Tire Surface Research Articles

INFLUENCE OF VERTICAL LOAD ON BRAKING FORCE AND TYRE ADHESION COEFFICIENT OF VEHICLE WHEEL

Influence of vertical load on the adhesion coefficient of automobile wheel in the braking mode on the basis of experimental researches is analyzed. Research results of different authors concerning the degree of the influence of various factors on the adhesion coefficient are presented. It is known that the fundamental basis of vehicle active safety is its braking properties, and the nature of braking depends on the interaction of motorcar tires with road surfaces. Such interaction in the theory of a car is usually described by the adhesion coefficient, which can be implemented both in the longitudinal and transverse directions relative to the rotation area of the vehicle wheels. Experimental researches on rolling car wheel of locking border have demonstrated that a high change of filling speed of the brake chamber does not contribute to increasing the braking efficiency and consequently, the work of the modulator in the mode of intensive filling of brake chamber makes no sense. Vice versa, as experimental researches have demonstrated, the reduction of filling rate of the brake chamber increases the efficiency of braking, although at the initial moment of time, due to the low braking torque, the efficiency is slightly underestimated. Considering the inconsistency of the adhesion coefficient in automotive practice will allow modeling dynamics of vehicle inhibition with automatic regulation systems at a higher level and with greater reliability. Increasing the vehicle mass leads to a decrease in the coupling properties of its tires and consequently to reduce the amount of deceleration, reducing its mass, vice versa increases the coupling properties between the tire and support surface, which positively affects the performance of the vehicle braking (its slowing increases).

Degradation of scrap tyre by Bacillus sp. – Kinetic aspects of major environmental parameters and identification of potential growth substrates

This study aimed to elucidate some kinetic aspects involved during the degradation of waste scrap tyre by a Bacillus sp. previously isolated. After a 5-day cultivation, 2.03 ± 0.22% and 0.005 ± 0.001% of weight loss were observed for tyre sample and control group, respectively. The potential organic compounds leached out from tyre, identified by GC-MS, mainly consisted of n-alkanes and some alkylated phenols. A mixture of tetradecane, nonadecane, and 2,4-di-tert-butylphenol (60 mg l−1 total concentration) supported the isolate growth during the 5-day cultivation. The n-alkanes were removed more effectively (tetradecane, 64.93% and nonadecane, 47.92%) than the alkylated phenol (3.03%), contributing to the tyre degradation by Bacillus sp. observed. The optimal conditions were determined as 6.70 mg l−1 dissolved oxygen concentration, pH 7, 10% (v/v) inoculum size, 30 °C, and 120 mm2 tyre surface area. The highest maximum specific growth rate (μmax) (0.06 OD unit d−1 for S and SI) and the shortest lag phases (0.28 d for S and 0.17 d for SI) were obtained under the optimized conditions for the Bacillus sp. incubation. The electron micrographs showed the isolate ability to colonize the waste tyre surface.

Tire aerodynamics with actual tire geometry, road contact and tire deformation

Tire aerodynamics with actual tire geometry, road contact and tire deformation pose tough computational challenges. The challenges include (1) the complexity of an actual tire geometry with longitudinal and transverse grooves, (2) the spin of the tire, (3) maintaining accurate representation of the boundary layers near the tire while being able to deal with the flow-domain topology change created by the road contact and tire deformation, and (4) the turbulent nature of the flow. A new space–time (ST) computational method, “ST-SI-TC-IGA,” is enabling us to address these challenges. The core component of the ST-SI-TC-IGA is the ST Variational Multiscale (ST-VMS) method, and the other key components are the ST Slip Interface (ST-SI) and ST Topology Change (ST-TC) methods and the ST Isogeometric Analysis (ST-IGA). The VMS feature of the ST-VMS addresses the challenge created by the turbulent nature of the flow, the moving-mesh feature of the ST framework enables high-resolution flow computation near the moving fluid–solid interfaces, and the higher-order accuracy of the ST framework strengthens both features. The ST-SI enables moving-mesh computation with the tire spinning. The mesh covering the tire spins with it, and the SI between the spinning mesh and the rest of the mesh accurately connects the two sides of the solution. The ST-TC enables moving-mesh computation even with the TC created by the contact between the tire and the road. It deals with the contact while maintaining high-resolution flow representation near the tire. Integration of the ST-SI and ST-TC enables high-resolution representation even though parts of the SI are coinciding with the tire and road surfaces. It also enables dealing with the tire–road contact location change and contact sliding. By integrating the ST-IGA with the ST-SI and ST-TC, in addition to having a more accurate representation of the tire geometry and increased accuracy in the flow solution, the element density in the tire grooves and in the narrow spaces near the contact areas is kept at a reasonable level. We present computations with the ST-SI-TC-IGA and two models of flow around a rotating tire with road contact and prescribed deformation. One is a simple 2D model for verification purposes, and one is a 3D model with an actual tire geometry and a deformation pattern provided by the tire company. The computations show the effectiveness of the ST-SI-TC-IGA in tire aerodynamics.

Reduced zinc leaching from scrap tire during pavement applications

Large quantities of scrap tires have been generated and accumulated over the years. However, a significant amount of them are stocked due to the lack of environmentally-friendly methods for disposing of, or reusing them. Because tires contain approximately 1–2% zinc by weight, leaching of zinc from scrap tires could be an environmental concern. In this research, we investigated the leaching of zinc from tire particles that are used with asphalt for pavement applications. The effects of tire particle size and pH on zinc leaching were also examined. Our results indicated that asphalt treatment significantly reduced zinc leaching from tires, and that it was also reduced by increasing the tire particle size and pH. The leaching of zinc was quantified by using a speciation-based modeling approach. The model parameters, namely, the total leachable zinc mass and the adsorption constant, can be used to predict the leaching of zinc under different conditions. The reduction in zinc leaching from asphalt-treated tire particles was due to the physical blocking of the tire surface by the asphalt. Results also indicated that, while the leaching of zinc and other selected toxic elements from untreated tire particles using simulated acid rain was not significant compared to the drinking water regulations, asphalt treatment during the pavement application further improved the environmental performance of the tire particles.

Enhanced hybrid removal of DEHP from contaminated water using Acinetobacter sp. immobilized on scrap tyres

This study investigates the biological removal enhancement of Di(2-ethylhexyl) phthalate (DEHP) by Acinetobacter sp., indigenous isolate, using waste tyres. The DEHP adsoption capacity was poor (2 mg/g) and the contaminant was almost completely removed after 3 days. When tyres were added with the isolate, the colony forming units (CFUs) increased with the incubation time, while the DEHP was almost completely removed within 2 days. The obtained results indicate both DEHP and Acinetobacter sp. sorbed/attached on tyre surface and the isolate utilized DEHP as carbon source to grow. Further studies are under way to better elucidate the exact DEHP removal mechanism.

Use of explicit finite-element formulation to predict the rolling radius and slip of an agricultural tire during travel over loose soil

Theoretically, there is zero slip between two bodies when there is no relative motion in their contact points. In the contact between a wheel and a surface, zero slip can be obtained only in the case of a single contact point. In this case, the wheel and the surface must be rigid. The theoretical zero-slip condition can’t be obtained in the contact between tire and terrain surface. In much of the scientific literature, two alternatives are suggested for a practical definition of the zero-slip condition: the point at which the gross traction force is equal to zero, or the point at which the net traction force is equal to zero. In the ASABE (2013), there is still no unique definition for the practical zero-slip condition. According to the definition of zero-slip condition, the rolling radius is not constant and depends on the slip.A detailed finite-element model using Lagrangian elements was built for each tire, taking into account the effect of all tire materials and their arrangement, lug shape, and inflation pressure. The soil model was built with Eulerian elements, which allow a large degree of deformation and flow of the soil. The initial verification experiments of the tire models were conducted by pressing the tires against a rigid plane. Each tire was examined under several different inflation pressures. Very good correlations were obtained between the experimental and model results. The verification test for the gross and net traction forces was performed in the soil-bin laboratory at the Technion. Special equipment was built, including a heavy dragging platform and a cell to hook the tire. This equipment allows control of the tire slip. The net traction force, gross traction force, and vertical load were measured in each test. Good correlations were obtained between the experimental and model results.Using the FEM model developed, some definitions for zero-slip condition were examined. The results indicate that the best criterion for zero-slip condition is definition of the point at which the gross traction force is equal to zero.

Optimization of major environmental parameters to degrade scrap tyres by Bacillus sp.

The possibility to degrade spent rubber and tyre waste using microorganisms to reduce environmental threats has been considered. The present study investigated the optimization of major environmental parameters (pH, temperature, dissolved oxygen concentration, inoculum size, and tyre surface area) that would enhance the Bacillus sp. growth, an indigenous bacterial isolated from scrap tyres. The optimal conditions were determined as pH 7, 30°C, 6.7 mg/L dissolved oxygen, 10% (v/v) inoculum size, and 120 mm2 tyre surface area. Further detailed investigation is under way to pinpoint the exact organic compound(s) leached out from tyre, as growth substrate(s) for Bacillus sp.

Dynamic interaction of suspension-type monorail vehicle and bridge: Numerical simulation and experiment

Abstract To evaluate the dynamic behaviour of suspension-type monorail (STM) system, a coupled dynamic model of the STM vehicle-bridge system has been developed based on multibody dynamics and finite element (FE) theory. In the model, both the spatial vehicle model with 21 degrees of freedom and the 3-dimensional FE model of the bridge structure for a particular STM system are established by using ANSYS parametric design language (APDL). The vehicle subsystem is coupled with the bridge subsystem through the contact relation between the vehicle tire and bridge inner surface. Then, a mixed explicit and implicit integration method is used to solve the coupled dynamic model. Finally, the dynamic responses of the vehicle-bridge system are calculated by adopting the established model, which are compared with the field test data. Results show that the simulation with the proposed dynamic model is in good agreement with the filed test data. Some apparent discrepancies can be distinguished when the bridge is treated as rigid body and flexible body, respectively, showing the importance of considering the flexible bridge and demonstrating several modelling advantages of the proposed coupled dynamic model. Overall, the train has good operation stability, and the lateral stability of car body is worse than its vertical stability because of the special vehicle structure. The first-order natural frequencies of the bridge in the vertical and lateral-torsional directions are about 5.60 Hz and 2.27 Hz, respectively. The bridge lateral acceleration is significantly larger than the vertical accelerations at the bridge middle-span section due to the low lateral stiffness of the bridge. These conclusions could provide a useful guidance for design of the STM system.

A nonlinear multi-spring tire model for dynamic analysis of vehicle-bridge interaction system considering separation and road roughness

This paper proposes a nonlinear multi-spring tire (NMST) model for dynamic analysis of vehicle-bridge interaction (VBI) system considering separation and surface roughness. First, a nonlinear single-spring tire (NSST) model is developed, which can only provide compression force rather than extension force. By introducing it into VBI system, the dynamic interaction problem considering separation and road roughness becomes a typical dynamic problem with material nonlinearity which can be easily solved by the combination of Newmark method and Newton method: the coupled governing equations never change whatever the tire separates from the bridge or not. It is more convenient because iterative process is required in conventional method to check the separation status and once separation occurs, the coupled governing equations have to change and decouple into independent equations corresponding to vehicle and bridge, respectively. It is then extended to NMST model which is more realistic because the contact surface of tire and road are of finite size instead of a point and the tire usually cannot touch the bottom of valleys in the road profile. In the numerical examples, it can be found that the dynamic responses of both bridge and vehicle obtained by NMST model are better than those obtained by NSST model because they have lower high frequency components, which is closer to the observation in the field testing. The proposed NMST model can be easily incorporated into various VBI models, which benefits for numerical study of dynamic responses of both vehicle and bridge and indirect methods to identify modal properties and local damage of bridge structures.

Undercarriage heat power in aircraft landing

This paper analyse the energy flow which generates heat and causes wear during the acceleration period of undercarriage wheels after aircraft touchdown on the runway. In this acceleration period, a sliding between the wheel tyre and runway surface takes place. The sliding friction causes high temperature which emits pollution smoke and produces excessive tyre wear. A model based on mechanical dynamics is established for analysing the high temperature, heat transfer rate to tyre and concrete runway. The effect of adopting a pre-rotation device is also analysed in order to lower the temperature and reduce the tyre wear. The width of tyre is shown also having significant effect on the raised temperature. A blackened runway is believed to have changed the heat conduction therefore affecting the landing quality.

Research on Machine Vision Inspection Technology of Tire Nail Hole

To solve the problem in the detection of tire nail holes which is caused by manual positioning or X-ray radiation, a machine vision technology-assisted highvoltage discharge detection system is designed to effectively detect the nail holes and accurately locate the holes. The Otsu is used to perform binarization of the image after the grayscale conversion. And the position of the nail hole is precisely positioned by tracking the object tracker of a specific color. After 5 groups of actual tests, we can accurately identify the location of the tire surface diameter of 2.5mm and above through holes, with the detection rate up to 92%.

Case study on aircraft tyre wear in Y12 aircraft tyres

ABSTRACTThe primary objective of this research was to analyse the discrepancies in polymeric properties in Y12 aircraft tyres after 50 landings. Tensile strength and elongation test, abrasion test and hardness tests were carried out for the nose and main gear tyres after the completion of 50 landings. Surface morphologies of the tyre samples were observed using SEM. ISO specifications were followed for each experimental method during testing. There was a reduction in both median tensile strength and elongation at break in aircraft tyres after 50 landings but the reduction rate of both parameters were lower in Tyre 2 (nose wheel tyre) compared with Tyre 1 (left main wheel tyre) and Tyre 3 (right main wheel tyre). The highest percentage of mean volume loss was reported for Tyre 3 (3.88%). In addition, the least percentage of mean volume loss was obtained in Tyre 2 (2.98%). The percentage of hardness reduction was highest in Tyre 2 (6.9%). The surface roughness was induced to the tyre surface after completion of 50 landings.

Numerical and Experimental Predictions of Texture-Related Influences on Rolling Resistance

To overcome rolling resistance (RR) a typical vehicle on average consumes 4152 MJ/119 L of fuel annually as a result of both vehicle and pavement factors. A slight improvement in surface texture arrangement may therefore decrease fuel consumption bringing substantial long-term socio-economic benefits. This aligns with ever-tighter limits on CO2 in the USA (163 g/km until 2025) fostering sustainable construction/exploitation of tires/pavements. This paper describes a multi-scale 3-D numerical methodology to calculate micro-distortional RR and contact indentations of surface aggregates into visco-elastic tread compound accounting for loading, velocity, temperature, and compound properties. It consists of a micro-scale tread block single aggregate model and a macro-scale car tire finite element model, rolling in steady-state mode over a rigid smooth surface. The surface texture is idealized in terms of hemispherical indenters. The micro-distortional RR estimates are based on contact force and energy lost per single stone. The computed contact/normal forces peak significantly due to visco-elastic effects at the beginning of the tire–surface contact phase, followed by a gradually relaxing stress region with a sudden release at the end of the interaction. The contact forces appear to be of a reasonable distribution and magnitude. It is found that micro-distortional RR is higher on a rougher and sparsely packed surface compared with a smoother and more tightly packed case. To determine the total tire-related RR, macro-distortional RR can then be added. The predictions were qualitatively confirmed and adjusted against real bituminous mixes by experimental testing, showing a reasonable agreement.

Prediction of Sound Absorption of Stacked Granular Materials for Normal and Oblique Incident Sound Waves

Tire-road noise is a problem in many (densely) populated areas. It can be significantly reduced by using porous asphalt concrete. A challenge is to develop porous asphalt concrete, such that the most dominant frequencies in tire-road noise will be absorbed by the road surface. It is especially important to also reduce and absorb oblique incident sound waves, since tires radiate noise normal to the tire surface, which means oblique incident waves on the road surface. Predicting the behavior of porous asphalt concrete using models is complex, especially when non-local effects and scattering effects are included. The objective of this paper is to show a modeling approach to predict sound absorption for oblique incident waves in three-dimensional porous materials. Using this method, one is able to predict the sound absorption of porous road surfaces in the design phase. This modeling approach includes a two-step approach in which first the viscothermal energy dissipation inside the pores between the rigid materials (stones) are estimated and then, secondly, the non-local effects such as scattering on the st ones within the porous road surface are computed using a finite element model. The combination of both sound fields gives the total sound field in and above the three-dimensional porous material, which is used to determine the sound absorption coefficient. The analytical viscothermal and scattering solution are discussed in this paper and the modeling approach is validated with experiments using a box with stacked marbles for several angles of incidence.

Modeling of Contact Patch in Dual-Chamber Pneumatic Tires

ABSTRACT This study presents an investigation of the inner tire surface strain measurement by using piezoelectric polymer transducers adhered on the inner liner of the tire, acting as strain sensors in both conventional and dual-chamber tires. The piezoelectric elements generate electrical charges when strain is applied. The inner liner tire strain can be found from the generated charge. A wireless data logger was employed to measure and transmit the measured signals from the piezoelectric elements to a PC to store and display the readout signals in real time. The strain data can be used as a monitoring system to recognize tire-loading conditions (e.g., traction, braking, and cornering) in smart tire technology. Finite element simulations, using ABAQUS, were employed to estimate tire deformation patterns in both conventional and dual-chamber tires for pure rolling and steady-state cornering conditions for different inflation pressures to simulate on-road and off-road riding tire performances and to compare with the experimental results obtained from both the piezoelectric transducers and tire test rig.

Adaptive Feature Selection and Feature Fusion for Semi-supervised Classification

Labeling of data is often difficult, expensive, and time consuming since efforts of experienced human annotators are required, and often we have large number of samples and noisy data. Co-training is a practical and powerful semi-supervised learning method as it yields high classification accuracy with a training data set containing only a small set of labeled data. For successful co-training performance, two important conditions need to be satisfied for the features: diversity and sufficiency. In this paper, we propose a novel mutual information based approach inspired by the idea of dependent component analysis to achieve feature splits that are maximally independent between-subsets (diverse) or within-subsets (sufficient). In addition, we demonstrate the application of the method to a real world problem, classification of laser tread mapping tire data. We introduce several features that are designed to highlight physical characteristics of the tire data, as well as local or global descriptors, such as histograms, gradients, or representations in other domains. Results from both simulations and tire image classification confirm that co-training with the proposed feature set and feature splits consistently yields higher accuracy than supervised classification, when using only a small set of labeled training data is available. The proposed method presents a very promising complement to time consuming and subjective expert labeling of data, reducing expert efforts to a minimum. Further results show that by using a probabilistic multi-layer perceptron classifier as the base learner in co-training, our method leads to very meaningful continuous measures for the progression of irregular wear on tire surface.

Dynamics of Tire Crossing on a Gapped Road Surface

The safety of cars and trucks crossing gapped road surfaces can be affected by their operational speed, mass, and the tire and road surface characteristics. As part of a research on the safety of road vehicles crossing discontinuous road surfaces, the dynamic behavior of a single tire passing a gap has been examined as reported in this paper. First, the kinematics of a tire crossing the gap in the road surface is analytically formulated. The formulation has shown that the tire exhibits three distinct (single-point, two-point, and flying) modes of travel depending on its operational speed. The dynamics of the tire are larger in single-point mode that exhibits two critical velocities, which have been validated using a nonlinear arbitrary Lagrangian Eulerian method in the finite-element framework. The validated analytical model has shown that the critical velocity is mainly affected by the mass of the overburden. Introduction

トレッド内部の変形を利用したタイヤと接地面間の摩擦係数測定

トレッド内部の変形を利用したタイヤと接地面間の摩擦係数測定

FEM-BEM analysis of tyre-pavement noise on porous asphalt surfaces with different textures

Pavement surface characteristics such as surface texture and acoustic absorption play important roles in tyre-pavement interaction noise. The present study aims to investigate the effects of pavement surface texture and porous surface on tyre-pavement noise using a coupled modelling approach with finite element method–boundary element (FEM-BEM) analysis. A radial tyre model was first built using FEM, and tyre surface accelerations under the excitation from pavement texture were obtained from modal analysis. The radiation sound fields caused by tyre vibration were then solved using BEM for noise prediction. Texture profiles and sound absorption coefficients of different pavement surface types were considered in the analysis. The prediction results were calibrated and validated with the measurements reported in the literature. The results show that, with proper calibration, the proposed numerical model can predict sound pressure levels and overall noise with specific inputs of surface texture spectra and acoustic absorption spectra. In general, the surface type with the higher texture levels usually generates greater noise for both porous and non-porous surfaces. The overall noise decreases with the increase of porosity under the same surface texture condition. However, the noise variation due to different sound adsorption coefficients of porous pavement is not as significant as the effect of surface texture on noise.

Investigation of the influence of vertical force on the contact between truck tyre and road using finite element analyses

In the modern context of automobile integration with the emerging technologies of the interconnected society, the interaction between tyre and road is an element of major importance for automobile safety systems such as the intelligent tyres, as well as for passenger comfort, fuel economy, environmental protection, infrastructure and vehicle durability. The tyre-road contact generates the distribution of forces exerted on each unit area in the contact patch, therefore the distribution of contact stresses on three orthogonal directions. The numerical investigation of stresses distribution in the contact patch requires the development of finite element models capable of accurately describing the interaction between tyre and rolling surface. The complex finite element model developed for the 11R22.5 truck tyre has been used for investigating the influence of vertical force on the distributions of contact stresses. In addition to these contributions, the paper presents aspects related to the simulation of truck tyre radial stiffness. The influence of tyre rolling has not been taken into consideration, as the purpose of the current research is the investigation of tyre-road contact in stationary conditions.