Whittle B. , Norton R.
Published: June 2006

Methodology is described for the indoor simulation of tire wear. The motivation for developing indoor simulations was the need to establish consistent test results in reduced time and costs. Descriptions are given of two different indoor test facilities, a PC-based laser scanning system for quantifying tire wear and an on-vehicle tire force measurement system for replicating road histories in the laboratory. Case studies illustrate (1) the influence of tire load history on wear, in particular city cornering versus highway driving and drive torque versus free rolling, (2) the influence of a 3 m road wheel versus a fiat belt on wear, and (3) detailed comparisons between vehicle-tested and indoor-tested tires. Results indicate good correlation between indoor and fleet testing.
Two-Dimensional Contact Pressure Distribution of a Radial Tire in Motion
Authors: Shiobara H. , Akasaka T. , Kagami S.
Published: June 2006

The two-dimensional contact pressure distribution of a running radial tire under load is a fundamental property of the tire structure. The two-dimensional contact pressure distribution in the static case and the one-dimensional contact pressure distribution in the dynamic case were previously analyzed for a spring bedded ring model consisting of a composite belt ring and a spring system for the sidewall and the tread rubber.

In this paper, a Voigt-type viscoelastic spring system is assumed for the sidewall and the tread rubber. We analyzed the dynamic deformation of the belt ring in a steady state, and obtained the two-dimensional dynamic contact pressure distribution at speeds up to approximately 60 km/h. The predicted contact pressure distribution for a model with appropriate values for the damping coefficient of each constituent rubber is shown to be in good agreement with experimental results.

It is a characteristic feature that increasing velocity yields an increase in the pressure at the leading edge of the crown centerline in the contact area and at the trailing edge of the shoulder line.
Stress Analysis of Tire Sections
Authors: Wang T-M. , Daniel I. M. , Huang K.
Published: June 2006

An experimental stress-strain analysis by means of the Moiré method was conducted in the area of the tread and belt regions of tire sections. A special loading fixture was designed to support the tire section and load it in a manner simulating service loading and allowing for Moiré measurements. The specimen was loaded by imposing a uniform fixed deflection on the tread surface and increasing the internal pressure in steps. Moiré fringe patterns were recorded and analyzed to obtain strain components at various locations of interest. Maximum strains in the range of 1–7% were determined for an effective inflation pressure of 690 kPa (100 psi). These results were in substantial agreement with results obtained by a finite element stress analysis.
An Investigation of the Slip of a Tire Tread
Authors: Lazeration J. J.
Published: June 2006

Tire performance such as handling, noise, traction, wear, etc., is determined ultimately in the tire footprint. The nature of the distribution of the contact stresses within the tire footprint determine whether or not the tire tread adheres to the road or slips relative to the road surface. Loss of adhesion between the tire tread and the road can be extreme as in gross slippage resulting in the loss of vehicle control or it can be subtle as in the small magnitude slippage that promotes treadwear. This paper presents results from an experimental characterization of the slip between the tread of a free-rolling tire and a simulated road surface. Trajectories of discrete points on the tread surface were measured from the entrance to the exit of the footprint and were used to calculate the total slip of each point. The relationship between the average slip of the tire and toe angle was established. Also, the relationship between toe, camber, and the distribution of tread slip and velocity across the tire footprint, was investigated in this paper.
The Use of Tangential X-Ray Tools in the Analysis of Tire/Wheel Mismatch
Authors: Gerhardt J. S. , Fuller R. L. , Follen G. D. , Schnuth C. L.
Published: June 2006

This paper introduces and discusses the use of tangential x-rays as a tool and technique for analysis of fitment of the tire/wheel contact area or bead seat area for any pneumatic tire/wheel assembly. The bead seat area of pneumatic tires has long been an area of “intrigue” owing to its hidden nature. This technique is demonstrated in the analysis of a progressive degradation of a casing ply turn-up in a tire. The tangential x-ray methodology permits observation of the structural elements in a tire while it is mounted and inflated. The process makes it possible to answer definitively many questions relating to the fitment of a tire to a rim. The paper includes examples of bead and component identification and placement. More importantly, tangential x-ray analysis helps in the evaluation of minute tear anomalies and their propagation during use.
Techniques for Determining the Parameters of a Two-Dimensional Tire Model for the Study of Ride Comfort
Authors: Mancosu F. , Matrascia G. , Cheli F.
Published: June 2006

A rigid ring model of the tire for the study of in-plane dynamics and a new technique for determining the parameters of the model are presented in this paper. This model can be used for studying the comfort of vehicles, problems of driving, and braking problems in the longitudinal direction. Comparison with finite element models shows that the rigid ring model of the tire is capable of describing the in-plane eigenmode shapes in the frequency range of 0–130 Hz. The well-known “brush model,” integrated into the tire model, is introduced to take into account the slide phenomena in the contact patch. The parameters of the model can be correlated with the physical properties of the tire so that designers can take advantage of such a correlation in the development of new tires in terms of time, cost, and performance. The technique used to determine the parameters of the model for some automobile tires include the direct measurements of some physical properties (mass, moment of inertia, stiffness) and a method of identification applied on the results from a dynamic test. The model is able to predict experimental data in terms of natural frequencies and relative dampings. Results from the application of this technique on two tires are reported.
Friction Mechanism of Tread Blocks on Snow Surfaces
Authors: Mundl R. , Meschke G. , Liederer W.
Published: June 2006

Evaluation of tread pattern designs with respect to performance of winter tires on snow is still predominantly based on empirical knowledge. To gain greater insight into the complex interaction between the elastic tread block and the inelastically deforming snow, numerical simulations by means of the Finite Element Method (FEM) were carried out in conjunction with experimental investigations. An elastoplastic material model for snow was developed. Calibration of the model parameters is based on shear and compression tests conducted on specimens made of natural and artificial snow. Good correlation is obtained between results from laboratory experiments and from numerical simulations with respect to the deformations and the frictional behavior of a single rubber block sliding on snow.
Tire Modeling by Finite Elements
Authors: Faria L. O. , Oden J. T. , Yavari B. , Tworzydlo W. W. , Bass J. M. , Becker E. B.
Published: June 2006

Recent advances in the development of a general three-dimensional finite element methodology for modeling large deformation steady state behavior of tire structures is presented. The new developments outlined here include the extension of the material modeling capabilities to include viscoelastic materials and a generalization of the formulation of the rolling contact problem to include special nonlinear constraints. These constraints include normal contact load, applied torque, and constant pressure-volume. Several new test problems and examples of tire analysis are presented.
The Flat-Trac II® Machine, the State-of-the-Art in Tire Force and Moment Measurement
Authors: Pottinger M. G.
Published: June 2006

This paper summarizes the technology of the Flat-Trac II® machine and then demonstrates its capabilities as a tool for the 1990s. Specific emphasis is placed on the machine's ability to contribute valid data to the study of residual pull, highway speed uniformity, dynamic steer (sinusoidal and simulated step), behavior in the limit, and simultaneous steer, camber, and torqued behavior.
An Approach to Vehicle Pull Using a Tire Finite Element Model
Authors: Murakoshi H. , Ide H. , Nishihata S.
Published: June 2006

A vehicle sometimes drifts in a straight lane. This is caused by wind, road contour, suspension alignment, and tire properties. In this paper, characteristic tire properties which affect vehicle pull are defined and analyzed by the finite element method. The effect of tire construction and tread pattern on these characteristics are discussed.