Wheel Stiffness Research Articles

Hoist Sheave Structure Optimization and Lightweight

To ensure wheel body of the hoisting sheave strength and stability condition. For the purpose of wheel body lightweighting. There are two schemes to reduce body weight.Reduce the spokes at the same time increase the ring stiffened plate, and reduce the spokes at the same time change the spokes width and thickness.The wheel body was established based on Pro/E 3D geometric model. Import the mesh in the Workbench of ANSYS software for finite element model. Statics analysis to select the optimized scheme. Establish a hoisting sheave wheel body under the actual working condition of widening the width - deformation - wheel weight relational table. Analysis to lightweight at the same time ensure that stiffness of wheel,then it can obtaine the optimal result.

Influence of wheel configuration on wheelchair basketball performance: Wheel stiffness, tyre type and tyre orientation

The aim of the current investigation was to explore the lateral stiffness of different sports wheelchair wheels available to athletes in ‘new’ and ‘used’ conditions and to determine the effect of (a) stiffness, (b) tyre type (clincher vs. tubular) and (c) tyre orientation on the physiological and biomechanical responses to submaximal and maximal effort propulsion specific to wheelchair basketball. Eight able-bodied individuals participated in the laboratory-based testing, which took place on a wheelchair ergometer at two fixed speeds (1.1 and 2.2 m s−1). Outcome measures were power output and physiological demand (oxygen uptake and heart rate). Three participants with experience of over-ground sports wheelchair propulsion also performed 2 × 20 m sprints in each wheel configuration. Results revealed that wheels differed significantly in lateral stiffness with the ‘new’ Spinergy wheel shown to be the stiffest (678.2 ± 102.1 N mm−1). However the effects of stiffness on physiological demand were minimal compared to tyre type whereby tubular tyres significantly reduced the rolling resistance and power output in relation to clincher tyres. Therefore tyre type (and subsequently inflation pressure) remains the most important aspect of wheel specification for athletes to consider and monitor when configuring a sports wheelchair.

Vibration and dynamic loads in external gear pumps

This paper presents the model for simulation of vibration and dynamic loads in external gear pumps. The calculation has been carried out in Matlab/Simulink program. The vibrations of gears are excited due to the variable pressure forces and variable stiffness of the gearing. In this model the stiffness and damping coefficient of sliding bearings as well as the bending stiffness of gear wheels have been included. The influence of pressure and rotational speed on the dynamic forces in the bearings have been analyzed.

Influence of Wheel Stiffness on Vehicle Dynamic Performance

Influence of Wheel Stiffness on Vehicle Dynamic Performance

Effect of tilting angle on the dynamics of tilting table driven by worm and worm wheel

The dynamics of tilting table behaves differently during five-axis machining due to the constant changes of the position of its center of mass which leads to different forces acting on parts of the transmission system. In this research, the lumped parameter method is used to model the dynamics of tilting table driven by worm and worm wheel in the tilting direction, where the varying stiffness of the transmission system at different tilting angles is considered. The impact testing experiments of tilting table system with tilting angles from 0° to 90° are also performed to verify the analytical model. The results from sensitivity analysis show that the three stiffnesses have a great effect on the variation of system natural frequency in the tilting direction, including the equivalent tangential meshing stiffness of worm and worm wheel, the torsional stiffness of worm wheel shaft, and the axial stiffness of worm supporting bearings. Moreover, the variations of system natural frequency with the three stiffnesses at different tilting angles are further investigated.

주행 중 실내소음과 Wheel의 Lateral Dynamic Stiffness와의 상관관계에 대한 시험적 연구

현재 소비자들이 자동차를 선택하는 여러 이유 중에서, NVH 성능이 아주 중요한 역할을 하고 있다. 근래 하이브리드 및 전기자동차들은 전통적인 차량의 주요 소음원 이었던 엔진의 소음이 거의 발생되지 않아 자동차 실내의 소음에 대한 관심은 더욱 커지고 있다. 해외 참고문헌에 의하면 자동차 휠의 높은 Lateral Dynamic Stiffness(LDS)가 운전 중 발생되는 Structure Bone Noise(SBN)를 저감시키는 것으로 기술되어 있다. 하지만 유효한 기준 및 시험적 결과가 미비하여, 본 연구에서는 LDS가 서로 다른 휠에 동일 타이어를 부착하여 실내소음을 시험 측정하였다. 그 결과 휠의 LDS에 따라 실내소음이 변화되는 것을 확인하였다. 이는 휠의 최적설계로 실내소음의 저감이 가능할수 있다.

Effect of Contact Stiffness of Grinding Wheel on Ground Surface Roughness and Residual Stock Removal of Workpiece

In the grinding operation, grinding wheels are deformed by grinding forces, so that residual stock removal of the workpiece takes place. Since this residual stock removal of the workpiece causes low machining efficiency and deterioration of machining accuracy, high hardness grinding wheels may be selected in order to obtain high machining efficiency and/or high quality machining accuracy. On the other hand, when grinding operations used by low hardness grinding wheels are carried out, it is well known that ground surface roughness is smaller than in case of higher hardness grinding wheels. From such a viewpoint, this study aims to investigate experimentally the effect of the contact stiffness of grinding wheel on the ground surface roughness and the residual stock removal of the workpiece. Grinding operations were carried out using three grinding wheels which are different hardness type, and ground surface roughness and residual stock removal of the workpiece were measured. The contact stiffness of grinding wheel was calculated by a support stiffness of single abrasive grain and a contact area between grinding wheel and workpiece. Comparing the contact stiffness of grinding wheel with the ground surface roughness and the residual stock removal of the workpiece, it was known that ground surface roughness increases and residual stock removal of workpiece decreases with increaseing the contact stiffness of grinding wheel. From these results, since elastic deformation of the grinding wheel changed depending on the suppot stiffness of single abrasive grain, it was clarified that the ground surface roughness and the residual stock removal of the workpiece were changed by the contact stiffness of grinding wheel.

New generation of resilient wheels bonatrans for tram cars

This papers deals with the new design of resilient wheels with high radial elasticity comparing another designs. The aim of this new wheel design is to increase passenger comfort and noise reduction during service of tram cars in cities. Tyre of the wheel is designed also as brake disc. In this paper will be describe also results of laboratory test of the wheel stiffness and comparison with previous wheel generation including other wheel parameters. Because primary role of the wheel is done by rubber segments also its results will be described.

Efficiency of resilient wheels on the alleviation of railway ground vibrations

The aim of this paper is to show how resilient wheels, initially used for reducing the noise generated at the wheel/rail contact and stresses on wheels, are also efficient for reducing ground vibrations. Brussels tramway T2000 is considered as an example. A prediction model as complete as possible is used, taking into account the track and the vehicle dynamics. A multibody approach is chosen to describe the vehicle behaviour, over a finite element model for the track. The soil is modelled with the finite/infinite element approach, taking into account the layered configuration of the ground. Three variants of tram are analysed, focusing on the resilient wheel stiffness. The stiffness and damping properties of the wheels are obtained by updating a finite element model. A validation step is presented, based on measurements at the soil surface during the passing of the tram over a rough rail and a local rail defect. A modal decomposition is applied on the vehicle model with emphasis on relevant modal contributions in the wheel/rail forces. A sensitivity analysis of the resilient wheels stiffness is performed, showing a meaningful decrease of ground vibrations using a soft resilient material. This study shows that the vehicle dynamics intervenes in the onset of the vibration waves in the soil and demonstrates the real interest of a compound vehicle/track/soil model in the design of this kind of wheel.

Calculation of the Contact Stiffness of Grinding Wheel

It is considered that the contact stiffness between the grinding wheel and the workpiece depends on the number of the abrasive grains in contact with the workpiece and the support stiffness of a single abrasive grain. In this paper, the calculating method of the theoritical contact stiffness of grinding wheel in grinding operation was proposed. Comparing calculated results of the contact stiffness in grinding operation with measured it in the stationary state, the contact stiffness of the grinding wheel in grinding operation was investigated.

Effect of Wheel Elasticity on Grinding Stability

Grinding stability was analyzed concerned with contact deformation and contact stiffness of wheels. Elastic deformations of the grinding wheel were measured with inductance sensors. Dynamic grinding system model was set up. Relation between contact stiffness and chatter growing index was analyzed. Chatter suppression experiments with variable grinding speeds were carried out. When wheel is in contact with a workpiece, contact deformation can occur. The contact stiffness of grinding wheel is a variable. The relation between chatter growing index and contact stiffness is an increasing function. Chatter growing index can be decreased by lowering contact stiffness of wheel. The grinding system stability will be improved with variable grinding speed.

Contact Stiffness of Grinding Wheels due to the Difference of Table Feed Rate

Usually, the contact stiffness between a grinding wheel and a workpiece has been measured in a stationary state. So, in this study, the contact stiffness under the grinding operation is measured under different table feed rate of the workpiece. From this result, it is known that, while the contact stiffness in the stationary state increases with the increase of the contact force, the contact stiffness under the grinding operation decreases with the increase of the normal grinding force relating the table feed rate. In this paper, since the number of contacting abrasive grain with workpiece is constant irrespective of the table feed rate, and the residual stock removal of workpiece is varied by the table feed rate, it is clarified that the contact stiffness under the grinding operation differs from the contact stiffness measured by the stationary state.

An analytical model to study the radial stiffness and spoke load distribution in a modern racing bicycle wheel

A theoretical study has been carried out to analyse the behaviour of the structural components used with a modern spoked bicycle wheel when loaded at the hub axle and supported at the rim. The work has involved developing some general equations for calculating the contributions which the axially loaded spokes and the bending flexure of the rim make to hub displacement and hence hub-to-rim wheel stiffness. The work considers the effect which the spoke tightening preload has on the distribution of load throughout the wheel and also the influence it has on wheel stiffness. The developed theory has been applied to some modern racing cycle wheels which have just a few spokes and use a relatively rigid, part tubular cross-section rim. Such designs are evaluated, using actual mechanical properties, and their behaviour is discussed against more traditional multi-spoke wheel designs which have relatively much more flexible rims. The theory has been compared with the results obtained from experimentally load testing a bicycle wheel using 12 and 18 spoke variants.

On Steering Control of Commercial Three-Axle Vehicle

The steering control laws of commercial three-axle vehicle are studied based on the closed-loop control model of the driver-vehicle-road. The steering characteristics of the three-axle vehicle can be improved through adding the steering of rear wheels. For a series of combined roads defined as standard roads where the vehicle is tested, a new proposal to optimize the design parameters of the steering system is presented. The cornering stiffness of front, middle and rear wheels and outer disturbance are considered as uncertain parameters varying over a limited range. A new controller of model-following variable structure is constructed and used for controlling front and rear wheels steering of the actual vehicle, so that the steering characteristics of the uncertain vehicle model and nonlinear vehicle model can follow the characteristics of the reference model (nominal model), namely, the vehicle can keep the same steering characteristics as the nominal model on the different roads. Simulation results have demonstrated that the proposed method is reasonable and practicable.

Molecular dynamics simulation of effect of grinding wheel stiffness on nanogrinding process

This paper intends to address an approach of Molecular Dynamics (MD) simulation to clarify the material deformation and removal mechanism between an abrasive grain and workpiece. The workpiece and the abrasive grain are assumed to consist of mono-crystalline copper and rigid diamond, respectively. In the present simulation model, influence of the stiffness of grinding wheel or polishing pad is taken into consideration. From the simulation results, relationships between material removal process and dynamics of the slip deformation, influence of the grinding wheel stiffness on the chip formation process and the actual depth of cut and so on, are clarified. These results indicate that the MD simulation has an advantage in deciding the stiffness of the tools and in estimating the actual depth of cut.

Finite element analysis and optimization of composite wheelchair wheels

A methodology for the design of Paralympics wheelchair wheels has been developed and provided a framework for comparison between design solutions. Finite element analysis was used as a tool to develop an understanding of wheel design, provide a basis for evaluation of design solutions, and as a mean of design optimisation. A finite element model of an existing wheel design was created and analysed. It was found that the pushrim was significantly over designed for the application. As such, wheel improvement focused on redesign of this component. A number of design solutions were analysed and compared based on weight, rotational moment of inertia, side profile surface area, and wheel stiffness. From this, it was decided that a thin pushrim attached via spokes to the rim and the hub in a tangential spoking pattern would offer the best solution.

An evaluation of the effects of handpiece speed, abrasive characteristics, and polishing load on the flexural strength of polished ceramics

Many studies on the strengthening effects of grinding and polishing, as well as heat treatment on ceramics, are not well standardized or use commercially available industrial polishing systems. The reported effectiveness of these strengthening mechanisms on ceramics may not be applicable to clinical dentistry. The purpose of this study was to evaluate the effects of controlled polishing on the flexural strength of dental ceramics by using a custom-made machine that applied standardized loads and speeds that coincided with the mean loads and speeds used by experienced prosthodontists. A total of 140 aluminous dental ceramic bar-shaped specimens (Vitadur Alpha Enamel) measuring 1.5 x 2.0 x 25 mm were fabricated and divided into 12 groups (for most groups, n=10). Specimens were untreated, polished with different polishing systems, polished at different speeds, ground and autoglazed, polished and autoglazed, autoglazed and polished, polished with loose (paste) and bonded abrasives, or overglazed. Simulated clinical polishing was performed on the ceramic specimens by using a customized polishing apparatus that allowed independent control over the relevant polishing parameters (abrasive hardness, applied load, linear speed, rotational velocity, and wheel stiffness). Flexural strength (MPa) was measured with a 4-point bending test, and subjective surface roughness was assessed with scanning electron microscopy. Autoglazing was performed at various stages of the polishing sequence to determine the effects of polishing on surface stresses. Mean values, standard deviations, independent-sample t tests, 1-way and 2-way analyses of variance, Dunnett t tests and Kruskal-Wallis tests were applied to the data (alpha=.05). Under a clinical load of 0.6 N for a coarse polishing wheel, 1.0 N for a medium polishing wheel, and 1.3 N for a fine polishing wheel, a linear speed of 499 mm/min, and a rotational velocity of 10,000 rpm, the use of clinical polishing instruments did not affect the flexural strength of the aluminous ceramics studied (P=.274). At higher rotational velocity (20,000 rpm), specimens polished with the diamond polishing system produced statistically weaker specimens compared with those that had been polished at 10,000 rpm (P=.019). Autoglazing treatment of the diamond-polished specimens did not reverse the strength degradation (P=.125). Conversely, diamond polishing of the autoglazed specimens resulted in significant flexural strength reduction (P=.029). Fine-diamond-bonded abrasive significantly reduced flexural strength (P=.025). Simulated clinical polishing at 10,000 rpm did not appear to substantially strengthen or weaken the ceramic specimens. Polishing at 20,000 rpm reduced flexural strength of the ceramic bars.

A Study on the Contact Stiffness of Grinding Wheels

A Study on the Contact Stiffness of Grinding Wheels

Study on Elasticity of Grinding Wheels (Modeling and Calculating the Stiffness of Grinding Wheels)

In order to clarify the mechanical phenomena of grinding wheels in the contact area with workpieces, a mathematical model of wheel is proposed and a static analysis of grinding wheels is carried out. As the first step of this study, a wheel model consisting of rigid abrasive grains and bonds as spring elements with stiffness k is proposed. ln this model, grinding abrasives are uniformly arranged in body centered lattice and successive two grains are connected by a bond with static stiffness k. The amount of static stiffness of bond k deeply affecting on the mechanical phenomena in contact area is calculated with FEM analysis and the three points bending test of abrasive sticks. As the results of analysis, it can be clarified that the amount of k is determined only depending on the Brain size and the mechanical phenomena of grinding wheel in the contact area can be explained by using the amount of the static stiffness k.

211 レジノイド砥石の結合剤の静剛性

211 レジノイド砥石の結合剤の静剛性