Tire Profile Research Articles

The influence of the tyre air cavity on the rolling noise

Road traffic is the main source of environmental noise. While combustion noise has been reduced over the years, it appears to be difficult to reduce rolling noise. Even for electrical vehicles at moderate speeds rolling noise is a main contributor to the exterior noise. The main cause of rolling noise is the excitation of vibrations on the tyre structure by contact forces due to varying road roughness and/or tyre profile. However, we know that when rolling over obstacles like rails or bridge joints, the cavity noise due to the excitation of tyre cavity modes is clearly audible. Therefore, one can assume that cavity modes also contribute to tyre/road noise on rough roads. This paper makes the attempt to demonstrate the contribution of cavity noise as function of road roughness and tyre profile. The Chalmers tyre/road interaction model is used for the simulations. A modified radiation model allows for calculating the contribution of each individual tyre mode to the radiated sound. In this way the contribution of the cavity modes can be determined. Results indicate that at least for rough road surfaces the contribution of the cavity modes is of importance for the exterior sound.

Investigation of tyre rim protectors on the aerodynamics of a passenger vehicle

The wheels of a passenger vehicle contribute to a significant part of the vehicle’s aerodynamic drag. The previous research has shown that the flow is sensitive to small geometrical variations of the tyre, such as its shoulder profile and tread pattern. This work investigates the effect of altering the tyre profile in the transition region between the tyre and the rim by adding a so-called rim protector. Full-scale wind tunnel tests capturing forces, flow fields and surface pressures were conducted for three tyre variants in combination with two rim configurations on a crossover SUV. With a low rim protector, the forces and flow fields were similar to the reference tyre without a rim protector for both rims. With a wide, protruding, rim protector on the open rim, a larger and more outwashed front wheel wake was obtained with differences in the vortex structures, resulting in a drag penalty of 0.017CD\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$0.017~C_D$$\\end{document}. The altered front wheel wake reduced the shielding of the rear wheel, resulting in differences in the rear wheel wake and base pressure. With a closed rim, the differences with the wide rim protector were much smaller with only a slight drag increase compared to the reference, demonstrating that there can be a strong interaction between the tyre and rim design.

ЭНЕРГЕТИЧЕСКАЯ МАТЕМАТИЧЕСКАЯ МОДЕЛЬ ОПРЫСКИВАТЕЛЯ

The research was carried out in order to develop an energy mathematical model of a plant protection unit with a trailed sprayer, which makes it possible to optimize the parameters and operating modes, taking into account their influence on the size and loss of crop yield. For comparison with the tendencies of changes in the parameters of sprayers established in practice, computational experiments were performed using the developed mathematical model. The object of study is an analogue of MTZ-82 tractor, the main parameters of which (mass, engine power, kinematic length, etc.) can be changed, an analogue of a trailed sprayer with variable parameters (width, operating speed, tank volume, drawbar length, location of the center of mass, profile width and support wheel diameter, etc.). The optimization criterion was composite and included the sum of direct and indirect energy costs during the operation of the unit, taking into account the energy of the crop lost due to deviations from the optimal parameters and operating modes of the sprayer. Incorrect choice of unit parameters leads to yield losses, resulting from its decrease due to a violation of the deadline for performing a technological operation to protect crops from weeds, trampling down part of the crops by the unit's movers during processing, especially if there is no possibility of turning outside the field, due to soil compaction in the zone of growth and development of plant root systems. Computational experiments carried out using the developed energy mathematical model showed that an increase in sprayer coverage from 16 to 32 m at an aggregate speed of 12 km/h leads to a decrease in total energy costs from 3250 MJ/ha to 1692 MJ/ha, an increase in the unit speed from 7 to 12 km/h, with a working width of 32 m reduces the total energy costs from 1971 to 1692 MJ/ha. Reducing the width of the sprayer wheel tire profile from 0.6 to 0.2 m is accompanied by a decrease in total energy costs from 2793 MJ/ha to 1692 MJ/ha.

Characterisation of the flow around passenger vehicle wheels with varying tyre profiles

The flow around wheels contributes to a significant part of the aerodynamic drag of passenger vehicles, which is crucial for overall energy efficiency. The rotation and bluff-body geometry of the wheels result in a complex flow field that is sensitive to geometrical variations such as the tyre geometry, tread pattern, tyre deformation and rim design.In this work, wind tunnel tests were performed with a full-scale crossover SUV, using two rim configurations and three tyres. Utilising flow field measurements and time-resolved surface pressure measurements, the main features of the flow were identified for three sets of tyres with distinct shoulder profiles and sidewall geometry. The main differences were found close to the ground. With a narrower sidewall, a smaller contact patch vortex was formed, reducing the drag. Combining the narrow sidewall with a narrow tread, the more rounded shoulder created a larger contact patch vortex and pronounced the vortex from the outer downstream tyre shoulder.Comparing closed and open rims, the same overall flow mechanisms were observed but their relative importance was altered. An interaction between the tyre and rim design was found, mainly in terms of how the front wheel wakes affect the rear wheels.

An integrated analytical model for friction characteristics of aircraft tire on wet runway pavement

The challenging issues of tire-water-pavement interaction are to determine the deformed tire profile and the effective tire-pavement contact length due to water intrusion. This study aims to develop an integrated analytical model to analyze friction characteristics of an aircraft tire on wet runway pavement. The tire-water-pavement interaction model consists of the Brush model for tire-pavement contact and the flexible ring model for tire deformation with consideration of hydrodynamic force. The feasible contact footprint and the deformed tire profile are solved using an interactive process between two models. The model shows the ability to predict friction coefficients at various tire loading, velocity, slip ratio, and water conditions. The thicker water film depth causes the reduction of tire-pavement contact length and the increases of hydrodynamic force, resulting in poor skid resistance of pavement. The calculated friction coefficients at different velocities are further used to predict hydroplaning speed and calculate braking distance of aircraft tire. The results demonstrate the significant effect of water depth on the risk of aircraft hydroplaning and overrun on runway pavement.

Tire dependence for the aerodynamics of yawed bicycle wheels

The aerodynamic characteristics of a modern road cycling wheel in cross wind are studied through force- and planar PIV measurements in the TU Delft Open Jet Facility. The performance of the 62 mm deep rim is evaluated for three tire profiles, and yaw angles up to 24°. All measurements are executed at 12.5 m/s (45 km/h) freestream- and wheel-rotational velocity. The wheel's rim-tire section in crosswind is found to behave similar to an airfoil at incidence, ultimately resulting in a reduction of the wheel's aerodynamic resistance with increasing yaw angle magnitude. This phenomenon, also referred to as the sail-effect, is limited by the stall angle of the tire-rim profile. The stall angle is found to depend critically on the tire's surface structure. Larger stall angles, resulting in lower resistance, are obtained if the tire profile triggers laminar-to-turbulent boundary layer transition.

Finite Element Simulation of Radial Tire Building and Shaping Processes Using an Elasto-Viscoplastic Model

The comprehensive tire building and shaping processes are investigated through the finite element method (FEM) in this article. The mechanical properties of the uncured rubber from different tire components are investigated through cyclic loading-unloading experiments under different strain rates. Based on the experiments, an elasto-viscoplastic constitutive model is adopted to describe the mechanical behaviors of the uncured rubber. The distinct mechanical properties, including the stress level, hysteresis and residual strain, of the uncured rubber can all be well characterized. The whole tire building process (including component winding, rubber bladder inflation, component stitching and carcass band folding-back) and the shaping process are simulated using this constitutive model. The simulated green tire profile is in good agreement with the actual profile obtained through 3D scanning. The deformation and stress of the rubber components and the cord reinforcements during production can be obtained from the FE simulation, which is helpful for judging the rationality of the tire construction design. Finally, the influence of the parameter “drum width” is investigated, and the simulated result is found to be consistent with the experimental observations, which verifies the effectiveness of the simulation. The established simulation strategy provides some guiding significance for the improvement of tire design parameters and the elimination of tire production defects.

Evaluation of Agriculture Tires Deformation Using Innovative 3D Scanning Method

This study presents the results of research related to agriculture tire deformation under variable vertical load and inflation pressure. The research objects were two tires of the same size and different internal structures. Three levels of inflation pressure and five levels of vertical load were used. The loaded tire with each inflation pressure was scanned using the 3D scanner—the effect of this operation was a three-dimensional image of a tire part (near the place of contact with the surface). The next step was the creation of vertical and horizontal cross-sections of the tire profile, which allowed the analysis of tested parameters: profile height, location of the point of maximum tire deflection, the width of the tire profile, and the area of horizontal cross-sections. Finally, the mathematical model was formulated, describing contact areas of horizontal cross-sections as a function of the factors. Based on the conducted research, it was stated that an increase in vertical load caused reductions in both types of heights. Moreover, the width of tire profiles and the area of horizontal cross-sections increased due to the increase in vertical load (for bias-ply, increases were smaller than for radial tires). Similar changes were observed after the reduction of inflation pressure.

Use of 3D scanning technique to determine tire deformation in static conditions

This paper presents an innovative digital method to analyse agricultural tire profiles based on pictures. From this method, we can conclude that the tire deformation is caused by the changes in vertical load and inflation pressure. The first stage in this method is 3D-scanning; the vertical cross-section is created from the obtained picture of the tested tire. From this cross-section, the deflection of the tire can be determined. Then, the horizontal cross-section is created - this operation allows determining the tire’s contact area at the highest vertical deformation. Obtained results can be useful to create the tire deformation characteristic. In turn, the contact pressure values can be determined (even through laboratory testing, without research in field conditions). The knowledge about contact pressure allows taking some actions to reduce soil compaction. In the description of the method, the radial tire was used, but the structure and equipment of the test bench allow the use of cross-ply tires with different dimensions.

TYRE PROFILE ARITHMETIC AND PERFORMANCE PARAMETER: A REVIEW OF VEHICLE USERS AND VULCANIZERS’ COGNIZANCE ON CAR TYRE MAINTENANCE TO CURB ROAD ACCIDENTS

Ageing car tyres are a hidden hazard and recipe for road accidents. Many vehicle users and their cohorts seem unconcerned and ignorant about tyre profile and its implications on human lives and livelihood. This study reviewed car users’ and vulcanizers’ comprehension of basic arithmetic of vehicle tyre profile to instigate best practices as well as instil proper maintenance culture. Out of 307 participants, purposive and convenient sampling were employed to select 292 vehicle users and a snowball to contact 15 vulcanizers. Results after a short interview analysis revealed that car users are aware of tyre inflation pressure and could identify the rim diameter of car tyres. Meanwhile, a significant number of users couldn’t tell where to locate their vehicle tyre specification details on their cars and were also unable to interpret tyre profiles including; tyre life cycle, tyre blend, tyre speed rating and load index. Although the majority of the vehicle users carried spare tyres, most of them do not check the conditions of their spare tyres until they are in need. Responses from vulcanizers revealed that most vehicle users do not bother about tyre expiry dates but rather prefer tyre fixing to tyre replacements. It is recommended that the Leaders of Transport Unions of commercial vehicles need to ensure proper load weight of vehicles before setting off from their terminals. Drivers and Vehicle License Authority (DVLA) needs to ensure healthy tyre condition before issuing roadworthy certificates. National Road Safety Authority (NRSA) must maximize sensitization campaigns towards proper tyre maintenance practices to reduce tyre failure accidents.

Aerodynamics of a cycling wheel in crosswind by coaxial volumetric velocimetry

The aerodynamic characteristics of a modern road cycling wheel in crosswind are studied through force measurements and 3D velocimetry in TU Delft’s Open Jet Facility. The performance of the 62 mm deep rim is evaluated for two tire profiles, and yaw angles up to 20◦ . All measurements are executed at 12.5 m/s (45 km/h) freestream- and wheel-rotational velocity. The wheel’s rim-tire section in crosswind is found to behave similar to an airfoil at incidence, ultimately resulting in a reduction of the wheel’s aerodynamic resistance with increasing yaw angle magnitude. This trend, also referred to as the sail-effect, is limited by the stall angle of the tire-rim profile. The stall angle is found to be dependent on the tire surface texture and varies between 14◦ and 20◦.

SIDE SLIP OF WHEELS WITH LOW AND ULTRA-LOW PROFILE TIRES OF A PERSONAL CAR NEGOTIATING A TURN

This article studies the influence of the speed of a car with low and ultra-low profile tires, 14ʹʹ and 16ʹʹ, negotiating a turn through an interactive software system developed by us in the MATLAB environment. The changes of the normal and lateral loads of the wheels are obtained and the characteristics of the side slip angle (known as side slip) of the pneumatic tires are determined. Taking into account the side slip of the wheels, the software determines the center of the turn. The characteristics for the normal and lateral loads and of the side slip of the wheels for both types of tires are given. The influence of the tire profile on the handling characteristics is analysed. Recommendations are proposed for a personal car’s motion in a turn with both types of tires.

Approach of Pavement Surface Layer Degradation Caused by Tire Contact Using Semi-Analytical Model.

New methods of degradations on the pavement’s surface, such as top-down cracking and delamination, caused by the repeated passage of heavy vehicles led to questions about the impact of the contact between the tire and the pavement. In fact, to increase the service life of the structures, future road design methods must have a precise knowledge of the consequences of the contact parameters on the state of stress and deformation in the pavement. In this paper, tractive rolling contact under the effect of friction is modeled by Kalker’s theory using a semi-analytical method (SAM). A tire profile is performed thanks to a digitization by fringes or a photogrammetry technique. The effect of rolling on the main surface extension deformations is then highlighted to study top cracking. At the end of the SAM calculation, contact areas are closed to 200 μdef, exceeding the allowable micro-deformation limit for the initiation of cracking. In addition, results on the main strain directions also give information on the direction of cracking (initiation of longitudinal or transverse cracks). The cracking then becomes evident, leading to a reduced service life.

Tire–pavement tractive rolling contact under turning conditions: towards pavement top-down cracking

ABSTRACT This paper describes the elastic tire–pavement tractive rolling contact, by means of a semi-analytical method, in order to analyse top-down cracking. The model includes the actual tire profile and assumes the tyre to be elastic, linear and homogeneous, as modelled by an equivalent Young's modulus. The pavement is modelled as a half-space layer composed of asphalt concrete acting as a homogeneous elastic material. Results display the vertical contact stress and shear contact stress in both braking and turning cases; they also highlight the stick/slip zones within the contact area. When applied, these stresses allow computing the tensile strain responses at the pavement surface. Analysis shows that the maximum tensile strains are able to cause top-down cracking. Such strains are higher than the level considered in current pavement design models. A top-down cracking analysis is ultimately conducted according to the French method of bottom-up pavement design.

Effect of Railcar Wheel Tire Profiles on the Contact Stress Level in Subway Rails

The statistical analysis performed on the defectiveness of rails in the Kiev subway railway shows that the main cause of the occurrence of most defects is the contact fatigue of the rail material. The paper presents modern concepts of crack growth in the railhead. It has been found that one of the most promising directions of studying the stress-strain state of rails and the crack growth process is a numerical simulation, which results on the contact interaction between rails and subway rolling stock wheels are presented. During the simulation, the problem was solved in an elastic formulation. We considered R50, R65, and UIC60 rail profiles, standard railway wheels, and wheels whose tire profile was developed by the Minetek closed joint-stock company. The conditions for the rail–wheel interaction corresponded to train movement on the straight section of the track without slipping. The effect of the wheel tire profile on the contact stress level in rails of different types has been assessed. Comparison of the maximum equivalent stress levels for a different combination of rail and wheel types shows that the best combination (in terms of reducing the contact stress level) for the straight sections of the subway track is an R50 rail with a gradient of 1 in 20 and 1 in 10 taper wheel, whose profile corresponds to GOST 9036-88. When wheels with the profile developed by the Minetek company are used, the maximum equivalent stress level in the contact zone is over 1000 MPa for all rail types. It is higher than the yield strength of rail steel, which will accelerate wear and give rise to low-cycle fatigue cracks with subsequent formation of contact fatigue defects.

Characterization and Modelling of Various Sized Mountain Bike Tires and the Effects of Tire Tread Knobs and Inflation Pressure

Mountain bikes continue to be the largest segment of U.S. bicycle sales, totaling some USD 577.5 million in 2017 alone. One of the distinguishing features of the mountain bike is relatively wide tires with thick, knobby treads. Although some work has been done on characterizing street and commuter bicycle tires, little or no data have been published on off-road bicycle tires. This work presents laboratory measurements of inflated tire profiles, tire contact patch footprints, and force and moment data, as well as static lateral and radial stiffness for various modern mountain bike tire sizes including plus size and fat bike tires. Pacejka’s Motorcycle Magic Formula tire model was applied and used to compare results. A basic model of tire lateral stiffness incorporating individual tread knobs as springs in parallel with the overall tread and the inflated carcass as springs in series was derived. Finally, the influence of inflation pressure was also examined. Results demonstrated appreciable differences in tire performance between 29 × 2.3”, 27.5 × 2.8”, 29 × 3”, and 26 × 4” knobby tires. The proposed simple model to combine tread knob and carcass stiffness offered a good approximation, whereas inflation pressure had a strong effect on mountain bike tire behavior.

ТЕОРЕТИЧЕСКИЕ ПРЕДПОСЫЛКИ СОЗДАНИЯ МАТЕМАТИЧЕСКОЙ МОДЕЛИ ТЯГОВОГО КПД ТРАКТОРА

To identify the main parameters of the tractor - its mass, engine power, wheel diameter and its profile width (four-parameter optimization) using the optimization criterion - the total energy costs (taking into account the energy of the crop lost due to the non-optimality of these parameters), it is necessary to have a mathematical model for calculation of engine power through the traction coefficient of performance of the tractor. The traction efficiency of the tractor is calculated through f is the coefficient of resistance to rolling of the tractor wheel and d is the coefficient of slipping of the tractor wheel. An analysis of the applied theory developed by previous researchers showed that the values f and d depend on the weight of the tractor coming to one wheel G, the diameter D and the width of the profile of the wheel B, the pressure in its tires ρw, the hardness of the soil H, the effort on the tractor hook Pkp and its speed V. During the analysis, it was found that the larger the diameter of the wheel, the width of the tire profile, the less the vertical load on the wheel and the pressure in the tires, the less the resistance to rolling the wheel over the soil being compacted. It is concluded that the study of the nature of the change in the coefficient of resistance to rolling wheels f and their slipping d from the above factors must be carried out jointly, because they influence each other. The absence of acceptable mathematical dependences for calculating the indicated coefficients, with the simultaneous action of all identified factors, leads to the need for a seven-factor experiment to identify the dependencies f =j (G, D, b, ρw, H, Ркр, V) and δ =ψ (G, D, b, ρw, H, Ркр, V), which is very difficult in operating conditions, therefore, using the similarity theory, it is necessary to reduce the number of factors in the experiment to four.

Method of ensuring the active and operational safety of a motor vehicle with a science-based choice of a tire profile family with regard to the characteristics changes of shock absorbers

This work contains a description and method of ensuring the active and operational safety of a motor vehicle with a science-based choice of the tire profile family with regard to the characteristics changes of shock absorbers. A specific example of the application of this method is given.

НЕОБХОДИМОСТЬ НАУЧНО ОБОСНОВАННОГО ВЫБОРА СЕРИИ ПРОФИЛЯ ШИН ПРИ ИХ ЗАМЕНЕ ДЛЯ ОБЕСПЕЧЕНИЯ БЕЗОПАСНОСТИ

PURPOSE. The purpose of the paper is to justify the need for a scientific selection of a series of tire profiles when replacing tires in order to ensure vehicle safety. METHODS. The study uses the methods of mathematical statistics, mathematical modeling and provides a detailed analysis of the scientific and technical documentation on the topic of the research. RESULTS AND THEIR DISCUSSION. The article presents the statistical data on the wear of tire protector and shock absorbers and provides the criteria for the critical threshold of their life. Description is given to the selection features of lower series tire replacement. The results and analysis of comparative tests on the evaluation of shock absorber wear effect on the braking length of vehicles equipped and not equipped with ABS and ESP systems are presented. A formula is given for determining the conditional probability of the coincidence between the road accident and vehicle movement with wheel breakaways from the road. The results of calculations by the formula are presented as well. It is concluded that this probability can be more than 20% for road conditions in the territory of the Russian Federation. The amplitude-frequency characteristics of the relative accelerations of the vehicle body and wheel movements are constructed and analyzed. It is noted that the replacement of worn tires with the tires of a lower profile even if shock absorbers are serviceable significantly raises wheel vibrations (2 times), which increases the likelihood of wheel breakaway from the road and reduces the safety of motor vehicles. CONCLUSIONS. It is necessary to develop a methodology for scientifically based selection of a tire profile series when replacing tires taking into account the condition of shock absorbers in order to improve the safety of motor vehicles.

Analytical justification of the load capacity of pneumatic tires for tractors and agricultural machinery

Information on the parameters and operating modes of pneumatic tires for tractors and agricultural machinery is contained in state standards in the form of tables in digital form. The variety of types, sizes and designs of tires makes it difficult to determine the tire parameters taking into account conditions and operating modes. The information on the tire parameters is insufficient due to the lack of information about the contact area of the tire with a solid support surface. The article suggests the dependences of the load-carrying capacity of a tire on the generalized geometric parameter equal to the product of the outer diameter and width of the tire profile. The area of contact is an important parameter that affects the traction characteristics of the tractor, the depth of the track when driving on a plowed field and the resistance to movement of the tractor. New terms have been introduced - the theoretical and actual contact areas of the pneumatic tire. The dependence of the theoretical contact area on the generalized parameter equal to the product of the outer diameter and width of the tire profile for diagonal and radial tires is obtained. The cross-section method is used, by means of which the bus contact is cut off from the shell. In this case, the internal forces of the pneumatic tire framework are transformed into real external forces. The analytical dependence of the load capacity of a pneumatic tire is obtained, representing the algebraic sum of the lifting force of the shell and the vertical force of the frame. The universal formula is proposed for determining the actual contour area of the tire contact, in which the contact length and width are used. The values of the length and width of the contact, as well as the ratio of these quantities, are determined experimentally for different loads and pressures, the contact length being determined by the proposed analytical method.