Wheel Vibration Research Articles

Speckle-interferometry in the Investigation of Large-size Gas Turbine Engine Structures Vibration

A speckle-interferometer plant has been developed to investigate bladed turbo-machinery wheels vibration. A plant optical arrangement and an object under investigation are placed on a massive holographic plate. Turbine wheel vibration frequencies and modes of one of the aircraft engines are given which have been obtained using this plant. Another speckle-interferometer has been designed requiring no interferometer plate (table) to investigate part vibration under working area conditions. With the help of this plant, investigation of fan blades lot vibration frequencies and modes has been performed.

基于灵敏度分析的某轻卡方向盘怠速抖动治理研究

某轻型载货汽车方向盘在怠速工况下抖动严重，利用模态试验分析其怠速抖动原因，发现方向盘模态频率与发动机二阶点火频率接近，引起共振现象。为降低方向盘振动，结合有限元分析方法和灵敏度分析，调整方向盘结构和仪表台横梁管柱的厚度，对转向系统进行结构优化，从而改变方向盘的固有频率，远离发动机的二阶点火频率，减小共振。最后通过试验验证了改进措施的有效性。 The steering wheel of a light truck has a jitter problem in the idle condition. We used modal test to analyze the jitter reason under idle condition. It is found that the modal frequency of the steering wheel is close to the second order ignition frequency of the engine so the resonance of the steering wheel appears. In order to reduce the steering wheel vibration, we combined with the finite element analysis method and sensitivity analysis method. We adjusted the structure of the steering wheel and the thickness of the instrument panel beam to optimize the structure, thereby changing the natural frequency of the steering wheel. Measures works and the natural frequency was far from the second order ignition frequency of the engine. Finally, the effectiveness and rationality of the improvements were verified through tests.

Analysis of high frequency vibration of tram monobloc wheel

European Environmental Agency estimates that about 120 million people in the EU (over 30% of the total population) are exposed to traffic noise above 55 Ldn dB. It is estimated that 10% of the EU population is exposed to noise associated with the rail traffic. The two main sources of traffic noise comes from vehicles engines and the noise generated in the contact between the wheel and the road. In the latter the considerable part the noise is due to phenomena occurring in a wheel tram – rail system. Therefore, the problem of reducing the noise generated by railway vehicles is the subject of many studies, both experimental and theoretical. Commonly used wheel trams so called "resilient wheels" are equipped with layer made of a resilient material, e.g. rubber, between the tread and the wheel disc. But the monobloc tram wheel is the standard design against which should be carried out the studies on reduction of noise in wheel-rail system. This paper presents the results of calculations related to eigenforms, eigenfrequencies and Frequency Response Function of a three-dimensional model of a monobloc tram wheel. The calculations were carried out using the finite element method. Vibration analysis was performed for the range to 5 kHz. Analysis carried out has shown that the wheel tread plays a more important role in the generation of high-frequency vibrations.

Numerical analysis and optimization of wheel vibrations and radiation noises of the high-speed train

Finite element and boundary element models of the standard wheel, damping wheels and S-type damping wheels were established and compared. The radial vibration and axial vibration of the standard wheel could be reduced to decrease the vibro-acoustic radiation. Regarding damping wheels and S-type damping wheels, the coupling between the radial vibration and axial vibrations of 1 pitch circle could be reduced to decrease the radiation noise. The vibration acceleration in the tread, rim and web plate was significantly improved after applying damping in the standard wheel. If the web plate was changed into S-type structure, the vibration acceleration of the wheel at three positions was further reduced. The radiation noise of S-type damping wheels was significantly improved. The radiation noise of the web plate was significantly greater than that of the tread, which was caused by the larger radiation area of the web plate.

Nonstationary Vibration Signal Analysis Using Wavelet-Based Time–Frequency Filter and Wigner–Ville Distribution

Vibration responses of nonlinear or time-varying dynamical systems are always nonstationary. Time–frequency representation becomes a necessary approach to analysis such signals. In this paper, a nonstationary vibration analysis method based on continuous wavelet transform (CWT) and Wigner–Ville distribution (WVD) is presented. In order to avoid the cross-terms in the original WVD, a time–frequency filter created by wavelet spectrum is employed to filter the time–frequency distribution (TFD). This process eliminates cross-terms and maintains high time–frequency resolution. The improved WVD is applied to both simulated and practical time-varying systems. Bat echolocation signal, train wheel vibration, and bridge vibration under a moving train are used to assess the proposed method. Comparison results show that the improved WVD is free of cross-terms, effective in identifying time-varying frequencies and is more accurate than the wavelet time–frequency spectrum.

Analysis of factors related to vertical vibration of continuous alternate wheels for omnidirectional mobile robots

Omnidirectional mobile robots (OMRs) are capable of arbitrary motions in arbitrary directions without changing the direction of wheels since they perform 3-DOF (degree of freedoms) motions on a plane. Various omnidirectional wheels including the continuous alternate wheel (CAW) with passive rollers for OMRs have been researched. The CAW has been developed for the purpose of minimizing vibration. The CAW has alternating inner and outer rollers around the wheel which makes nearly continuous contact with the ground. The ideal CAW reduce vibration for certain; however, the real CAW fail to do so due to various errors. In this regard, more research is needed to bring vibration under acceptable tolerance. In this paper, vertical vibration characteristics of the real CAW with tolerance are researched. Simulation models of CAWs are implemented using flexible body dynamics of Recurdyn. To verify vibration characteristics of the model, simulation results are compared with experimental results from the improved CAW with five rollers set (CAW5). Vertical vibration is affected by various factors: geometry errors, the gap, the thickness of flexible body, the angular velocity, the alignment angle, the load and the elasticity of flexible body, etc. To efficiently analyze the effects of various factors, dynamic simulations are conducted using Taguchi method. As a result, it is found that the main factors which affect vibration are the angular velocity and the alignment angle followed by the geometry errors, the load, the elasticity of flexible body, the thickness of flexible body and the gap. This process can be applied to the analysis of the other omnidirectional wheels with passive rollers.

Investigation of waviness error in surface grinding of large axisymmetric aspheric lenses

Waviness error is one of the most critical errors in the large aspheric lenses grinding and one that has a strong impact on the performance of the optical system. In this article, the waviness error of large axisymmetric aspheric lenses for X-axis direction as well as Z-axis direction is analyzed by employing grate parallel grinding method. The grinding wheel vibration and Z-axis interpolation pace are regarded as the main causes of the surface waviness error. Furthermore, to reduce the waviness error, the influence of grinding parameters on waviness error is investigated. The waviness errors measured during grinding experiments are in good agreement with the theoretical results and the appropriate grinding parameters are recommended.

Vibration Characteristics of Roundabout Swing of HAWT Wind Wheel

Modal testing was used to show that the roundabout swing was a natural vibration mode of the wind wheel of a horizontal-axis wind turbine (HAWT). During the vibration, the blade root was simultaneously subjected to bending and rotary shear stresses. A method for indirect testing and determination of the dynamic frequencies of the typical vibrations of the wind wheel was developed, based on the frequency-holding characteristic of each subsignal during the transmission of the multiple mixed-vibration signals. The developed method enabled simple and accurate acquisition of the dynamic frequencies without destruction of the flow and structural fields. The dynamic vibration stress of the roundabout swing was found to be significantly stronger than those of the first- and second-order flexural vibrations of the blades. By a combination of numerical simulations and tests, it was determined that the pneumatic circumferential force was the primary determinant of the roundabout swing vibration frequencies, the relationship being quadratic. The roundabout swing vibration potentially offers new explanations and analytical pathways regarding the behavior of horizontal-axis wind turbines, which have been found to be frequently involved in fatigue-damage accidents within periods shorter than their design lives.

Design Optimization of a Mecanum Wheel to Reduce Vertical Vibrations by the Consideration of Equivalent Stiffness

Mecanum wheels are capable of moving a vehicle to any direction instantaneously by the combination of independent wheel rotations. Because the mecanum wheel is composed of a hub and rollers, however, it has unavoidable drawbacks such as vertical and horizontal vibrations due to the sequential contacts between rollers and ground. In order to investigate the dynamic characteristics of a mecanum wheel, we made a prototype and performed experiments to measure the vertical vibrations. Interestingly, it was observed that the vertical accelerations were asymmetric with respect to the average value of signals; the vibration signals of upward and downward directions show quite different shape. This asymmetric phenomenon was confirmed through the dynamic simulations performed by RecurDyn. In addition, the peak-to-peak and RMS values of the displacements and accelerations were calculated to investigate the effects of the curvature of rollers on the vertical vibrations of the vehicle. Furthermore, we proposed a mecanum wheel having a spring to attenuate the vibrations. It was also noted that the significant reduction of the vertical accelerations was observed due to the absence of the spring. Finally, considering the equivalent stiffness of the mecanum wheel for several different fillet radii, we found the optimal geometric design which minimizes the vertical vibration of a mecanum wheel.

Electromagnetic induction energy harvester for high-speed railroad applications

The objective was the development of an energy harvester for the hot-box detector of the HEMU-430 project high-speed train in Korea. In this study, we attempt the development of energy harvesters that incorporate a monitoring system in the train wheel bearing. We verified the use of electromagnetic induction as an effective method for harvesting energy from low-frequency vibration through the environmental test. We applied mechanical, electromagnetic, and electrical modeling processes to maximize the relative motion between core parts, and the optimization should be done using a mass spring damping model. We analyzed the wheel vibration sources at speeds between 300 and 400 km/h, fabricated a prototype of the energy harvester, and used a reinforced material for the practical application. Based on analyses of the static and fatigue properties of different materials, we decided the proper material as Invar 42. We also secured the structural stability by FEM. Our onboard measurement revealed that the generation characteristics of a narrow band resonance module capable of operating at a specific resonance frequency could be verified. The results of environmental tests confirmed that the Invar 42 cantilever beam–type electromagnetic induction energy harvester could be used as a model of a highly durable system.

Diagnostic methods of a bladed disc mode shape evaluation used for shrouded blades in steam turbines

This paper deals with advanced methods for the evaluation of a bladed disc behavior in terms of the wheel vibration and blade service time consumption. These methods are developed as parts of the noncontact vibration monitoring system of the steam turbine shrouded blades. The proposed methods utilize the time-frequency processing (cross spectra) and the method using least squares to analyse the data from the optical and magnetoresistive sensors, which are mounted in the stator radially above the rotor blades. Fundamentally, the blade vibrations are detected during the blade passages under the sensors and the following signal processing, which covers also the proposed methods, leads to the estimation of the blade residual service life. The prototype system implementing above mentioned techniques was installed into the last stage of the new steam turbine (LP part). The methods for bladed disc mode shape evaluation were successfully verified on the signals, which were obtained during the commission operation of the turbine.

Comparison of Control Strategies Applied to Nonlinear Quarterly Car Passive Suspension System

Road unevenness causes wheel and engine vibration which in turn lead to internal noise in automobiles. Developing a reliable control algorithm for vehicle suspension system is quite cumbersome due to the nonlinear nature of the system coupled with the issue of improving compromise between the conflicting demands of ride comfort and road handling. This paper presents a comparison of Fuzzy, Neural Network (NN) inverse control and Nonlinear Proportional Integral Derivative (NPID) control applied to the quarterly car passive suspension system. The performances of the controllers were evaluated based on rise time, settling time and peak time as illustrated via set-points tracking. The simulation results indicated that the performances of the Fuzzy controller and NPID are slightly better than neural network inverse control which could be due to lack of obtaining an accurate inverse plant model. The Fuzzy controller and NPID may serve as an alternative and valuable control schemes for the system

Interaction of In-wheel permanent magnet synchronous motor with tire dynamics

Drive wheel systems combined with the in-wheel permanent magnet synchronous motor (I-PMSM) and the tire are highly electromechanical-coupled. However, the deformation dynamics of this system, which may influence the system performance, is neglected in most existing literatures. For this reason, a deformable tire and a detailed I-PMSM are modeled using Matlab/Simulink. Furthermore, the influence of tire/road contact interface is accurately described by the non-linear relaxation length-based model and magic formula pragmatic model. The drive wheel model used in this paper is closer to that of a real tire in contrast to the rigid tire model which is widely used. Based on the near-precise model mentioned above, the sensitivity of the dynamic tire and I-PMSM parameters to the relative error of slip ratio estimation is analyzed. Additionally, the torsional and longitudinal vibrations of the drive wheel are presented both in time and frequency domains when a quarter vehicle is started under conditions of a specific torque curve, which includes an abrupt torque change from 30 N · m to 200 N · m. The parameters sensitivity on drive wheel vibrations is also studied, and the parameters include the mass distribution ratio of tire, the tire torsional stiffness, the tire damping coefficient, and the hysteresis band of the PMSM current control algorithm. Finally, different target torque curves are compared in the simulation, which shows that the estimation error of the slip ratio gets violent, and the longitudinal force includes more fluctuation components with the increasing change rate of the torque. This paper analyzes the influence of the drive wheel deformation on the vehicle dynamic control, and provides useful information regarding the electric vehicle traction control.

Effect of wheel load on wheel vibration and sound radiation

The current researches of wheel vibration and sound radiation mainly focus on the low noise damped wheel. Compared with the traditional research, the relationship between the sound and wheel/rail contact is difficulty and worth studying. However, there are few studies on the effect of wheel load on wheel vibration and sound radiation. In this paper, laboratory test carried out in a semi-anechoic room investigates the effect of wheel load on wheel natural frequencies, damping ratios, wheel vibration and its sound radiation. The laboratory test results show that the vibration of the wheel and total sound radiation decrease significantly with the increase of the wheel load from 0 t to 1 t. The sound energy level of the wheel decreases by 3.7 dB. When the wheel load exceeds 1 t, the attenuation trend of the vibration and sound radiation of the wheel becomes slow. And the increase of the wheel load causes the growth of the wheel natural frequencies and the mode damping ratios. Based on the finite element method (FEM) and boundary element method (BEM), a rolling noise prediction model is developed to calculate the influence of wheel load on the wheel vibration and sound radiation. In the calculation, the used wheel/rail excitation is the measured wheel/rail roughness. The calculated results show that the sound power level of the wheel decreases by about 0.4 dB when the wheel load increases by 0.5 t. The sound radiation of the wheel decreases slowly with wheel load increase, and this conclusion is verified by the field test. This research systematically studies the effect of wheel load on wheel vibration and sound radiation, gives the relationship between the sound and wheel/rail contact and analyzes the reasons, therefore, it provides a reference for further research.

On some rotor-dynamical phenomena of high-speed trains

The paper is devoted to radial and out-of-plane vibration of railway wheels and to wheelset stability as key elements affecting high-speed vehicle dynamics, noise emission, and safety. In the present study, railway wheel tire is treated as a curved beam with various beam models, and the wheel plates are modeled as Winkler’s elastic foundation. New results are presented concerning the influence of the residual stresses on the corrugation and poligonalization of wheels as well as wave propagation in the wheel tire.

Expert System Based on Fuzzy Rules for Monitoring and Diagnosis of Operation Conditions in Rotating Machines

This work provides a detection method for failure in rotating machines based on a change of vibration pattern and offers the diagnosis about the operation conditions using Fuzzy Logic. A mechanic structure (as an experimental prototype where faults can be inserted) called Rotating System has been used. The vibration standard of the Rotating System, called "The Spectral Signature", has been obtained. The changes in the vibration standard have been analyzed and used as parameters for detecting incipient failures, as well as their condition evolution, allowing predictive monitoring and planning of maintenance. The faults analyzed in this work are caused due to insertion of asymmetric masses for unbalancing in the axle wheel. The system for diagnosing Fuzzy System was calibrated to detect and diagnose the conditions: normal, incipient failure, maintenance, and danger, using linguistic variables. The frequency of rotation and the amplitudes of vibration of the axle wheel are considered in each situation as parameters for analysis, diagnostic, for the decision by the Expert System based on Fuzzy rules. The results confirm that the proposed method is useful for detecting incipient failures, monitoring the evolution of severity and offering grants for planning and decision making about maintenance or prevention of rotating machines.

Wheel squeal noise: A simplified model to simulate the effect of rolling speed and angle of attack

The sound pressure level of wheel squeal has been shown to increase with angle of attack and rolling speed in both field and laboratory tests. However, the exact causes behind the manner of increase are still unknown. To investigate this, a simplified analytical vibration model in the time domain is integrated with nonlinear rolling contact theory developed for wheel squeal. This model is used to simulate the vibration velocity of a test rig wheel at different rolling speeds and angles of attack. The simulated vibration velocities correlate well in the trend with the recorded sound pressure levels of wheel squeal in laboratory tests. Lateral creepage and force at various angles of attack and rolling speeds in the rolling contact are simulated. It is found that due to the interaction of wheel vibration, lateral force and creepage, the vibration velocity amplitude of the wheel increases with angle of attack and rolling speed. The generation mechanism of wheel squeal is explained from the view of energy input per cycle of vibration. Furthermore, the reasons why the sound pressure levels of wheel squeal increase with rolling speed and angle of attack are investigated, and these phenomena are explained theoretically based on energy input and the nonlinear creep behaviour.

A numerical investigation of curve squeal in the case of constant wheel/rail friction

Curve squeal is commonly attributed to self-excited vibrations of the railway wheel, which arise due to a large lateral creepage of the wheel tyre on the top of the rail during curving. The phenomenon involves stick/slip oscillations in the wheel/rail contact and is therefore strongly dependent on the prevailing friction conditions. The mechanism causing the instability is, however, still a subject of controversial discussion. Most authors introduce the negative slope of the friction characteristic as a source of the instability, while others have found that squeal can also occur in the case of constant friction due to the coupling between normal and tangential dynamics. As a contribution to this discussion, a detailed model for high-frequency wheel/rail interaction during curving is presented in this paper and evaluated in the case of constant friction. The interaction model is formulated in the time domain and includes the coupling between normal and tangential directions. Track and wheel are described as linear systems using pre-calculated impulse response functions that are derived from detailed finite element models. The nonlinear, non-steady state contact model is based on an influence function method for the elastic half-space. Real measured wheel and rail profiles are used. Numerical results from the interaction model confirm that stick/slip oscillations occur also in the case of constant friction. The choice of the lateral creepage, the value of the friction coefficient and the lateral contact position on the wheel tread are seen to have a strong influence on the occurrence and amplitude of the stick/slip oscillations. The results from the interaction model are in good qualitative agreement with previously published findings on curve squeal.

Study on the torsional vibration of a hybrid electric vehicle powertrain with compound planetary power-split electronic continuous variable transmission

A torsional vibration dynamic model is established with the commercial software ADAMS to predict the torsional vibration characteristics of a compound planetary power-split hybrid electric vehicle. By calculating and simulating the built model in ADAMS, the natural frequencies and corresponding modes are obtained. The results agree well with previous work, which derives the conclusions by solution of the system dynamics equations of hybrid driveline. Moreover, the main factors that influence the torsional vibration of the powertrain under the excitation of engine and electric motors are analyzed by the forced vibration analysis. The calculated results show that the low frequencies occur mainly in the torsional vibration of wheels and vehicle, while the high orders are related to the torsional vibration of differential, sun gears and planets. The results also show that the amplitude of torsional vibration of driveline is the lowest when the damping and stiffness of torsional damper are 15 Nms/rad and 618 Nm/rad respectively, the halfshaft stiffness is 2760 Nm/rad and the rotational inertial of engine is 0.42 kgm2. The research can be used to support the further development of the power-split hybrid electric vehicle.

Time-dependent vibration frequency reliability analysis of blade vibration of compressor wheel of turbocharger for vehicle application

Blade vibration failure is one of the main failure modes of compressor wheel of turbocharger for vehicle application. The existing models for evaluating the reliability of blade vibration of compressor wheel are static, and can not reflect the relationship between the reliability of compressor wheel with blade vibration failure mode and the life parameter. For the blade vibration failure mode of compressor wheel of turbocharger, the reliability evaluation method is studied. Taking a compressor wheel of turbocharger for vehicle application as an example, the blade vibration characteristics and how they change with the operating parameters of turbocharger are analyzed. The failure criterion for blade vibration mode of compressor wheel is built with the Campbell diagram, and taking the effect of the dispersity of blade natural vibration frequency and randomness of turbocharger operating speed into account, time-dependent reliability models of compressor wheel with blade vibration failure mode are derived, which embody the parameters of blade natural vibration frequency, turbocharger operating speed, the blade number of compressor wheel, life index and minimum number of resonance, etc. Finally, the rule governing the reliability and failure rate of compressor wheel and the method for determining the reliable life of compressor with blade vibration is presented. A method is proposed to evaluate the reliability of compressor wheel with blade vibration failure mode time-dependently.