Tire Research Articles

Tensegrital wheel for enhanced planetary surface mobility: Part 2 - Performance assessment of a ruggedized, double-layer tensegrital wheel

This paper details ProtoInnovations’ work on a novel wheel design concept for planetary mobility. The tensegrital wheel for enhanced surface mobility exploits the geometric and mechanical attributes of tensegrity to mimic the compliant and load-distributing properties of a pneumatic tire using space-qualified materials. The third iteration of these wheel concepts, dubbed the TW3, was subject to particular scrutiny. In this paper, we explore the development of the TW3 and evaluate its performance in lab tests, performed at ProtoInnovation’s in-house testing facility, and field experiments, performed in conjunction with NASA Ames Research Center at the Atacama Rover Astrobiology Drilling Studies (ARADS). We compare the TW3 performance to baseline wheels and conclude with suggestions for further tensegrital wheel development.

Tensegrital wheel for enhanced planetary surface mobility: Part 1 – Design and evolution

This paper follows ProtoInnovations’ development of a line of novel wheel concepts built with tensegrity principles for planetary mobility. The goal of these tensegrital wheels for enhanced planetary surface mobility is to exploit the geometric and mechanical attributes of tensegrity to mimic the compliant and load-distributing properties of a pneumatic tire using space-qualified methods and materials. In this paper we present our tensegrity design process and the evolution of our tensegrital wheel concepts. We conclude with an exploration of the tensegrital wheel’s potential with regards to planetary exploration applications and summarize considerations and improvements for future tensegrital wheel research.

Static and Dynamic Analysis of Non-Pneumatic Tires Based on Experimental and Numerical Methods

Since the beginning of their production, pneumatic tires have experienced tremendous improvements in structure and materials, becoming the dominant design in the world tires market. Nevertheless, relying upon pressurized air, they are affected by maintenance and security issues that can lead to fatal accidents. Therefore, tire-makers are investigating new tire designs, called Airless or Non-Pneumatic, with the aim of removing air-related problems. The research about such tires is still at an early stage, especially if compared to the one conducted on the pneumatic ones. In this paper, the development of a methodology capable of studying the mechanical behavior of a Non-Pneumatic Tire (NPT) by means of experimental data and numerical approach is illustrated. The experimental activities consisted of a scanner acquisition of the NPT and a footprint analysis for the calculation of the radial stiffness and contact patch pressure distribution. Moreover, the Digital Image Correlation (DIC) technique was applied to carry out a more specific study about the spoke’s deformation. From the acquired 3D model, a calculation of the NPT vertical deflection with finite element analysis (FEA) was performed—validating the model and then submitting it to a steady state analysis—that allows the simulation of a steady state rolling tire with the possibility to replicate different values of slip ratio. The results of the experimental activities are in good agreement with the ones obtained with FEA, further validating the developed methodology.

Multi-axis stiffness and road contact characteristics of honeycomb wheels: A parametric analysis using Taguchi method

Three-dimensional finite element (FE) models of a non-pneumatic wheel (NPW) with three different honeycomb cell angles are developed and verified to investigate their multi-axis stiffness and road contact characteristics. The experiment designs based on L8(27) and L9(34) orthogonal arrays are subsequently formulated to identify influential design factors affecting the wheel response measures and their nonlinear effects. The multi-axis stiffness of the NPW are strongly influenced by the spokes design parameters, although the yaw stiffness is mostly affected by the tread parameters. The road contact properties, however, are dominantly affected by the annular beam and tread design parameters. The results from these experiment designs are effectively used to establish guidance for design tuning of the NPW for realizing desirable stiffness and road contact properties. A L16(215) orthogonal array experiment is further formulated to study the interactions among the influential design factors in view of the multi-axis stiffness and road contact responses of the wheel. The results showed negligible contributions due to interactions among the design factors. It is shown that the NPW design parameters can be tuned to achieve multi-axis stiffness properties comparable to those of the pneumatic tires.

Fatigue life prediction and influencing factors analysis of mesh flexible spoke non-pneumatic tire

A mesh flexible spoke non-pneumatic tire is designed to avoid tire burst and other hidden dangers in the traditional pneumatic tires, and improve driving safety. The purpose of this study is to explore the fatigue performance and fatigue life prediction method of the non-pneumatic tire and analyze the influence of structural parameters on the fatigue life of non-pneumatic tire. Based on the crack propagation method of energy release rate by J-integral, the fatigue life of the meshed flexible spoke non-pneumatic tire is predicted. Using numerical simulation method, the influence of key structural parameters, such as the curvature, unit angle and thickness of the lateral spoke and the tread thickness, on tire fatigue life is studied. The results show that the fatigue life prediction method proposed can be used to predict the fatigue life of flexible spoke non-pneumatic tire, and the fatigue life of non-pneumatic tire with flexible spoke can be improved by selecting appropriate structural parameters, which could provide some reference for the structural optimization design of the fatigue performance of the non-pneumatic tire.

The strength of the communication elements of pneumatic tires as composite material

The mechanical properties at the boundary of the distribution of the rubber matrix and metal and fabric fibrous materials as a separate area in the mechanism of crack inhibition and its effect on the durability of pneumatic tires during the accumulation of damage during operation are considered. Experimental studies on the stratification of the elements of the composition of the tire material in samples made from different parts of the car tire. The strength at the contact boundary "rubber matrix-fibers of metal cord" and between the fibers of the cord, which allows to assess the total strength of the tire material as a composition of reinforcing elements and the matrix in the accumulation of damage created during operation, artificial the nature and behavior of the rupture of the samples during the tests, the morphology of fracture on the surface of the interaction of the reinforcing fibers of the wire with the rubber matrix was evaluated.

A STATE OF ART AND PROSPECTS OF USED PNEUMATIC TIRES MANAGEMENT (REVIEW)

The basic data on the volume of production of pneumatic tires in the world and in Ukraine are presented. The need to improve the ways of handling pneumatic tires that have lost their con-sumer properties (worn out tires as a result of their intended use and tires rejected as a result of passing quality control during their manufacture) is shown as one of the most dangerous for the environment and promising in terms of using their properties. A detailed classification of methods for handling worn out and defective tires is proposed and a critical analysis of each of them is given. Particular attention is paid to the methods of utilization of tires, in particular, recycling, which makes it possible to efficiently use the secondary raw materials obtained from tires directly for their intended purpose. The features of physical, physicochemical and chemical processing methods, in particular combustion, gasification, pyrolysis of tires and their frag-ments, as well as the prospects for their decomposition under the influence of environmental factors, in particular microorganisms, are also considered. The main ways of solving the prob-lem of tires that have lost their consumer properties in Ukraine are proposed. Bibl. 88, Fig. 2.

Tiny yet tough: Maximizing the toughness of fiber-reinforced soft composites in the absence of a fiber-fracture mechanism

Tiny yet tough: Maximizing the toughness of fiber-reinforced soft composites in the absence of a fiber-fracture mechanism

Localization accuracy of a robot platform using indoor positioning methods in a realistic outdoor setting

Summary Precise localization and reliable navigation are of crucial importance in order to fully automatize tasks in agriculture using field robots in an outdoor environment. However, under certain conditions, absolute localization accuracy of outdoor positioning systems, mainly global navigation satellite systems (GNSS), might drop under a critical threshold. Thus, field robots must rely on indoor positioning methods such as laser scanners and adaptive Monte Carlo localization (AMCL) in order to maintain necessary localization accuracy. Here, the localization accuracy of the field robot “Mathilda” using such an indoor positioning method is evaluated in a realistic scenario, in this case, an outdoor laboratory with plant pots aligned in rows. For this, the positioning error of the robot was determined using a motion capture system. The results showed a mean absolute distance error over all positions of 198.9 mm and a mean angular error over all positions of 4.9°. Most likely, limitations by the differential drive system, the large pneumatic tires, and unsatisfactory path planning are responsible for this large deviation.

Effect of Spoke Design and Material Nonlinearity on Non-Pneumatic Tire Stiffness and Durability Performance

Non-pneumatic tire has been widely used due to their advantages of no run-flat, no need of air maintenance, low rolling resistance, and improvement of passengers comfort due to its better shock absorption. It has variety of application in the military vehicle, earthmovers, lunar rover, stair climbing vehicles etc. Recently UPTIS (Unique Puncture-Proof Tire System) non pneumatic tire has been introduced for passenger vehicles. In this study three different design configuration Tweel, Honeycomb and newly developed UPTIS have been compared. Effect of Polyurethane (PU) material nonlinearity have also been introduced by applying 5 different nonlinear PU material property in the spokes. The combined analysis of the PU material nonlinearity and spoke design configuration on the overall tire stiffness and spoke damage prediction is analysed using 3-Dimensional FEM simulations performed in ANSYS 16.0. It has been observed that Mooney Rivlin 5-parameter model is best to capture all 5 studied PU materials the nonlinearity. Effect of material nonlinearity on various spoke designs have been studied. The best combination of spoke design and the use of nonlinear material have been suggested in terms of riding comfort, tire stiffness and durability performance.

Miniaturized Stacked Die QFN for Tire Pressure Monitoring System Applications

Tire Pressure Monitoring Systems (TPMS) are electronic wireless systems that monitor and report air pressure inside pneumatic tires in real time. An example of a TPMS module integrated with the valve stem and showing the typical tire mounting location is shown in Figure 1. For their safety and fuel economy benefits, starting with the mid-2000's, active TPMS were mandated on many vehicles worldwide. The NHTS estimates that there are approximately 23,000 accidents and 535 fatalities annually involving tire underinflation and blowouts [1]. The use of TPMS has been shown to result in improved fuel economy and therefore reduced carbon emissions [2]. TPMS in passenger vehicles was mandated in the US as of Sept. 1, 2007 under the TREAD Act, in the European Union as of Nov. 1, 2012 and in South Korea as of Jan.1, 2013. Countries like Russia, Indonesia, the Philippines, Israel, Malaysia, Turkey and many others soon followed [3].
 The first TPMS systems were large and bulky with a significant electronics content [4]. Since that time TPMS electronics have gotten more energy efficient and form factors have come down dramatically. This paper will outline an effort to miniaturize an existing 1.0 mm pitch, 7x7x2.2 mm body size 24 lead QFN (Quad Flat No Leads) TPMS down to a 4x4x1.98 mm body size QFN with 0.5 mm pitch that would still meet automotive AEC Grade 1 reliability requirements. The original 7x7 mm three die QFN package consisted of an ASIC, a pressure sensor and an accelerometer. This miniaturization led to many technical challenges at both the package and board level. This paper will primarily address the board level reliability (BLR) challenges encountered due to the large silicon to package ratio along with the 50% reduction in pitch. Through a series of test vehicles with variables such as QFN leadframe surface finish, lead shape and size, wettable flank (WF) technology and anchors pads, the BLR was successfully improved to the point where it met application requirements.

Isogeometric Analysis for Tire Simulations: From Mesh Generation to High Precision Results

ABSTRACTIsogeometric analysis (IGA) has become an alternative to standard finite element analysis (FEA) in many areas of engineering. Its powerful tools for model generation and flexibility of basis functions make this relatively new approach attractive for tire analysis and its computational challenges.This contribution summarizes the benefits of IGA for complex tire simulations starting from model generation and the subsequent transition to the environment of numerical analysis without losing accuracy at the parametrizing stage. It presents results of further development work on earlier pioneering examples of the application of IGA in pneumatic tire analysis. In addition to the analysis of vertical stiffness, for the first time, velocity and acceleration fields are addressed and compared with experimental results and standard FEA simulations, with a focus on benefits of the continuity of basis functions within the contact patch. The numerical issues that arise in IGA at the enforcement of contact and the application of inelastic materials with inclusions of reinforcing layers are studied. Moreover, the important advantages of the possibility to use higher order functions for simulations of tire maneuvers are addressed within the steady-state framework. Numerical examples are provided to illustrate the capabilities of IGA. Concluding remarks on the results close the publication.

Две модели резинокордного слоя

Breker layers in a pneumatic tire are an important part in the tire construction. These layers have a metal cord resulting in substantial bending stiffness. When homogenizing such layers, a “shave” method is applied to the breaker layer. This results in a thinner layer having adequate stiffness in both tension and bending. In this work, a phenomenological approach is used to obtain the effective properties of a homogeneous anisotropic hyper elastic material of an equivalent layer. Two models utilize transverse isotropic or orthotropic potential used to describe the homogenized properties. Comparison is made between these models for the “shaved” rubber-cord layer based on numerical experiments. In both cases, the potentials are built on the basis of the Treloar or Mooney potentials. Note that in the case of an inhomogeneous thin layer, the traditional definition of homogenization needs to be modified. In previous works of the authors, it was proposed to determine 3D averaged elastic properties of a layer by surrounding it with a homogeneous material. This makes it possible to correctly take into account the fact that the boundary effect from the upper to lower surfaces that penetrates through the whole periodicity cell. A set of local problems formulated for the periodicity cell is proposed. This set is sufficient for determining elastic potential material parameters. Nonlinear local problems on a periodic cell are solved and the material constants of the elastic potential are determined. The applicability of the orthotropic potential (second model) is determined for the “shaved” layer. It was found that orthotropic properties are manifested relative to longitudinal shears. The results show the suitability of the proposed potential and the scheme for determining the material parameters.

SIDE SLIP OF WHEELS WITH LOW AND ULTRA-LOW PROFILE TIRES OF A PERSONAL CAR NEGOTIATING A TURN

This article studies the influence of the speed of a car with low and ultra-low profile tires, 14ʹʹ and 16ʹʹ, negotiating a turn through an interactive software system developed by us in the MATLAB environment. The changes of the normal and lateral loads of the wheels are obtained and the characteristics of the side slip angle (known as side slip) of the pneumatic tires are determined. Taking into account the side slip of the wheels, the software determines the center of the turn. The characteristics for the normal and lateral loads and of the side slip of the wheels for both types of tires are given. The influence of the tire profile on the handling characteristics is analysed. Recommendations are proposed for a personal car’s motion in a turn with both types of tires.

Substantiation of prospective direction for developing devices to reglate pressure in truck tires

Analysis of the theory of the car and its basic elements makes it possible to state the exceptional importance of the pneumatic tire, which provides movement during the operation of the vehicle. The most important parameter that characterizes the condition of the pneumatic tire is the pressure, which can fluctuate during movement, but, at the same time, is a controlled parameter due to the possibility of inflating the tire in the presence of special devices during movement. Methodology. The purpose of the article is a reasonable prospect of creating new models of devices for tire pressure regulation in trucks. To achieve this goal, the methods of hypothesis, mathematical modeling to confirm it, methods of analysis, generalization were used. Results. The article proves that under the influence of the load on the wheel, the air temperature in the tires will be different and, accordingly, there will be differences in the pressure parameters in the pneumatic tires of trucks. In this regard, the solution to the issue of tire pressure regulation in trucks should be considered from the standpoint of differentiated pressure regulation, taking into account the difference in pressure parameters, which allows pumping each individual tire without a forced stop. Originality. The scientific novelty of the article is that it substantiates the promising direction of development of pressure monitoring devices in truck tires based on the analysis of the theoretical model of heating the pneumatic tires. Practical value. The practical significance of the study is that the article identifies the need to change approaches to pressure regulation based on the transition from centralized pumping systems to pumping systems based on a differentiated approach to individual air pressure control systems in truck tires.

Time factor research of tires tread wear for selfpropelled scraper

Abstract. Problem. The publications analysis about the self-propelled scrapers use on sites of road and reclamation construction is showed that during the performance of working operations there is unacceptable wear of the tires tread as a result of the intensive sliding on the support surface. Over time, the pneumatic tires wear leads to decrease on the durability of the wheeled mover or tire failure as a result of the carcass rupture and the tread delamination. In its turn, the time factor of the tire tread wear depends directly on the duration of the scraper operating cycle, which implements the traction and transport modes. Goal. The life time increasing of the wheeled mover for the self-propelled scraper by reducing the tire tread wear. Methodology. Analytical methods for interaction process research of the pneumatic tires with support surface are used. Mathematical modeling methods were used to determine the time factor of the tire tread wear during scraping. Results. Dependencies for determining the duration of operating cycle components according to the elliptical scheme of scraping organization are presented. Based on the proposed mathematical model, such as takes into account the force, speed and time factors, the fractions of tire tread wear are determined by the components of the scraper operating cycle, which including its maneuvering in the face. It was found that most often the tire tread wear occurs when moving of the soil-loaded scraper. The presented calculation results of the tire life time according to the proposed method are showed the sufficient convergencewith the scraper performance attributes, taking into account only the abrasive mechanism of the tire tread wear. Originality. To determine the life time of pneumatic tires for the self-propelled scraper, as the most fully combined characteristic features of the traction and transport machine, it is proposed to use the preferred mechanism of tire tread wear – abrasive, as well as the deformation models of the pneumatic tire and support surface. Practical value. The use of the proposed method for calculating the tire tread wear will to make the life time forecast of the wheeled mover for the self-propelled scraper at the design stage and to determine the reasonable needs for material and technical means of this machine operation.

CFD study of aerodynamic performance of non-pneumatic tyre with hexagonal spokes

Non-pneumatic tyres (NPT) provide a greater advantage over the pneumatic type owing to their construct which increases the reliability of the tyre operation and effectively reduces maintenance involved. Analysing the aerodynamic forces acting on a NPT becomes a crucial factor in understanding it’s suitability for practical implementation. In the present work, the aerodynamic performance of a NPT using CFD tool – SimScale® is studied. This work includes a comparative study of a pneumatic tyre, a NPT with wedge spokes and a NPT with hexagonal spokes (NPT-HS). The effect of air velocity, steering (yaw) angle and camber angle on the aerodynamic performance of the NPT-HS is evaluated using CFD. By increasing the steering angle from 0° to 15°, the lift coefficient decreases by 37% approximately at all velocities. Whereas drag coefficient initially decreases by 21% till 7.5° steering angle and then starts increasing. Increasing camber angle from 0° to 1.5°, both drag and lift coefficients goes on decreasing by approximately 7% and 27% respectively.

Determination of tangential properties of a single pneumatic tire in the vehicle braking mode of a vehicle

Problem. In the event of circumstances that may cause a traffic accident (accident), drivers apply emergency braking, which usually leads to the blocking of car wheels and the formation on the road surface of track information from pneumatic tires. If automated brake force control systems are installed in the brake actuator of the vehicle, the tracking information from the pneumatic tires may be absent or weak, and the braking efficiency of the wheeled vehicle will depend on the angular deformation of the tire relative to the road surface, which in turn is limited. coupling properties in the contact spot "tire-road surface". Goal. The aim of the work is to improve the method of determining the angle of twist of the pneumatic tire of a single car wheel in the mode of its braking by taking into account the effects of the coefficient of friction-sliding on roads with high traction. Methodology the peculiarities of twisting the pneumatic tire of a car wheel with a single busbar in the mode of vehicle braking on roads with low and high coefficient of friction - sliding are considered. The analysis of the model of dynamic change of the tire twist angle depending on the sliding of the tire tread elements in the spot of contact with the road surface is performed, and the results of simulation modeling are obtained, which are confirmed by experimental experiments. Originality. An empirical dependence is proposed, which takes into account the nature of the decrease in the value of the angle of twist of the tire on roads with high traction properties. Practical value. The obtained results of simulation modeling according to the proposed dependence determine that the highest indicators of torsional rigidity of the pneumatic tire are reached at a tire pressure of 0.8 MPa and a vertical load on it of about 2.6 104 N.

Study of 3D printing for forming spoke of non-pneumatic tire using finite element method

Over the last decade, non-pneumatic tire (NPT) was developed by replacing air in traditional pneumatic tire with polyurethane (PU) spoke. However, there are some limitations in building complex shape of spokes. Recently, the 3D printing technique has been used to form complex part of real products. Consequently, it can use to build the complex spoke of NPT. This research aimed to study the possibility of using 3D printing technique to build the complex shape of spoke for NPT. This can be done by studying the mechanical properties of 3D printing material suitable for NPT’s spoke. The PU filament was printed into tensile specimens to carry out the stress-strain relationship by using universal testing machine. The finite element (FE) model of NPT was then created using mechanical parameters of the tension result. The vertical stiffness testing on the NPT model was analyzed. The NPT performance to support the vertical load of real NPT and FE model with original material was carried out to compare with the 3D printing model. Furthermore, the advantage and disadvantage including limitation of using 3D printing technique to manufacture the NPT spoke were discussed.

Design, Construct and Evaluation of a Single Row Hand-Pushed Mechanical Weed Control Machine

Weed control is one of the major problems in crop and vegetable production in Nigeria. Most of the peasant farmers use manual weeders in their cultivation, a process that is costly, labour intensive and time consuming. The process does not also give the farmer adequate returns to enable him breakeven. It is, therefore, necessary to design a weeding equipment which minimize the human effort and provide efficient work output for the peasant farmer. This study focus on designing, construction and evaluation of a hand-pushed weed control machine that would eliminate the challenges being faced by the farmer in weeding. Materials selected to suit the construction of the weeder are durable and locally available, easily replaced if damaged and at affordable cost. They include mild steel (3mm, 5mm), 30 mm circular (hollow) pipes, 10 mm diameter steel rod, and 40 cm pneumatic tyre. The developed weeding machine was evaluated in the experimental farm of IAR with impressive results. It works well in sandy loam soil of about 25.65% moisture content and requires less labour force compared to the manual hoe. It has about 84.7% weeding efficiency, 0.0129ha/hr effectivefield capacity, 0.019ha/hr theoretical field capacity and 68% field efficiency. The average cost of the weeding is N21, 000:00.
 Keywords: Manual weeding, hand-pushed weeder, weeding efficiency, field efficiency