Browse Topic: Tires

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Recurrent Neural Network Model for On-Board Estimation of the Side-Slip Angle in a Four-Wheel Drive and Steering Vehicle15-17-01-00039/23/2023
Abstract A valuable quantity for analyzing the lateral dynamics of road vehicles is the side-slip angle, that is, the angle between the vehicle’s longitudinal axis and its speed direction. A reliable real-time side-slip angle value enables several features, such as stability controls, identification of understeer and oversteer conditions, estimation of lateral forces during cornering, or tire grip and wear estimation. Since the direct measurement of this variable can only be done with complex and expensive devices, it is worth trying to estimate it through virtual sensors based on mathematical models. This article illustrates a methodology for real-time on-board estimation of the side-slip angle through a machine learning model (SSE—side-slip estimator). It exploits a recurrent neural network trained and tested via on-road experimental data acquisition. In particular, the machine learning model only uses input signals from a standard road car sensor configuration. The model adaptability to different road conditions and tire wear levels has been verified through a sensitivity analysis and model testing on real-world data proves the robustness and accuracy of the proposed solution achieving a root mean square error (RMSE) of 0.18 deg and a maximum absolute error of 1.52 deg on the test dataset. The proposed model can be considered as a reliable and cheap potential solution for the real-time on-board side-slip angle estimation in serial cars.
Giuliacci, Tiziano Alberto, Ballesio, Stefano, Fainello, Marco, Mair, Ulrich, King, Julian
Topological Optimization of Non-Pneumatic Unique Puncture-Proof Tire System Spoke Design for Tire Performance15-17-01-00017/18/2023
Abstract Non-pneumatic tires (NPTs) have been widely used due to their advantages of no occurrence of puncture-related problems, no need of air maintenance, low rolling resistance, and improvement of passenger comfort due to its better shock absorption. It has a variety of applications as in earthmovers, planetary rover, stair-climbing vehicles, and the like. Recently, the unique puncture-proof tire system (UPTIS) NPT has been introduced for passenger vehicles segment. The spoke design of NPT-UPTIS has a significant effect on the overall working performance of tire. Optimized tire performance is a crucial factor for consumers and original equipment manufacturers (OEMs). Hence to optimize the spoke design of NPT-UPTIS spoke, the top and bottom curve of spoke profile have been described in the form of analytical equations. A generative design concept has been introduced to create around 50,000 spoke profiles. Finite element model (FEM) model is developed to evaluate the stiffness and damage-resisting performance of NPT-UPTIS spoke. The FEM methodology has also been validated with average accuracy of more than 95% for experimental vertical stiffness for commercial NPT-Tweel. The stiffness and damage-resisting performance of generated designs have been predicted with the help of machine learning regression models, which were trained on the FEM results of 200 such designs. These 50,000 generated designs have been categorized in four different categories based on different level of stiffness and damage resistance performance. In this study, one optimized design from each category has been selected and their performance have been validated with 3D FEM simulation. It has been found that the suggested topology optimization approach is efficient to generate UPTIS spoke designs with having ±30% stiffness with 17%, 40%, and 56% more damage resistance performances with respect to the starting reference design.
Dhrangdhariya, Priyankkumar, Maiti, Soumyadipta, Rai, Beena
Minimum Operational and Maintenance Responsibilities for Aircraft Tire UsageARP5265C (Historical)9/20/2021
This SAE Aerospace Recommended Practice (ARP) sets forth criteria for the installation, inflation, inspection, and maintenance of aircraft tires and the maintenance of the operating environment to ensure the safety of support personnel and the safe operation of the aircraft.
A-5C Aircraft Tires Committee
Speed Planning System for Commercial Vehicles in Mountainous Areas2021-01-01264/6/2021
There are a large number of curves and slopes in the mountainous areas. Unreasonable acceleration and deceleration in these areas will increase the burden of the brake system and the fuel consumption of the vehicle. The main purpose of this paper is to introduce a speed planning and promotion system for commercial vehicles in mountainous areas. The wind, slope, curve, engine brake, and rolling resistances are analyzed to establish the thermal model of the brake system. Based on the thermal model, the safe speed of the brake system is acquired. The maximum safe speed on the turning section is generated by the vehicle dynamic model. And the economic speed is calculated according to the fuel consumption model. The planning speed is provided based on these models. This system can guide the driver to handle the vehicle speed more reasonably. According to the simulation, compared to cruise control, speed planning can save fuel consumption at a mean value of 9.13% in typical mountainous areas. The field test of a typical commercial vehicle shows that this system can increase fuel efficiency by 4.26% compared to an experienced driver during a journey in a mountainous area.
Peng, Dengzhi, Fang, Kekui, Tian, Zhongpeng, Zhang, Yuxiao, Tan, Gangfeng
Wheels/Rims - Truck and Bus - Performance Requirements and Test Procedures for Radial and Cornering FatigueJ267_202102 (Current)2/4/2021
This SAE Recommended Practice provides minimum performance target and uniform laboratory procedures for fatigue testing of wheels and demountable rims intended for normal highway use on trucks, buses, truck-trailers, and multipurpose vehicles. Users may establish design criteria exceeding the minimum performance target for added confidence in a design. The cycle target noted in Tables 1 and 2 are based on Weibull statistics using two parameter, median ranks, 50% confidence level and 90% reliability, and beta equal to two, typically noted as B10C50. For other wheels intended for normal highway use and temporary use on passenger cars, light trucks, and multipurpose vehicles, refer to SAE J328. For wheels used on trailers drawn by passenger cars, light trucks, or multipurpose vehicles, refer to SAE J1204. For bolt together military wheels, refer to SAE J1992. This document does not cover other special application wheels and rims.
Truck and Bus Wheel Committee
Dynamic Cleat Test with Perpendicular and Inclined CleatsJ2730_202101 (Current)1/13/2021
This SAE Recommended Practice describes a test method for measuring the forces and moments generated at a high frequency response spindle when a rolling tire impacts a cleat. The cleat is configured either with its crest perpendicular, 90 degrees, to the path of the tire or optionally with its crest inclined at an angle to the path of the tire. The carriage to which the spindle is attached is rigidly constrained in position during each test condition to provide a good approximation to fixed loaded radius operation. The method discussed in this document provides impact force and moment time histories essentially free from variations due to tire non-uniformities. The method applies to any size tire so long as the equipment is properly scaled to conduct the measurements for the intended test tire. The data are suitable for use in determining parameters for road load models and for comparative evaluations of the measured properties in research and development.
Vehicle Dynamics Standards Committee
Rolling Resistance Measurement Procedure for Passenger Car, Light Truck, and Highway Truck and Bus TiresJ1269_202012 (Current)12/22/2020
This SAE Recommended Practice applies to the laboratory measurement of rolling resistance of pneumatic passenger car, light truck, and highway truck and bus tires. The procedure applies only to the steady-state operation of free-rolling tires at zero slip and inclination angles; it includes the following three basic methods:
Highway Tire Committee
STANDARD FOR TIRE TRACEABILITY CONTENT AND FORMAT FOR THE RADIO-FREQUENCY IDENTIFICATION (RFID) TAG AND ASSOCIATED TIRE DATA SETUSCAR39-1 (Current)11/19/2020
This standard describes a requirement for automotive tire traceability. It includes a definition of the RFID tag and the associated tire data set that can be accessed using the RFID tag as an identifier. The standard describes a unique identification and the associated data set for each tire produced by the tire fabricator. This data will either be provided or transmitted at the time of shipment to retailers, wholesalers or original equipment vehicle manufacturers. Tire identification code and data may be used for error proofing, determining the tire specifications or supporting any inquiries that occur for the duration of its automotive life.
USCAR
Rolling Resistance Measurement Procedure for Highway Truck and Bus TiresJ1379_202011 (Current)11/12/2020
This recommended practice applies to the laboratory measurement of the rolling resistance of pneumatic tires designed primarily for use on trucks and buses in normal highway service, as defined by the Tire and Rim Association, Inc. (TRA); it does not include light truck tires (designated LT). The procedure applies only to straight, free-rolling tires under steady-state operation and includes the following three basic methods:
Truck and Bus Tire Committee
The Measurement of Highway Truck and Bus Tire Rolling ResistanceJ1380_202011 (Current)11/9/2020
The force, torque, and energy methods of measurement are all in common use and should yield the same test results. Effects of steering, traction, and non steady-state tire operations are excluded from the recommended practice because they are still in the research stage. Methods of correcting laboratory data to road conditions are being developed.
Truck and Bus Tire Committee
Wheel ChocksJ348_202010 (Current)10/19/2020
This SAE standard presents the basic information required for the design and manufacture of a wheel chock.
Truck and Bus Tire Committee
Tire Overspeed Landing TestARP5257B (Current)9/18/2020
This document covers the basis of, and test procedure for, an overspeed landing test on aircraft tires with rated speeds of 190 mph (306 km/h) and above. The conditions requiring an overspeed test, alternatives, test requirements and pass/fail criteria are addressed.
A-5C Aircraft Tires Committee
Experimental Study of Tread Rubber Compound Effects on Tire Performance on Ice02-13-02-00066/16/2020
Mechanical and thermal properties of the rubber compounds of a tire play an important role in the overall performance of the tire when it is in contact with the terrain. Although there are many studies conducted on the properties of the rubber compounds of the tire to improve some of the tire characteristics, such as the wear of the tread, there are a limited number of studies that focused on the performance of the tire when it is in contact with ice. This study is a part of a more comprehensive project looking into the tire-ice performance and modeling. In this study, to understand the effect of different rubber compounds on the tire performance, three identical tires from the same company have been chosen. The tires’ only difference is the material properties of the rubber. Two approaches have been implemented in this study. For the first approach, several tests were conducted for the chosen tires at Terramechanics, Multibody, and Vehicle Systems (TMVS) laboratory at Virginia Tech to compare their performance experimentally. For the second approach, a tire-ice model has been used to compute the height of the water film created at the contact patch. As will be shown in this study, an increase in the height of water film results in a decrease in the friction coefficient, which is one of the most critical parameters for the tire performance. By having this knowledge, the performance of the three tires considered in the study was compared using the developed tire-ice model, based on the values obtained for the height of the water film. It is shown that the results obtained by simulation coincide with the results obtained experimentally. The results from this study show the sensitivity of the magnitude of the tractive force with respect to parameters such as tire temperature, normal load, etc. The results also indicate that the tire with the lowest value of Young’s modulus has the highest traction among all three tires used in this study.
Mousavi, Hoda, Sandu, Corina
Road Load Measurement Using Onboard Anemometry and Coastdown TechniquesJ2263_202005 (Current)5/26/2020
This SAE Recommended Practice establishes a procedure for determination of vehicle road load force for speeds between 115 km/h and 15 km/h (or between 70 mph and 10 mph). It employs the coastdown method and applies to vehicles designed for on-road operation. The final result is a model of road load force (as a function of speed) during operation on a dry, level road under reference conditions of 20 °C (68 °F), 98.21 kPa (29.00 in-Hg), no wind, no precipitation, and the transmission in neutral.
Light Duty Vehicle Performance and Economy Measure Committee
A Multi-Resonant Speed Piezoelectric Beam Device for Harvesting Energy from Vehicle Wheels2020-01-12364/14/2020
This work analyzes a cantilevered piezoelectric beam device for harvesting energy from the simultaneous rotation and translational vibration of vehicle wheels. The device attaches to the wheel rim so that it displaces tangentially during operation. A lumped-parameter analytical model for the coupled electromechanical system is derived. The device has one natural frequency that is speed-dependent because of centripetal acceleration affecting the total stiffness of the device. Even though the device has one natural frequency, it experiences three resonances as the rotation speed varies. One resonance occurs when the rotation speed coincides with the speed-dependent natural frequency of the device. The other two resonances are associated with excitations from the vibration of the vehicle wheel. The device’s parameters are chosen so that these three resonances occur when the wheel travels near 30 mph, 55 mph, and 70 mph. There are two excitation frequencies that give these resonant speeds, and both choices differ from the conventional selection of the device’s natural frequency to match the excitation frequency. Instead, the device’s natural frequency must be either above or below the natural frequency for these resonances to occur at the intended speeds. The maximum energy harvested by the device is more than 45 milliwatts at each resonance. The speed bandwidths are quantified near each resonance, and, even though the resonances are linear, bandwidths of a few mph demonstrate the robustness of the device to changing vehicle speeds. The sensitivity of the power harvested by the device to the input vibration frequency and equivalent resistance of the electrical load is numerically examined. The power harvested by this device is sufficiently large to permit sensing and communication for next generation intelligent tire applications.
Cooley, Christopher
Research on Factors to Influence Coasting Resistance for Electric Vehicles2020-01-10684/14/2020
The research on coasting resistance is vital to electric vehicles, since the smaller the coasting resistance, the longer the coast-down distance. Vehicle coast resistance consists of rolling resistance, vehicle inner resistance and the aerodynamic drag. The vehicle inner resistance is mainly caused by driveline’s friction loss and oil splash loss. The rolling resistance is decided by tire resistance coefficient, which is influenced by tires and road conditions. And the aerodynamic drag is affected by vehicle’s shape and air. In this paper, four factors including tire pressure, road surface condition, atmosphere temperature, and recirculation on or off are examined. Experimental tests have been conducted on three different vehicles: one subcompact sedan, one compact sedan and one subcompact SUV. Then experimental results have been imported to simulation model to investigate the corresponding influence on NEDC range. The outcome shows that, when the tire pressure is 20% less, the average coasting resistance is increased by 1% to 3% depending on vehicle types, which indicates a decrease in NEDC range by around 2%. And with atmosphere temperature in 6 to 32°C range, the resistance is decreased by 0.48% for every 1°C increased. On wet road surface, the average coasting resistance is increased by 10% - 20%, which could decrease the NEDC range by 6% to 12%. As for the recirculation on or off, one vehicle with inside air recirculation on experiences an average 6% coasting resistance reduction. Other two vehicles have similar coasting resistances whether the recirculation is on or off. The overall results give a better understanding on how the coasting resistance is influenced by various factors and can instruct future vehicle’s low coasting resistance development. More factors such as brake calipers, tire size, and other corresponding influences will be studied in future tests.
Gong, Guan, Zhao, Chen, Zhou, Xiaohang, Deng, Chenghao, Jiang, Hanli, Yu, Cheng, Yu, Fuyong, Ren, Yong, Zhou, Anjian
A Study on the Effect of Tire Temperature and Rolling Speed on the Vehicle Handling Response2020-01-12354/14/2020
Rubber is a non-linear viscoelastic material which properties depend upon several factors. In a tire two of these factors, namely the temperature and excitation frequency, are significantly influenced by the vehicle operating conditions. In the past years, applied research studied how rubber viscoelastic characteristics affect structural and frictional tire properties. The present study focuses on how these effects interact with the vehicle handling response. Based on state of the art theory of friction, structural properties of rubber and on experimental evidence, the dependency of key tire parameters on temperature and rolling speed is established. These results are then used in combination with a single-track vehicle model to assess their impact on key vehicle parameters; as an example, the understeer coefficient, yaw resonance peak / damping and maximum acceleration are studied. Furthermore, to ensure accurate results in realistic situations, a novel tire thermodynamic model is used in combination with a detailed 14 degrees of freedom vehicle model in a numerical simulation environment. The simulations permit to study the mutual effects between tire temperature, rolling speed and vehicle dynamics. Quantitative figures are given that determine the impact on the specific vehicle handling parameters in different operating conditions. It is finally concluded that, in most cases, a higher tire temperature and / or higher rolling speed results in a degradation of the vehicle handling response.
Lugaro, Carlo, Alirezaei, Mohsen, Konstantinou, Ioannis, Behera, Abhijeet
An Experimental Methodology for Measuring Resistance Forces of Light-Duty Vehicles under Real-World Conditions and the Impact on Fuel Consumption2020-01-03834/14/2020
A vital element of any vehicle-certification test is the use of representative values for the vehicle resistance forces. In most certification procedures, including the WLTP recently adopted by the EU, the latter is achieved mainly through coast down tests. Subsequently, the resistance values measured are used for setting up the chassis-dyno resistances applied during the laboratory measurements. These reference values are obtained under controlled conditions, while a series of corrections are applied to make the test procedure more repeatable and reproducible. In real driving, the actual vehicle road loads are influenced by a series of factors leading to a divergence between the certified fuel consumption values, and the real-world ones. An approach of calculating representative road loads during on-road tests can help to obtain a more unobstructed view of vehicle efficiency and, when needed, confirm the officially declared road loads. This approach is also essential for validating simulations and achieving better estimates of the actual fuel consumption, a requirement introduced by the new policy adopted in the EU. In this study, a series of on-road experiments were conducted, under real-world conditions, on three vehicles, belonging to different vehicle body-categories, a supermini, a B segment cross-over city car, and a light-duty commercial vehicle. A wheel rim torque-measurement system (strain gauge torque sensors) was used to record the torque at the wheels accompanied by a wheel rotational-speed sensor. The present paper presents the results and investigates the capacity of such kind of tests to measure road loads with precision and accuracy. The calculated resistance forces are compared against the ones officially declared at type approval or measured via dedicated coast down tests. Results show satisfactory accuracy and repeatability, ranging within a ±3-7% range for the aerodynamic resistance, and point out margins for improvement. Simulation models are subsequently used to quantify the impact on real-world fuel consumption and CO2 emissions. The road loads measured using the method lead to similar fuel consumption simulation results as the official road loads with deviations in total simulated CO2 emissions remaining within ±6% of the measured values in the majority of the cases.
Komnos, Dimitrios, Fontaras, Georgios, Ntziachristos, Leonidas, Pavlovic, Jelica, Ciuffo, Biagio
High-Resolution Circumferential Tire Tread Three-Dimensional Profiling Using Laser Section Technique and Photometric Stereo Technique02-13-01-00013/16/2020
This article presents an approach for circumferential tire tread profiling using Laser Section (LS) technique and Photometric Stereo (PS) technique. The proposed approach uses a digital camera as the only data acquisition device, and one laser line generator and sixteen 5 mm white LEDs to provide different lighting conditions. LS technique uses the illumination of the laser line generator to measure the depth profile of one cross section of the tire surface, while PS technique utilizes the difference of the appearance of the tire surface under different lighting conditions to recover the geometry information of the tire tread with pixel resolution. The fusion of the two techniques results in a high-resolution three-dimensional (3D) profiling of the tire tread. A system to apply the proposed approach was developed, with the necessary calibration steps explained, with a step motor for circumferential measurement. The performance of the proposed approach was validated with a 225/60R16 tire using the system. As shown in the experimental result, the proposed approach has successfully measured the circumferential tire tread profiling with 31 μm spatial resolution.
Song, Mengyu, Furukawa, Tomonari
Passenger and Light Truck Tire Traction Device Profile Determination and ClassificationJ1232_202003 (Current)3/11/2020
The purpose of this SAE Recommended Practice is to set up a guide as to body, frame, and wheelhouse clearances required to accommodate tire traction devices (e.g., tire chains), and to provide a means of classifying these devices according to their maximum profile. In addition, it enables the vehicle manufacturer to specify the proper traction devices for each vehicle. This report is intended to apply to passenger cars and light trucks up to 4535 kg (10 001 lb) GVW. This document is not to be construed as approving traction device operation at conditions exceeding manufacturer's specifications, although short periods of such operations may be required for test purposes.
Highway Tire Committee
Residual Aligning Moment TestJ1988_202003 (Current)3/11/2020
This SAE Recommended Practice describes the determination of tire pull force properties for an uninclined tire (SAE J670e) on a laboratory flat surface tire force and moment machine. It is suitable for accurately determining pull forces and residual aligning moments for passenger and light-truck tires. These properties are important determinants of vehicle trim (See section 2.1.2). They describe steady-state, free-rolling pull effects ascribable to tires. The test method described in this document is suitable for comparative evaluation of tires for research and development purposes. The method is also suitable for modeling when followed carefully.
Highway Tire Committee
The Effect of Structural Damping Foam on Tire Vibration10-04-02-00062/28/2020
During the vehicle design state, vehicle noise and vibration are taken into consideration. The tire is a large contributor to the noise and vibration experienced inside the vehicle cabin. Any unevenness or asperities in the road cause the tire structure to vibrate, which in turn causes components in the vehicle to vibrate and generate noise. It is common in the industry to use foam inserts inside the tire air cavity that reduces the noise generated. This foam is typically intended to reduce a specific resonance in the tire-the resonance due to the air cavity. Recently, there is interest in using foam as a structural damper to reduce structural resonances in the tire. A new analytical tire model for determining the effect that structural damping foam has on the noise and vibration characteristics of the tire has been developed. The theoretical formulation of this model is presented, as well as comparison with experiments and a parametric analysis of the model. The model shows good agreement with experimental results and also gives some additional insights into how the tires’ response can be altered by different design parameters.
Sams, Thomas
Rolling Resistance Measurement Procedure for Passenger Car, Light Truck, and Highway Truck and Bus TiresJ1269_201912 (Historical)12/10/2019
This SAE Recommended Practice applies to the laboratory measurement of rolling resistance of pneumatic passenger car, light truck, and highway truck and bus tires. The procedure applies only to the steady-state operation of free-rolling tires at zero slip and inclination angles; it includes the following three basic methods:
Highway Tire Committee
Effect of Tyre Inflation Pressure on Rolling Resistance: Comparing the Values of Coefficient of Rolling Resistance and Rolling Resistance at Variable Tyre Inflation Pressure2019-28-241511/21/2019
1. Rolling resistance, is nothing but the rolling drag, is the force resisting the motion when a body rolls on a surface. It is mainly caused by non-elastic effects; that is, not all the energy needed for deformation of the wheel, roadbed, etc. It is recovered when the pressure is removed, in the form of hysteresis losses and permanent deformation of the tyre surface. So, the rolling resistance contributes to the deformation of roadbed as well as tyre surface of the vehicle. Factors contributing in rolling resistance are tyre inflation pressure, wheel diameter, speed, load on wheel, surface adhesion, sliding and relative micro-sliding between the surfaces of contact. In this concerned paper we are significantly working on effect of tyre inflation pressure on rolling resistance and taking all other factors constraint.
Tripathi, Siddharth, Karwal, Amit Kumar, Mishra, Mukund, Wazir, Dushyant
Performance Gains of Load Sensing Brake Force Distribution in Motorcycles2019-28-242611/21/2019
Commercial motorcycles and scooters incorporate independent circuits for front and rear brake actuation, thus precluding load-dependent brake force distribution. In all cases of manual brake force modulation between the front and rear wheels, there is poor compensation for the changes in wheel loads on the account of longitudinal weight transfer, thus making it challenging to provide an adequate braking force to each wheel. The ratio in which the braking force should be distributed between the front and the rear wheels is dependent on the motorcycle’s geometry, weight distribution, mechanical sizing of braking system components, and is a variable based on the instantaneous deceleration. This connotes that a fixed bias of front and rear braking forces can be optimized only for a narrow range of motorcycle’s deceleration. Maximum braking performance occurs just prior to wheel lock-up, as a sliding tire provides less grip than a rolling tire. This is also the scenario when both the tires are doing the maximum work in decelerating the motorcycle. Therefore an optimal brake force distribution is one that locks both the wheels at the same instant. In practice, however, a rider would avoid a front wheel lock-up as it would make the motorcycle challenging to steer. In theory, an apt distribution of the braking forces between the front and rear wheels maximizes the overall braking efficiency of the motorcycle whilst reducing its stopping distance. This paper examines the plausible performance gains of load sensing brake force distribution in a motorcycle.
Chakraborty, Apurva
Tire Burst Test MethodologyARP6265 (Current)10/17/2019
This document describes a recommended test procedure to assess the burst characteristics of tires used on 14CFR Part 25 or similar transport airplanes.
A-5C Aircraft Tires Committee
Continental Tire rolls towards a smart-and-connected future19AUTP10_0910/1/2019
It is difficult to become emotional about tires except when they-literally-let us down. But tires are set to get smarter, communicate more effectively and react to changing road conditions. Each of these will play a role in meeting the demands of autonomous- and electric-vehicle (AV/EV) development. “They will be tires that take care of themselves and provide highly supported driving,” said Dr. Philipp Struck, Continental Tire's head of tire line development. “Mobile data will be essential as we become more autonomous and drive more EVs.”
Birch, Stuart
Stability of Wheel Tractors during Braking2019-01-21429/15/2019
The dynamic distribution of normal reactions between the axles of the wheeled tractor has a significant impact on the stability against skidding and the wheeled tractor braking effectiveness. At the same time, the clarification of the normal reactions distribution between the axles allows to choose more rational braking forces distribution between the axles. It is shown that the best way to ensure the highest braking efficiency is the braking mode when the rear wheels of the tractor are at the blocking limit. An assessment of the expediency of installing brake mechanisms on only one axle of the tractor was made. The increase of braking efficiency of wheeled tractors with all brake wheels provided that they ensure directional stability is considered. The laws of braking forces distribution between the axles of wheel tractors for different sequence of wheels locking are determined. Using the method of partial accelerations an improved method for estimating the effect of a brake system on the stability of wheeled tractor is proposed. The criterion in the form of angular acceleration in the road plane ώz, by the value and sign of which one we can estimate the operational stability of the brake mechanisms has obtained.
Podrigalo, Mikhail, Kholodov, Mykhailo, Klets, Dmytro, Dubinin, Yevhen, Savchenkov, Borys, Koryak, Alexander, Rudzinskyi, Volodymyr, Viktoriia, Zadorozhnia, Polianskyi, Oleksandr
Electrifying Long-Haul Freight—Part I: Review of Drag, Rolling Resistance, and Weight Reduction Potential02-12-03-00179/5/2019
Abstract Electric heavy-duty tractor-trailers (EHDTT) offer an important option to reduce greenhouse gases (GHG) for the transportation sector. However, to increase the range of the EHDTT, this effort investigates critical vehicle design features that demonstrate a gain in overall freight efficiency of the vehicle. Specifically, factors affecting aerodynamics, rolling resistance, and gross vehicle weight are essential to arrive at practical input parameters for a comprehensive numerical model of the EHDTT, developed by the authors in a subsequent paper. For example, drag reduction devices like skirts, deturbulators, vortex generators, covers, and other commercially available apparatuses result in an aggregated coefficient of drag of 0.367. Furthermore, a mixed utilization of single-wide tires and dual tires allows for an optimized trade-off between low rolling resistance tires, traction, and durability. Lastly, a combination of different lightweight vehicle components manufactured from aluminum and magnesium alloys, carbon fiber composites, titanium, and high-strength steel presents a substantial reduction in overall vehicle weight. Overall, a comparison of a potential EHDTT with a standard Class-8 heavy-duty tractor-trailer (HDTT) reveals a possible reduction in the aerodynamic coefficient of drag by 40%, rolling resistance by 21%, and vehicle weight by approximately 37% prior to electrification. These improvements provide a stronger baseline for electrification to increase the overall range and longevity of an EHDTT making them a more viable option in the market. However, to achieve these advances still requires significant research into commercial feasibility and real-world data under varying conditions with enhanced simulation tools playing a meaningful role.
Depcik, Christopher, Gaire, Anmesh, Gray, Jamee, Hall, Zachary, Maharjan, Anjana, Pinto, Darren, Prinsloo, Arno
Empirical Investigation on the Effects of Rolling Resistance and Weight on Fuel Economy of Medium-Duty Trucks02-12-03-00168/28/2019
Abstract Vehicle rolling resistance and weight are two of the factors that affect fuel economy. The vehicle tire rolling resistance has a more significant influence than aerodynamics drags on fuel economy at lower vehicle speeds, particularly true for medium- and heavy-duty trucks. Less vehicle weight reduces inertia loads, uphill grade resistance, and rolling resistance. The influence of weight on the fuel economy can be considerable particularly in light- to medium-duty truck classes because the weight makes up a larger portion of gross vehicle weight. This article presents an empirical investigation and a numerical analysis of the influences of rolling resistance and weight on the fuel economy of medium-duty trucks. The experimental tests include various tires and payloads applied on a total of 21vehicle configurations over three road profiles. These tests assessed the sensitivity of the vehicle’s fuel economy toward rolling resistance and weight. Several experimental results showed inconsistent and counterintuitive trends of the effects of rolling resistance coefficients and weights on fuel economy. The consequences of rolling resistance and vehicle payload are compound and influenced by vehicle speed, road profile, and tire pressure. The irregularities of weight variances’ impact on rolling resistance requires further investigation in the strain level of the tire deformation.
Liao, Gene Y., Card, Brandon, O’Malley, Molly
Determination of a Tyre’s Rolling Resistance Using Parallel Rheological Framework2019-01-50696/20/2019
Nowadays, rolling resistance sits at the core of tyre development goals because of its considerable effect on the car’s fuel economy. In contrast to the experimental method, the finite element (FE) method offers an inexpensive and efficient estimation technique. However, the FE technique is yet to be a fully developed product particularly for rolling-resistance estimation. An assessment is conducted to study the role of material viscoelasticity representation in FE, in linear and non-linear forms, through the use of Prony series and parallel rheological framework (PRF) models, respectively, on the tyre’s rolling-resistance calculation and its accuracy. A unique approach was introduced to estimate the rolling resistance according to the tyre’s hysteresis energy coefficient. The non-linear PRF choice resulted in rolling-resistance calculations that reasonably match that of the experimental work and the literature for various vertical load and inflation cases, whereas the Prony series option was found irresponsive to the tyre’s deformation in which it gave unreliable and infinitesimal outputs.
Aldhufairi, Hamad Sarhan, Olatunbosun, Oluremi, Essa, Khamis
Development of an Accelerated Test for Tire Flat-Spotting2019-01-15096/5/2019
Tire flat-spotting occurs when tires remain in a loaded condition without rolling for an extended period of time, and can be temporary or permanent depending on the length of storage, vehicle loading and environmental factors. Tire non-uniformity caused from flat-spots often induce shake and shimmy vibration in vehicles due to increased tire-wheel force variation input into the chassis. This results in increased warranty costs for OEMs and tire suppliers and customer dis-satisfaction in third-party quality surveys such as J. D. Power IQS. Flat-spotting is of particular concern for slow-moving vehicle inventory parked for long periods at plants and/or dealership lots. OEMs often stipulate or recommend inventory storage practices for dealers that require physical movement of vehicles at some set duration to reduce the risk of tires developing permanent flat-spots. OEMs also provide component level flat-spotting requirements to tire manufacturers during sourcing and specification timing to secure their internal requirements and targets. The study in this paper initially determined real-world flat-spotting levels on an actual vehicle during the adverse summer months of Arizona. Tire uniformity measured on a high-speed uniformity machine were used as an indicator of flat-spotting performance. Using an environmental chamber and custom designed loading fixtures, appropriate loads and temperatures were applied simultaneously to develop an accelerated test criteria that duplicated real-world flat-spotting behavior. The study outlined in this paper developed a two-day test using equivalent vehicle loading and elevated temperatures that produced the equivalent tire flat-spotting of a 30-day real-world storage during adverse summer conditions. This accelerated test allows a quick evaluation of tire flat-spotting performance that can be expected in adverse real-world conditions. Over the long term, it is estimated that such testing will generate more precise specifications for tire manufacturers, drive better inventory management and storage practices, reduce warranty costs and improve customer satisfaction.
Kavarana, Farokh, Fritz, Scott
System Interactions Affecting NVH Performance of an Electric Vehicle Drivetrain2019-01-15456/5/2019
The paper will present an integrated approach to system NVH analysis, which gives an insight into the system response in an EV driveline due to electrical and mechanical excitations; namely rotor mechanical imbalance, electrical machine torque ripple, and stator radial force shapes. The paper will address the fact that, as part of a practical design exercise, different subsystems and components may achieve design maturity at different times. It is therefore important to understand to what extent various drivetrain components may be considered in isolation, and at what point it becomes necessary to consider the interactions present in the full system. The paper will compare predicted NVH performance of a representative EV traction motor when different boundary conditions are considered; for example, when considering the motor being bested in isolation as part of a typical test setup, and when included in a representative drivetrain. For each configuration, the response to mechanical and electro-mechanical noise mechanisms will be assessed, and the fidelity of simulation required to achieve an appropriate engineering insight will be considered. From these studies, the best practice for the assessment of NVH as part of a holistic design process will be discussed. Consideration will be made of the factors which may influence the choice of simulation approach; for example, the level of design maturity, the availability and reliability of system data, and the design targets which are to be addressed.
Michon, Melanie, Holehouse, Robert, Shahaj, Annabel, Jafarali, Hisham, Janakiraman, Venkatakrishna
Design Optimization of a Hybrid Spur GearF-0075-2019-146745/13/2019
This study develops an optimization technique for a sinusoidal interlock design of a hybrid spur gear consisting of a metallic outer ring to support high contact stress bonded to a composite inner web for weight reduction. Two objectives (mass and shear traction on the metal-composite interface under static loading conditions) were minimized for four design variables subject to two constraints. Borg MOEA, a multi-objective evolutionary algorithm developed at The Pennsylvania State University, and an in-house finite element solver were used to generate Pareto-optimal solutions to this design problem. Two of the designs were then analyzed in greater detail to determine stress distributions throughout the gear. In the future, this technique will be refined and applied to optimization of more representative rotorcraft gears, with the aim of reducing drive train weight and meeting performance requirements.
Gauntt, Sean, Campbell, Robert, McIntyre, Sean
STANDARD FOR TIRE TRACEABILITY CONTENT AND FORMAT FOR THE RADIO-FREQUENCY IDENTIFICATION (RFID) TAG AND ASSOCIATED TIRE DATA SETUSCAR39 (Historical)4/17/2019
This standard describes a requirement for automotive tire traceability. It includes a definition of the RFID tag and the associated tire data set that can be accessed using the RFID tag as an identifier. The standard describes a unique identification and the associated data set for each tire produced by the tire fabricator. This data will either be provided or transmitted at the time of shipment to retailers, wholesalers or original equipment vehicle manufacturers. Tire identification code and data may be used for error proofing, determining the tire specifications or supporting any inquiries that occur for the duration of its automotive life.
USCAR
Multi-Chamber Tire Concept for Low Rolling-Resistance06-12-02-00094/8/2019
Rolling-resistance is leading the direction of numerous tire developments due to its significant effect on fuel consumption and CO2 emissions considering the vehicles in use globally. Many attempts were made to reduce rolling-resistance in vehicles, but with no or limited success due to tire complexity and trade-offs. This article investigates the concept of multiple chambers inside the tire as a potential alternative solution for reducing rolling-resistance. To accomplish that, novel multi-chamber designs were introduced and numerically simulated through finite-element (FE) modeling. The FE models were compared against a standard design as the baseline. The influences on rolling-resistance, grip, cornering, and mechanical comfort were studied. The multi-chambers tire model reduced rolling-resistance considerably with acceptable trade-offs. Independent air volumes isolating the tread from sidewalls would maintain tire’s profile effectively. Different air concentration across the tire’s chambers gave the tire extended versatility. Rolling non-uniformity depends upon inner-chambers’ stability, sidewalls’ flexibility and tire/chamber(s) integration.
Aldhufairi, Hamad Sarhan, Essa, Khamis, Olatunbosun, Oluremi
Uncertainty in Radius Determined by Multi-Point Curve Fits for Use in the Critical Curve Speed Formula2019-01-04284/2/2019
The critical curve speed formula used for estimating vehicle speed from yaw marks depends on the tire-to-road friction and the mark’s radius of curvature. This paper quantifies uncertainty in the radius when it is determined by fitting a circular arc to three or more points. A Monte Carlo analysis was used to generate points on a circular arc given three parameters: number of points n, arc angle θ, and point measurement error σ. For each iteration, circular fits were performed using three techniques. The results show that uncertainty in radius is reduced for increasing arc length, decreasing point measurement error, and increasing number of points used in the curve fit. Radius uncertainty is linear if the ratio of the standard deviation in point measurement error (σ) to the curve’s middle ordinate (m) is less than 0.1. The ratio σ/m should be less than 0.018 for a radius found using a 3-point circular fit to be within 5% of the actual value 95% of the time. Increasing the number of points used for the fit reduces uncertainty in radius: a 15-point fit reduces the 95% prediction interval width by up to 42%, or allows a shorter yaw mark arc angle with the same uncertainty in radius.
Heinrichs, Bradley, Mithrush, Troy
Research on Technique for Correction of Running Resistance with Focus on Tire Temperature and Tire Thermal Balance Model2019-01-06234/2/2019
At present, measurements of running resistance are conducted outdoors as a matter of course. Because of this, the ambient temperature at the time of the measurements has a considerable impact on the measurement data. The research discussed in this paper focused on the temperature characteristic of the tires and developed a new correction technique using a special rolling test apparatus. Specifically, using a tire rolling test apparatus that made it possible to vary the ambient temperature, measurements were conducted while varying the levels of factors other than temperature that affect rolling resistance (load, inflation pressure, and speed). Next, a regression analysis was applied to the data for each factor, and coefficients for a relational expression were derived, making it possible to derive a quadratic equation for the tire rolling resistance correction formula. It was verified that the application of the new correction formula reduced variation in running resistance from 2.7% (in the case of regulation correction) to 1.0%. In addition, in order to offer a simpler method of realizing the same correction, a technique for correction using a conventional tire rolling test apparatus and based on the material characteristics of the tire tread rubber was also developed. It was verified that this method allowed the same degree of correction. Giving consideration to the application of the method to future tire modeling, the development of heat generation and dissipation models for tire rolling tests was also examined. The addition of terms for the temperature characteristic of the tread rubber and heat generation and dissipation between the tire and the drum reduced error between measured and predicted values to ±0.6%.
Hotaka, Takeshi, Sakai, Tomonori, Miura, Hideki
Speed Analysis of Yawing Passenger Vehicles Following a Tire Tread Detachment2019-01-04184/2/2019
This paper presents yaw testing of vehicles with tread removed from tires at various locations. A 2004 Chevrolet Malibu and a 2003 Ford Expedition were included in the test series. The vehicles were accelerated up to speed and a large steering input was made to induce yaw. Speed at the beginning of the tire mark evidence varied between 33 mph and 73 mph. Both vehicles were instrumented to record over the ground speed, steering angle, yaw angle and in some tests, wheel speeds. The tire marks on the roadway were surveyed and photographed. The Critical Speed Formula has long been used by accident reconstructionists for estimating a vehicle’s speed at the beginning of yaw tire marks. The method has been validated by previous researchers to calculate the speed of a vehicle with four intact tires. This research extends the Critical Speed Formula to include yawing vehicles following a tread detachment event. The Critical Speed Formula was found to produce results of acceptable and known accuracy, provided the appropriate inputs are used for the given situation and several guidelines are observed. The inputs and guidelines for the use of the Critical Speed Formula for these tread detachment scenarios are discussed. For all tests analyzed, the tire mark evidence was documented with survey equipment, photographs and drone footage. In the past, it may have been necessary to take tire mark radius measurements in the field for use in the Critical Speed Formula. However, with the advent of modern documentation techniques, radius measurements can be taken from a scaled scene diagram and acceptable accuracy in the speed calculations can be achieved.
Beauchamp, Gray, Pentecost, David, Koch, Daniel, Bortles, William
An Analysis of Sport Bike Motorcycle Dynamics during Front Wheel Over-Braking2019-01-04264/2/2019
There is extensive literature on motorcycle skid/brake to stop testing on a host of motorcycle types, rider experience, brake system configurations and the associated deceleration rates. Very little information exists on deceleration rates involved with over-braking the front wheel. The subject of this paper addresses the deceleration rates of sport bike type motorcycles during over-braking of the front wheel. Based on the physics of a two-wheeled vehicle like the motorcycle, once the front wheel is over-braked and becomes locked, the rider has very little time to recover from the skid and often times falls. Another over-braking scenario, especially on sport bike type motorcycles, is the possibility of the rear wheel lifting and pitching over the front wheel. During the initial phase of braking, weight transfer to the front wheel occurs creating a greater level of traction. As the motorcycle begins to fall or pitch over, the weight on the front wheel decreases significantly and therefore the frictional force decreases significantly as well. The goal of this publication was to perform maximum front wheel brake testing that involves front wheel skid-to-fall as well as front wheel brake-to-pitch over scenarios on various sport bike motorcycles and determine an applicable deceleration rate. Three motorcycles; a 2002 Kawasaki ZRX1200R, a 2006 Yamaha YZF-R6, and a 2013 Ninja EX300 were subject to various maximum front wheel brake tests. The speed of the motorcycle at brake application ranged from 50 to 60 mph. The results of the testing concluded that the average deceleration rates during front wheel skid-to-fall tests were in the range of 0.32-0.8g depending on the lean angle of the motorcycle at brake application. The average deceleration rates for the front wheel brake-to-pitch over tests were in the range of 0.8-0.86g.
Fatzinger, Edward, Landerville, Jon, Bonsall, Jeffrey, Simacek, Daniel
Tire Ply-Steer, Conicity and Rolling Resistance - Analytical Formulae for Accurate Assessment of Vehicle Performance during Straight Running2019-01-12374/2/2019
The aim of the paper is to provide simple and accurate analytical formulae describing the straight motion of a road vehicle. Such formulae can be used to compute either the steering torque or the additional rolling resistance induced by vehicle side-slip angle. The paper introduces a revised formulation of the Handling Diagram Theory to take into account tire ply-steer, conicity and road banking. Pacejka’s Handling Diagram Theory is based on a relatively simple fully non-linear single track model. We will refer to the linear part of the Handling Diagram, since straight motion will be considered only. Both the elastokinematics of suspension system and tire characteristics are taken into account. The validation of the analytical expressions has been performed both theoretically and after a subjective-objective test campaign. By means of the new and unreferenced analytical formulae, practical hints are given to set to zero the steering torque during straight running. Additionally, the vehicle rolling resistance during straight motion is studied. It is found that front toe seems primarily set for reasons that are related to the steering system, other than tires. Reducing front toe could reduce energy consumption up to 1% on a WLTP mission.
Lattuada, Alessandro, Mastinu, Gianpiero, Matrascia, Giuseppe
Event Data Recorder Performance during High Speed Yaw Testing Subsequent to a Simulated Tire Tread Separation Event2019-01-06344/2/2019
This paper presents event data from the Sensing and Diagnostic Module (SDM) of a 2004 Chevrolet Malibu during high speed yaw testing. Yaw tests were performed using tires that were intact and tires that had the tread removed. The tires that had the tread removed were placed at various wheel positions on the vehicle (e.g. leading side - front, leading side -rear, trailing side - rear). This testing simulates the loss of control phase subsequent to a tread separation. Speeds up to 117 km/h (72.9 mph) were achieved. A simple electro-mechanical device was incorporated to the dynamic testing to simulate a low-severity non-deployment event that triggered the recording of pre-crash data by the SDM. The SDM data from the tests was imaged and compared to reference data from vehicle-mounted instrumentation recording wheel speed, steering angle, measured vehicle sideslip angle and GPS calculated over the ground speed. This paper examines the dynamic effect of high sideslip angles and changes to tire rolling radius, as a result of a tread separation, as it pertains to the accuracy of EDR reported vehicle speed.
Bortles, William, Koch, Daniel, Beauchamp, Gray, Pentecost, David, Rayburn, George, Hostetler, Ryan
DATC spells progress for defense prototyping19AUTP02_032/1/2019
A public-private partnership between the U.S. Army's TARDEC and SAE International is making it easier for suppliers to engage the government on military ground-vehicle technology projects. A slogging bureaucracy, miles of “red tape” and a sea of acronyms are just some of the hurdles that keep many suppliers from working with the U.S. defense industry on ground-vehicle projects. For years the government, led by the U.S. Army Tank-Automotive Research, Development and Engineering Center (TARDEC), sought to develop a streamlined procurement process. Their aim was to speed the adoption of private-sector innovations, particularly for prototype development, while expanding access for smaller, non-traditional military suppliers. A breakthrough came in 2016, when TARDEC partnered with SAE International's Industry Technologies Consortia affiliate to form the nonprofit Defense Automotive Technologies Consortium; DATC currently has 190 members-70% of which are non-traditionals. The consortium serves as a gateway between the government and the auto industry for OTA Prototype projects (OTAs, or Other Transaction Agreements, run for seven years, during which up to $700 million in projects can be awarded).
Brooke, Lindsay
A Probabilistic Approach to Hydroplaning Potential and Risk06-12-01-00051/30/2019
A major contributor to fatal vehicle crashes is hydroplaning, which has traditionally been reported at a specific vehicle speed for a given operating condition. However, hydroplaning is a complex phenomenon requiring a holistic, probabilistic, and multidisciplinary approach. The objective of this article is to develop a probabilistic approach to predict Hydroplaning Potential and Risk that integrates fundamental understanding of the interdependent factors: hydrology, fluid-solid interactions, tire mechanics, and vehicle dynamics. A novel theoretical treatment of Hydroplaning Potential and Risk is developed, and simulation results for the prediction of water film thickness and Hydroplaning Potential are presented. The results show the advantages of the current approach which could enable the improvement of road, vehicle, and tire design, resulting in greater safety of the traveling public.
Kang, Yong-suk, Nazari, Ashkan, Chen, Lu, Taheri, Saied, Ferris, John B., Flintsch, Gerardo, Battaglia, Francine
Investigation of Cabin Noise while Accelerating on Low Mu Track through Simulation Approach Using Full Vehicle ADAMS/Car Model2019-26-01791/9/2019
Cabin noise is a significant product quality criteria which enables the customers for product differentiation. There are various sources of cabin noise such as wind, structures(panels), engine, suspension, tire and roads. During product development phase, extensive tests has been conducted to improve vehicle dynamics behavior on various climatic conditions. One such test is accelerating vehicle on low mu or icy surface. While performing acceleration manoeuvre (tractions) on a low mu tracks, Cabin noise with source identified from front underbody & low tractive torque build up is reported. This undesirable behavior may occur due to following reason (1) Excitation of coupled modes between suspension and powertrain which induces torque fluctuation. (2) Transmissibility of various subsystem can be the reason for above problem statement. (3) Poorly chosen tire compounds and design leads to fluctuation in torque. A detailed simulation based study using ADAMS/CAR has been performed to assess the contribution of various full vehicle sub-systems, primarily suspension & powertrain sub-system towards the said problem statement. The dynamic interaction between road, suspension, powertrain and BIW has been is the focus of study both in time and frequency domain. This simulation helped understand the factor effects and contribution levels and correlates well with the subjective feel observed on the physical vehicle on low-mu track. This model has been further used to provide design recommendation on the compliance parameters to overcome the issue at hand. Test has been conducted with recommended tire grip properties and suspension bushing parameters which lead to reduction in cabin noise
Singh, Vivek, Prasad, Tej, Srivastava, Harshit
Analysis of Effect of Tire Inflation Pressure, Inflation Fluids, Load and Speed on Tire Performance2019-26-03681/9/2019
There are various losses associated with passenger vehicle that affect its fuel economy as it is being operated. These losses include losses at engine, driveline, aerodynamic and rolling losses. While engine, driveline and aerodynamic losses are inherent with the vehicle due to large number of parts that are assembled together, rolling loss is associated with the vehicle tires and it is the only part of the vehicle that comes in contact with the road surface. The rolling resistance of inflated tires is an important component of rolling resistance to vehicle motion and contributes to vehicle fuel consumption. Hence the effect of tire parameters such as inflation pressure, speed and load are the subject of much current interest. Also effect of type of inflation fluid on tire performance is a need of investigation. This work is focused on the design and development of tire testing setup to test the tire performance parameters like rolling resistance and tire temperature by varying the load, speed, inflation pressure and inflation fluids. Tire 135/70 R12 65 S was selected for testing. The test was conducted under various loads, speed, inflation pressure and inflation fluids were air and nitrogen. The result of experimental analysis shows that there is increase in rolling resistance and tire temperature with increase in speed and load. Also, the rolling resistance and tire temperature increases with decreasing the inflation pressure. For determining the better performance of tire among air and nitrogen, the test was conducted by varying the inflation pressure, load and speed. The results of experimental analysis shows that the tire with nitrogen gas resulted in to lower rolling resistance and lower tire temperature as compared with air.
Thombare, Dhananjay Ganpati
ABS Optimization for a Two-Wheeler Based on Tire-Road Friction Characteristics2019-26-00171/9/2019
Anti-lock Braking System (ABS) is a well-known active safety technology widely used in cars. Recently, it has become a mandatory safety feature for two-wheelers. In principle, ABS ensures an optimum braking performance by not allowing the tire to slip beyond a certain level. This guarantees steering stability and peak braking performance of the tire during panic braking situations. As the ABS controller depends on the tire characteristics information for its algorithm, a change in tire or pavement can vary the optimum operating range of ABS. In addition to this, motorcycle tires differ from a car tire in terms of its construction, dimension and compound. Therefore, the motorcycle tire’s performance envelope cannot be directly compared to a car tire. This work presents a methodology which aims to acquire the tire-road friction characteristics of three different tires for a study motorcycle on different friction surfaces through experimentation and estimation techniques. The optimum pressure release slip thresholds for the three tires on different surfaces are then determined from the obtained tire characteristics. Further, the ABS controller is calibrated based on the determined parameter set for the three study tires and the performance of the study motorcycle is evaluated. The chosen slip thresholds were able to utilize all the three tires sufficiently to meet the performance targets as set by IS14664.
Ranjan, Ashish, Srivastava, Shreyansh, Anantha, Prashanth
Effect of Ambient Temperature and Inflation Pressure on Tire Temperature2019-26-03601/9/2019
Tire failure is identified as a major cause of accidents on highways around the world in the recent past. A tire burst leads to loss of control of the vehicle which ends up in a catastrophe. There are various factors which are accounted for a tire burst. Heat buildup, aging of tire and cracks on tires are the major ones which are identified. A superior ability of the tire to dissipate the heat generated during operation is a major factor which prevents a tire failure. Other factors such as ambient temperature, inflation pressure etc. contributes to heat buildup which may ultimately result in tire failure. A combination of these factors might manifest as a tire failure at high speeds, the latter being an immediate cause of heat buildup. A dormant crack in the tire might develop if the temperature and pressure conditions are favorable, thus giving away at the weakest point. With regard to the temperature conditions, road conditions, inflation pressure checks etc. India is vulnerable to tire failures. It may be noted that present regulations in India does not mandate testing of aged tyres and Tire Pressure Monitoring System. The paper tries to examine the effect of high ambient temperature and low inflation pressure on aged tires. The paper tries to examine tires with high speed capability at underinflated condition. The importance of Tire Pressure Monitoring System in India is analyzed on the current tire models tested as per Global Technical Regulation Standard for tires.
Bharadwaj, Shreyas, Khairatkar, Vyankatesh
Tire Side Force Characteristics with the Coupling Effect of Vertical Load and Inflation Pressure10-03-01-000211/9/2018
The tire vertical load and inflation pressure have great influence on tire steady- and non-steady-state characteristics and, consequently, on the vehicle handling and stability. The objective of this article is to reveal the coupling effect of tire vertical load and inflation pressure on tire characteristics and then introduce an improved UniTire side force model including such coupling effect through experimental and theoretical analysis. First, the influence of the tire vertical load and inflation pressure on the tire characteristics is presented through experimental analysis. Second, the theoretical tire cornering stiffness and lateral relaxation length model are introduced to study the underlying mechanism of the coupling effect. Then, an improved UniTire side force model including the coupling effect of tire vertical load and inflation pressure is derived. Finally, the proposed improved UniTire side force model is validated through tire steady-state and transient data. The coupling effect of tire vertical load and inflation pressure on tire cornering stiffness and lateral relaxation length is decided by the variation of the half length of tire contact patch and the carcass stiffness caused by the tire vertical load and inflation pressure changes.
Guo, Konghui, Chen, Ping, Xu, Nan, Yang, Chao, Li, Fei
Assessing Tire Performance from Vehicle Dynamic Transfer Functions2018-32-004810/30/2018
The aim of this study is to develop techniques which can be used to assess tire performance for a motorcycle in a race track and correlate them with subjective perceptions of race riders. This approach focusses on using vehicle level performance parameters and transfer functions to assess tire performance. A subjective assessment study is performed to understand rider’s perception. Tire behavior is then studied by assessing the dynamic performance of the motorcycle in a race track. Analysis techniques are then developed to interpret the data measured and understand tire performance. Based on these techniques, vehicle dynamic parameters and transfer functions that can be used to asses tire performance are developed. Correlations between objective findings and subjective perceptions are then identified. These studies show that the choice of a tire in a race track is not only decided by tire grip but also by factors like steering effort, roll rates and feedbacks perceived by the rider from tires. The influence of these parameters on tire performance is analyzed and presented. The feedback perceived by riders from tires during maneuvers is analyzed using transfer functions and it is found that the slope of the curve between roll factor and lateral acceleration can be used to understand this perception. Influence of tires on high speed stability is then studied by developing a novel test procedure to test weave stability at the maximum speed of the motorcycle. The impact of tires on maneuverability and stability is then quantified using the results of these analysis techniques. Though this study is used to understand tire performance, it is shown that it can be extended to analyze the overall dynamic behavior of the motorcycle in a race track.
Mohan, Barath, Velagapudi, Sai Praveen, Raju, KVM
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