Tread Pattern Research Articles

Estimation of the Friction Behaviour of Rubber on Wet Rough Road, and Its Application to Tyre Wet Skid Resistance, Using Numerical Simulation

Tyre wet skid resistance greatly affects vehicle safety, and it is dependent on the frictional behaviour at the tyre–road interface; however, the currently available numerical models, using the finite element method, either neglect the road roughness or obtain the rightness using expensive computed tomography scans, rendering them inefficient and complex. This study aims to present an estimation method of rubber slides on a rough road, to study tyre wet skid resistance. A three-dimensional rough road model was established, using the harmonic superposition method; the sealing effect of the water film on a wet road was modelled in terms of the pseudo-hydrodynamic bearing effect; the contact pressure, hysteresis friction, and water film hydrodynamic lift force were calculated. Subsequently, a friction model was established that accounted for the road surface morphology, tyre properties, sliding speed, and contact pressure. The accuracy of the friction model was experimentally validated, using the published experimental results. The friction model was then adopted, to conduct a study of the wet skid resistance of a 205/55R16 tyre with two different tread patterns. The simulation results were consistent with the experimental results of braking distance on a wet road. Finally, the effects of road roughness, tread rubber, load, and inflation pressure on wet skid resistance were carried out and analysed. The works in this paper have important significance and practical value for the development of high-performance tyres.

The Effect of Tread Pattern Tires on Hard Compound Coefficient Rolling Resistance

Rolling resistance is the resistance of a wheel that will roll or rotate due to friction between the outer surface of the wheel and the track surface. This study aims to determine the effect of tread patterns on the coefficient of rolling resistance. The tires that will be used in this study are hard compounds with a ratio pattern and tread pattern raised by 2 mm with a tire hardness of 79.5 Ha, and using pressure variations at 30 Psi, 40 Psi, and 50 Psi. Coefficient value rolling resistance is 1.39% with a rolling resistance of 8.05 N. These results are produced by a hard compound with a tread pattern of 2 mm at a pressure of 50 Psi. Meanwhile, the rolling is 2.04% with a rolling resistance of 11.82 N. These results are produced by hard compound tires with a pattern at a tire pressure of 30 Psi.Keywords: compound, tread pattern, rolling resistance

Experimental investigation of tire traction performance on granular terrain

In this work, an indoor soil bin traction measurement system is developed to systematically investigate the traction behavior of an off-road tire in interaction with granular terrain. The system is composed of a soil bin, a single wheel test device, a soil mixing/compaction device and its control and data acquisition system. Then the traction performance parameters such as the wheel traction force, sinkage, soil deformation and/or failure mechanism are obtained and investigated by using the system under different working conditions (tire slip, wheel load, tread pattern, granular medium). The experimental results show that the wheel traction force and sinkage present high linear correlation with the tire slip and wheel load. The wheel traction force and sinkage are also found to be directly influenced by the tire tread patterns and granular media. Moreover, with the increase of slip, the shear failure of the soil terrain behind and under the tire becomes more obvious, and the ruts become more blurred. The trend of shear failure mode of the granular terrain from local shear failure to overall failure is becoming ever more obvious. However, under the same tire slip, the wheel loads (7663 N, 10163 N and 12663 N) have little effect on the failure mode of soil terrain. Finally, the experiments indicate that the trafficability of the off-road tires on the gravel terrain is better than that on the sand terrain. The traction performance of the groove tires under the same soil conditions is better than that of the smooth tires.

FIXATION AND EXAMINATION OF VOLUMETRIC TRACKS OF FOOTWEAR USING 3D SCANNING TECHNOLOGIES

The article is devoted to demonstrating the possibilities of using 3D scanning technologies to capture and study volumetric footprints. The author notes that traditional methods of visual fixation of such reflections (description, measurement, photography) are not informative enough, and the main method of object fixation (making plaster and other molds) is associated with the risk of significant damage to the fixed trace. At the same time, the use of contactless 3D scanners allows you to quickly, efficiently, and non-invasively create detailed digital 3D models of volumetric footprints. The author experimentally tested the fixation of shoe footprint in terms of inspection of the scene (at the place of its detection), scanning of the potential trace-forming object in terms of its separate inspection (in the laboratory), as well as a study of 3D models using laser 3D scanners Artec Leo and Artec Space Spider and Artec Studio 16 software. Possibilities of using Artec Studio 16 software to study and compare 3D models of forensically significant objects are demonstrated. The author’s experiments showed that with the use of 3D scanners with a scanning accuracy of up to 0.1 mm and the appropriate software, it is possible to scan and examine shoe prints with medium and large tread pattern elements, and using scanners with scanning accuracy up to 0.05 mm and more – fixation of traces left by shoes with more complex patterns of sole protector. The 3D models obtained in this way are accurate and detailed, accurately convey the size, shape, and color of scanned objects, and can be used for visual inspection and comparison of objects, and their visual demonstration (for example, in court). The level of detail of 3D models obtained with Artec Leo and Artec Space Spider allows comparative studies of shoe traces and the corresponding traceorming objects on their 3D models. Methods similar to those described in this article can be effectively used to capture and study other types of volumetric traces and their corresponding trace-forming objects: traces of tire treads and other parts of vehicles, breakage tools, bullet holes, etc. Key words: 3D scanning, 3D scanner, fixation, foot traces, comparative research.

The application of TreadMatch scans to aid the process of footwear mark comparison

Currently in the UK, if a person is arrested or charged with a recordable offence, they can have prints of their footwear taken whilst in custody. The tread pattern recorded in these prints can be searched for using the National Footwear Database to find out if the same footwear pattern has been recovered at previous crime scenes, generating forensic intelligence.TreadMatch is a digitised system for collecting footwear prints seized from detainees in custody for this purpose. Whilst its use for generating intelligence is accepted, validation experiments have not been conducted to understand its level of performance in assisting in forensic comparison purposes for identification, because in the absence of an incorporated scale, it is not known how well TreadMatch reproduces the pattern size of a tread, threatening the validity of the comparison. If it can be determined that the measurements of TreadMatch scans are consistent with the more commonly used aluminium powder test marks, this could save Police time and resources if the digital scans could be used for preliminary assessment prior to the footwear being physically submitted for evidential comparison. Therefore, this study set out to compare three different types of TreadMatch scans (‘dynamic’, ‘zoomed’ and ‘rolled’) for thirty different pieces of footwear, with test marks of the same footwear using the traditional method (fingerprint powder). Length and width measurements were obtained from each tread pattern using GNU Image Manipulation Program software. The resulting data were analysed to assess for agreement between TreadMatch scans and test marks using 95% Intraclass Correlation Coefficients (ICC) and 95% Bland-Altman plots of Limits of Agreement (LOA). Additionally, an intra-sample study using fifteen repeated measurements of the same piece of footwear for different TreadMatch scanning methods was carried out to support the larger validity study.95% ICC3,1 resulted in coefficients ranging from 0.99 to 1.00 across all measurements. 95% LOA displayed close agreement. There was less agreement and more variation displayed between the test marks and the TreadMatch rolled scans for both length and width measurements. This variation for hand-rolled prints must be taken into consideration and a standard approach developed. The study suggests TreadMatch can be used for preliminary assessments in assisting forensic comparisons, particularly for dynamic and zoomed prints.

Investigation of Tyre Pattern Effect on the Aerodynamics of a Passenger Vehicle

Abstract The wheels of a passenger vehicle are one of the major contributors to the total aerodynamic drag, making their aerodynamic performance a considerable factor for the overall energy efficiency of the vehicle. Previous studies have shown that the complex flow field created by the wheels is sensitive to small geometrical variations of the tyre and that features such as shoulder profile and tread pattern can have a significant impact on drag and lift. In this study, the DrivAer model is used to evaluate the flow fields and aerodynamics of four tyre tread patterns with two rim designs. Full-scale wind tunnel tests were conducted where forces, surface pressures and flow fields were measured. Numerical simulations were also performed to aid the analysis. Using a slick tyre as the reference, it was found that rain grooves typically reduced the drag, whereas the effect of lateral grooves was dependent on the rim configuration. For the lift forces, the largest lift variations were obtained for the front lift which, in general, was reduced by rain grooves and increased by lateral grooves, most notably for the closed rim. The importance of considering the parasitic lift force acting on the wheel drive units when comparing experiments and simulations was demonstrated.

Inspired by Tree Frog: Bionic Design of Tread Pattern and Its Wet Friction Properties

Inspired by Tree Frog: Bionic Design of Tread Pattern and Its Wet Friction Properties

Finite Element Analysis of elastomer: Case study – Rolling resistances of pneumatic and solid tyres

EU tyre labelling rules have been applied since November 1st, 2012, to inform about the performances of tyres on fuel efficiency (rolling resistance), safety (braking on wet surfaces) and noise (external noise). The tyre labels help customers to make their purchase decisions by trade off on tyre performances and prices. Consequently, manufacturers have to engineer their products so that their tyres are classified on top of the label categories. Tyre rolling resistance involves in many kinds of tyre knowledge such as rubber formulations, tyre structures and tyre tread patterns. Generally, 70% of tyre rolling resistance depends on the hysteresis properties of rubber compounds and 30% depends on other properties such as road conditions, tyre pressures, load carrying, vehicle speeds, and tyre tread designs. From this point of view, even if rubber compounds are formulated to have good hysteresis properties, they can help reduce tyre rolling resistance up to 70%. If tyre rolling resistance needs to be further reduced, tread designs have to be considered. Therefore, this case study will show how to reduce tyre rolling resistance by using Finite Element Analysis (FEA). Pneumatic light truck tyres were used to study their tread patterns, tread depths and contact areas affecting their rolling resistances, while solid tyres were used to study on their tread patterns, tread depths, contact areas and tyre structures affecting their rolling resistances. The FEA results showed that tread patterns had high effects on rolling resistance of pneumatic light truck tyres while they had little effects on solid tyres. Contact areas and tread depths affected rolling resistances of both tyres. Increase in contact areas reduced tyre rolling resistances while increase in tread depths resulted in higher tyre rolling resistances.

Introducing a procedure for predicting and reducing tire/road noise using a fast-computing hybrid model.

Prediction and reduction of tire noise are some of the main concerns of tire designers nowadays. Due to tire noise's sophisticated nature, low-noise tire design is like a maze path improbable to achieve without a scientific understanding of the underlying causes. This paper develops a knowledge-based hybrid model, incoherent summation of sounds generated and amplified by texture impact, tread impact, air-pumping, Helmholtz resonance, pipe resonance, horn effect, and air cavity resonance. The required data have been carried out by measuring C1 radial tires' noise levels in a semi-anechoic chamber. The developed model [with about a 1.7 dB(A) error on total noise prediction] presents mechanisms' contributions to the overall sound. The model is substituted with a fast-computing statistical model employing data generated based on Taguchi design. Machine learning methods are implemented for this aim, and the support vector machine provides the most accurate model. The proposed fast-computing hybrid model, developed based on a scientific description of underlying mechanisms, is applicable for noise reduction. The model's sensitivity to 21 tire parameters is analyzed, leading to valuable tips on lower tire noise. The results show the critical role of tread pattern characteristics, especially groove angle, in tire noise.

Deep Generative Tread Pattern Design Framework for Efficient Conceptual Design

Abstract Tire tread patterns have played an important role in the automotive industry because they directly affect automobile performances. The conventional tread pattern development process has successfully produced and manufactured many tire tread patterns. However, a conceptual design process, which is a major part of the whole process, is still time-consuming due to repetitive manual interaction works between designers and engineers. In the worst case, the whole design process must be performed again from the beginning to obtain the required results. In this study, a deep generative tread pattern design framework is proposed to automatically generate various tread patterns satisfying the target tire performances in the conceptual design process. The main concept of the proposed method is that desired tread patterns are obtained through optimization based on integrated functions, which combine generative models and tire performance evaluation functions. To strengthen the effectiveness of the proposed framework, suitable image pre-processing, generative adversarial networks (GANs), two-dimensional (2D) image-based tire performance evaluation functions, design generation, design exploration, and image post-processing methods are proposed with the help of domain knowledge of the tread pattern. The numerical results show that the proposed automatic design framework successfully creates various tread patterns satisfying the target tire performances such as summer, winter, or all-season patterns.

Fundamental Study on Optimal Design Method of Tread Patterns Simultaneously Realizing Functional Properties and Aesthetics

Tread patterns are grooves or notches carved into shoe soles and tire surfaces. They significantly affect physical performance, such as ease of running and stopping. In addition, the complexity of their design and the fact that they form the external shape of a product also demands their visual beauty. This study proposes a multi-objective optimal design method that simultaneously considers functional properties and aesthetics. First, the dataset of aesthetics evaluation is prepared based on the semantic differential method, and it is transformed into a convolutional neural network model using a machine learning technique. It enables the quantitative evaluation of the aesthetics of respective patterns. The physical performance indices are evaluated by the finite elements methods as well. Then we solve multi-objective optimization problems using a data-driven topology design method with physical and sensory indices as objective functions. Finally, we apply the proposed method to an example problem about tire tread patterns to verify its fundamental validity and effectiveness.

Modern understanding of the tread rubbers wear mechanism

The durability of pneumatic tires for earth-moving machines is characterized by ability to remain operational until the limit state occurs during maintenance or repair and is determined by lifetime until unacceptable wear of the tread pattern or tire failure due to rupture of the carcass, peeling of treads and other possible damage.
 However, wear is a more complex process than external friction, and is the result of the physicochemical and mechanical processes combined effect, which take place in the surface layer of contacting bodies. The task of preventing premature tire wear is complex and is associated with the ability to determine the wear mechanism.
 It was found that the wear of tread rubbers occurs according to a mixed wear mechanism under real operating conditions. The total wear intensity is determined by the ratio of individual types, but wear indicators can modify significantly when operating conditions change. An abrasive wear mechanism is implemented applied to pneumatic tires, which use on earth-moving machines and work in the most difficult and varied operating conditions at road and land-reclamation construction objects.

Tread rubber compound effect in winter tires: An experimental study

This paper presents an indoor experimental study focused on analyzing the effect of various tread rubber compounds on the tire performance on ice.A set of sixteen tires (two per rubber compound) with identical dimensions, construction, and tread pattern, but of different tread rubber compounds, was investigated using the Terramechanics Rig which measures all forces and moments acting on a tire that is rolling (free or with slip) on ice. All operational parameters (normal load, inflation pressure, ice static coefficient of friction, ice temperature) were kept constant. Testing the tires under free rolling provided insights into the effect of the tread rubber compound on the resistive forces.The investigation led to conclusive evidence that the tread rubber compound affects drawbar pull coefficient significantly (double for best than for the worst tire). It was found that the effect of the tread rubber compound in the lower slip region is most prominent, which is also where vehicles operate most of the time. The decrease in the stiffness is generally considered a positive sign for improvement in available friction but this cannot be a generalized conclusion when analyzing the tire as a whole, which is one of the major findings of this study.

The Influence of Microplastics from Ground Tyres on the Acute, Subchronical Toxicity and Microbial Respiration of Soil

As a rubber annular coat of rim wheels, tyres are inevitable parts of all vehicles in modern times. As to their composition, however, they represent a risk for the environment. During the use of tyres, tyre tread patterns become abraded, which results in its gradual wear and necessary re- placement. These micro and nano particles are then gradually extracted into the environment, namely soils and waters. Our research study was focused on the assessment of subchronical phytotoxicity (pot trial with a mixture of substrate and predetermined ratio of abrasion products lasting 28 days) and biological tests (testing phytotoxicity of leaches with predetermined ratio of abrasion products on Petri dishes). The biological tests were comprised two plant species—seeds of white mustard (Sinapis alba L.) and garden cress (Lepidium sativum L.). In the mixtures of substrate with determined shares of abrasion products (5%, 25%, 50% and 75%), respiration of CO2 was also established by means of soil microbial respiration (Solvita CO2-Burst). Substrates with 5% and 25% abrasion proportions showed increased biological activity as well as increased CO2-C emissions. The increasing share of abrasion products resulted in decreasing biological activity and decreasing CO2-C emissions. The results of subchronical phytotoxicity ranged from 62% to 94% with values below 90% indicating substrate phytotoxicity. The results of biological tests focused on the phytotoxicity of tested samples exhibiting values from 35% to 70% with respect to the germination index with values below 66% indicating the phytotoxicity of tyre abrasion products.

Characterization of dynamic response of asphalt pavement in dry and saturated conditions using the full-scale accelerated loading test

Asphalt pavement exhibits different dynamic responses to vehicle loading in saturated conditions and in dry conditions. It is essential to directly conduct field full-scale tests to systematically investigate comprehensive influence of water on dynamic response of asphalt pavement. However, real vehicles which were often applied in field tests might result in a certain deviation in dynamic responses measured from each field loading test due to the inevitable influence of the driver’s subjective operation and the tread pattern on vehicle wheel. This study adopted the full-scale accelerated loading test system to comprehensively characterize dynamic response of asphalt pavement in both dry and saturated conditions based on the strict control of loading vehicle’s path. The results indicated that dynamic responses showed relatively larger magnitudes in saturated condition than those in dry condition. Strain and stress respectively showed slowly increasing and decreasing trends with the increase of vehicle load and speed correspondingly. Pore water pressure was apparently sensitive to vehicle speed compared with vehicle load. Pore water pressure generated by the front axle wheels showed obviously larger magnitudes than those produced by the rear axle wheels due to the change in thickness of surface runoff. The transverse distribution of pore water pressure obtained from both field tests and numerical simulation exhibited consistent variation trends. Decline degree of pore water pressure magnitudes was obtained at 86.1% for the two adjacent testing points with a distance of 100 mm under the vehicle wheel, which proved the great influence of the tread pattern of vehicle wheel on the transverse distribution of dynamic pore water pressure. A prediction model of positive pore water pressure that considered vehicle load and speed was proposed.

Theoretical Tire Model for Wear Progress of Tires with Tread Pattern Considering Two-Dimensional Contact Patch

ABSTRACT A new theoretical tire model for the wear progress of tires with tread block pattern is developed considering a two-dimensional contact patch. In the model, the wear energy is calculated from the shear force and pressure distribution in a two-dimensional contact patch that are changed with not only shear forces in a contact patch but also with the wear and irregular wear of tires. The fore–aft shear force in a contact patch consists of six mechanisms related to slip ratio, camber, contact between a tire and a road, barrel deformation of a loaded block, rolling resistance, and a rolling tire with rounded crown shape, whereas the lateral shear force consists of three mechanisms related to slip angle/camber, contact of a tire with rounded crown shape, and barrel deformation of a loaded block. The heel and toe irregular wear and the progress of irregular wear under pure slip condition qualitatively agree with the conventional knowledge of tire engineers. The expected wear energy is introduced to predict the wear progress under combined slip condition in the wear course. Using the vehicle dynamics to predict the tire force history, a histogram of external forces is obtained by transforming from it. Calculating wear energies by changing slip angle and slip ratio, the relation between external forces and the wear energy is expressed as the response surface. Multiplying the wear energy by the histogram, the expected wear energy distribution in a block is calculated. Assuming that the worn depth is proportional to the expected wear energy, the wear progress is predicted.

Using Infrared Module and Laser Ranging Module to Monitor Tread Pattern of Powered Wheelchair

Using Infrared Module and Laser Ranging Module to Monitor Tread Pattern of Powered Wheelchair

Research on the Contradiction Mechanism of Tire Rolling Resistance and Grip Performance

ABSTRACTIn order to clarify the contradictory mechanism between tire rolling resistance and grip performance, 10 205/55 R16 radial tires with different tread patterns were selected as the research objects. Based on digital image correlation method, the pressure and deformation distribution in the contact area of test tires were obtained and the relevant grounding parameters were extracted. The partial least square regression (PLSR) method was used to establish the relationship between the identified grounding parameters and tire performance indicators. Using the bootstrap resampling method, the significance test of the PLSR coefficients were carried out, and the grounding characteristic parameters with significant explanatory effect on the performances were selected, identifying the main function area for the two performances. The results show that in order to improve the grip performance of the tire, it is necessary to reduce the transverse tensile strain of the tread in the contact area and increase the longitudinal tensile strain of the tread; but, with the increase of the longitudinal tensile strain, the rolling resistance of the tire will also increase, which leads to the contradiction between tire rolling resistance and grip performance.

Elimination of Stray Forces from Tire Dynamics Measurements or Beware the Backpath

ABSTRACT The forces that enter the mounted tire spindle of laboratory-type tire dynamics test machines include the following items: (1) direct tire-generated forces, tire nonuniformities, and tread pattern vibrations; (2) direct tire-transmitted rough road surface or cleat impact forces; (3) direct machine resonance-amplified versions of items 1 and 2; (4) machine frame backpath-transmitted versions of items 1–3; (5) dynamic loadcell crosstalk; (6) external noise from foundation vibrations; and (7) adjacent load station vibrations traveling through the machine frame. Although items 1 and 2 are sought in spindle vibration measurements, items 3–7 are also included in the mix and confound the measurement, confusing the analyst into thinking that machine properties are tire properties. Not only do items 3–6 not exist in vehicle operation but also comparison of results from one test machine to another can be an exercise in comparing machine to machine, not tire to tire. Tire dynamics measurements should simulate tires in roadway operation, not create a whole new set of problems that do not exist in vehicles. Elimination of item 7 paved the way to developing a tire failure warning system that operates on tire endurance test machines and can be adapted for operation on passenger vehicles to warn the driver of tire trouble. This article develops the theory of stray force measurement, describes a method for eliminating stray forces from experimental tire dynamics data, and provides experimental verification of the effectiveness of these methods.

Experimental Observations in Tire Cavity Resonance and Interactions with Periodic Noise Components

Tire cavity resonance is one of the major sources of tire-related in-cabin noise and vibration. It has gained more attention in recent years with the growth of the electric vehicle market. This is due to the absence of masking noise from the internal combustion engine and powertrain. Thus, the mitigation of this issue has become a critical task for tire and vehicle manufacturers. The excited cavity resonant frequency in an unloaded condition is typically between 170 - 220 Hz. However, multiple studies have shown that loading the tire will result in two dominant resonances transmitted into the cavity. Their corresponding mode shapes are typically described in terms of the direction of their characteristic acoustic pressure variation i.e., fore-aft cavity mode and vertical cavity mode. As the tire's rotational speed increases, in-cabin measurements show that the tire cavity resonant frequencies separate from each other. Further, interactions with the periodic component of tire noise at certain speeds are also observed. These periodic components can be attributed to tire non-uniformities and tread pattern related excitation. This interaction is perceived as tonal noise inside the vehicle cabin at discrete speeds. This work presents experimental results summarizing these findings.