Tire Life Research Articles

Solar energy generation potential along national highways

Energy generation using solar photovoltaic requires large area. As cost of the land is growing day by day, there is a strong requirement to use the available land as efficiently as possible. Here, we explored the potential of energy generation using the land above national road highways by constructing a roof structure. This space can contribute to the energy generation without extra cost for the land. It also results in energy efficiency, for example, improved vehicle movement and minimum energy for air conditioning of vehicles. Additionally, it also helps in minimum road repairs and longer vehicle tire life due to the effect of sun shade. Thus, the expenditure for wear and tear for road repairs is reduced considerably. From our modelling study, it is observed that the Ahmedabad-Rajkot highway can generate 104 MW of electricity (163 GWh of annual energy generation) and the Ahmedabad-Vadodara highway space can generate 61 MW of electricity (96 GWh of annual energy generation) for single-layer solar panels. If there are two layers of solar panels one over the other, the annual energy generation of the same highways, Ahmedabad-Rajkot and Ahmedabad-Vadodara, can be increased to 229 GWh and 140 GWh, respectively. If our concept is implemented throughout India, it not only increases the power generation to more than a few gigawatts of electricity but also has other various fringe benefits including longer road life, employment generation, reduced CO2 emission in environment, etc.

Regression and Failure Analysis of Dumper Tires: A Case Study for Iron Ore Mines

Mining industry is directly related to tire mounted equipments like dumpers. In case of dumpers, tire being the critical spare, is in extensive use. This study identifies thirteen critical causes for tire failures and impact and occurrence of these causes are also developed. Moreover, efforts have been made to establish tire life of dumpers, working in iron ore mines, in terms of run hours. It is suggested that the life of tires may be increased from its base value by a number of ways like monitoring tread depth, maintaining proper haul road conditions, using proper tread pattern and filling nitrogen gas inside the tires.

Chronobiologically Interpreted Ambulatory Blood Pressure Monitoring in Health and Disease

To detect vascular variability anomalies (VVAs), a blood pressure and heart rate profile around the clock for at least 7 days is a start. As a minimum, measurement every 60 or preferably 30 minutes for a week is needed, to be continued if abnormality is found, to assess the about 24-hour (circadian) variability that exists in all individuals. As a first dividend, one then also obtains a glimpse of 2 of the very many longer-than-circadian periodicities, the biological half-week and week. Certainly if we can have sensors and computer chips in our cars that continuously monitor the pressure over a tire's life, we should be able to do the same job for ourselves for diagnostic and therapeutic decisions. Healthcare today emphasizes wellness with recommendations for exercise and a proper diet, yet these evaluations may not be adequate. BP may be measured at a visit to the doctor or before an exercise session, along with measuring body weight and performing a physical exam. The seeds of disease are planted long before they are visible, and what appears to be normal from a conventional point of view may in fact be abnormal. Hidden alterations of physiological function, masked by the body's remarkable adaptive capabilities, may become visible through a new diagnostic and therapeutic realm—chronobiology—that reveals hitherto unseen abnormalities. The tools of chronobiology may yield additional dividends, such as the detection of physiological “loads” related to stress and stress relief and the undesirable effects of space weather upon personal events such as sudden cardiac death, societal events like terrorism and war, and natural disasters. Chronobiologically interpreted automatic ambulatory BP and heart rate (HR) monitoring (C-ABPM) may detect the antecedents of these types of events. C-ABPM is of interest in preventive cardiology, since it reveals new diagnoses as vascular variability anomalies (VVAs) and renders previous conventional diagnoses more reliable, such as that of an elevated BP. These VVAs include MESOR (midline-estimating statistic of rhythm)-hypertension, an elevation of the MESOR, which is diagnosed, like all other VVAs, only after 1 or preferably several replications of 7-day around-the-clock BP monitoring with available, affordable, and unobtrusive instrumentation. The recommendation for continuous C-ABPM recognizes several principles that constitute inseparably intertwined contributors to severe cardio-, cerebro- and renovascular diesase. C-ABPM gauges wear and tear of genetics, physical loads, and in particular mental stress placed upon individuals from “womb to tomb” by daily life, including weather in extraterrestrial space as well as that on earth, as a continuous surveillance paradigm preventing us from flying blind to a change from less than 5% to near 100% in the risk of a stroke within 6 years.

Study and Application of Homogeneous Rare Earth IR/NR Blends in Tread Compound of All-Steel TBR Tire

The homogeneous rare earth IR/NR blend applied in tread compound of all-steel TBR tire was investigated,and compare to Russian SKI-3, SKI-5/NR blends and NR.The results showed homogeneous rare earth IR/NR blend had similar vulcanization characteristics, dynamic mechanical properties and heat-aging resistance or even better. It was inspected that the appearance, balance, air bubbles, X-ray and homogeneity inspection test of the tires produced by homogeneous rare earth IR/NR blend by the tire factory,all the indicators were qualified. The tires passed the China National Quality Supervision and Inspection Center of rubber tire certification. The tires met the requirements of all-steel TBR tire.The homogeneous rare earth IR prepared by Petro China Jilin Petrochemical Company could 40 phr instead of NR using in tread compound of all-steel TBR tire,which could extend tire life and reduce tire material costs.

CARBON BLACK FOR RACING AND MOTORCYCLE TIRE TREADS. PERFORMANCE MODEL DEVELOPMENT

Abstract Racing tires and motorcycle tires present individual segments of the tire market. For instance, while the average life of car and truck tires is 50 000 miles, the average life of race tires is 100 miles. Because tires play a critical role in a race, technical demands to assure safety and performance are growing. Similarly, tires have a large influence on safety, handling/grip, and performance of the rapidly growing world fleet of motorcycles, due to the fact of only two wheels being in contact with the ground. Thus, the common feature of both market segments is that the typical tire compromise of wear, rolling resistance, and traction is strongly weighted toward traction. Most of the recent efforts of rubber scientists have been directed toward lowering rolling resistance of the tread compounds, which left a certain void in the science of compounding for racing and motorcycle treads. Particularly, the industrial assortment of polymers and fillers used for motorcycle treads is commonly different from that used for car or truck treads, but it is not known how the filler properties affect the hysteresis–stiffness compromise. The objective of this study is to evaluate the effects of the carbon black characteristics on the important properties of a typical racing and motorcycle tire tread compound. More than 50 individual carbon blacks were mixed in a SBR formulation. The acquired data were statistically analyzed, and a linear multiple regression model was developed to relate rubber properties (responses), such as static modulus, complex dynamic modulus, hysteresis, and viscosity to the key carbon black characteristics (variables) of surface area, structure, aggregate size distribution, and surface activity. Prediction profiles created from the model demonstrate rubber performance limits for the range of carbon blacks tested, and indicate the niches to provide required combinations of the rubber properties.

Crack propagation in pneumatic tires: Continuum mechanics and fracture mechanics approaches

In this paper, the fatigue life of pneumatic tires is investigated with particular focus on the phenomenon of belt separation. This phenomenon yields the propagation of fatigue cracks in the rubber separating the belts; not the separation of the rubber at the interfaces with the belts. Cracks at the belts edges are related among others to the high stress concentration due to the very different stiffness of the two materials. A steady-state rolling finite element model of the full tire is used to evaluate the stress and strain fields in the rubber at the edges of the belts. Suitable life predictors are defined and computed for the identification of the zones with a higher expectation of failure. For the evaluation of crack propagation in the bulk rubber material between different belts, in principle, two different approaches are employed associated with crack nucleation and crack growth. The two approaches are applied to the study of crack propagation in a truck tire and the results of different predictors are compared to crack propagation found in a real tire.

Reliability Analysis of Radial Tire

Aimed at the radial tire's randomness in the structural parameters and material properties, etc., took the strain energy density of the tire carcass ply turn-up end as the objective function on the basis of analysis of the tire’s main failure modes, chose the tire carcass ply turn-up height and the rubber material parameters as random variable by using the Finite Element sensitivity analysis method(DSA), On this basis, adopted Monte-Carlo stochastic finite element method to calculate the reliability of the fatigue life of tire.

Fatigue life prediction for radial truck tires using a global-local finite element method

A global-local finite element modeling technique is employed in this paper to predict the fatigue life of radial truck tires. This paper assumes that a flaw exists inside the tire, in the local model. The local model uses an FEM fracture analysis in conjunction with a global-local technique in ABAQUS. A 3D finite element local model calculates the energy release rate at the belt edge. Using the analysis of the local model, a study of the energy release rate is performed in the crack region and used to determine the crack growth rate analysis. The result considers how different driving conditions contribute to the detrimental effects of belt separation in truck tire failure. The calculation of the total mileage on four sizes of radial truck tires has performed on the belt edge separation. The effect of the change of belt width design on the fatigue lifetime of tire belt separation is discussed.

Prediction of the fatigue life of pneumatic tires

A method of the prediction of the fatigue life for parts of pneumatic tires based on the computation of the stress-strain state of the stress concentration areas in a rubber matrix and the self-heating temperature by means of the finite-element method and experimental fatigue curves for rubbercord composites has been developed. Multiple tensile tests of single-layer rubber-cord samples with a squared shape have been carried out, and fatigue curves under various test conditions and types of stress-strain states have been constructed. The fatigue life of the area of the edges of a breaker strip of a 9.00R20HC12 tire under a maximum working load and other parts of pneumatic tires is determined.

Enhancement of Tire Durability by Considering Air Flow Field

Abstract Rolling tire performance is frequently affected by multiple physics. For instance, dry handling is influenced by the tire temperature as a consequence of the heat generation by material viscosity and the heat transfer to ambient air. The general phenomenon is complex and even interactive in that the elasticity parameter affecting tire deformation is a function of the temperature and that the temperature depends considerably on the air flow on tire surface. This paper refers to connecting the different physics of outside air flow and thermomechanical system of tire. Especially, the heat transfer across tire surface is focused from the viewpoint of thermofluid dynamics. Macroscopic flow turbulence to accelerate the heat transfer is studied in a case study of the run-flat tire, where high temperature due to very large deformation is of a key issue. Numerical simulation is conducted in parallel to experimental works in assessing heat flow and temperature on the surface. It is shown that the proposed geometry of rib sidewall reduces the tire temperature and improves the tire life remarkably.

Effect of off-the-road tyre rotation practices on tyre life: a case study

This paper analyses the effect of one important off-the-road tyre maintenance practice, tyre rotation, on tyre life. Data were collected from the Kemess Mine and the relationships between tyre life, tyre wear rate and tyre rotation frequency were identified. Also, tyre rotation sequence acronyms were created to assist in analysing and determining rotation sequence at the Kemess Mine. In addition, engineering statistical approaches such as regression and correlation methods are used to analyse tyre rotation time. These quantitative results suggest that tyre life can be improved by adjusting the tyre rotation interval/frequency.

Evaluation of the effect of off-the-road tire air pressure setting on tire performance

This study presents analysis on the effect of tire air pressure setting at installation on tire life and wear rate. Also a look into the tire spike air pressure is conducted. The relevant data were collected from the Kemess Mine. An engineering statistical method-analysis of variance (ANOVA) is employed to determine and quantify the installation air pressure setting influence on tire life and wear rate. The quantitative results indicate the tire life and wear rate are influenced by higher installation air pressure settings. In addition, the wheel positions that have experienced most spike air pressures are identified.

Tire Pressure Monitoring [Applications of Control

Proper tire inflation pressure improves fuel economy, reduces braking distance, improves handling, and increases tire life, while underinflation creates overheating and can lead to accidents. Approximately 3/4 of all automobiles operate with at least one underinflated tire. Beginning with 2006 models, all passenger cars and trucks in the United States are required to have tire-pressure monitoring systems (TPMSs). A TPMS is a driver-assist system that warns the driver when the tire pressure is below or above the prescribed limits. TPMSs are classified into two categories, namely, direct and indirect. In direct TPMSs, the pressure drop is calculated based on actual pressure measurements through sensors. In contrast, measurements such as wheel speed are used in indirect TPMSs.

A Laboratory Method to Comprehensively Evaluate Abrasion, Traction and Rolling Resistance of Tire Tread Compounds

Abstract A laboratory test method has been developed which allows the evaluation of diverse properties of tire tread compounds on the same sample. The laboratory test instrument consists of a rotating abrasive disk against which a rubber sample wheel runs under a given load, slip angle and speed. All three force components acting on the wheel during the tests are recorded. By changing the variable values over a wide range practically all severities encountered in tire wear are covered. The well-known fact that compound ratings depend on the road testing conditions is verified. Most compounds are only significantly distinguishable against a control over a limited range of testing conditions. Using a road test simulation computer program based on the laboratory data shows that not only ratings correspond to practical experience but also calculated absolute tire life times do. Tests on surfaces of different coarseness and sharpness indicate that sharp coarse surfaces give the best results with road tests, which of necessity are mostly carried out on public roads of differing constitution. The abrasive surface can be wetted with water at different temperatures and hence either the friction force at a locked wheel or the side force at a slipping wheel can be measured over a wide range of temperatures and speeds. At small slip angles the side force is dominated by dynamic cornering stiffness of the compound, at large slip angles by the friction coefficient. In this case, too, good correlations to road experience exist over a limited range of testing conditions. Low water temperatures and low slip speed settings in the laboratory produce side force ratings, which correlate closely with ABS braking on the road High and higher slip speeds give ratings in close agreement with locked wheel braking on the road. A heatable/coolable disk enables traction measurements on ice and newly abrasion measurements on surfaces at elevated surface temperature. Ice surface temperatures between −5 °C and −25 °C are possible. Friction measurements show that the difference in compound rating between summer and winter compounds is maintained over the whole temperature range. New investigations show not only a differentiation between different winter tire treads qualities but also an excellent correlation between tire and laboratory results. As a new topic side force measurements on dry surfaces highlight the correlation to dry handling of tires. The tire tread compound contributes to this performance through its shear stiffness and its friction coefficient. The shear stiffness contributes to the response of the tire in directional changes. The friction coefficient determines the maximum force, which can be transmitted. A simple operation possibility for evaluation of determined side forces is demonstrated. In addition to antecedent investigations the rolling resistance of the rubber wheel can be measured over a range of loads and speeds with the slip angle set at zero. Again for these new results good correlations are achieved with practical experience. In particular, the dependence of the rolling resistance on the velocity and loads are pointed out. Ultimately a good correlation between tire test and laboratory test results was demonstrated.

Consideration of the frictional force on the crack surface and its implications for durability of tires

In order to find out a physical quantity which controls the fatigue life of a structure and to predict the fatigue life of tires, a finite element simulation methodology to use the cracking energy density (CED) and the virtual crack closure technique (VCCT) was proposed and applied to three different tires of a similar size. CED was calculated to predict the location of a crack initiation, and VCCT was used to obtain the strain energy release rate (SERR) at the tip of an initiated crack. Finite element simulations showed that SERR oscillated in the circumferential direction with its minimum occurring just before the contact zone and its maximum occurring just after the center of the contact zone, and SERR was affected significantly by the frictional force acting on the crack surface. In addition, a durability test was conducted to measure the fatigue life of the three tires. The comparison of SERR values with the test data revealed that the fatigue life increased as the amplitude of SERR decreased or as the R-ratio of SERR increased.

Contact pressure distribution and support angle optimization of kiln tyre

According to the shearing force character and the deformation coordination condition of shell at the station of supports, the mathematical models to calculate contact angle and contact pressure distribution between tyre and shell were set up, the formulae of bending moment and bending stress of tyre were obtained. Taking the maximum of tyre fatigue life as the optimal objective, the optimization model of tyre support angle was built. The computational results show that when tyre support angle is 30°, tyre life is far less than that when tyre support angle is optimal, which is 35.6°, and it is unsuitable to stipulate tyre support angle to be 30° in traditional design. The larger the load, the less the nominal stress amplitude increment of tyre, the more favorable the tyre fatigue life when tyre support angle is optimal.

Prediction of the Fatigue Life of Tires Using CED and VCCT

A new simulation methodology using the finite element method (FEM) was proposed to predict the fatigue life of tires. In the FEM simulation the cracking energy density (CED) was calculated, and the virtual crack closure technique (VCCT) was used to calculate the strain energy release rate (SERR) for a crack. First, a plane in an element on which CED had its maximum was determined, and a crack was created on the plane. Once a crack was introduced, another plane on which CED had its maximum was again determined, and the crack was further elongated along the plane. In addition, SERR was calculated for every crack increment by using VCCT, and it was represented as a function of the crack length. Then, the fatigue life of a tire was determined using Paris law. For Paris law, the initial crack length and the final crack length as well as the material constants should be known. In this paper, the initial crack length was set in a way that the fatigue life predicted by using Paris law became the same as the test data for a tire model (Tire A), and the final crack length was determined from the cross-section views of failed tires which showed cracks grown about halfway toward the carcass from the carcass turn-up edge. Finally, the fatigue life for another tire model (Tire B) was predicted by using Paris law, and the predicted fatigue life was compared with the test data.

Tire Design Methodology Based on Safety Factor to Satisfy Tire Life (Simulation Approach to Truck and Bus Tire Design)

Abstract A tire is not only simply made of rubber, but also twisted cord, which we can call FRR (Fiber Reinforced Rubber). The rubber in FRR is made of many materials, including rubber compound, carbon black, silica, and other materials. FRR is a double composite material, which means a particle reinforced material in a microscopic view and also a fiber reinforced one in a macroscopic view. Therefore, it is very difficult to apply fracture mechanics to the evaluation of tire durability on a practical tire design level. This paper gives a proposal for a new design methodology considering the actual tire condition which gives tire profile growth and rubber aging due to heat build-up under operation. These two issues are especially important for truck and bus tire design. Tire profile growth is a very important one because the change of tire profile induces different strains in the rubber at the same location in the tire during its life. We apply the FEM (Finite Element Modeling) based Double Inflation Pressure (DIP) method to simulate the experimental fact of the change of tire profile. In order to use the relationship between the change of the tire profile and change of rubber properties, like breaking strain in the tire as service time passes, the concept of safety factor is introduced. The low modulus rubber parts in the tire dominate the strain field and allow the large deformations of the tire. Safety factors derived from the strain field are called “Margin of Safety.” On the other hand, the durability of FRR, like the belt layer and carcass layer with the cord part, is evaluated by stress because the FRR part reacts to the stress of the internal pressure and load of the tire. But, the Margin of Safety of the rubber part is more important because the cord part has enough safety factor in comparison with the rubber part. Tire life is predicted with the Margin of Safety described above.

環境・衛生関連 タイヤにおける環境対応型新材料技術

Environment protection is and will be the most important aspect of the tire development. A study of tire's life cycle assessment (LCA) was conducted under Japan Rubber Manufacturers Association, and revealed that the usage stage accounts for more than 85% of total CO2 emission in an entire life cycle of a common tire. From this standpoint, reduction of rolling resistance (RR) is the most important requirement, followed by extension of service life, which contributes to all other stages. Following the development of silica-filled tread compound, further reduction of hysteresis loss had been achieved by development of new materials for silica system, such as dispersion additive and novel modified polymers. In addition, recent implementation of non-linear viscoelastic properties in the Finite Element Analysis has greatly improved the precision of tire RR prediction. This will allow efficient application of low hysteresis materials in tire design.

Contact Pressures and Energies Beneath Soft Tires: Modeling Effects of Central Tire Inflation–Equipped Heavy-Truck Traffic on Road Surfaces

Much has been made of the use of tires with low-inflation-pressure systems called central tire inflation (CTI) systems. Great benefits have been noted in numerous trials, including the reduced requirement for truck maintenance, improved gradeability, longer tire life, improved ride for drivers, reduced road rutting, and reduced road maintenance. Reports of successful field trials in the literature are confirmed by other supporting theoretical studies. However, the studies reported in the literature tend to relate to unsealed, unbound roads. Given that in some quarters there is now a desire to extend the benefits of the use of CTI to sealed roads, new questions arise. A full-scale, laboratory study was carried out at the University of Ulster, Northern Ireland. Both the normal and shear contact stresses were measured with a high-speed data logger connected to electronic sensors in the apparatus’s bed plate, as a tire ran over them. Tire pressures and loads were varied in this factorial study. The contact stresses were measured, and conclusions based on their distribution across the tire “contact patch” were presented. In addition, contact energies were inferred, and the consequences for sealed pavements were suggested.