Tire Aging Research Articles

Simulation of temperature field and optimisation of high-temperature parts for a giant mine tire

The temperature field of tires has a significant impact on the cracking aging and service life of tires. Therefore, the finite element simulations of the temperature field of the mining tire were carried out in this paper. The temperatures of the key parts of the tire were measured with the thermocouple under real working conditions. The deviation between the results of the simulation and the measurement is 1.3%. In addition, the function among the maximum temperature, the velocity and sinking amount of the tire was fitted using the simulating results of the temperature field under the nine types of working conditions. Further, based on the response surface method, the structure of the 1# strap layer with high temperature of the tire was optimised by taking the width of the strap layer, the distribution density of the steel wire and the angle of the steel wire arrangement as the independent variables, and the maximum temperature of the tire under steady rolling as the response value. Finally, the results show that the maximum temperature of the optimised model decreases by 3.06 °C compared to the original model.

Effect of functionality and loading procedure of liquid butadiene rubber on properties of silica-filled tire tread compounds

This study explores the utilization of liquid butadiene rubber (LqBR) as a processing aid in tire tread compounds, as a replacement for treated distillate aromatic extract (TDAE) oil, which is known to contribute to the extraction of organic materials during tire aging. Additionally, the influence of the silane-terminated functional group in LqBR and the procedure of LqBR addition are investigated. The results demonstrate a significant reduction in organic extraction when employing silane-terminated LqBR as a processing aid. Moreover, the performance of tire tread compounds is comparable or even superior to those incorporating TDAE oil, particularly when 80 % silane-terminated LqBR is added after the mixing of silica and coupling agent. The enhanced performance is attributed to homogeneous silica dispersion and robust filler-rubber interaction. These findings offer valuable insights into the optimization procedure for developing tire tread compounds utilizing functionalized LqBR as a processing aid, with the aim of improving tire tread applications.

Characterization of thermal-oxidative aging mechanism of commercial tires

The lifespan of tires is associated with the stability of chemical bonds in natural rubber compounds, and thermo-oxidative aging is the main cause of chemical bond breaking in commercial tires. The aim of this study was to characterize the belt thermal-oxidative aging mechanism of commercial tires to understand the damage to their mechanical properties owing to tire aging. Therefore, the mechanical, physicochemical, and thermal properties of virgin and tires aged on the road at varying mileages (0, 5,000, 25,000, 50,000, 100,000, and 150,000 km) were studied. Three types of aging processes were observed. Aging type I occurs under anaerobic and aerobic conditions and at low temperatures, type II occurs only under anaerobic conditions at high temperatures, and type III occurs under aerobic conditions and at high temperatures. Samples from tires at all mileage levels showed high thermal stability with mass loss occurring at 288 °C (TMAX). It was concluded that the main mechanism responsible for thermal-oxidative aging in commercial tires is the presence of oxygen and its diffusion between the liner and belt packages. Aging is a natural and an irreversible process. Therefore, ensuring compound stability is one of the approaches used by the tire industry and rubber product manufacturers to minimize the repair costs for the consumer and guarantee vehicular safety and tire structural performance.

Trends in particulate matter generation from truck and bus radial tires using a wear tester

AbstractThis study aimed to analyze the trend of particulate matter (PM) generation from tires by nonexhaust systems. These types of PM are lesser known than the airborne PM generated from automotive exhaust systems. Specimens with rubber formulations similar to commercial tires for trucks and buses were artificially abraded, and the generated PM was analyzed. Abrasion of a specimen made of butadiene rubber, which is a synthetic rubber, generated lesser PM than a natural rubber specimen. This reduction of PM generation was particularly significant for PM10. Furthermore, using carbon black (a filler in tires) having small sized particles, the generation of PM2.5 was reduced to a large extent. To study the influence of tire aging on the increased generation of PM, rubber specimens were analyzed after prolonged exposure to a high temperature.

Hygrothermal aging and water absorption behavior of radial tire composites

AbstractRadial tires (RT) are widely used in the automobile. However, the moisture absorption characteristics of the tire in the hygrothermal environment accelerate tire aging and affect the service life. This work focused on the water absorption behavior and durability of RT composites in the hygrothermal environment. The effects of aging in water at 30, 60, and 90°C on water absorption, chemical degradation, and internal structure of RT composites were investigated. The results showed that the water diffusion of RT composites followed the Fickian's law of diffusion in the initial stage. The kinetic parameters of water absorption were also determined at this stage and were closely related to the change of temperature. Then, moisture led to the poor interface and the degradation of RT composites. Natural rubber (NR) matrix swelled due to the invasion of water, which developed stresses that could cause microcracks of the matrix in the second stage. Moreover, moisture promoted hydrolysis of the NR matrix and agents in the third stage. The water molecules existed in unbound water and bound water, which made the water diffusion followed the Langmuir adsorption model.

Aging of tire and road wear particles in terrestrial and freshwater environments – A review on processes, testing, analysis and impact

The environmental fate of tire and road wear particles (TRWPs) receives increasing attention due to the per capita emission volumes of 0.2–5.5 kg/(cap year) and recent reports on the environmental hazard of TRWP constituents. It is expected that aging impacts TRWPs fate in the environment but detailed knowledge is quite limited, yet. Making use of information on tire aging, the available knowledge on environmental aging processes such as thermooxidation, photooxidation, ozonolysis, shear stress, biodegradation and leaching is reviewed here. Experimental techniques to simulate aging are addressed as are analytical techniques to determine aging induced changes of TRWPs, covering physical and chemical properties. The suitability of various tire wear test materials is discussed. Findings and methods from tire aging can be partially applied to study aging of TRWPs in the environment. There is a complex interplay between aging processes in the environment that needs to be considered in future aging studies. In addition to existing basic qualitative understanding of the aging processes, quantitative understanding of TRWP aging is largely lacking. Aging in the environment needs to consider the TRWPs as well as chemicals released. Next steps for filling the gaps in knowledge on aging of TRWPs in the environment are elaborated.

Vehicle Tire Text Reader: Text Spotting and Rectifying for Small, Curved, and Rotated Characters

Tire burst of vehicles is one of the main causes of highway accidents. Furthermore, tire aging is the most important cause of tire burst. It will be of great significance to traffic safety, through identifying the tire text code (TTC) to determine whether or not a tire is over the service life. In this article, a coarse-to-fine method of detection and rectification for TTC is proposed. First, text regions are located using the deep convolutional neural network (DCNN) model. Second, through fitting the tire circle curve, the close-up image of TTC is rotated to a positive direction. Third, a text boundary points’ generation strategy is proposed, which is based on the rotating bounding box of each character. Fourth, the curved text is rectified and input to the DCNN recognition model. On the tire image dataset, the detection accuracy of TTC and characters is 94% and 96.5% respectively, and the recognition accuracy is 94.5%. Through additional experimental results, it is proven that the proposed method has strong robustness to illumination and camera shooting angle, which can meet the real-time detection and recognition requirements as well.

The effect of different types of ageing on adhesive properties of steel cord. Salt aging

The development of the world automotive industry is aimed at creating new, both in design and properties of tires that can operate in high dynamic loads under different operating conditions. The most probable cause of aging of automobile tires is considered in the article; one of methods of laboratory tests for the accelerated aging of system rubber-metal cord is described. The dependence of the influence of the metal cord design on the adhesion characteristics of the rubberized metal cord and its resistance to aging is also analyzed.

ゴムの状態変化

Belt separation, the final stage of belt edge crack growth, is discussed to illustrate the influence of tire aging to durability. The resistance to crack propagation of aged rubbers correlates well with extension ratio at break λb, which is considered to represent the extent of crosslinking due to oxidative aging. Resistance to crack propagation falls with decreasing λb, i. e., with crosslinking during aging. Consequently, aging of tire causes deterioration of resistance to belt separation. Reduced oxygen permeation through tire wall, by means of nitrogen inflation and use of halogenated butyl rubber for inner liner, leads to better durability. It is also found that lower temperature mixing leads to better aging resistance and tire durability.

ゴムの状態変化

The log λb vs. log M100 mapping, using the relation λb ∝ M100-0.75 as a reference, which held for the change caused by crosslinking, has been found effective to classify the tensile property changes due to aging under various laboratory conditions. The method was now applied for the rubber parts of PCR tires used in the field. Four types of change patterns, as found in the laboratory, were also found in tire aging. Although the aging conditions in tire agreed with those of laboratory in some cases, other cases also appeared to exist. The reasons were discussed by means of special condition added to the tire parts during field use.

Tire aging: a human factors analysis of failure to warn and inform

A scenario of an automotive accident caused by tire failure is given followed by a human factors analysis of the information available to consumers on tire aging. Consumers have not been told that the age of the tire is a safety concern. It is not easy to decode the date of manufacture on tires. More publicity and prominent warnings are needed to communicate the dangers of older tires. Also, better ways to present the date of manufacture so that consumers can more easily and accurately assess tire age are needed.

Effect of Text Format on Determining Tires' Date of Manufacture

Previous research indicates that most consumers are unaware that older tires can deteriorate and lead to tread separation which could result in crashes. Even if they were to know about this hazard, the task of determining the date of manufacture (DOM) on tires is difficult. In the U.S., consumers must decode a 4 digit number at the end of a longer U.S. Department of Transportation (DOT) identification number in small, black print embossed onto black sidewalls. Eighty-three participants (45 students and 38 adult non-students) were asked to decode 6 different date of manufacture (DOM) markings. Analyses showed that people have difficulty with determining dates in the current U.S. DOT format and that date formats resembling common U.S. date representations were more understandable to participants. Additionally, only half of the participants reported having knowledge of tire aging issues and few have looked at the DOT identification number before participating in this research. Discussed are implications for date formatting, followed by guidance on designing a more consumer-friendly DOM. Language: en

Erroneous or Arrhenius—Potential Impact of Oven Temperature Variations on Laboratory Aging of Tires

Abstract During the American Society for Testing and Materials (ASTM) F09.30 Tire Aging Task Group’s development of a test standard for the accelerated oven aging of tires, seemingly erroneous results were obtained from a single test method being conducted by multiple facilities. Ultimately, these differences were associated with variations in oven temperature among the sites involved. The Arrhenius Law provides a means of understanding the potential impact of oven temperature variation on thermal oxidative aging of tires and is used to draw inferences with respect to both laboratory oven aging and local ambient temperatures. Limitations of applying the Arrhenius equation, possible actions to compensate for oven-to-oven and within-an-oven temperature variation, and suggestions for potential validating experiments are also discussed.

Gas Transport in the Tire Aging Test and Intracarcass Pressure Issues

Abstract Development of the laboratory-based accelerated service life testing—“tire aging test”—encountered difficulties due to the complexity of multidisciplinary processes in the tire materials and structures while trying to induce thermooxidative degradation similar to that taking place in the “worst case” in-service. Preliminary experience with the oven aging at elevated temperatures showed that in some light truck tires damaging conditions occur in the form of sidewall blisters/detachments and casing separations due to inflation gas built up in interior tire layers during oven aging, even prior the roadwheel endurance testing (DOT HS 810 799, Research Report to Congress on Tire Aging), National Highway Traffic Safety Administration (NHTSA), Washington, D.C., 2007, http://www.cbsatlanta.com/download/2010/0512/23529107.pdf). Analysis and comprehensive modeling techniques are developed for gas diffusion and oxidation in the tire structure, with focus on the intracarcass pressure (ICP) build-up predictions. In finite element models, the temperature dependent diffusion properties are used with account for their high heterogeneity in different tire components. Results of transient simulations predict higher oxidation/degradation rate in the sidewall and a detrimental effect of ICP build-up for Load Range E tires—mainly due to excessive nitrogen permeation. Influence of the butyl liner barrier permeability and gauge is evaluated, as well as impact of other tire construction variations. Predicted trends agree with the available observations and measurements. ICP levels in simulations of the long-term gas diffusion under regular service conditions are significantly lower than in the oven aging test modeling. Mechanical aspects of the ICP-induced sidewall separation are also discussed. Modified aging test conditions are proposed that will greatly reduce the deleterious side-effect of the ICP buildup, as assessed in simulations.

Rubber Oxidation and Tire Aging - A Review

Abstract While a new tire may have excellent resistance to crack initiation and propagation between the steel belts, an aged tire of the exact same construction can exhibit dramatically reduced crack growth resistance, which in some cases may contribute to tire failure. This article will review the research that has gone into quantifying the rate of oxidation the steel belt rubber oxidizes in different climates from tire samples retrieved from consumers' vehicles. The information obtained from the field is then compared to data collected from various resources attempting to develop accelerated tire aging protocols. Finally, methods for potentially improving tire aging are reviewed.

Numerical Model for Nitrogen Tire Inflation

Abstract The scope of this study was twofold: (1) to quantify the contribution nitrogen inflation would have on oxidative aging of tires and (2) measure the improvement nitrogen tire inflation may have on inflation pressure retention. A previously developed tool for diffusion-limited oxidation was used to simulate aging behavior at 25 and 60 °C. Oven-accelerated tire aging (60 °C) data for different inflation media was used for successful validation of the model, and it was shown that aging rates for higher oxygen concentrations tend toward a constant value. For lower temperatures, the use of nitrogen was shown to produce lower oxygen concentration in the wedge and bead regions of the tire geometry considered when compared to air inflation. By using 95% pure nitrogen (that is, the actual nitrogen concentration in the tire cavity), a 25% reduction in aging rate (for the tire wedge) and a 35% reduction in the initial flux of mass out of the tire (a measure of inflation pressure retention) were calculated.

Rubber aging in tires. Part 1: Field results

Oxidative aging of skim and wedge rubber inside the tire results in a loss of peel strength and tensile properties of these rubber materials, which has been found to increase the likelihood of tread separations in certain tires. In order to develop an accelerated laboratory tire aging test, we have carried out extensive field and laboratory studies of rubber property change in tires. This paper describes the analysis of rubber oxidation in a specific set of tires collected from the field. In particular, we determine the rate of property loss under worst-case environmental conditions and analyze the implications of variability in aging results. The analysis is used in a companion paper to develop acceleration factors for different laboratory tests.

People Do Not Identify Tire Aging as a Safety Hazard

Tires are among the most critical components of motor vehicles, requiring proper maintenance to minimize the risks of accidents associated with failure. Tire failures at high speeds in vehicles such as SUVs have resulted in vehicle rollovers, serious injuries and occupant death. Tire degradation, as a result of age-related factors, can be contributor to tire failure for which many people may have little awareness. A total of 225 participants (101 non-student adults and 124 college students) were asked to list all contributors that they believed could cause tire problems. Although most respondents mentioned one or more causes of tire failure, only 4.0% of the participants mentioned tire aging as a cause. These results suggest that a substantial proportion of the population is not aware of tire aging as a potential hazard. Implications for a multi-method labeling and warning system are described

Numerical Simulation of Thermal Oxidation in Automotive Tires

Abstract A finite element kinetic model has been developed to interpret issues related to accelerated aging of tires. The model is based on the Basic Autoxidation Scheme and incorporates mass transport limitations related to diffusion of oxygen into the layered elastomer system. The extent of oxidation is calculated at different locations within the tire as a function of time and temperature. Results for aging rates due to thermal oxidation predicted by the model are compared to experimentally derived data such as crosslink density, elongation-to-break and modulus variation. Comparative results for aging rates in different regions of the tire suggest that a reasonable accelerated oven testing temperature range is 60 °C to 70 °C. Additionally, initial results for predicted aging rates for a rolling tire are presenting indicating the thermal oxidation plays a large role in tire aging.

Correlation of Rubber Properties between Field Aged Tires and Laboratory Aged Tires

Abstract The kinetics of aging of key tire properties both in the field and in oven exposures at different temperatures has been interpreted by using a combination of empirical models and accelerated shift factors. Crosslink density and rubber modulus increase with aging while peel strength and elongation-to-break decrease. In the case of oven aging, the rate of property change increases from 40 °C to 70 °C and then decreases. In the case of field aging, the rate of property change is greatest in hotter climates such as Phoenix and is slower in cooler climates such as Detroit. Spare tires age at a rate that is ∼70% as fast as on-road tires. Below 70 °C, the rate data for all of the aging changes can be fit to an Arrenhius relationship with an activation energy of ∼69 kJ/mole, a value that is consistent with the aging process resulting from diffusion limited oxidation. The measured acceleration factor of oven aging at 70 °C relative to on-road aging in Phoenix is independent of the property change measured confirming that it is possible to chemically age tires in ovens. It takes 6–7 weeks of oven aging at 70 °C to produce a tire that is aged 4 years in Phoenix. Field results show that the rate of tire aging varies by over a factor of 5 for the different tire types and brands studied in this work. The implications for tire durability testing are discussed.