Wheel Noise Research Articles

A synthesized airless tyre traffic sound scenario for health impact assessment

Within the LEON-T project, a composite wheel is being developed that is aimed to reduce noise from the tyre-road interaction by removing the air filled cavity entirely and by allowing the tread belt be permeable, thus reducing air pressure build-up in the contact patch. Parallel to the developement of the composite "airless tyre" the potential health impact from reducing noise by adopting such a composite wheel has been investigated by synthesizing the sound of a composite wheel. The synthesized sound has then been used to create different traffic flow scenarios used for laboratory studies of effects on sleep from noise. Results indicate positive effects on health through less sleep disturbance from composite wheel noise as compared to ordinary tyre noise. This paper describes the synthesis process and the scenarios used for the sleep laboratory experiments.

A model of the rotating rigid wheelset and its influence on the wheel and track rolling noise

The dynamic and acoustic behaviour of the railway wheel is defined by its numerous vibration modes and natural frequencies. The modes whose contribution to the rolling noise radiation are predominant generally have 2 or more nodal diameters and appear above 2 kHz. The vibration due to these modes is decoupled from the rest of the wheelset, allowing the wheel to be treated separately. The error produced in the wheel noise prediction by this treatment appears at the low and medium frequencies and is negligible since the wheel emission occurs mainly at the high frequency range. However, given the dynamic coupling between the wheel and track, the changes in the dynamics of the former affect the latter, whose radiation is predominantly in the low and medium frequency range. Therefore, in order to correctly study both elements, it is necessary to include the contribution of the rest of the wheelset in the wheel response. In this work, this contribution is introduced through an analytical approach considering the rigid body motion of the wheelset and a benchmarking against an equivalent numerical formulation is carried out for validation purposes. In addition, the inertial effects associated with the rotation under straight circulation conditions are considered.

Influences of wheel polygon amplitude on wheel-rail vibration and sound radiation

Wheel polygon amplitude can greatly affect wheel-rail vibration and sound radiation. Based on multi-body dynamics theory, a vehicle-track rigid-flexible coupling dynamics model was established. According to the actual running wear condition of the wheel, the wheel-rail vibration response was calculated and analyzed (the order of wheel polygons is 20, and the polygon amplitude is 0.01/0.02/0.03/0.04 mm, respectively). Together with the finite element/boundary model of the wheel, the calculated wheel-rail force was used as an external incentive to analyze the effects of polygon amplitude on the time-frequency domain of wheel noise. The research results show that: when the polygon order is 20, with the increase of polygon amplitude, the wheel-rail vertical force and the acceleration of wheel, rail and track slab increase gradually. It’s also found that the rail acceleration is obviously more sensitive to the amplitude than the track slab acceleration, while the vertical displacement of the rail and track slab is less sensitive to the polygon amplitude. At the same amplitude, the closer to the wheel rolling line, the more obvious the sound pressure decreases with the increase of height. At different amplitudes, the sound pressure at different positions will increase with the rise of the polygon amplitude. The root mean square value of sound power increases gradually with the addition of amplitude: When the amplitude changes from 0.01 mm to 0.04 mm, the calculated sound power increases by 4.1 dB.

승용차 운전대 소음의 라우드니스와 불확도 평가

Loudness is one of the most important parameters in sound quality. In this study, Zwicker’s loudness (standardized in ISO 532-1) for steering wheel noise of a car is evaluated. In addition, a measurement uncertainty model is proposed and the uncertainty is evaluated because it is recommended to evaluate the uncertainty in all measurements possible. The main components of the uncertainty are calibration values of the sound pressure measurement system and measurement repeatability. The results show that the uncertainty in the loudness is 2.3 %. This is a lower value than the ISO 532-1 recommended value of 5 %.

Experimental investigation of microvibrations induced by reaction wheels on earth observation satellite

The evaluation of microvibrations effect is crucial for the success of remote sensing missions. The moving parts on the satellite such as reaction wheels can create microvibrations disturbances, which cause degradation of image quality. In our paper we present an experimental investigation methodology for on-ground quantification of wheel noise disturbance transmitted through the structure to the payload. This assessment was carried out for the ALSAT-1B satellite integrating a medium resolution payload. The angular motion along imager bore sight was measured using accelerometers and verified against image quality and mission requirement. The on ground experimental methodology suggests that the effect of microvibrations on a camera can be verified directly.

Reduction in High-Frequency Wheel Noise/Vibration of Railway Vehicles Using Piezoelectric Shunt

We propose the application of a resonant shunt to wheels to reduce the high-frequency wheel noise generated by railway vehicles. High-frequency wheel noise is caused by the resonance of wheels owing to contact between rails and wheels. A resonant shunt is applied at specific frequencies to reduce wheel resonance. In this work, the high-frequency noise generated by a wheel moving on a curved railway track was analyzed and compared with the dynamic characteristics of the wheel. Further, to reproduce the high-frequency noise of the wheel, an external electric signal was input to a piezoelectric patch connected to the wheel to generate noise and vibration at the natural frequency of the wheel. The optimum mounting position of the piezoelectric patch was determined by numerically analyzing the strain energy of the wheel. Piezoelectric patches were connected to their respective resonant shunts to form a vibration reduction array. A synthetic inductor was tuned to effectively reduce the high-frequency vibration and noise of the wheel generated at its natural frequency. In the wheel excited at its natural frequency, vibration and noise were reduced by approximately 4–10 dB and 8–12 dB(A), respectively. In the wheels that were simultaneously excited at two natural frequencies, vibration and noise were reduced by 5 dB and 5 dB(A), respectively. The results showed that the resonant shunt could effectively reduce the noise and vibration generated by the wheel. Therefore, the resonant shunt is an effective circuit system for reducing noise and vibration even in large structures.

Simulation and Optimization of Acoustic Package of Dash Panel Based on SEA

The instrument panel assembly is an important structure to shield powertrain noise and front wheel noise, and the instrument panel sound insulation system plays a key role in it. Therefore, the sound insulation characteristics of the instrument panel sound insulation components appear particularly important. In the existing technology, the acoustic design of instrument panel mostly adopts the reverse design method and pays little attention to the forward design of acoustic system, which tends to lead to the shortcomings such as inaccurate acoustic design and poor acoustic design quality. The reverse design also restricts the development cycle, so the control and design of acoustic performance cannot be realized in the initial stage of design. Based on the above problems, the statistical energy model of the dashboard model was established by combining the statistical energy flow method and the proxy model method, and the influences of different acoustic cladding layers, different thickness, leakage, and new material microfibers on the sound insulation parameters of the front coaming were simulated. The general rules that affect the sound insulation performance of the structure are obtained. On this basis, multiobjective genetic algorithm and proxy model method are used to optimize the insertion loss of the front panel acoustic pack and the weight of the dashboard by introducing multiobjective variable and experimental design method, so as to obtain the best solution to meet the requirements of insertion loss and lightweight acoustic pack of the dashboard. It is of great engineering significance for the development of acoustic components for forward design instrument panel.

A comparison between off and on-body control surfaces for the FW-H equation: Application to a non-compact landing gear wheel

This work is a contribution to the ongoing debate about the role of quadrupoles in low Mach number flows, studied through the use of solid and permeable surface Ffowcs-Williams & Hawkings (FW-H) integrals for landing gear numerical noise predictions. It rests upon the key idea that the dominance of surface sources over volume sources can only be guaranteed when the compact-source condition is met. We propose here to express this property as a condition on the smallness of the product between the Mach and Strouhal numbers, or formally as MSt < 1. We consider a canonical isolated wheel, that basically consists in a shallow circular cavity inscribed in a coin-like cylinder, thus presenting few different length scales, as compared to a full landing gear assembly. Zonal Detached Eddy Simulations are performed on several gradually refined grids to assess the grid convergence of the numerical result. In particular, important computational effort is put into the accurate resolution of acoustic waves up to Strouhal numbers such that MSt > 1. Overall, determining the real significance of quadrupoles was challenging as numerical errors or misleading effects such as near-field terms, surface discretization, or source domain truncation biased the initial permeable surface results. Even when these sources of bias are removed, non-negligible differences are found between the solid and permeable noise spectra at non-compact St values, while both formulations are equivalent at lower Strouhal numbers. The analysis of these differences is extended to the determination of their impact on frequency-domain noise maps obtained with the DAMAS algorithm fed with far-field signals computed with both FW-H approaches. A tentative interpretation of the wheel noise sources is finally proposed, highlighting the dominant role of the scattering of aerodynamic sources by the cavity downstream edge at low Strouhal numbers, while wake sources dominate at higher Strouhal numbers.

Accurate and robust odometry by fusing monocular visual, inertial, and wheel encoder

Tracking the pose of a robot has been gaining importance in the field of Robotics, e.g., paving the way for robot navigation. In recent years, monocular visual–inertial odometry (VIO) is widely used to do the pose estimation due to its good performance and low cost. However, VIO cannot estimate the scale or orientation accurately when robots move along straight lines or circular arcs on the ground. To address the problem, in this paper we take the wheel encoder into account, which can provide us with stable translation information as well as small accumulated errors and momentary slippage errors. By jointly considering the kinematic constraints and the planar moving features, an odometry algorithm tightly coupled with monocular camera, IMU, and wheel encoder is proposed to get robust and accurate pose sensing for mobile robots, which mainly contains three steps. First, we present the wheel encoder preintegration theory and noise propagation formula based on the kinematic mobile robot model, which is the basis of accurate estimation in backend optimization. Second, we adopt a robust initialization method to obtain good initial values of gyroscope bias and visual scale in reality, by making full use of the camera, IMU and wheel encoder measurements. Third, we bound the high computation complexity with a marginalization strategy that conditionally eliminates unnecessary measurements in the sliding window. We implement a prototype and several extensive experiments showing that our system can achieve robust and accurate pose estimation, in terms of the scale, orientation and location, compared with the state-of-the-art.

Separation of rail and wheel contributions to pass-by noise with sparse regularization methods

This paper proposes a method for separating rail and wheel noise contributions via sparse regularization of microphone array data. The underlying idea is to promote sparse solutions, which jointly approximate the two noise contributions with few non-zero coefficients. The main hypothesis is that the acoustic field radiated by the rail is sparse in a dictionary of plane waves, that the acoustic field radiated by the wheels is sparse in a dictionary of moving sources, and that both acoustic fields are dense in the opposite dictionaries. How well this happens is studied with the coherence between the plane waves and the moving sources. The strength of the proposed approach is that it does not require static tests prior to the pass-by. The separation is performed in three main steps, executed in the time-frequency domain. First, the rail contribution is separated from the total pass-by noise using matching pursuit optimization, promoting solutions with a limited number of plane waves per frequency. Second, the residual between the total pass-by noise and the estimated rail noise is calculated. And third, the wheel contribution is separated from the residual via ℓ1-norm minimization, promoting solutions that are row-sparse at all frequencies. The separation performance is investigated with synthetic data, and validated with experimental data against reference predictions with the TWINS software, for pass-by noise measurements of trains running at 40, 80 and 160 km/h.

Case study: An improvement study of damping ring applied to wheel noise and vibration control

The friction damping (FD) ring is a kind of low-cost and efficient damping device that has been used for decades in noise and vibration control of railway wheels. Preload is one of the most important parameters that affect the noise reduction effect of an FD ring. An acoustic characteristic test of a railway wheel with a rectangular cross-section FD ring under different preloads was carried out in the laboratory. The noise results show that there is an optimum preload that makes the total sound pressure level (SPL) of the wheels the lowest. However, at the same time, a new phenomenon in which the noise attenuation time increased with the increase in preload was observed. The phenomenon is explained by acoustic and modal tests, as well as a single degree of freedom system. Modal results show that, with the increase of the preload on an FD ring, modal damping of several modes of the wheel was correspondingly reduced, and the duration of noise was lengthened accordingly. To solve this problem, a new type of constrained layer damping (CLD) ring was designed based on the modal strain energy (MSE) method. A comparative experiment was conducted between the CLD ring and FD ring, including an acoustic test and modal test. The modal test results show that the CLD ring can provide a greater damping ratio in most frequencies of the wheel, especially the low frequencies corresponding to the noise attenuation time. Acoustic results show that the CLD ring has superior performance both in the time domain and frequency domain to the FD ring.

Prediction and energy contribution analysis of interior noise in a high-speed train based on modified energy finite element analysis

Abstract Compared with traditional finite element analysis and statistical energy analysis, the energy finite element analysis (EFEA) has the advantages of small computations and solving local responses in large-scale complex structures. In this paper, the structural sound insulation effect is introduced to EFEA for predicting and analyzing interior noise responses of extruded structures in a high-speed train. Firstly, the carriage structure and cavity models are established based on EFEA theory, and model parameters are obtained through experiments and effective simulations. Mechanical and acoustic excitation sources of the high-speed train are extracted through multi-body dynamic simulation, acoustic finite element method and nonlinear acoustic solution. The reliability of predicted excitations is validated by verifying the amplitude peak frequency bands. The interior noise responses at several observations are obtained and in good agreement with on-site test results, and the EFEA prediction model of interior noise is verified accurately. Secondly, the energy contribution of exterior excitation sources to interior noise responses is analyzed based on EFEA model. The results indicate that acoustic excitations dominate the acoustic energy in the frequency bands above 800 Hz, and the energy contribution of mechanical excitations and acoustic excitations is relatively close in the frequency bands below 600 Hz. The contribution of aerodynamic noise excitations is predominantly concentrated in the frequency bands below 500 Hz, while that of wheel-rail noise excitations is concentrated in the frequency bands above 800 Hz. In the frequency bands below 1250 Hz, the energy contribution of rail noise excitations is much more important than that of wheel noise excitations, while their contribution gets gradually close in the frequency bands above 1600 Hz. Besides, the acoustic excitations at the bottom of the carriage are quite important sources. Finally, wheel-rail noise excitations are optimized with spoke-shielding damping wheels and dynamic vibration absorbers, and the sound pressure level in the amplitude peak bands is reduced by about 8 dB. The interior noise responses are reduced by about 3–5 dB in the frequency bands above 800 Hz, and total loudness, sharpness and roughness at different locations are decreasing by more than 1 sone, 0.05 acum and 0.03 asper respectively. Therefore, wheel-rail noise optimizations have good reduction effects on interior noise responses in the high frequency bands.

Assessment of measurement-based methods for separating wheel and track contributions to railway rolling noise

The noise produced during a train pass-by originates from several different sources such as propulsion noise, noise from auxiliary equipment, aerodynamic noise and rolling noise. The rolling noise is radiated by the wheels and the track and is excited by the wheel and rail unevenness, usually referred to as roughness. The current TSI Noise certification method, which must be satisfied by all new mainline trains in Europe, relies on the use of a reference track to quantify the noise from new vehicles. The reference track is defined by an upper limit of the rail roughness and a lower limit of the track decay rate (TDR). However, since neither the rail roughness nor the track radiation can be completely neglected, the result cannot be taken as representing only the vehicle noise and the measurement does not allow separate identification of the noise radiated by wheel and track. It is even likely that further reductions in the limit values for new rolling stock cannot be achieved on current tracks. There is therefore a need for a method to separate the noise into these two components reliably and cheaply. The purpose of the current study is to assess existing and new methods for rolling noise separation. Field tests have been carried out under controlled conditions, allowing the different methods to be compared. The TWINS model is used with measured vibration data to give reference estimates of the wheel and track noise components. Six different methods are then considered that can be used to estimate the track component. It is found that most of these methods can obtain the track component of noise with acceptable accuracy. However, apart from the TWINS model, the wheel noise component could only be estimated directly using three methods and unfortunately these did not give satisfactory results in the current tests.

Source localization of wheel noise above 10 kHz generated on a curved section of high-speed railway line

Source localization of wheel noise above 10 kHz generated on a curved section of high-speed railway line

The noise generated by a landing gear wheel with hub and rim cavities

Wheels are one of the major noise sources of landing gears. Accurate numerical predictions of wheel noise can provide an insight into the physical mechanism of landing gear noise generation and can aid in the design of noise control devices. The major noise sources of a 33% scaled isolated landing gear wheel are investigated by simulating three different wheel configurations using high-order numerical simulations to compute the flow field and the FW-H equation to obtain the far-field acoustic pressures. The baseline configuration is a wheel with a hub cavity and two rim cavities. Two additional simulations are performed; one with the hub cavity covered (NHC) and the other with both the hub cavity and rim cavities covered (NHCRC). These simulations isolate the effects of the hub cavity and rim cavities on the overall wheel noise. The surface flow patterns are visualised by shear stress lines and show that the flow separations and attachments on the side of the wheel, in both the baseline and the configuration with only the hub cavity covered, are significantly reduced by covering both the hub and rim cavities. A frequency-domain FW-H equation is used to identify the noise source regions on the surface of the wheel. The tyre is the main low frequency noise source and shows a lift dipole and side force dipole pattern depending on the frequency. The hub cavity is identified as the dominant middle frequency noise source and radiates in a frequency range centered around the first and second depth modes of the cylindrical hub cavity. The rim cavities are the main high-frequency noise sources. With the hub cavity and rim cavities covered, the largest reduction in Overall Sound Pressure Level (OASPL) is achieved in the hub side direction. In the other directivities, there is also a reduction in the radiated sound.

The Effect of Slab Track on Wheel/Rail Rolling Noise in High Speed Railway

The slab track of high speed railway has higher environmental noise emissions caused by a train running than the ballasted track. In order to predict and control wheel/rail rolling noise radiation due to roughness of wheel and rail running surface on slab track, a model is developed to calculate wheel/rail rolling noise of the slab track and analyze the influences of railway slab structure parameters on wheel/rail rolling noise. The results show that the rail noise occurs mainly in the middle and high frequency ranges of 500–2000Hz. The wheel noise is chiefly in the high frequency ranges of 1600–4000Hz, and the track slab noise radiates in the frequency ranges of 125–500Hz. Instantaneous noise pressure of the rail is first, the slab is second, the wheel is in between. The weights of the slab have more influence on emissions of the slab, but have little impact on noise emission of the wheel and rail. Below 500Hz, the greater weight of the slab is, the greater noise emission of the slab is, but above 500Hz,...

AN IMPROVED GENETIC ALGORITHM AND ITS APPLICATION TO CRACK EXAMINATION

In this paper, a rail crack examination method based on an optimized complex evolutionary algorithm is proposed. The proposed approach has overcome the problems in which the fault diagnosis of wavelet packet decomposition is easily influenced by environmental factors, and the traditional genetic algorithm has a slow convergence speed and is prone to prematurity. In current method, to control the convergence performance, the diversity probability Pg is added in the update operation. According to the characteristics of rail crack fault signal, optimization function and cost function which consider the information in time and frequency domains are constructed and the information extraction is effectively realized. From field testing, the obtained results demonstrate that the present crack fault examination algorithm has higher accuracy rate, faster convergence rate and good stability. The present research work not only make up for the deficiency of traditional algorithm, but also provides a new examination method for wheel and rail noise fault diagnosis.

Statistical Energy Analysis of Subway Wheel/Track Noise

Dividing wheel-track system of subway into a series of sub-systems, the statistical energy analysis (SEA) model of wheel/track system is established. The factors affecting the wheel/track noise, such as modal density, damping loss factors, coupling loss factors, are gotten by theoretical analysis combined with experiments. The calculated results show that the track noise is about 4.5 dB(A) higher than the wheel noise at 160 km/h, and the wheel noise is reduced by 2.8 dB(A) at 160 km/h and by 2.3 dB(A) at 90 km/h by attaching damped layer plates to the wheels, but the total reduction is only 0.9 dB(A) at 160 km/h and 0.4 dB(A) at 90 km/h, so the attempts to reduce the total noise should exert noise control measures on the track, not on the wheel.

The Optimization of the Design of a Railway Wheel in Terms of the Acoustic Radiation under the Vertical Excitation

Railway wheel acoustic radiation takes a large proportion of the wheel-rail noise . This paper mainly focuses the ways to reduce railway wheel acoustic radiation to control wheel-rail acoustic radiation, and ultimately to reduce the railway environmental noise. In this paper, Optimization mathematical model of wheel acoustic radiation is built according to the wheel vibration and acoustic radiation theory, and obtaining the section optimization and acoustic radiation power of wheel by drawing up the genetic algorithm (GA) program and analyzing the acoustic radiation of the wheel according to Finite element and boundary element model. The result shows that the optimized acoustic power is reduced to some extent, even by 2dB at the peak point within 5000Hz. Since high-speed railways are put into operation in China, it has been more convenient for people to go out. However, serious railway environmental noise occurs by the way. The noise produced when the train is running affects not only passengers and working staff on the train, but also environment and residents around the railway. For this reason, to reduce the noise with proper measures is good for environment protection, sustained and healthy development of rail transportation as well. According to wheel-rail noise theory, the main approaches to reduce noise as follows:(1) Adopt damped wheel. (2) Add rubber isolation layer between tread and web of the wheel to form resilient wheel. (3) Optimize the wheel shape. (4) Reduce acoustic radiation efficiency of the wheel. This paper discusses how to reduce acoustic radiation of the wheel and railway environmental noise according to optimize the wheel shape by mainly analyzing the wheel of high frequency radiation noise.

Vibro-acoustic characterization of railway wheels

For many years the problem of noise generated by trains has had an increasing importance; in this paper, attention is focused on the noise generated by the train wheels due to their vibration. Today there are many kinds of railway wheels which are affected by different noise generation mechanisms. If the traditional and well known solid wheel is considered, a lot of data is already present in the literature both concerning the vibration and the noise point of view. On the other hand, the widely used resilient wheels are not so well known in their vibratory and acoustic behaviour as in the case of solid ones. The extensive experimentation presented and commented in this paper looks for a confirmation of some literature data first, and then it gives new results. Particularly the vibro-acoustic characterization of different kinds of wheels (both solid and resilient ones) has been carried out, in order to have a comparison between the behaviour of the newly built wheels and the older ones, representing the state of the art. Besides it has been shown that a detailed modal analysis of the suspended wheel coupled to sound measurements can give useful information about the wheel noise emission in its normal operating conditions.