Wheel Disc Research Articles

Novel steel wheel design based on multi-objective topology optimization

This paper aims to propose a multi-objective topology optimization methodology for steel wheel, in which both the compliance and eigenfrequencies are regarded as static and dynamic optimization objectives. Compromise programming method is employed to define the objectives of multi-objective and multi-stiffness topology optimizations, whereas mean-frequency formulation is adopted to settle eigenfrequencies of free vibration optimization. To obtain a clear and useful topology optimization result, cyclical symmetry and manufacturing constraints are set, the influences of which on the outcomes are also discussed. With an appropriate value of the minimum member size, a rough topology optimization of the steel wheel is obtained. The optimization result is modified according to the actual structure and manufacturing process. Moreover, based on this result, eight different steel wheel modes are established to analyze the influence of the manufacturing process and draw beads on the wheel performance through finite element simulation. Simulation results are verified by conducting a stress test of a commercially available wheel. Compared with its initial design, the optimized wheel disc exhibited decreased mass at 0.15 Kg at percentage of 4.57%, manifesting the effectiveness of the proposed method.

A mathematical model for simulating and manufacturing ball end mill

The performance of ball end mill cutters in cutting operations is influenced by the configuration of the rake and clearance faces in the ball component. From the mathematical design of a cutting edge curve, the rake face can be defined by the rake angle and the width of the rake face at each cross section along the cutting edge. We propose the fundamental conditions that must govern the engagement between the grinding wheel and the designed rake face in order to avoid interference while machining a ball end mill. As a result, a new mathematical model for determining the wheel location and a software program for simulating the generation of the rake face of a ball end mill are proposed. In addition, methods for grinding the clearance face in both concave and flat-shapes are introduced. The flute surface generated by a disk wheel during the grinding process is determined on the basis of a tangency condition. The results of the experiment and the simulation are compared to validate the proposed model.

Nonlinear time heteronymous damping in nonlinear parametric planetary systems

The analysis of dynamics of time heteronymous weakly and strongly nonlinear planetary transmission systems with kinematic couplings–gears constitutes a study of complicated function of many parameters including the material of gears, damping properties and damping viscous properties of lubricating oil film in the gear mesh. The purpose of this theoretical preexperimental study is to educe the methodology that makes possible to analyse the influence of all parameter variants in the area of linear and nonlinear systems with constant and time variable damping on internal dynamics. More precise dynamic analysis of such systems leads to mathematical–physical models, whose motions are described by ordinary deterministic nonlinear time heteronymous differential equations at the application of mass discretization. Their solution leads to the method of transformation of the nonlinear boundary problem of differential equations into the equivalent problem of solving integro-differential systems of equations by the method of decomposition of solving kernels of Green’s type and by the method of successive approximations. The structures with lightening holes in cog wheel discs are characterized by time variable damping in gear meshes. In this paper, the examples of resonance bifurcation characteristics in the gear mesh give a comparison between two variants with lightening wheel discs and the variant with full wheel disc, i.e. two variants with time variable quadratic damping and the variant with the constant one.

Plate forging of drawn cup with flange including thickening of corners

A plate forging of a drawn cup with a flange including thickening of corners was developed to improve the stiffness of the cup. In a 3-stage stamping process, the bottom and flange corners of the cup with a flange were thickened by the plate forging. A circular blank was drawn with conical punches in the 1st and 2nd stages. In the 3rd stage, the bottom and flange corners were thickened by flattening the conical bottom of the cup with a flange. Both the bottom and flange corners of the cup were thickened by compressing the flange corner in the latter half of the 3rd stage. The amounts of thickening at both corners were improved by modification of intermediate shape. The thickening was concentrated around the two corners by preventing the thickening of the inclined portion. A wheel disk was formed by 6-stage stamping having the following three stages. The disk had 15% and 10% thickening at the bottom and flange corners, respectively, and the bending stiffness of the disk was increased. It was found that the proposed plate forging of sheet metal was considerably effective in increasing in the stiffness and reducing in the weight of automobile parts.

Multi-stage Stamping Including Thickening of Corners of Drawn Cup

A 3-stage stamping process including thickening of bottom and flange corners of a cup with a flange was developed to improve the fatigue strength of a mild steel cup. A circular blank is drawn with conical punches in the 1st and 2nd stages, and the bottom and flange corners were thickened by flattening the conical bottom of the cup with a flange in the 3rd stage. The amounts of thickening at both corners were improved by contact of the inclined portion between the two corners with the inner punch in the 3rd stage, thus the thickening was concentrated around the two corners by preventing the thickening of the inclined portion. A wheel disk formed by 6-stage stamping having the following three stages has 15% and 10% thickening at the bottom and flange corners, respectively, and the bending rigidity was 1.7 times as large as that without thickening. It was found that the proposed stamping method is effective in reducing the part weight and production cost.

Investigation on rolling sliding wear behavior of wheel steel by laser dispersed treatment

To improve wear resistance of wheel steels under rolling–sliding wear conditions, a novel technique named laser dispersed treatment (LDT) was used by forming a regular scattered hardening pattern distributed on the surface of wheel disc, which can avoid soft zones induced by tempering effect or cracks in the overlapped region. The wear rate of LDT wheel disc was evaluated by twin-disc wear testing machine in comparison with the untreated disc. The microstructure of LDT wheel disc and untreated disc was characterized by optical microscopy (OM), X-ray diffraction (XRD) and scanning electron microscopy (SEM). This study focuses on the relationship between the of microstructure and wear resistance of laser treated zone. It is shown that a higher wear resistance of laser treated zone is attributed to the strain strengthen of retained austenite during wearing and the compressive stress within laser treated zone. The laser dispersed treatment on wheel may be a useful technique to improve the wear resistance of wheel without harmful influence on rail.

The influence of high-frequency vibrations on derailment stability coefficient of cars at wheel flange climbing on the rail

Purpose. Taking into account the traffic safety priority on the railway transport the search of factors promoting increase of derailment stability coefficient is an actual task. Purpose of the paper is the influence researches of the high-frequency vibrations on the train traffic safety parameter. In this case the special form of the wheel rim, at which its rigidity changes according to the harmonious law, was considered as a source of vibrations. Methodology. For the analysis of the vibration influence on the change of friction coefficient values the methods of so called vibrational mechanics were used. For determination of vibration amplitudes through moving the wheel flange points the finite-elements method was also used in the paper. Findings. During calculations it was established that the derailment stability coefficient to a great extent depends on the friction coefficient between wheel and rail. The paper shows that the friction coefficient in turn is influenced by the high-frequency vibrations. The form of the wheel rim was considered as a vibration source and the parameters characterizing vibration were calculated. It was given the quantitative estimation of the friction coefficient change under the vibration influence. It was also scientifically based the high-frequency vibration influence on the derailment stability coefficient. Originality. The paper proved the possibility of high-frequency vibration influence on the derailment stability coefficient. The studies theoretically substantiated the traffic safety increase in the presence of vibrations in the contact area of the wheel flange with the rail caused by special form of the wheel disc. Practical value. It is shown that the use of undulating wheel disc form do not constitute a threat to the traffic safety, and the availability of high-frequency vibration can reduce the derailment probability.

The principle of profile modified face-gear grinding based on disk wheel

In view of the disadvantages of the current grinding method for profile modified spur face-gear, a progressive grinding method is developed. The third action principle of modified spur face-gear driving and the mathematical model of parabolic rack cutter, spur gear cutter, disk wheel and modified spur face-gear are established, based on the theories of differential geometry and gear mesh. The calculation method of swing angle range of the complete grinding of the profile modified spur face-gear is established through the research on the surface contact line area. The simulation processing test based on Vericut software verifies the feasibility and correctness of the method developed. The study provides an effective approach to highly efficient and precise grinding of the profile modified spur face-gear.

The effect of friction modifiers on wheel/rail isolation at low axle loads

Signalling block occupancy is triggered by the wheelset of a rail vehicle ‘shunting’ the track circuit. The main cause of loss of shunting is the many materials that can be present on the rail head. These include iron oxides, leaves, ballast dust, oil, as well as products deliberately applied to the rail/wheel such as grease, friction modifiers, lubricants and sand. These may lead to an indication that a signal block is unoccupied when a train is actually present. Friction modifiers (FMs) are being increasingly used for reduction of noise, lateral forces, wear, rolling contact fatigue, etc. The Kelsan® high positive friction (HPF) solid stick FM is applied directly to the wheel tread creating a thin film. Although no effects have been observed during field operation, the intention in this work was to build on previous studies and evaluate conductance across a wider range of contact conditions as studies have shown that loss of shunt is more common with light axle loads where films could have a greater effect. The testing was performed at a contact pressure of 470 MPa (equating to a 4.9 tonne axle load). An HPF stick was spring loaded against the rotating wheel disc to generate a FM film at the contact. Tests were run to measure the impedance across the discs using a modified TI21 track circuit. Static testing was also performed using discs with a pre-generated HPF film. Analysis of the results showed that the application of HPF friction modifier had no significant effect on the measured level of impedance. The highest impedance levels were recorded under pure rolling (0% slip) where FMs were not being applied. In cases where the application of FM increased impedance, the recorded impedance values were still lower than the highest values measured in the absence of a FM. This is of key relevance as several light rail operators coast their trains.

Inverse identification of wheel–rail contact forces based on observation of wheel disc strains: an evaluation of three numerical algorithms

In this paper, three numerical algorithms for the identification of wheel–rail contact forces based on measured wheel disc strains on an instrumented railway wheelset are discussed and compared. The three algorithms include one approach resting on static calibration, one that is applying a Kalman filter and the third is exploiting an inverse identification scheme. To demonstrate and evaluate the alternative methods, two load cases including periodic excitation by sinusoidal wheel–rail irregularities and transient excitation by an insulated rail joint are considered. Based on a previously presented vehicle–track interaction model in the time domain, load scenarios are defined by taking the calculated vertical wheel–rail contact forces as the reference force to be re-identified by the proposed algorithms. The reference contact forces are applied on a finite element model of the wheel to generate synthetic observation data, that is, radial strains at the positions of the strain gauges, serving as input to the identification procedures. It is concluded that the inverse identification scheme leads to superior accuracy at higher computational cost. If on-line implementation and evaluation is required, the Kalman filter generates better accuracy than the static calibration approach.

121 加速するホイールの空力特性と可視化解析(移動体の空力特性)

In recent years, bicycles are attracted as lower environmental burden transfer. Then, amateur competitors keep increasing, and they began to indicate data of aerodynamic specification of bicycle components as frames, spokes, helmets and wheels. This study verified the effects of Sub9 produced by Zipp. Zipp argues this wheel "produce forward lift" in a wind angle of 12 to 18 degrees. Therefore, we made 3 kinds of wheels, plain disk, normal disk wheel and Sub9 model. Those were used as a drag force measurement and flow visualization, and investigated in non-rotate conditions and rotate conditions. Drag force of each model was measured with three components load cell. Flow visualization in a smoke wind tunnel was also carried out in a vertical plane. As a result, Sub9 produced little thrust over wind angle of 16 degrees. Plain disk have similar specification to Sub9, and normal disk wheel is the worst wheel in this study. The results of the flow visualization also explain these phenomena well.

122 横風におけるDISK仕様自転車の隊列に関する研究(移動体の空力特性)

122 横風におけるDISK仕様自転車の隊列に関する研究(移動体の空力特性)

Development of hot rolled steel sheet with 600 MPa UTS for automotive wheel application

The aim of this paper is to develop a steel having tensile strength of 600MPa minimum combined with good formability, hole expansion and fatigue strength through a new metallurgical approach for such application. The steel, thus developed, has been successfully applied to automotive wheel disc making. Discs made of 600MPa strength showed improved durability in dynamic cornering fatigue and dynamic radial fatigue test. This novel steel will be a solution to solve the lack of stretch flangeability and bendability of advanced high strength steel (AHSS) sheets such as dual phase (DP) and transformation induced plasticity (TRIP) steels.

Biomechanical evaluation of supermarket cashiers before and after a redesign of the checkout counter

An experiment was carried out on supermarket cashiers to evaluate the time, kinematic and electromyographic changes, in both sitting and standing positions, following the redesign of a checkout counter. The novelty of the prototype checkout counter is a disk wheel placed in the bagging area, which is designed to avoid the cashier having to manually push products along the bagging area. The kinematic evaluation was based on the upper limb and trunk range of motions (RoM). The electromyographic parameters assessed were mean and maximum muscular activations. Three factors were taken into account: design (before and after redesign), posture (standing or sitting) and bagging area (anterior or posterior). The results show that the RoM values are lowest after the intervention and in the standing position. Mean and maximum muscular activation patterns are similar. Differences related to the bagging area in which the goods were released also emerged. The disk wheel represents a valid aid for reducing biomechanical overload in cashiers; the standing position is biomechanically more advantageous. Practitioner Summary: EMG and optoelectronic motion analysis systems are useful for the quantitative assessment of the effects of the redesign of the workplace biomechanical risk. Our results suggest that a disk wheel positioned in the bagging area reduces the biomechanical risk for cashiers and increases time spent resting.

A New Method of Temperature Measure of Rotary Wheel Disc

First of all, the working principle of infrared thermometer and the structural principle sketch map for measuring the temperature of rotary wheel disc through infrared thermometric technology are briefly introduced from the physics aspect. Secondly, the type of infrared thermometer is selected according to the practical request of low or high temperature measure of rotary wheel disc. Finally, the same point temperature of the turbine wheel disc of an engine is measured through infrared thermometer and thermoelectric couple in the heating status, and the measure results are compared, which dictates that the infrared thermometric system could achieve an upper detection precision and satisfy the practical engineering request.

Fatigue life prediction of a heavy vehicle steel wheel under radial loads by using finite element analysis

The origin of fatigue failure that occurs on the air ventilation holes of a newly designed heavy commercial vehicle steel wheel in dynamic radial fatigue tests is studied. In these tests, all of the test samples failed in the same regions. The cause of this damage was studied via finite element analysis. In order to determine the reason of the fatigue failure, stress analysis was performed via the finite element method. In this way, stress concentrated regions, where fatigue failure is expected, were determined. Mechanical properties of the wheel material were determined by tensile tests and hardness measurements. The fatigue life of the damaged wheel was estimated using the stress–life (S–N) approach, utilising the ultimate tensile strength of the processed wheel material and the Marin factors determined for the critical regions. To extend the life of the wheel disc and delay the onset of fatigue, design enhancement solutions were applied.

A Generic Model for Spiral Groove Grinding

As to spiral groove grinding, convertionally was based on envelope theory, a formed wheel was needed to be designed and manufactured, and then this wheel was used to grind the specified spiral groove. This paper tried to find the other way to manufacture the specified spiral groove with common disc wheel or dish wheels. A generic model for groove grinding is presented in this paper. With the model, the groove geometries can be calculated under certain grinding parameters. The relations between the grinding parameter and groove geometries were studied numreically. A test was done and the results proved the model is correct. This technology make the spiral groove virtual machining possible. The technology is also a real DFM (Design For Manufacture), because the design process for spiral groove is the process for selecting manufacure parameters.

Development of high strength hot rolled steel sheet for wheel disc application

A hot rolled steel with unique combination of high strength and excellent ductility coupled with high hole expansion ratio has been developed for automotive applications using a new metallurgical approach. The steel chemistry and processing parameters were designed in such a way that austenite–ferrite phase transformation takes place at lower temperature with interphase precipitation of very fine carbides. A fine ferritic microstructure was produced with an average grain size of 3·4 μm resulting into attractive mechanical properties. Interphase precipitation was used as one of the major strengthening mechanisms apart from grain refinement. This led to an achievement of tensile strength as high as 800 MPa (min.) with an excellent stretch formability and low impact transition temperature. This is a potential grade with unique features which can have wider applications.

A model of a reinforced tyre with a rod protector

A tyre design consisting of a steel-cord-reinforced rigid bond with sides connected to the wheel disc and a protector(tread) in contact with the road is examined. The tread is in the form of a set of rods connected by one end to the band, with the other end either free or in contact with the road. The rod end in contact with the road is acted upon by a force applied from the road, represented by a force normal to the road plane and a shear force due to dry friction. If the modulus of the shear force does not exceed the magnitude of the normal force multiplied by the dry friction coefficient, there is no slip at the contact point. In the opposite case, the rod end will be displaced along the road by an amount sufficient to distribute the normal and shear forces. The dynamics of longitudinal and transverse strains of the rods in contact with the road is analysed using the motion separation method in the quasi-static approximation. The behaviour of the tread rods as a function of the vertical displacement of the wheel centre is investigated, the contact area is found and the conditions are determined under which the contact area is divided into parts in which either slip of the rod ends occurs or does not occur, depending on the magnitude of the longitudinal displacement of the wheel centre or its turning relative to the horizontal axis. An analogue of a continuous model of a rod-like tread is considered, and the magnitudes of the forces and moments are found as a function of the wheel disc displacements. The equations of wheel rolling are obtained, and the conditions under which steady motions exist are found.

Contact defects initiation in railroad wheels – Experience, experiments and modelling

Main results of comprehensive research of rolling contact defects initiation are presented in this contribution. Description of own experimental study has been preceded by practical experience of a wheelset producer. A line rolling/sliding contact case with creepage of 0.75% was investigated using a unique test machine. The rail disc was made from Class C steel grade while the wheel disc from R7T steel grade. Unlike the standard twin-disc test, the diameter of the rail disc was 2.6 times bigger than the diameter of the wheel disc. Development of contact cracks and accumulation of shear strain for the wheel material R7T during rolling contact loading were namely evaluated. On the basis of test conditions, simulation by FEM was performed. As the result, very good prediction of shear strain accumulation was achieved using the AbdelKarim–Ohno cyclic plasticity model. The proposed computational strategy can be used for fatigue life prediction till initiation of a crack caused by low-cycle fatigue or by ratcheting failure.