Pass-by Test Research Articles

Towards the development of measurement and analysis method for aerodynamic noise emission from high speed train: the UIC Aeronoise Project

The increase of railway lines operating at speeds above 250 km/h has shifted the attention towards environmental noise emissions by aerodynamic noise, dominant at these speeds. Adding complexity to the issue, while railway noise emissions at conventional speeds are concentrated in the lower parts of the train, aerodynamic noise emissions are distributed along the train at different heights and depending on the train design. Assessment of aerodynamic noise emissions of high speed train has been endeavored using microphone arrays, implementing different variants of the wave beamforming algorithm. This method involves a quite complex post-processing, and also numerical quantification of results is not immediate. UIC AERONOISE project has aimed at developing a simplified pass-by test methodology capable of quantifying aerodynamic noise emissions from high speed , using exclusively a limited number of standard instrumentation microphones. This methodology has been validated theoretically and is currently undergoing experimental tests. Fundamental points in this methodology are explained in this contribution, together with results achieved so far.

Distribution characteristics and prediction method of tire–road AE noise in the monitoring of prestressed hollow slab bridges

During the acoustic emission (AE) monitoring of bridge, the AE signal we need can be easily masked by tire–road noise. To find out how much this noise affects the AE monitoring results of the bridge. In this study, controlled pass-by tests were carried out to collect the tire–road AE signals made by cars, buses, and heavy trucks with different speeds, where AE sensors are placed at multiple positions on the pavement and bottom deck of the bridge. In each case, the intensity and spectrum of AE noise were analyzed. Results show that the intensity of the tire–road AE noise increases with the speed, and the bandwidth of the main frequency increases slightly with the increasing speed. The peak frequency of the tire–road AE noise produced by the vehicles is approximately 2 kHz, and the AE energy distributes between 0 and 25 kHz. The proposed prediction method based on the characteristics of tire–road AE noise can effectively predict noise.

Performance Evaluation on the Application of MAST and RCC on a Cambodian Rural Road: A Case Study

Cambodia’s transportation sector has exhibited tremendous growth in the past decades together with its economic advancement. However, these improvements are only focused on the national and provincial roads, leaving the rural roads underdeveloped. A large percentage of the rural roads in Cambodia are unpaved while those paved roads are in deteriorated condition, making these rural roads prone to structural failure when subjected to heavy truck traffic and massive rainfall. Therefore, an innovative pavement material shall be used in the construction and rehabilitation of Cambodian rural roads. In this study, a composite pavement testbed consisting of a roller compacted cement (RCC) base layer and a modified double bituminous surface treatment (DBST), namely multi-layered bituminous surface treatment (MAST), was constructed in Cambodia and its performance was evaluated. To have a point of comparison, the testbed was divided into three sections with varying combinations of surface and base layer: (1) MAST surface with an RCC base, (2) MAST surface with an aggregate base, and (3) DBST surface with an aggregate base. Initially, a visual inspection was conducted to investigate the surface condition of the testbed. To assess the structural capacity, a light-falling weight deflectometer device was used. Meanwhile, the surface roughness was evaluated through the sand patch test. Lastly, the pass-by test was performed to quantify the noise level of the pavement. Based on the results, the proposed composite pavement performed significantly superior to the typical pavement in Cambodia, which is the third section. In summary, the composite pavement with MAST as the surface layer and RCC as the base layer was observed to be suitable for heavy truck traffic loading and the environmental conditions of Cambodia.

Developing Assumptions for the Tram Noise Attenuation Passive System Using the Noise Maps Analysis Method

The paper presents experimental research carried out to determine the possible actions to reduce the noise generated by trams in a highly urbanised area. A few design strategies affecting tram ride quality have been presented – especially in the aspect of the acoustic phenomena. Main sources of the noise in trams were characterised. The paper includes selected results of comprehensive studies of tram noise in the pass-by test based on the authors’ research methodology. The tests were carried out on various types of trams to recognise the acoustic phenomena characteristic for the rolling stock in a selected tram system. The results of the measurements were analysed both in the field of amplitudes based on noise maps and in respect to frequencies based on noise spectra. The results indicated the rolling noise as important issue demanding taking some actions in order to reduce its level. In this area, elements for the application of individual attenuation solutions, i.e. at the source and during propagation, were presented. The results of the measurements were used as input data to the assumptions of the noise attenuation passive system, which was the final outcome of the study. Dedicated external dampers were used in the case of wheel and rail pairs, where the dominant power of the noise is emitted. The acoustic properties of the bogie area and the bogie side covers were redeveloped to hamper the noise propagation, which is a novel application. The presented results indicate measurable benefits from the applied solutions on the tram noise reduction.

Life E-VIA: Prototypal Low-Noise Road Surface for the Reduction of Electric Vehicle Rolling Noise in Urban Area

Abstract In both the current and foreseen context of significant development of the electric vehicle (EV) fleet, a future increasing ratio of EVs in the urban traffic is expected, still enhanced in low-emission zones involving bans or restricted access to other vehicles. EVs are known to be quieter than conventional vehicles at low speed because of a low motor noise emission, resulting in a higher prevalence of rolling noise in the environmental noise. EVs differ from conventional vehicles in several parameters that can influence tyre/road noise, like weight and torque. The LIFE E-VIA project objectives consist in developing, implementing and assessing a low-noise road surface for light EV traffic in urban conditions, optimised from an acoustical and life cycle perspective. In parallel, an optimisation of EV tyres is investigated. Prior to forthcoming layout in Florence (Italy) for assessment under real traffic conditions, a prototypal road surface has been implemented and evaluated on a test track in Nantes (France). Preliminary tests carried out with different EVs on several road surfaces highlighted the variability of noise emission over vehicle types and pavements, leading to specific ranking. Two prototype versions of a low-noise road surface have been laid out in Nantes, respectively without and with crumb rubber. Both of them have been acoustically assessed with on-board microphones (CPX method) and at roadside (CPB method and microphone array). Constant speed, acceleration and deceleration conditions were considered for pass-by tests. Other acoustical or physical parameters have been measured: acoustic absorption, 3D-texture, mechanical impedance and skid resistance properties (BPN and MPD). In comparison with a reference DAC 0/10 road surface, very usual in France, a roadside noise reduction up to 4 dB(A) was found at steady pass-by speed 50 km/h. Grip values are very high and macrotexture levels moderate. Lastly, mixtures durability is analysed with laboratory tests.

An Indoor Solution to an Outdoor Problem

How indoor pass-by testing helps vehicle OEMs comply with new noise limits

Accurate and controled vehicle pass-by noise emission quantification in real life traffic

Noise emission from individual vehicle largely contributes to city pollution and has serious health impact. The standards towards vehicle manufactures consists in pass-by testing with specific acceleration conditions which are not representative of all real driving. For the 2015/996 EU directive, the vehicle source model is inspired of the preceding pass-by standard with derived data represented the propulsion and rolling noise sources. Anyhow, those sources are underestimated due to driving behavior, aged and modified vehicle, road surface, meteorological conditions... The true data collection of vehicle pass-by would be interesting. Moreover, some of the countries are reflecting on how to fight against those extremely noisy vehicle exceeding noise limit with efficient monitoring systems. This paper presents an innovative tool able to detect, identify and quantify the noise emission of individual pass-by vehicle in real life traffic. It is based on the combination of array and video processing. Compared to the state of the art and thanks to MEMs technology, the system is optimized and designed to quantify the individual noise vehicle emission regarding standard with controlled measurement and accurate processing. If the conditions are not respected to properly qualify the pass-by regarding the system limits, the data are ignored. It aims at constructing large and accurate database useful to determine average noise levels and/or acceptable noise limits per vehicle category.

Advanced acoustic signal analysis used for wheel-flat detection

One of the most important aspects in the operation of rail vehicles is the implementation of transport while ensuring safety and comfort of passengers. Technical condition of the wheel rolling surfaces has a direct impact on these factors. These elements are subject to wear and tear in a continuous and discrete form. One of the discrete wear forms is the wheel-flat on wheel rolling surfaces that generate impulse noise. This translates into a significant deterioration of vibroacoustic comfort, and in extreme cases also to a greater risk associated with e.g. derailment of the vehicle. Therefore, it is desirable in particular by the rolling stock operator to carry out cyclic diagnostics and monitoring of the condition of wheel rolling surfaces. This paper is a continuation in a series of research articles carried out by the authors related to vibroacoustic diagnostics of wheel rolling surfaces in light rail vehicles. As part of this article, acoustic measurements were carried out at a dedicated track-side system during so-called pass-by tests. Acoustic signals were analyzed in accordance with the Fourier and Hilbert transforms. Additionally, the main assumptions of vibroacoustic diagnostics and analyses of point measures were used. This allowed for the development of yet another way of monitoring the occurrence of the problem of wheel flats in rail vehicles.

Load-carrying capacity evaluation of girder bridge using moving vehicle

Efficient and reliable load-carrying capacity evaluation of deficient bridges is essential for bridge maintenance and management. Based on load-carrying capacity evaluation of an existing bridge, operator can formulate strategies and implement countermeasures such as repair, strengthening or traffic regulation. Currently, static load test is used widely for evaluation of bridge load-carrying capacity. The test, however, is often considered expensive and requires massive traffic closure that hinders frequent implementation on highway or bridges in the rural area. In this paper, an efficient method for load-carrying capacity evaluation of girder bridges based on displacement under moving vehicle is proposed. The method consists of three main procedures, namely, radar-based dynamic displacement measurement under truck pass-by test, influence line extraction, and estimation of the displacement under the static load test scenario. Based on these procedures, evaluation of load-carrying capacity is conducted following the AASHTO manual. The method was verified in numerical simulations using three-dimensional finite element model of typical girder bridge under vehicle loading. Effects of vehicle weight, vehicle speed, and road roughness on the accuracy of displacement estimation were investigated in the numerical simulations. Full-scale implementation of the method was conducted on a simply supported prestressed concrete girder bridge to investigate feasibility of the proposed method and to provide guidance for practical application. The results reveal that load rating factor of the girders can be reliably evaluated. The evaluation process was also more effective and economical than the conventional method.

Long-Term Asphalt Trial: Results of Acoustic Tests After Three Years

In 2013, VicRoads initiated a long-term trial to investigate the acoustic performance of various asphalt pavements constructed as variations to the standard specification for Victorian roads (Simpson et al. in Proceedings of the 26th Australian Road Research Board (ARRB) conference, Sydney, Australia, 2014). Acoustic testing of these five variations included statistical pass-by tests, as well as close proximity (ISO/DIS 11819-2 in Acoustics—measurement of the influence of road surfaces on traffic noise—Part 2: the close-proximity method, International Standard Organization, Geneva, 2013) and on-board sound intensity measurements (AASHTO TP 76-12 in Standard method of test for measurement of tire/pavement noise using the on-board sound intensity (OBSI) method. American Association of State Highway and Transportation Officials, Washington, 2012). The data collected from the most recent trials are presented along with that previously gathered over the first 3 years of the trial. The best-performing section of pavement was found to be a wearing surface that was treated by diamond grinding, and that showed a consistent improvement in noise reduction of up to 3 dB(A) over the standard open-graded asphalt.

A Computational Fluid Dynamics Model for Investigating Air-Pumping Mechanisms in Air-Borne Tire Noise

ABSTRACT The reduction in power train noise over the past decade has led to an increased focus in reducing tire/road noise, largely due to the environmental concerns related to road traffic noise in industrial countries. Computational fluid dynamic (CFD) simulations conducted using ANSYS FLUENT are presented here with the objective of understanding air-pumping noise-generation mechanisms due to tire/road interaction. The CFD model employs a large eddy simulation turbulence modeling approach, in which the filtered compressible Navier-Stokes equations are solved to obtain temporally and spatially accurate near-field pressure fluctuations for a two-dimensional (2D) tire geometry with (1) one groove and (2) two grooves. In addition, the Ffowcs-Williams and Hawkings (FW-H) acoustic model is used to predict far-field acoustics. The deformation of the grooves, as the tire rotates, is represented by prescribed sidewall movements. Consequently, the solution to the numerical problem is obtained through a single process, thereby enabling the prediction of small-scale air pumping, horn effect, and far-field acoustics in a single simulation. The acoustic characteristics associated with air pumping are studied through spectral analysis tools, and comparisons show that the additional groove on the horn geometry alters the spectral characteristics of air pumping. Validation of the model is conducted through qualitative and quantitative comparisons with previous studies. These simulations are intended to provide a deeper understanding about the small-scale noise generation as well as the near-field and far-field acoustics, thereby paving the way for the automotive manufacturer to compare a variety of air-related tire noise characteristics without spending time and money for vehicle pass-by tests.

Failure Mechanism of Expansion Joints in a Suspension Bridge

Premature failure of expansion joints is a concern for bridge owners. After opening to traffic, the Jiangyin suspension bridge experienced frequent damage in expansion joints, and the problem remained unsolved even after replacement with new expansion joints and installation of viscous dampers at the girder end. This paper aims to clarify the failure mechanism of the expansion joints based on field test results. The field tests consist of three scenarios: static test, influence line test, and truck pass-by test. The tests aimed to investigate the behavior of expansion joints on both global and local scales. In the static and the influence line tests, it was found that strain response of the expansion joint is affected by the girder deformation, which reflects effect of global behavior of the bridge on the expansion joints. The truck pass-by test result shows that direct impact of heavy truck axles could induce high strain in expansion joints, which indicates that the expansion joints are affected by vehicle axle loading on a local scale. These results are in accordance with the premature failures observed in the expansion joints of the Jiangyin Bridge.

Adaptive Noise Parameter Determination Based on a Particle Filter Algorithm

Due to the growing number of vehicles using the national road networks that link major urban centers, traffic noise is becoming a major issue in relation to the transportation system. Thus, it is important to determine noise model parameters to predict road traffic noise levels as part of an environmental assessment, according to traffic volume and pavement surface type. To determine the parameters of a noise prediction model, statistical pass-by and close proximity tests are required. This paper provides a parameter determination procedure for noise prediction models through an adaptive particle filter (PF) algorithm, based on using a weigh-in-motion system, which obtains vehicle velocities and types, as well as step-up microphones, which measure the combined noises emitted by various vehicle types. Finally, an evaluation of the adaptive noise parameter determination algorithm was carried out to assess the agreement between predictions and measurements.

Blind Source Separation Applied to Indoor Vehicle Pass-By Measurements

Indoor vehicle pass-by noise applications deal with measuring the exterior noise from a vehicle fixed on a chassis dynamometer in a large hemi-anechoic room. During a standardised acceleration test, the noise is measured with an array of microphones placed in the far-field, and the overall noise level versus vehicle position can be simulated. The indoor facility allows controlled and repeatable measurements independent of weather. For engineering purposes, pass-by contribution analysis can be included in the test leading to information about the pass-by noise contribution from major noise sources. This work presents a novel application of blind source separation to vehicle measurements from an indoor pass-by measurement campaign. In contrast to the classical transfer path approach using point sources for modelling vehicle noise sources and combining an operational measurement with transfer functions, the blind approach does not consider a specific noise source model. It only assumes that the noise is produces by a set of independent noise sources using only a single operational measurement for a given vehicle condition as input. Near-field microphone measurements are blindly separated into independent components and further correlated with the signals measured at the far-field indoor pass-by microphones to get the time-domain contributions. Finally, we apply the indoor simulated pass-by algorithm to produce noise contribution levels as a function of vehicle position. We discuss the specified application of blind source separation to vehicle measurements for different operating conditions from a real indoor pass-by test. Separation of tyre and engine related noise at tyre near-field microphones is verified. Furthermore, the tyre pass-by noise contribution is extracted from the overall vehicle measurement.

Decomposition and visualization of vehicle noise sources with transfer path acoustical holography

Decomposition of noise sources is an essential step to reduce the vehicle pass-by noise. Dynamic transfer path analysis has been used to describe the relation between the noise sources of the vehicle and the response point in the pass-by test. A transfer path acoustical holography method is introduced to decompose and visualize the vehicle pass-by noise sources, and the method is illustrated with a simulation of four moving point sources. The decomposition results for the four sources using transfer path acoustical holography are compared with that using acoustical holography method. It shows that the transfer path acoustical holography method has a better decomposition result. Finally, the proposed method is used to decompose the contributions of the sources in a commercial truck. The results show that the transfer path acoustical holography can be used to decompose and visualize the vehicle's noise sources in the pass-by test.

서울시 배수성 아스팔트 포장의 기능적 평가 연구

The functional evaluation of constructed permeable pavements was conducted in terms of water permeable performance and noise reduction measurements in Seoul city. The field measurements of noise was based on two methods such as pass-by and novel close proximity(NCPX). The pass-by test and NCPX method are related to noise propagation and tire/pavement interaction noise measurement, respectively. For the water permeable tests, five sections were chosen; furthermore, the measurements were conducted for both of wheel path and non-wheel path area. For the pass-by measurement, three sections were chosen; furthermore, two different locations, which were near measurement point to traffic noise and far measurement point inside park or hosing complex, were selected for each section. Finally, tire/pavement interaction noise measurements were carried out at four locations. The results show that the functional performance of water permeability and noise reduction was well remained within 2 or 3 years after permeable pavement construction.

Decomposition of moving vehicle noise with dynamic transfer model and acoustic holograph

Identifying the moving noise of vehicles is the important step to make the optimal countermeasures. A dynamic transfer path model was proposed to describe the relation between the sources on the vehicle and the test point on the ground.The noise signals both from the vehicle and the pass-by test were simultaneously recorded with a wireless device. The parameters in the dynamic model were estimated, and the results with singular value decomposition and Tikhonov regularization were compared using simulation and experiment. The contribution of the sources was decomposed with the dynamic transfer model and acoustic holograph at any test location. Finally, the proposed method was used to decompose the contributions of the sources in a bus. The results show: the dynamic transfer path analysis could be used to identify each of the noise sources and decompose their contribution in the pass-by test.

The effect of time on the contribution of asphalt rubber mixtures to noise abatement

Road pavement surface layers incorporating rubberized asphalt binders have recently been recommended as a measure to mitigate noise. At first their acoustical performance seems to be superior to that shown by conventional layers. Nevertheless, the knowledge in relation to their behavior throughout their lifetime is limited. This research, carried out over several road sections with open graded and gap-graded mixtures, two of which with rubberized asphalt, by means of controlled pass-by tests, is aimed at observing and studying these type of mixes over a time span of 3 years

포장노면과 타이어간의 마찰음 분석을 통한 교통소음예측 소프트웨어 개발

고속도로 이용차량의 증가와 함께 차량의 대형화와 고속화로 인해 고속도로 교통 소음레벨이 높아지고 있으며 저소음 포장노면 및 방음시설 설치 요청도 급격하게 증가하고 있다. 따라서 고속도로 교통소음으로 인한 민원예방과 함께 효율적이고 경제적인 소음저감 대책을 수립하기 위해서는 정확한 소음 예측 기술 마련이 필요하다. 본 연구에서는 시험도로에 포설된 다양한 포장노면에 대해서 CPX(Close Proximity Test) 및 Pass-by 소음 계측 방법을 혼용한 소음 계측 데이터를 이용하였고 차종별 단독 주행 시험을 실시하여 차량 및 노면별 음향파워레벨 산정식이 마련된 데이터를 이용하였다. 아울러, 상기 산정식의 정확성을 검증하기 위하여 고속도로 12개 지점에 대한 총 38회의 소음 계측한 데이터를 이용하여 해당 지점에 대한 소음 예측 모델을 구성하여 측정값과 예측값을 비교 평가하였다. 최종적으로 3차원 GUI 기능을 지원하는 도로교통 소음 예측 프로그램 KRON(Korea Road Noise)을 개발하였다. 이와 더불어 각 포장형태별 및 차종별에 따른 소음특성을 분석하였다. Domestic economic development, industrialization, and urbanization have brought along not only increased highway traffic but also elevated traffic noise levels. Thus, it is necessary to accurately predict the traffic noise levels in order to address the public demand of alleviating the noise levels in urban areas. In this study, the method of evaluating the sound power level of road traffic was investigated in terms of considering the types of road surface and vehicle, based on previous researches. Regarding CPX (Close Proximity Test) and Pass-by test, the measured noise data of Test Road of Korea Highway Corporation were utilized in order to construct the database of sound power levels of various vehicles. Specifically, the 38 noise measurement and analysis in 1/1-octave band frequencies at 12 pre-selected sites were carried out, considering topography and road surface. Finally, the comparison study was conducted between predicted and measured data in terms of traffic noise. The traffic noise prediction was based on the KRON (Korea Road Noise) program, which was developed being equipped wit 3-dimensional GUI. In addition, the traffic noise characteristics were evaluated in terms of vehicle types and pavement surface conditions.

Low speed exterior vehicle voise and the effect of pavement type

For operating conditions of cruise and moderate acceleration, the exterior noise emission of light vehicles is typically dominated by tire/pavement noise at speeds of 50 km/h or greater. At a test speed of 56 km/h, it has been found that pavement type can create a 10 dB or more variation in tire/pavement noise. This has significant implications for both community noise and vehicle noise emission testing. In this paper, the results tire/pavement noise measurements for over 40 different pavements in Europe and the United States are reported. These pavements include research surfaces, existing roadways, and ISO 10844 passby test surfaces. Measurements were conducted using an on-board sound intensity methodology that has been correlated to cruise-by noise levels. These results are discussed in terms of the revisions being considered for the newly revised ISO 362 passby test procedure and the ISO 10844 test surface specification. Additionally, a case history of community traffic noise reduction achieved by use of a quieter pavement is reviewed to demonstrate the importance of the pavement in low speed vehicle noise emissions.