Structure Of Wheels Research Articles

Optimization of Impact Resistant Throwable Unmanned Ground Vehicle Using Mathematical Modeling Techniques

Unmanned Ground Vehicles are used for various reasons. One of them is used in search and rescue operations which are known as Throwable Unmanned Ground Vehicles. It is a type of Unmanned Ground Vehicle which can sustain falls from several meters. Such vehicles are easily deployable, lightweight and impact resistant. Wheels play an important role since they absorb most of the impact. To optimize the performance of such vehicle, mathematical modeling is necessary. In this research paper, the main goal is to model the system mathematically. Parameters like impact forces, elasticity, Young’s modulus and duration of impact depend highly on material properties and structure of wheels. Results show the effect of certain parameters on wheel’s design and materials. For that purpose three materials are chosen PCTPE, carbon fiber, and vulcanized rubber for wheels. Impact forces, and duration of time are plotted against height of fall and diameter of the wheel for these materials.

Wheel and axle defect detection based on deep learning

With technological innovations in the world of high-speed railways, railways have become an indispensable and important part of life. As a key part of the train, the safety of the wheels and axles cannot be ignored. Industry often uses non-destructive testing (NDT) methods, and because of the special structure of wheels and axles, we commonly use phased-array ultrasonic testing. However, the disadvantage is that ultrasonic inspection methods rely too much on the intuition of skilled workers and as the workload increases, a large amount of data is not used effectively, which can easily lead to safety hazards. To deal with these issues, an efficient detection method emerges as the times require. we collected ultrasound-based B-scan defect data for wheels and axles, by expert manual annotation to establish a database of various types of defects in wheels and axles of existing trains. By using the improved YOLO-v5-based algorithm for training validation and testing, improving the feature extraction layer and adding a small target detection layer for difficult defects. Finally, by adding an attention mechanism to improve the training accuracy and using active learning strategies for data enhancement to make it more applicable to ultrasound images, the experiments significantly improved detection efficiency and stability, with a high defect detection rate and a significantly decreased false alarm rate. The algorithm has good performance with laboratory data. The algorithm has good performance in laboratory data and can meet the application requirements in the actual wheel and axle inspection data, we tested more than 3000 different pictures which are all from the real data collected by ultrasonic testing, with the defect detection alarms reaching 100%, detection speed reaching real-time detection, and false alarms being controlled to within 2%. More importantly, with the self-upgraded of algorithm and new data collection, the detection efficiency will improve gradually.

Die structure optimization study for magnesium alloy wheel formed by backward extrusion

The current magnesium (Mg) alloy wheel formed by backward extrusion (BE) often has upper rim cracking and coarse microstructure at the spokes to reduce the yield, and a reasonable die structure design is an important factor to improve the yield of the wheel, therefore, this poses new challenges on the die structure of Mg alloy wheels. The paper selected four parameters for the three positions of the wheel for optimizing the die structure by analyzing the forming characteristics and defects of Mg alloy wheels. Based on the actual extrusion conditions of the Mg alloy wheel, a numerical model of Mg alloy wheels formed by BE was established, and the effect of a single parameter on the physical field of the forming process was analyzed by numerical simulation in turn, and then the four parameters of the die structure were progressively combined and optimized to determine the better three positions of the Mg alloy wheel die, while an experimental trial was conducted to verify the accuracy of the results of this study. The results show that increasing the spoke thickness, decreasing the spoke inclination angle, increasing the punch fillet radius and increasing the inner fillet radius of the upper rim can effectively improve the metal flow and make the billet filling more smoothly. The optimized die structure can make the temperature at the wheel bottom lower and evenly distributed, the stress concentration at the window is relieved, the filling at the upper rim is complete, and the macroscopic tearing phenomenon disappears.

Construction analysis of non-pneumatic tires

Non-pneumatic tires are not a new construction. The first information about them appeared before the invention of pneumatic tires. Appropriate materials and design for the flexible structure and band of modern non-pressure wheels are designed to mimic the functions of compressed air of a pneumatic tire. Mentioning the elements of the wheel structure will determine the nature of the load carring. Mentioning the elements of the wheel structure will determine the nature of the load transfer. Currently, the dominant form of flexible structure are: single spokes and a cellular structure made of polygons. The band comprises at least one reinforcement layer of inextensible material. The number of reinforcement layers and their shape will influence the behavior of the wheel during loading. Keywords: mechanical engineering, non-pneumatic tire, wheel

IMPROVEMENT OF ABRASIVE TOOLS BY INCREASING THEIR STRUCTURAL AND MECHANICAL CHARACTERISTICS

On the basis of an analytical review, the current directions for improving abrasive tools are identified - the use of a mixture of abrasive materials and the introduction of a filler into the structure of abrasive wheels to improve their characteristics. Keywords:ABRASIVE TOOL, FILLER, MODIFICATION, STRENGTH, INTEGRATED APPROACH. sf-visteh@mail.ru

Roller-Skating of Mammalian Quadrupedal Robot With Passive Wheels Inspired by Human

Human can achieve roller-skating utilizing passive wheels to improve movement speed. Inspired by human roller-skating, a new dynamic roller-skating gait of a typical mammalian quadrupedal robot with passive wheels is proposed to promote mobile efficiency. According to the motion characteristics of human dynamic roller-skating, a simple structure of passive wheels installed on feet is designed for the mammalian quadrupedal robot to achieve this dynamic roller-skating without adding any active joints. Imitating human roller-skating, this dynamic roller-skating gait based on the bilateral symmetry can achieve the linear and turning motion. The Poincare map and the skating inverted pendulum model derived from human roller-skating are used to simplify the controller of the quadrupedal robot without considering real dynamical characteristics. The proposed roller-skating gait is verified in simulations and experiments. The results prove that the roller-skating gait has higher speed and efficiency than the conventional trotting gait.

Wheel design and motion analysis of a new heavy-duty AGV in aircraft assembly lines

PurposeThe flexible automatic transportation and manual assembly jobs for large aircraft components demand an automated guided vehicle (AGV) system with heavy-duty capacity and omnidirectional movability. This paper aims to propose a four driving-steering wheels-four supporting-steering wheels (4DSW-4SSW) layout plan to enhance the controllability and moving stability of AGV.Design/methodology/approachThe anti-vibration structure of DS wheels and high-torque steering mechanism of SS wheels with tapered rolling bearings are rigorously designed to meet the functional requirements. Based on the specific wheel layout and vehicle dynamics, the rotational kinematic model as well as the straight and rotational dynamic models of AGV are established by the authors. To well verify the motion characteristics of wheels under heavy load in three motion states including straight motion, self-rotation and rotation around a certain point, the simulations in ADAMS and factory experiments have all been conducted.FindingsSimulation results indicate that normal and friction forces of DS wheels and SS wheels are very stable except for some small oscillations, which are caused by non-center load distribution on AGV. Experimental results on driving speed of AGV have directly demonstrated that its positioning accuracy is enough for use in real aircraft assembly lines.Practical implicationsThe designed AGV system has been applied to the final assembly line of a certain aircraft in Aviation Industry Corporation of China, Ltd, whose assembly efficiency and flexibility have been significantly improved.Originality/valueA new layout plan of wheels for an omnidirectional heavy-duty AGV is proposed, which enhances the operating and moving capacity of AGV. A function of human-machine collaboration is also offered by the AGV for transporting large workpieces intelligently and economically in aerospace and other heavy industries.

Low-temperature cementation – perspective technology of hardening of toothed parts

The structure, properties and geometrical accuracy of gear wheels after chemical heat treatment which cementation was carried out at 930°C and 870°C are investigated. Advantage of low-temperature cementation of toothed parts in size of a radial runout, fluctuation of a side clearance, ovality of an internal opening and the area of a spot of contact between teeths of the strengthened gear wheels is shown. Influence of structure of the endothermic atmosphere on mechanical properties and intensity of saturation by carbon steel 15HGN2TA and 20HGNMTA is investigated. It is established that increase in content of hydrogen from 20% to 40% in the endoatmosphere increases saturation speed carbon steel by 10 – 34%, excludes their hydrogen saturation and keeps indicators of mechanical properties of the cemented parts. The technology of chemical heat treatment of toothed parts including cementation at 870°C in the endothermic atmosphere containing 40% of hydrogen in the structure is developed and recommended for application.

Determining the Volume-size Pore Space Parameters in the Grinding Wheels

In forming structural and mechanical properties and performance criteria of a grinding wheel, pores are a key player. They are stochastically distributed in the shard of the wheel, have a random size and shape in the limited volume of the wheel shard, which makes it difficult to determine the volume-size parameters of the pore space in the grinding wheel.Experimental and analytical studies of the wheels on the ceramic bond allowed authors to reveal a porosity and pore size dependence on the size of grain, hardness, and structure of wheels, taking into account the type and the quality index of abrasives and also the method of tool modification. It was found that the tool porosity increases with increasing its structure number and decreasing hardness and size of grain.On the basis of obtained experimental data, an equation was compiled that reflects the power relationship between the porosity of a serial standard tool and its structural characteristics. By varying the structural characteristics of wheels, it is possible to determine the optimal porosity required for the grinding process in each concrete case.A comparison of experimental and calculated data on determining porosity of tools with different structural characteristics has shown that the difference in the values of porosity is within the range of 5 ÷ 8 %.Mathematical and statistical processing of experimental data, taking into account the dependence of the pore diameter on structural characteristics of the abrasive tool, allowed us to define a dependence of the pore size on the size of grain and porosity. The pore size grows with increasing size of grains and structure number and decreases with increasing hardness of the abrasive tool. The calculated pore size values differ from those experimentally obtained in the range of 5 – 12% with a confidence probability of 95 %.The presented calculation dependences and experimental data allowed authors to determine the porosity and the pore size of the tool through its GOST-normalized structural characteristics, as well as to make a rational choice of the tool for specified grinding modes and conditions.

Zastosowanie technik mikroskopowych do weryfikacji poprawności wprowadzenia substancji impregnującej w strukturę ściernic z ziarnami SG™ i SiCg

Zastosowanie technik mikroskopowych do weryfikacji poprawności wprowadzenia substancji impregnującej w strukturę ściernic z ziarnami SG™ i SiCg

A novel design of a desiccant rotary wheel for passive ventilation applications

Rotary desiccant wheels are used to regulate the relative humidity of airstreams. These are commonly integrated into Heating, Ventilation and Air-Conditioning units to reduce the relative humidity of incoming ventilation air. To maximise the surface area, desiccant materials are arranged in a honeycomb matrix structure which results in a high pressure drop across the device requiring fans and blowers to provide adequate ventilation. This restricts the use of rotary desiccant wheels to mechanical ventilation systems. Passive ventilation systems are able to deliver adequate ventilation air but cannot control the humidity of the incoming air. To overcome this, the traditional honeycomb matrix structure of rotary desiccant wheels was redesigned to maintain a pressure drop value below 2Pa, which is required for passive ventilation purposes. In addition to this, the temperature of the regeneration air for desorption was lowered. Radial blades extending out from the centre of a wheel to the circumference were coated in silica gel particles to form a rotary desiccant wheel. Computational Fluid Dynamics (CFD) modelling of the design was validated using experimental data. Reduction in relative humidity up to 55% was seen from the system whilst maintaining a low pressure drop across the new design. As an outcome of the work presented in this paper, a UK patent GB1506768.9 has been accepted.

A multi-criteria methodology for effectiveness assessment of internal cylindrical grinding process with modified grinding wheels

One of the possible engineering solutions in developing grinding technology is modifying the structure of the grinding wheels. This solution is applicable and feasible for industrial conditions as it does not require interfering with the construction of the grinding machine. This article presents an important aspect of the development of new grinding wheels, which uses multiple criteria to evaluate their effectiveness in the grinding process. An analysis of previously used methods of grinding effectiveness evaluation was performed. A number of criteria for evaluating the most important expenditures and effects of these processes were highlighted. Next, a comparative evaluation of effectiveness of the six suggested grinding wheel modifications with sintered microcrystalline corundum grains and ceramic bond was performed. These grinding wheels were characterized by the following structural modifications: zone-diversified structure, modification of the bond microstructure, microdiscontinuities of the grinding wheel active surface, sandwich structure with a centrifugal system for provision of the coolant into the grinding zone as well as impregnated grinding wheel. Additionally, a grinding wheel whose structure was composed of a number of modifications was considered. The essential advantages and disadvantages of the structural types of small-sized grinding wheels for peripheral grinding were determined. The results of the analysis of the effectiveness of the suggested solutions showed that it is possible to adjust the grinding wheel construction to the expected results of the given grinding operation as well as the technological conditions. It is also possible to combine these modifications in order to obtain additional synergetic effect of their positive influence on the grinding process.

A dual-scale analysis of a desiccant wheel with a novel organic–inorganic hybrid adsorbent for energy recovery

Desiccant wheels have been extensively used for energy recovery of ventilation air from buildings. Performance of these wheels is influenced by many factors like the material properties, wheel matrix structures, operating conditions and fluid parameters. Previous studies only involved the macro-scale heat and mass transfer in the wheels and the system performance, by neglecting the micro-scale properties of wheel materials. In this study, a dual-scale modeling approach was proposed for a desiccant wheel with a novel organic–inorganic hybrid adsorbent (HA) material which combines high adsorption capability with good mechanical durability. The proposed dual-scale model included a micro-scale molecular dynamics (MD) sub-model for adsorbent material, a macro-scale sub-model for heat and mass transfer in matrix channels and system performance evaluation. The two sub-models were linked together through information exchange to form the dual-scale model. Through modeling, the effects of the micro physical–chemical properties of materials and macro structure of wheels, as well as the operating parameters on system performance were investigated. With the dual-scale model as a design tool, material compositions were optimized. The moisture adsorption capacity of the material was two times higher than that of silica gel B at high relative humidities. Consequently the sensible and latent effectiveness were improved by 12% and 30% respectively.

Analysis of heat conduction in a drum brake system of the wheeled armored personnel carriers

This paper is an integrated study performed over the Braking System of the Wheeled Armored Personnel Carriers. It mainly aims to analyze the heat transfer process which is present in almost any industrial and natural process. The vehicle drum brake systems can generate extremely high temperatures under high but short duration braking loads or under relatively light but continuous braking. For the proper conduct of the special vehicles mission in rough terrain, we are talking about, on one hand, the importance of the possibility of immobilization and retaining position and, on the other hand, during the braking process, the importance movement stability and reversibility or reversibility, to an encounter with an obstacle. Heat transfer processes influence the performance of the braking system. In the braking phase, kinetic energy transforms into thermal energy resulting in intense heating and high temperature states of analyzed vehicle wheels. In the present work a finite element model for the temperature distribution in a brake drum is developed, by employing commercial finite element software, ANSYS. These structural and thermal FEA models will simulate entire braking event. The heat generated during braking causes distortion which modifies thermoelastic contact pressure distribution drum-shoe interface. In order to capture the effect of heat, a transient thermal analysis is performed in order to predict the temperature distribution transitional brake components. Drum brakes are checked both mechanical and thermal. These tests aim to establish their sustainability in terms of wear and the variation coefficient of friction between the friction surfaces with increasing temperature. Modeling using simulation programs led eventually to the establishment of actual thermal load of the mechanism of brake components. It was drawn the efficiency characteristic by plotting the coefficient of effectiveness relative to the coefficient of friction shoe-drum. Thus induced thermal loads determine thermo mechanical behavior of the structure of wheels. Study the transfer of heat generated during braking is useful because results can improve and validate existing theory or may lead to the development of a mathematical model to simulate the behavior of the brake system for various tactical and operational situations. Conclusions of this paper are relevant because theoretical data analysis results are validated by experimental research.

Determination of the diamond wheel structure in high-speed grinding using nanoindentation techniques: experimental and numerical simulation

Grinding at high speeds (over 80 m/s) is a complex process requiring deep understanding for successful deployment. This article describes ways of improving the integrity of the structure of diamond grinding wheels for high-speed regimes using nanoindentation techniques, as well as the prospects for their solution, using mathematical modelling methods.

The Vehicles ESP Safe Test System Based on Aid Wheels Breaking Control Vehicle System

The structure of the aid wheels braking control vehicle system is projected, and the system dynamic model is set up. Based on the Matlab/Simulink, establish the dynamic simulation system of the aid wheels braking control vehicle system for the Chery A3 car. Using the brake / drive integrated ESP control principle, based on the simulation model, respectively simulate and analyze the ESP control performances of the vehicle system and the aid wheels braking control vehicle system in different simulation conditions, under steer and over steer. The study results indicate that, based on the aid wheels braking control vehicle system, when there is no ESP control or ESP control system failure, the system can ensure the safety of vehicle effectively; and when with ESP control system, the ESP control performances of the aid wheels braking control vehicle system and the vehicle system have remarkable consistency. The aid wheels braking control vehicle system provides a basis for the vehicle stability control performance research.

Modeling thermal effects in braking systems of railway vehicles

The modeling of thermal effects has become increasingly important in product design in different transport means, road vehicles, airplanes, railway vehicles, and so forth. The thermal analysis is a very important stage in the study of braking systems, especially of railway vehicles, where it is necessary to brake huge masses, because the thermal load of a braked railway wheel prevails compared to other types of loads. In the braking phase, kinetic energy transforms into thermal energy resulting in intense heating and high temperature states of railway wheels. Thus induced thermal loads determine thermomechanical behavior of the structure of railway wheels. In cases of thermal overloads, which mainly occur as a result of long-term braking on down-grade railroads, the generation of stresses and deformations occurs, whose consequences are the appearance of cracks on the rim of a wheel and the final total wheel defect. The importance to precisely determine the temperature distribution caused by the transfer process of the heat generated during braking due to the friction on contact surfaces of the braking system makes it a challenging research task. Therefore, the thermal analysis of a block-braked solid railway wheel of a 444 class locomotive of the national railway operator Serbian Railways is processed in detail in this paper, using analytical and numerical modeling of thermal effects during long-term braking for maintaining a constant speed on a down-grade railroad.

Unique Helical Triangle Molecular Geometry Induced by Dipole–Dipole Interactions

Abstract Novel helix-peptide wheels, in which three helices were connected by using a template, were prepared, and the dipole–dipole interactions among the helices were studied in relation to the formation of a planar triangle structure containing three helices. The helical segments had a 310-helix structure. 13C spin-lattice relaxation time (T1) measurements showed that the helical segments had restricted mobility. Deuterium exchange rates of amide protons were accelerated in the helix-peptide wheels compared to the respective linear helix peptides, suggesting that there is torsion on the cylindrical shape. Therefore, the predominant structure of the helix-peptide wheels is a planar triangle in solution. Further, the triangle structure was successfully transferred onto a gold substrate.

Development of a Reconfigurable Mobile Robot and Precise Position Estimation Based on Extended Kalman Filter

This paper presents design concepts of a reconfiguration mobile robot developed in Hannam University and experimental results of position estimation by multiple sensors. In order to achieve high reliability and mobility in maneuver, driving motors of the mobile robot are assembled inside the wheels of the mobile robot, and the rhombus-shaped structure of the mobile robot with four wheels yields as good adaptability to rough terrain as a six-wheel mobile robot. Since the proposed mobile robot receives multiple sensor signals from odometers and an orientation sensor, states related to position and orientation of the mobile robot are optimally calculated by the extended Kalman filter. Experimental results show that tracking errors of the mobile robot can be reduced remarkably by the optimal state observer.

Structural stability of giant polyoxomolybdate molecules as probed by EXAFS

Recent progress in synthesis of “giant” polyoxomolybdate (POM) molecules that have a structure of hollow spheres or wheels and size of several nanometers in diameter has emphasized the need in their accurate structural investigation. Our temperature-dependent EXAFS studies demonstrated that the first generation POM molecules containing 132 Mo atoms, undergo irreversible structural transformations at ca. 500 K, while the recently synthesized second generation POM at ca. 400 K. The number of different structural units in these molecules can be accurately obtained from EXAFS analysis and compared with model structure calculations. In our method of analysis, we use theoretical calculations of pair radial distribution functions from the model structures as initial approximations to analyze the structures of these molecules. Our analysis allowed us to identify the new POM structure as a giant sphere, similar to the {Mo132} structure but containing 522 Mo atoms. Our results also demonstrate that the structural rigidity of different building blocks of these molecules can be quantitatively probed by EXAFS.