bluuebunny/crossref_metadata_2025 huggingface dataset:
Finite Element Modeling of a Homogeneous Pneumatic Tire Subjected To Footprint Loadings
Authors: Ridha R. A. , Satyamurthy K. , Hirschfelt L. R.
Published: June 2006

In this paper, we use an approach which involves 3D finite elements and a contact algorithm. For a given deflection of the hub, the algorithm computes the nodes that come into contact with a predefined contact plane, and the magnitudes of the contact forces at the nodes. Thus, the algorithm computes the size and shape of the footprint, and the contact forces at the FE nodes. To illustrate the technique, we analyze a homogeneous tire subjected to footprint loading. The computed shapes and sizes of the footprint area at different levels of rim deflection are shown to be in good agreement with experimental results. The computed tire profiles and the load-deflection response of the tire are also in good agreement with experimental results. The computed results include the distribution of stress, strain, and strain energy density within the tire, and the changes in this distribution with applied footprint loadings.
Effect of Tire Tread Pattern on Groove Wander of Motorcycles
Authors: Doi T. , Ikeda K.
Published: June 2006

Water on a road surface can dangerously lower the coefficient of friction of vehicle tires. One way to reduce the water thickness is to cut many “rain grooves” into the pavement parallel to its edges. Such grooves, however, can exert unwanted side forces, particularly on motorcycle tires where driver reaction can cause accidents. This “grove wander” is somewhat related to vehicle geometry, but is more strongly related to interaction between road grooves and tire tread grooves. From studies of this interaction we have developed principles for tread groove design that can be evaluated from relative spacing of tread grooves and pavement grooves, as well as by subjective road tests.
Textile Mechanics Model of a Pneumatic Tire
Authors: Miller C. , Popper P. , Gilmour P. W. , Schaffers W. J.
Published: June 2006

A mathematical model to analyze the structural behavior of a pneumatic tire is described. The model consists of a series of unidirectional layers of tire cord bonded together in a contoured shape to form a laminated structure. The number of cord layers and the properties and orientation of the cords in each layer can be varied to represent various sections such as the belt and sidewall of a radial construction. The model includes only membrane stresses, but permits large deformations and geometric rearrangement of the cords. Inputs to the model include the initial uninflated tire geometry (mold shape), properties and arrangement of cords and rubber, and the applied load distribution. Model outputs include shape, cord tension distributions, and interply shear stresses. A selection of results from the model are presented for a particular radial tire, and a comparison is made between the calculated and experimentally observed shapes. The results are interpreted in terms of the fundamental mechanical behavior of the system.
Analytical Models for the Deformation and Adhesion Components of Rubber Friction
Authors: Schapery R. A.
Published: June 2006

Fourier methods of analysis are employed to develop linear viscoelastic stress and displacement solutions for use in contact problems, and then some exact results for contact area and the deformation component of the friction coefficient are derived for materials whose complex modulus obeys a power law in frequency. A model for predicting waves of detachment resulting from adhesion is proposed, and it is shown that an analogy exists whereby the solution method for sliding without adhesion can be used to predict these waves and the resulting frictional force.
A Note on a New Tire Cord Adhesion Test
Authors: Nicholson D. W. , Livingston D. I. , Fielding-Russell G. S. , Gent A. N.
Published: June 2006

A new tire cord adhesion test is described. The test piece contains two opposite, symmetrically embedded cord ends that are pulled during testing. Failure is initiated at the cord ends and propagates as an adhesive failure until one cord becomes detached. Representative experimental results are given.
A New Tire Cord Adhesion Test
Authors: Nicholson D. W. , Livingston D. I. , Fielding-Russell G. S.
Published: June 2006

A new tire cord adhesion test is reported. Although developed primarily for measuring adhesion of rubber to tire cord, the test is applicable to any cord- or wire-reinforced composite, for example, rubber hose or belting. The specimen is a rubber bar of square cross section containing two partially embedded cord ends opposite each other. Upon the application of sufficient tensile force to the cords, failure is initiated at the tip of the embedded end and proceeds along the cord to the exterior, resulting in pull-out of one of the ends. This result contrasts with the initiation of failure in a specimen of the pull-through type containing a throughgoing cord. In the latter specimen, failure initiates where the cord emerges from the rubber and runs back into the interior.

Failure is adhesive when pull-out occurs. Under special conditions cohesive failure (tear) occurs and the specimen is cleaved transversely. Reproducibility is excellent and the test has high discriminating power. A theoretical equation permits calculation of the energy of adhesion.
Analysis of Rubber Friction by the Fast Fourier Transform
Authors: Schapery R. A.
Published: June 2006

A numerical method for solving contact problems is developed and then used to predict friction (without adhesion) between rubber in plane strain and periodic arrays of parabolic and triangular substrate asperities; the numerical method itself, which is based on the fast Fourier transform algorithm, is not limited to these asperity shapes. Also, effects of superposing two and more scales of texture are described. Some generalizations and related applications, such as analysis of tire traction, are then discussed.
Effect of Slip Rate on the Peak Braking Coefficient of Automobile Tires
Authors: Boyd P. L. , Walston W. H.
Published: June 2006

The peak braking coefficient was measured for five tires at six slip rates on three wet surfaces. In addition, a slick tire was tested on dry asphalt in a similar fashion. The difference in braking coefficient for a tire-pavement combination over the range of slip rate varied from 3.6 to 33.6%. In general, the effect of slip rate was more pronounced with slick tires and low friction surfaces. In cases where statistically significant differences existed on wet surfaces, the highest friction coefficients occurred most often at intermediate slip rates (between 36 and 100%/s), and the lower friction coefficients usually were obtained at both very high and very low slip rates. It is hypothesized that a reduction in the slip rate causes an increase in the peak braking coefficient on a dry surface but increases the probability of partial hydroplaning on a wet surface. The balance between these two conflicting effects causes the peak braking coefficient to be maximum at intermediate slip rates on many wet surfaces.
The Relationship Between Texture and Pavement Friction
Authors: Henry J. J.
Published: June 2006

The transient slip method is shown to be a useful technique to evaluate the speed dependence of pavement friction. From the results of transient slip tests with a standard test tire, it is possible to predict skid resistance, speed gradients, and side force coefficients. Transient slip data can be predicted from wet pavement macro-texture and microtexture and, therefore, skid resistance-speed gradients and side force coefficients can be predicted from texture measurements.
Deformation of the Pneumatic Tire
Authors: Patel H. P. , Zorowski C. F.
Published: June 2006

A finite element model is presented for analysis of axisymmetric static loadings of a bias ply pneumatic tire. The model can predict deformed shapes and the resulting cord forces in the tire. The tire is considered as a thin shell of revolution with membrane and bending stiffness. Its material properties are assumed to be linearly orthotropic. Large axisymmetric deformations studied with the proposed model gave very close approximations to the actual situation. The predicted cord forces matched the experimental values very closely.
A Note on Filtering Techniques
Authors: Neill A. H. , Boyd P. L. , Hinch J.
Published: June 2006

The peak braking coefficient of tires has been measured on an over-the-road tire traction tester using a variety of active electronic filters. Filters are identified that produce an accurate peak braking coefficient measurement by visual chart interpretation or digital sampling methods.
Automatic Tread Gaging Machine
Authors: Ludwig G. S. , Brenner F. C.
Published: June 2006

An automatic tread gaging machine has been developed. It consists of three component systems: (1) a laser gaging head, (2) a tire handling device, and (3) a computer that controls the movement of the tire handling machine, processes the data, and computes the least-squares straight line from which a wear rate may be estimated. Experimental tests show that the machine has good repeatability. In comparisons with measurements obtained by a hand gage, the automatic machine gives smaller average groove depths. The difference before and after a period of wear for both methods of measurement are the same. Wear rates estimated from the slopes of straight lines fitted to both sets of data are not significantly different.
A Selected Review of Winter Driving Aids
Authors: Williams H.
Published: June 2006

This report describes briefly the evolution of winter driving aids that accompanied the evolution of the tire. Examples are given of patents issued for antiskid devices and tire additives. Discussion of mud and snow tires, studs, and chains follows. It is concluded that chains are the best winter driving aid available despite their drawbacks.
Rubber Emissivity and the Thermal State of Tires
Authors: Browne A. L. , Wickliffe L. E.
Published: June 2006

An experimental procedure is described for obtaining accurate values of emissivity for materials of low thermal conductivity such as rubber. This procedure is then used to obtain data for the emissivity of tire tread, white sidewall, black sidewall, and inner-liner surfaces. The significance of these results to infrared (IR) temperature measurement and to the analytical modeling of the thermal state of a tire is discussed.
A Note on Groove Depth Changes Without Wear
Authors: Brenner F. C.
Published: June 2006

Tread wear rates during first wear measured by groove depth and weight changes do not always agree. Sometimes, the groove depth method shows a high rate and the weight loss method a low rate. Reported here are experiments designed to determine if grooves show depth changes without wear.

Four tires were measured before mounting on a wheel, after mounting and inflation, and after inflation and storage. The mounted and inflated tires showed shallower shoulder grooves and deeper center grooves than the unmounted tires. In a second experiment, tires were measured immediately after a tread wear test and then stored mounted for two weeks before remeasuring. Each groove became deeper, and there was no change in the crown radius of any tire.
Tire Wear Rates
Authors: Brenner F. C.
Published: June 2006

During the early stages of tire wear, the wear rate determined from groove depth measurements may reflect a dimensional change not associated with rubber loss, that is superimposed on the tread loss. The combined effect can be fit with an exponential decay curve relating groove depth to miles run. A method for separating any shape change effect from wear rate effects is suggested.
A Simple Tire Deformation Model for the Transient Aspect of Hydroplaning
Authors: Agrawal S. K. , Henry J. J.
Published: June 2006

When a nonrotating tire moves from a quasi-dry section to a flooded section of pavement, a transition from a nonhydroplaning to a hydroplaning state takes place; during this transition, the tire deforms continuously. With the assumption that each instant during this transition represents an equilibrium state, a tire deformation model is developed. The deformation is computed by modeling a nonrotating tire as a semi-infinite solid, and by replacing the effects of tire inflation pressure and vertical load by a modified elastic modulus. The close agreement between the predicted results from the model and the experimentally measured tire deformation values at a limited number of points on the tire contact surface suggests that the semi-infinite-solid model for the tire deformation computations is a reasonable technique for determining tire elastic behavior under hydroplaning condition.
Parametric Study of Convective Heat Transfer Coefficients at the Tire Surface
Authors: Browne A. L. , Wickliffe L. E.
Published: June 2006

Analyses have shown that the thermal state of a tire is influenced by both the size of and variation in the value of the convective heat transfer coefficient at the tire surface. In the work reported here, a test facility was constructed to permit the determination of convective heat transfer coefficients under a broad range of operating conditions. Data were obtained to show the effects of air speed, boundary layer thickness and turbulence level, humidity, tire surface contamination, tire surface roughness and unevenness, and tire surface wetness on convective heat transfer coefficients. The significance of these results to tire power loss is discussed.
Distribution of Speed and Acceleration on a Tread Wear Course
Authors: Ludwig G. S. , Brenner F. C.
Published: June 2006

Belted bias and radial Course Monitoring Tires were run over the National Highway Traffic Safety Administration tread wear course at San Angelo on a vehicle instrumented to measure lateral and longitudinal accelerations, speed, and number of wheel rotations. The data were recorded as histograms. The distribution of speed, the distributions of lateral and longitudinal acceleration, and the number of acceleration level crossings are given. Acceleration data for segments of the course are also given.
Contouring the Tire Sidewall with Moire
Authors: Browne A. L.
Published: June 2006

Knowledge of the tire sidewall deformation is necessary for accurate modeling of the response of a pneumatic tire to applied forces. An experimental method, the moire fringe technique, is described which permits the contouring of the tire surface under all normal operating conditions. Results are presented for a series of tests which were conducted to determine the tire sidewall deformation due to static loading, centrifugal force, combined vertical and centrifugal loading, and high speed operation (during which standing waves are present in the tire sidewall).
Compression of an Inflated Tube Between Rigid Surfaces as an Elementary Tire Mechanics Model
Authors: Nicholson D. W.
Published: June 2006

An infinitely long membrane tube under lateral compression between various rigid surfaces is used as a model to illustrate the load carrying mechanism in tires. The surfaces include parallel flat plates, indentors, and surfaces which are flat and parallel except for a semicircular hump. Such configurations are relevant to deflection of tires against flat ground, the plunger test of tire behavior, and tire enveloping properties.

In the flat plate case, compression rate appreciably affects both the force-deflection relations and strength. But even at its weakest the structure bursts only at very high deflection. In the indentor case, burst cannot occur unless the initial pressure exceeds a value dependent on the indentor radius to which behavior is otherwise insensitive. Regarding envelopment, the magnitude of the disturbance due to the presence of a hump increases with decreasing tube inflation pressure.
Nondestructive Inspection of Aircraft Tires by Pulse-Echo Ultrasonics
Authors: McConnell G. K. , Klinman R.
Published: June 2006

Recent technological advances in ultrasonic flaw detecting apparatus (broad band characteristic) have shown that ultrasonic pulse-echo inspection of aircraft tires is now possible. The acoustic properties of rubber and rubber composites have been studied so that optimum system requirements may be determined. A prototype inspection system has been constructed to demonstrate the ability of pulse-echo ultrasonics to locate critical internal flaws and structural elements in tires. Electronic and mechanical refinements necessary to complete automated inspection systems are discussed and the importance of defect standards for aircraft tires considered.
Wet Skid Resistance of Car and Truck Tires
Authors: Dijks A.
Published: June 2006

Two test trailers for measuring tire characteristics are described. One of the trailers is specially built for testing car tires and can steer, camber, and brake the test tire. This trailer is provided with a five component measuring hub. The second trailer, for testing truck tires, is restricted to braking only.

Braking forces are measured with a dynamometer. The determination of peak and locked wheel braking force coefficients is discussed. In addition, for car tires, a method for obtaining side force coefficients is given. Test results are given for both car and truck tires showing the influence of road surface texture, speed, and tread depth on skid resistance, and the results are compared.
Analysis of Rim and Belt Constraints on the Forces and Motions of a Tire Model
Authors: Nicholson D. W.
Published: June 2006

A model is proposed for the influence of the rim and the belt on load carrying in tires. It consists of an infinitely long, inflated, thin-walled tube whose cross-sectional geometry is constrained by two rigid plates. The model structure is subjected to a vertical load, a transverse load, and a rotational moment. A general set of equations is derived in terms of one inflation and two geometric parameters. Methods of numerical solution are given which hold whether forces or deflections are the independent variables. Numerical results are given for the case of slow motions and deflections specified.
Comparative Study of Tread Depth Measurement Techniques
Authors: Brenner F. C. , Kondo A.
Published: June 2006

Although there are over 20 organizations in the United States engaged in tread life evaluation by average groove depth measurements, no previous attempt has been made to compare the results obtained by the variety of procedures in use. Therefore, ASTM Committee F-9 on Tires organized an experiment in which four tires were measured at 14 laboratories representing most major tire producers and independent test houses. Each participant measured the tires following his normal practice. In several laboratories the tires were measured by each of their operators.

The data show in general that there are significant differences between laboratories but none between operators within a laboratory. Precision and accuracy vary between laboratories. Practices between laboratories vary greatly with respect to the number and locations at which measurements are made. On ribbed tires, 7 of 14 measured all grooves at 10 positions in each. For snow tires, there was no most common practice.
Fore-Aft Stiffness Characteristics Of Pneumatic Tires
Authors: Dodge R. N. , Clark S. K.
Published: June 2006

A simple mathematical model is proposed for estimating the fore-aft elastic stiffness of pneumatic tires. This model is based upon two idealized solutions, the first being that for the extensional stiffness of a pressurized tube reinforced with inextensible cords, while the second solution is that for the shear deformation of an unpressurized elastic tube. The combination of these two elements allows one to estimate fore-aft stiffness characteristics of pneumatic tires. The validity of the proposed model was tested by static measurements at different inflation pressures of the fore-aft spring rates of four tires varying in size and construction. Additional structural data required for the analytical solution of the model were also obtained from these tires. Comparison of the calculated and experimental results indicates that the trends are generally correct, although close correlation between experiment and calculation is difficult to obtain.
Correcting Vehicle Shake
Authors: Neill A. H. , Kondo A.
Published: June 2006

The mechanisms which cause shake on smooth roads and the procedures and equipment for removing it are reviewed. A critical comparison of various on- and off-the-car tire balancing methods is made. The effectiveness of tire grinding and trueing is reviewed with emphasis on the total system behavior. A statistical evaluation and analysis is presented of the potential errors contributed by off-the-car balancing and the vehicle itself, considering the imbalance vector components inherent in tire-rim assemblies and vehicle axles. The use of a liquid tire balancer is also investigated.
Analysis for Tire Mold Design
Authors: Ridha R. A.
Published: June 2006

An analysis is presented for determining tire deformation due to shrinkage. The analysis uses composite theory and the finite element technique in modeling the material properties and the structural behavior. The constant strain toroidal shell element developed by Wilson for small displacement and isotropic properties is modified for orthotropic properties which depend on the element location. Temperature history and the buildup of shrink forces during cure are determined experimentally. The shrink forces are represented by a set of equivalent loads applied at the nodes. Good correlation is obtained between calculated and experimental displacements. The analysis is applied in relating the mold shape to the final shape of the tire.
A Method for Evaluation of Carbon Blacks and Correlation with Road Wear Ratings
Authors: Cotten G. R. , Dannenberg E. M.
Published: June 2006

Prediction of tread wear from laboratory tests can be a valuable guide in the development of improved carbon blacks and controlling the quality of normal production. We have developed two tests which give good correlation with actual road wear data on over 100 experimental blacks. One test involves running Akron angle abrasion on a compound with only 30 phr of carbon black where differences in abrasion resistance are magnified. The other test measures surface activity towards the polymer by determining bound rubber content of a heat-treated nonproductive mix. By using both tests together, tread wear ratings of blacks used in this study could be predicted almost as well as by a single, controlled, multisectional road test with five tires run for 8000–10,000 miles.
Energy Losses in Tires
Authors: Walter J. D. , Conant F. S.
Published: June 2006

Tire rotation is impeded by a drag force of 10 to 20 lb per 1000-lb load in normal vehicle operation. The principal cause is hysteresis, which is a function of the viscoelastic properties of the rubber and cord components, the way these materials are used in the tire, and the way the tire is operated. The influence of material properties has been well documented, and many laboratory tests have been developed for their measurement. Of even greater importance to energy losses, however, is tire construction. This subject is developed by consideration of the forces and moments involved in tire operation and of the mechanisms of energy loss. The importance of service conditions is emphasized by a discussion of the factors influencing rolling resistance. Tire rolling losses can be an important fraction of the total power consumption in low-powered vehicles. Future trends in tire engineering, and their effects on rolling resistance, are discussed.
Power Requirements of Tires and Fuel Economy
Authors: Schuring D. J. , Bird K. D. , Martin J. F.
Published: June 2006

The torque input of a pneumatic tire in various operating modes is analyzed and the tests required to determine the energy consumption of a tire are discussed. The effects of most operating variables (slip angle, longitudinal slip, vertical load, speed, and tire type) are illustrated by data obtained on the Calspan Tire Research Facility. The energy expended by the tires is combined with other vehicle losses, and the magnitude of possible fuel savings by the use of low-loss tires is estimated.
Tire Deformation During Dynamic Hydroplaning
Authors: Browne A. L.
Published: June 2006

Past analyses indicate that tire carcass deformation is necessary for the dynamic hydroplaning of pneumatic tires. This study presents analytical and experimental confirmation of this theory. The ways in which the results can be used to assist in studying the effects of the tire carcass and tread pattern on wet traction are discussed.
Stresses and Strains in Tires
Authors: Janssen M. L. , Walter J. D.
Published: June 2006

Stress and strain patterns developed in each of several regions of automobile tires have been mapped by using methods particularly suited to each region. Miniature force transducers were used to measure (1) the cord stresses due to shaping tires during vulcanization, (2) the change in cord stress patterns caused by postinflation, and (3) the cord loads caused by tire inflation and by cornering. Liquid metal gages were used to measure rubber strains on tire surfaces. A photoelastic method was used to measure the strain distribution interior to the tire under simulated load. In each of these procedures, particular attention was given to the differences in properties among bias, belted bias, and radial ply tires.
Establishment and Calibration of a Tread Wear Test Course
Authors: Brenner F. C. , Kondo A. , Barton F. W.
Published: June 2006

The authors describe the process by which they designed and calibrated a course for the evaluation of the tread life of passenger car tires.

Their method of design consisted of running specific radial, belted bias, and bias tires, called course monitoring tires, over a route and measuring the rate of wear on each construction. The course was then modified to increase or decrease the rates of wear until a desired result was obtained.

The results of a test following the tread life evaluation are reported. The test was run using prototype course monitoring and other commercial tires. A second test was run using samples of course monitoring tires from specially purchased lots. The primary purpose of this test was to measure the variability of tires within each lot.
A Note on Heat Generation Due to Surface Rubbing
Authors: Clark S. K.
Published: June 2006

The question of heat generation by frictional rubbing is examined from the point of view of material elastic properties. Theory suggests and evidence is presented that low modulus materials tend to generate more internal heat during rubbing then high modulus materials of similar thermal properties.
Tire Vibration Studies: The State of the Art
Authors: Potts G. R. , Csora T. T.
Published: June 2006

General principles of mechanical vibration enigneering are used to discuss the total tire vibration problem in terms of three necessary factors: an excitation force, a transmitter, and a receiver of the vibratory force. The present state of knowledge for each of these factors is discussed and an overall goal for reduction of vehicle vibration is formulated. Current experiments for investigating tire vibration transmissibility are described and the results presented: the first used an electrohydraulic shaker; the second used time average holography, in order to see tires, and investigated impact wave propagation in tires with double-pulsed laser holography. Results show that it is difficult to reduce tire transmissibility and to shift resonant frequencies; however, this may be accomplished by introducing small amounts of body ply crown angles in radial tires (0–20 deg). Results of the impact wave propagation tests are beginning to reveal the true nature of what happens when a tire strikes a sharp bump.
Tire Tread Pattern Sound Generation
Authors: Willett P. R.
Published: June 2006

An assessment of a mathematical method of synthesizing tire sound spectra is presented. The method is based on the summation of phasors and the calculated spectra are conveniently generated as computer printout in the form of bar graphs. The technique, its usefulness, its limitations, and the implications of using such a model are discussed. The results have been substantiated experimentally, thus enabling optimum tread element lengths and sequences to be determined at the design stage, within the known limitations of the model.
Wet Braking Traction Validation
Authors: Neill A. H.
Published: June 2006

This report presents comparative wet traction data on a sample of tires from locked wheel tests run by the Safety Research Laboratory of the National Highway Traffic Safety Administration in order to develop a data base for establishing traction standards. Identical tests were run on three surfaces at the Texas Transportation Institute and on two surfaces at the Uniform Tire Quality Grading Treadwear and Traction Test Facility, Goodfellow Air Force Base. The precision of these results demonstrates the feasibility of (1) using a two-wheeled skid trailer for locked wheel tire traction grading and (2) constructing surfaces which will remain stable for the purpose of traction testing.
Influence of Wheel Angular Deceleration Rate on Peak Braking Force on Wet Roads
Authors: Wild R. E.
Published: June 2006

The peak braking force produced by six tires was measured on three wetted surfaces at five different wheel lockup rates. It was found that the maximum braking force obtained from passenger car tires operated on wet surfaces can be significantly affected by wheel angular deceleration rate. The maximum difference between two values of peak braking force produced by two different lockup rates on the same tire was 33%. Tires with minimal tread patterns exhibited no sensitivity to changes in lockup rate.
Peak Wet Braking Coefficient Measurement
Authors: Beauregard C. F.
Published: June 2006

The effect of brake application time and data filtering frequency on peak braking coefficient measurements are discussed. The study was conducted using the vehicle deceleration method, essentially in accordance with ASTM procedure Testing Tires for Wet Traction in Straight-Ahead Braking Using Highway Vehicles (F 403-74). It is shown that within the range covered in this program, the brake application time does not influence peak braking coefficient measurements. The selection of the data filtering frequency is shown to be very critical and dependent on brake application rate.
Dynamic Response of Tires
Authors: Schuring D. J.
Published: June 2006

Tire tests were performed under time-varying inputs on the Calspan Tire Research Facility with a G78-14 belted tire at low speeds and path frequencies up to 6 rad/ft (20 rad/m). Both slip angle and vertical load were varied, either separately and periodically or in combination. The combination simulated actual time histories of slip angle and load measured in road accident avoidance tests.

For path frequencies up to 0.2 rad/ft (0.7 rad/m), attenuation of lateral force and aligning torque amplitudes was negligibly small. However, both lagged static values substantially, leading to dynamic offsets in these quantities. The offsets appeared to be the most significant factors for tires. Their effect on the dynamic response of a vehicle remains to be investigated.
Dynamic Indoor Tire Testing and Fourier Transform Analysis
Authors: Sekula P. J. , Hall G. L. , Potts G. R. , Conant F. S.
Published: June 2006

Laboratory tire tests for dynamic spring rate and damping, steady state forces and moments, rolling radius, and cornering force transient measurements are described. Data are shown for bias, belted bias, and radial constructions in a range of automobile tire sizes. The significant differences in the results are noted on all tests for the three tire constructions.
Natural Frequencies of the Bias Tire
Authors: Hirano M. , Akasaka T.
Published: June 2006

The lowest natural frequencies of a bias tire under inflation pressure are deduced by assuming the bias tire as a composite structure of a bias-laminated, toroidal membrane shell and rigorously taking three displacement components into consideration. The point collocation method is used to solve a derived system of differential equations with variable coefficients. It is found that the lowest natural frequencies calculated for two kinds of bias tire agree well with the corresponding experimental results in a wide range of inflation pressure.
The Effect of Longitudinal Force on Bias and Radial Tires
Authors: Phillips B. D. A.
Published: June 2006

Tests were carried out to compare the effect of longitudinal force on the lateral force and aligning moment produced by a bias and a radial tire for different slip angles. Small differences occurred in the lateral force-driving force characteristics at low slip angles. Large differences occurred between the aligning moment-longitudinal force characteristics of the two tires, when the bias but not the radial tire exhibited a negative aligning moment upon the application of a braking force. These differences were caused mainly by differences in the pressure distributions in the contact patches of the two tires.
A Method for Computing the Radial Deformation Characteristics of Belted Tires
Authors: Koutny F.
Published: June 2006

This work proceeds from the idea that the air pressure in the tire is the preponderant component of elasticity. It is possible to construct a simple relationship between the stress and the reduction of the volume after deformation from the equivalence of the work of the deforming load to the work done on the air content of the tire. The description of the procedures for calculating the volume in the case of belted tires forms the essential portion of the present report. A comparison is given between calculated and measured deformation characteristics and results of measurements of pressure in deformed, belted tires.
On the Mechanical Behavior of the Orthotropic Cord-Rubber Composite
Authors: Pósfalvi Ö.
Published: June 2006

The effective elastic properties of the cord-rubber composite are deduced from the principle of virtual work. Such a composite must be compliant in the noncord directions and therefore undergo large deformations. The Rivlin-Mooney equation is used to derive the effective Poisson's ratio and Young's modulus of the composite and as a basis for their measurement in uniaxial tension.
A Note on the Volume Change of Tires During Warm-Up
Authors: Schuring D. J.
Published: June 2006

Increasing the temperature produces a decrease in tire volume. After longer times the volume tends to increase again. The initial decrease is attributed to the predominance of the Gough-Joule effect over thermal expansion and the delayed increase, to creep.
Steel Ribbon Belt Reinforcement Mechanics
Authors: Daniels B. K.
Published: June 2006

Satisfactory performance of steel ribbon belted radial tires of standard basic design is possible. The key to good fatigue life is that flexure is accommodated by shear of the rubber between the plies instead of by compression as in a twisted cord. Belt angle controls part of the fatigue mechanism but stress and lifetime are insensitive to its value.

Several mechanisms combine to give a fatigue life that is independent of ribbon width below 1.7 mm (65 mils). Above 1.7 mm width in-plane flexure causes fatigue life to drop rapidly. No improvement from changed ribbon thickness is predicted.

Tread life appears to be better with ribbon than with cord, but the reason for this is not clear. Ribbon packing geometry gives superior nail penetration resistance.
Predicting the Effect of Tire Tread Pattern Design on Thick Film Wet Traction
Authors: Browne A. L.
Published: June 2006

An analytical tool is presented for the prediction of the effects of changes in tread pattern design on thick film wet traction performance. Results are reported for studies in which the analysis, implemented on a digital computer, was used to determine the effect of different tread geometry features, among these being the number, width, and lateral spacing of longitudinal grooves and the angle of zigzags in longitudinal grooves, on thick film wet traction. These results are shown to be in good agreement with experimental data appearing in the literature and are used to formulate guidelines for tread groove network design practice.
Stress Analysis of a Tire Under Vertical Load by a Finite Element Method
Authors: Kaga H. , Okamoto K. , Tozawa Y.
Published: June 2006

An analysis by the finite element method and a related computer program is presented for an axisymmetric solid under asymmetric loads. Calculations are carried out on displacements and internal stresses and strains of a radial tire loaded on a road wheel of 600-mm diameter, a road wheel of 1707-mm diameter, and a flat plate. Agreement between calculated and experimental displacements and cord forces is quite satisfactory. The principal shear strain concentrates at the belt edge, and the strain energy increases with decreasing drum diameter. Tire temperature measurements show that the strain energy in the tire is closely related to the internal temperature rise.
On Standing Waves in Tires
Authors: Padovan J.
Published: June 2006

By using a comprehensive rotating laminated shell model of the tire, the effects of viscoelastic damping on the standing wave phenomenon are investigated in more detail than was previously possible. The shell theory employed is a nonlinear version of Novoshilov's work and the onset of the standing wave is characterized as a small dynamic deformation superposed on a finite deformation. To expand the scope of the model, the viscoelastic constitutive law is treated as either of the differential or hereditary integral type. The solution for the stated model is obtained by the finite element procedure, and the results of several numerical experiments are presented. The substantial role of viscoelastic effects in the development of the standing wave phenomenon of tires is emphasized by the results.
A Note on the Measurement of Runway Traction
Authors: Wahi M. K.
Published: June 2006

The ability to predict the stopping performance of aircraft is closely related to the accurate measurement of peak traction at the tire-runway interface. Efforts to correlate ground vehicle measurements with automotive tires to airplane performance have not been very successful. Major differences exist between automotive tires and the Type VII aircraft tires that contribute to this lack of correlation. Additionally, the ground vehicle should also have a brake cycling device. A tire model law is being developed to achieve a better correlation.
Deformation and Cord Tension of a Bias Tire in Contact with the Road
Authors: Akasaka T. , Kabe K.
Published: June 2006

The deformation properties and cord tension distribution of a bias tire in contact with the road are analyzed by assuming the tire carcass under inflation pressure to be a toroidal membrane shell of elliptical cross section having a hyperbolic type of orthotropy and the tire tread to be an elastic foundation. Displacement components of a carcass are approximated by an appropriate linear combination of finite terms and are determined by the principle of minimum potential energy. Numerical results for the deformation properties and the cord tension distribution agree well with the corresponding experimental results.
Tire Vibrations
Authors: Potts G. R. , Bell C. A. , Charek L. T. , Roy T. K.
Published: June 2006

Natural frequencies and vibrating motions are determined in terms of the material and geometric properties of a radial tire modeled as a thin ring on an elastic foundation. Experimental checks of resonant frequencies show good agreement. Forced vibration solutions obtained are shown to consist of a superposition of resonant vibrations, each rotating around the tire at a rate depending on the mode number and the tire rotational speed. Theoretical rolling speeds that are upper bounds at which standing waves occur are determined and checked experimentally. Digital Fourier transform, transfer function, and modal analysis techniques used to determine the resonant mode shapes of a radial tire reveal that antiresonances are the primary transmitters of vibration to the tire axle.
A Note on Gough Stiffness and Tread Life
Authors: Daniels B. K.
Published: June 2006

The Gough in-plane bending stiffness of JR78-15 radial tires with various belt constructions was calculated by the continuum method. The resulting smooth curve of experimental tread life versus Gough stiffness agreed with previously published data.
A procedure for laser hazard classification under the Z136.1-2000 American National Standard for Safe Use of Lasers
Authors: Thomas Robert J. , Rockwell Benjamin A. , Marshall Wesley J. , Aldrich Robert C. , Zimmerman Sheldon A. , Rockwell R. James
Published: June 2006

Over the past few years, a comprehensive rewrite of the American National Standard for Safe Use of Lasers (ANSI Z136.1) has been conducted. The ANSI Z136.1 is a user standard, as opposed to a manufacturer standard like the Federal Laser Product Performance Standard. As such, differing philosophies for hazard classification and application of safety control measures apply, based upon the user’s perspective. Here we present the second in a series of tutorial articles designed to clarify laser hazard analysis procedures under this new ANSI Standard. The procedure presented allows the reader to effectively determine the appropriate hazard classification for a small-source laser by using known laser output parameters in a step-by-step analysis.
Physical–computational model to describe the interaction between a laser beam and a powder jet in laser surface processing
Authors: Diniz Neto O. O. , Vilar R.
Published: June 2006

Frequently laser surface treatments use a powder jet in conjunction with the laser beam. In this study we present a physical–computational model to describe the interaction between a laser beam and a powder jet. The model can be used to calculate the spatial distribution of particle temperature and laser beam attenuation at any moment and all over the region where the laser and particle beams interact. In calculating particle temperature, the attenuation of the laser beam by the particles themselves is taken into account. In the model, the influence of the physical parameters of the particles, of the laser beam, and of the interaction between them are clearly identified and easy to manipulate so that they can be adjusted to optimize the laser surface treatment. With certain simplifying assumptions, the computational structure of the model enables to take into consideration the variation of the materials properties that govern the process with temperature. The model was applied to two cases studies, the first assuming that all parameters are constant with temperature, and the second one considering that the specific heat and reflectivity vary with temperature. A systematic study of the behavior of the average particle temperature, power attenuation, and mass of particles melted as a function of the powder feed rate, and diameter and velocity of the particles was carried out.
A multi-input and multioutput dynamic model for laser marking of ceramic materials
Authors: Peligrad A. A. , Zhou E. , Morton D. , Li L.
Published: June 2006

There are many process parameters that influence the results of laser marking of ceramic materials. Some parameters should be kept within certain tolerance limits to ensure the expected quality of the laser processing. Hence a closed loop control system may be desirable during the process for quality control. For this, an accurate multi-input and multioutput dynamic model was developed for laser marking of ceramic materials to gain insight in the process behavior. As a case study, laser marking of clay tiles was applied. The observable signals considered were melt pool temperature and melt pool geometry, measured by using a pyrometer and a fast charge coupled device camera. The input quantities investigated were laser power and traverse speed. The work shows that there was a good agreement (errors less than 1%) between the measured data and the model predicted outputs given by an ARX (3, 3, 0) model for the operating point.
On the mechanisms of wetting characteristics modification for selected metallic materials by means of high power diode laser radiation
Authors: Lawrence J. , Li L.
Published: June 2006

This work elucidates and analyzes the factors responsible for modifications to the wettability characteristics of metallic materials after high power diode laser (HPDL) treatment. It was found that interaction of EN3 and EN8 mild steel with HPDL radiation resulted in the wettability characteristics of the mild steels altering to various degrees depending upon the laser processing parameters. Such changes in the wettability characteristics of the mild steels were found to be due essentially to: (i) modifications to the surface roughness; (ii) changes in the surface O2 content; and (iii) the increase in the polar component of the surface energy. All of these factors were seen to influence the wettability characteristics of the mild steels, however, the degree of influence exerted by each was found to differ. Work was therefore conducted to isolate each of these influential factors, thereby allowing the magnitude of their influence to be determined. This analysis revealed that surface roughness was the primary influential factor governing changes in θ and hence the wettability characteristics of the mild steels. Surface energy, by way of microstructural changes, was also shown to influence to a lesser extent changes in the wettability characteristics, while surface O2 content, by way of process gas, was found to play a minor role in inducing changes in the wettability characteristics of the mild steels.
Human behavioral factors in laser safety
Authors: Mannix Rick
Published: June 2006

While training, engineering controls, warning signs/systems, and protective eyewear are emphasized in laser safety programs, laser-related accidents do occur in facilities without obvious deficiencies in those areas. Problems still occur because of insufficient attention to administrative safety issues directly related to human nature and behavioral factors. Common safety problems associated with behavioral factors are discussed. Personal experiences of the author, including lessons learned, are included. The issues are discussed within the context of laser safety, but they are relevant to other fields of safety, as well.