| 1. |
- Ahlinder, Sven, et al.
(author)
-
A study of parameters affecting noise on a heavy duty DI engine
- 2007
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In: SAE Technical Papers. - 400 Commonwealth Drive, Warrendale, PA, United States : SAE International. - 0148-7191 .- 2688-3627.
-
Conference paper (peer-reviewed)abstract
- On a 13 liter Direct Injection Heavy duty diesel engine, noise and cylinder pressure have been measured in order to investigate if noise can be estimated from cylinder pressure. The idea of filtering cylinder pressure to obtain noise has been tested. This idea implies that the engine works as a linear filter. The linear relation between cylinder pressure frequencies and noise frequencies seems quite poor and the method probably does not work on the engine tested. When measuring noise, on the other hand, multivariate low order polynomials work well to study the trade-off between measured noise, fuel consumption, NOx and Soot. This implies that the huge datasets gathered with modern electronically controlled engines can be handled this way. Copyright © 2007 Society of Automotive Engineers of Japan, Inc.
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| 2. |
- Ahrens, Jens, 1978, et al.
(author)
-
Tutorial on scaling of the discrete fourier transform and the implied physical units of the spectra of time-discrete signals
- 2020
-
In: 148th Audio Engineering Society International Convention.
-
Conference paper (peer-reviewed)abstract
- The combination of the time-discrete property of digital signals together with the commonly employed definition of the discrete Fourier transform (DFT) can cause ambiguity when interpreting magnitude spectra with respect to the physical unit of the signal under consideration. Standardized scaling of spectra increases the comparability of frequency-domain data that are published in scientific articles or data sheets of commercial products. We present and discuss in this tutorial a collection of the most relevant scaling options for DFT spectra to yield amplitude spectra, power spectra, and power density spectra, and we illustrate how an implied physical unit of the underlying signal is reflected by the magnitude of the spectrum. The tutorial is accompanied by Matlab/Octave scripts that demonstrate the different cases.
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| 3. |
- Alves, Sonia, et al.
(author)
-
Urban sound planning - The SONORUS project
- 2016
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In: Proceedings of the INTER-NOISE 2016 - 45th International Congress and Exposition on Noise Control Engineering: Towards a Quieter Future. ; , s. 2319-2328
-
Conference paper (peer-reviewed)abstract
- Sound is still insufficiently considered in most urban planning processes, resulting in unsatisfactory sonic environments that might even present health risks to citizens. No matter how complex and challenging the planning project might be, the creation or preservation of acoustically favorable environments should be part of urban planning. To support this process, the SONORUS project developed a holistic approach for urban sound planning and showed its benefits with practical test cases. The goal of the holistic approach is to facilitate the integration of sonic planning in an earlier stage of the planning process by combining different approaches and by providing new tools and methods, thus enabling urban planners to achieve healthy and supportive sound scenarios.
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| 4. |
- Amiryarahmadi, Nata, et al.
(author)
-
A virtual design studio for low frequency impact sound from walking
- 2021
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In: Acta Acustica. - : European Acoustics Association, EAA. - 2681-4617 .- 1022-4793. ; 5
-
Journal article (peer-reviewed)abstract
- Experience with wooden multi-storey houses have shown that impact sound insulation is one of most critical issues to ensure a good indoor environment. Even in cases where the impact sound insulation is fulfilled, people perceive the sound from e.g. walking neighbours as very disturbing. To investigate the subjective perception, a test facility is needed which allows for a coherent evaluation of different floor designs by listening test. The facility should ensure, that when comparing different floors, the same excitation by a walker and the same receiving room are involved. Only the floor design should be changed. As a consequence the spread in the data will only be due to the spread in the perception by subjects. In this paper a virtual design tool for low frequency impact sound insulation is presented, which consists of four parts; measured walking forces, floor models, an auralisation system which consists of a grid of loudspeakers simulating the vibration of the floor and a receiving room furnished as a common living room. In a pilot study a listening test is carried out for 13 different floors with different impact sound spectra at frequencies below 100 Hz. The results indicate that the judged annoyance strongly correlates with the judged loudness. However, there is a substantial spread observed in between the subjects participating in the listening tests. To understand this spread, a more extended study is needed with more participants and a classification of the subjects with respect to criteria such as noise sensitivity or age.
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| 5. |
- Amiryarahmadi, Nata, 1982, et al.
(author)
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Application of LMS Algorithm to Measure Low-Frequency Transient Forces from Human Walking
- 2016
-
In: Acta Acustica united with Acustica. - : S. Hirzel Verlag GmbH. - 1610-1928 .- 1861-9959. ; 102:1, s. 23-34
-
Journal article (peer-reviewed)abstract
- Measurement and modeling of low frequency ground reaction forces (GRFs) from human walking have been the subjects of research in different fields from biomechanics to civil engineering and structural dynamics. Many of the existing models are developed based on experiments which alter natural walking by for example presence of force transducers, limitations in the speed and path of walking and replacing the real floor with a transducerfacilitated measurement rig. These alterations result in contact forces which do not represent real GRFs. In this study, a time-domain inverse measurement method based on LMS algorithm is used to measure low-frequency (
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| 6. |
- Amiryarahmadi, Nata, et al.
(author)
-
Identification of low-frequency forces induced by footsteps on lightweight floors
- 2016
-
In: Acta Acoustica united with Acustica. - : S. Hirzel Verlag GmbH. - 1610-1928 .- 1861-9959. ; 102:1, s. 45-57
-
Journal article (peer-reviewed)abstract
- Despite many advantages of wooden buildings, low-frequency noise disturbance, mainly from human footsteps on timber floors, is a major hindrance for widespread application of wood in multi-storey buildings. In many cases the impact noise evaluations of the wooden floors according to ISO 140-7 and ISO 717-2 standards do not correspond to subjective experiences. This study aims to investigate the characteristics of footstep forces to support further studies related to discrepancies between standard evaluations and low-frequency noise disturbances in lightweight buildings. Transient footstep forces in vertical direction made by different walkers and different footwear on two floor structures were measured and compared. The vertical footstep forces were then compared with the impact forces made by a standard tapping machine. Analysis revealed that footstep forces contain large amplitudes at low frequencies (20 < f < 50) which are not included in the standard evaluation procedure. Therefore, by extending the frequency range of the standard measurements down to 20 Hz and designing an accurate adaptation term for evaluations, a better correlation between standard impact noise evaluations and acoustic performance of the lightweight buildings might be achieved.
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| 7. |
- Amiryarahmadi, Nata, et al.
(author)
-
Subjective evaluation of impact sound from footsteps
- 2023
-
In: Proceedings of the 10<sup>th</sup> Convention of theEuropean Acoustics AssociationForum Acusticum 2023. ; , s. 2467-
-
Conference paper (peer-reviewed)abstract
- Low-frequency impact sound caused by upstairs neighbors walking on the floor is a key acoustic challenge regarding lightweight floors and a major source of disturbance particularly in wooden buildings. To investigate the effect of floor design on the perceived walking sound, a virtual design tool has been developed, which allows for auralising the impact sounds containing low frequencies down to 20 Hz. Using this tool, footstep sounds on 10 different lightweight floors were auralised by a loudspeaker grid mounted in the ceiling of an acoustically controlled lab, which is furnished as a common living room. The walking sounds were subjectively evaluated through listening tests while the subjects were sitting freely on a sofa without needing to use any extra listening equipment. The listening test results suggest that loudness, thumpiness and reverberation are correlated with the perceived annoyance. The results also indicate a correlation between annoyance and age as well as the individual experience of earlier exposure to noise.
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| 8. |
- Amiryarahmadi, Nata, et al.
(author)
-
Subjective evaluation of impact sound from footsteps
- 2023
-
In: <em>Proceedings of Forum Acusticum</em>. - : European Acoustics Association, EAA. ; , s. 2467-
-
Conference paper (peer-reviewed)abstract
- Low-frequency impact sound caused by upstairs neighbors walking on the floor is a key acoustic challenge regarding lightweight floors and a major source of disturbance particularly in wooden buildings. To investigate the effect of floor design on the perceived walking sound, a virtual design tool has been developed, which allows for auralising the impact sounds containing low frequencies down to 20 Hz. Using this tool, footstep sounds on 10 different lightweight floors were auralised by a loudspeaker grid mounted in the ceiling of an acoustically controlled lab, which is furnished as a common living room. The walking sounds were subjectively evaluated through listening tests while the subjects were sitting freely on a sofa without needing to use any extra listening equipment. The listening test results suggest that loudness, thumpiness and reverberation are correlated with the perceived annoyance. The results also indicate a correlation between annoyance and age as well as the individual experience of earlier exposure to noise. © 2023 First author et al. This is an open-access article distributed under the terms of the Creative Commons Attribution 3.0 Unported License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
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| 9. |
- Amiryarahmadi, Nata, 1982, et al.
(author)
-
Time-domain model of a tapping machine
- 2011
-
In: Proceedings - 6th Forum Acusticum 2011, Aalborg, 27 June - 1 July 2011. - 2221-3767. ; , s. 1713-1718
-
Conference paper (peer-reviewed)abstract
- In the past few years the use of lightweight buildings made of prefabricated wooden elements has become more common. Ease of installation, high accuracy and lightness of such buildings has attracted builders and designers. Sweden, having a large coverage of renewable forests has an increasing interest in multi-storey wooden buildings. However noise and vibration in wooden buildings is an issue of concern especially low frequency impact sound due to footsteps. Impact sound insulation of floors can be measured based on ISO 140-7 using standardized tapping machine as excitation source. Experience has shown that in many cases the results obtained by this method do not correlate with annoyance experienced by inhabitants. On the other hand, the method presented in ISO 140-7 has usually shown to be relevant for the evaluation of impact sound transmission of concrete floors. Discovering the source of this contradiction requires deeper understanding of the impact process. A first step would be to find the difference between contact forces of the tapping machine on different floor materials. One could then correlate it with inhabitants’ perceived annoyance. This paper is the first step of this investigation which is a part of a Swedish research project called AkuLite. In this work a time-dependent model based on Hertz’s contact law is presented for the tapping machine. The model is validated by measurements on a homogeneous concrete floor. Also the contribution of parameters such as damping and stiffness of floor material on the resulting impact force and vibrations is studied.
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| 10. |
- Amlinger, Hanna
(author)
-
Reduction of Audible Noise of a Traction Motor at PWM Operation
- 2018
-
Licentiate thesis (other academic/artistic)abstract
- A dominating source for the radiated acoustic noise from a train at low speeds is the traction motor. This noise originates from electromagnetic forces acting on the structure resulting in vibrations on the surface and thus radiated noise. It is often perceived as annoying due to its tonal nature. To achieve a desirable acoustic behavior, and also to meet legal requirements, it is of great importance to thoroughly understand the generation of noise of electromagnetic origin in the motor and also to be able to control it to a low level.In this work, experimental tests have been performed on a traction motor operated from pulse width modulated (PWM) converter. A PWM converter outputs a quasi-sinusoidal voltage created from switched voltage pulses of different widths. The resulting main vibrations at PWM operation and their causes have been analyzed. It is concluded that an appropriate selection of the PWM switching frequency, that is the rate at which the voltage is switched, is a powerful tool to influence the noise of electromagnetic origin. Changing the switching frequency shifts the frequencies of the exciting electromagnetic forces. Further experimental investigations show that the trend is that the resulting sound power level decreases with increasing switching frequency and eventually the sound power level reaches an almost constant level. The underlying physical phenomena for the reduced sound power level is different for different frequency ranges. It is proposed that the traction motor, similar to a thin walled cylindrical structure, shows a constant vibration over force response above a certain frequency. This is investigated using numerical simulations of simplified models. Above this certain frequency, where the area of high modal density is dominating, the noise reducing effect of further increasing the switching frequency is limited.
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| 11. |
- Andersson, Patrik, 1974, et al.
(author)
-
A Method for Experimental Collection of Global Material Data for Tyres
- 2001
-
In: Nordic Vibration Research 2001, Stockholm, Sweden (The Scandianvian Vibration Society, www.svib.se).
-
Conference paper (other academic/artistic)abstract
- For the modelling of the dynamic behaviour of tyres material data are required. Depending on the character of the model these will have different quality. Modelling with global structures such as beams or plates, representative data for the global bending stiffness, global mass etc. are needed. These data do not represent the details of the tyre structure but the combined properties of the structure. Therefore it is not possible to cut out samples of the tyre and determine the global material properties by measurements on these samples. Consequently it is necessary to estimate the material parameter by measurements carried out on the complete tyre. Results from such measurements will be related to the model used for the tyre (e.g. ring model, orthotropic plate, etc.). The material data obtained in such way are consequently a function of both the tyre structure and the model, which is used to update the data. A method for experimental collection of global material data for tyres has been developed. This method is based on the experimental characterisation of tyres by driving point and transfer mobilities and the use of the orthotropic plate tyre model for updating the material data.
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| 12. |
- Andersson, Patrik, 1974, et al.
(author)
-
A study of forces and noise generation in a contact including adhesive bonds
- 2004
-
In: Nordic Vibration Research 2004, June 3-4, (The Scandinavian Vibration Society, www.svib.se).
-
Conference paper (peer-reviewed)abstract
- Paper to be published.Adhesive forces are present in the contact between a road surface and a rolling tyre. Theses forces may add up to substantial adherence forces, causing stick-snap excitation of tread blocks, high frequency noise generation, and increased rolling resistance. An experimental setup was designed to study the process when a tyre tread block sample was pressed onto a road surface sample, and hastily removed. Time variation of contact forces and sound pressure were measured. The same situation was modelled using a time domain model of two elastic bodies in non-linear dynamic contact. The contact area is spatially discretised in contact points and the contact problem is solved using an elastic half-space. The response of the block is calculated by convoluting the forces with pre-calculated impulse responses of the same block, which is modelled as a mass-spring system. The adhesive bounds are included by allowing negative contact forces; the contact at a point breaks when the calculated contact force reaches a specified negative value. Typical results from the experimental setup and the model are presented. It is concluded that the experimental setup is suitable for investigating the detachment process of the tread block and that the model is able to qualitatively capture the contact force and noise generation.
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| 13. |
- Andersson, Patrik, 1974, et al.
(author)
-
Experimental Study of High Frequency Response of Tyres
- 2003
-
In: EuroNoise2003, May 19-21 2003, Naples, Italy.
-
Conference paper (peer-reviewed)abstract
- Most traditional tyre models concern the low and middle frequency ranges. It is necessary to include higher frequencies for improved accuracy in tyre/road interaction models. Often only the radial direction is included, although the tangential direction may be important, especially studying stick slip motion in the contact between tyre and road surface. Designing models requires insight into the behaviour of the tyre structure at higher frequencies. To add insight of high frequency behaviour, experimental studies were done on four different tyres with the same internal design but with different tread patterns. The results of this study underline the importance of the local deformation when forces act with small excitation areas on the tread. Adequate consideration of the tread properties in the tyre/road interaction models is thus of importance to obtain the correct local contact force distribution. This is most important for the tangential driving point mobility. Tread patterns are shown mainly to modify the flexural stiffness and mass in comparison to smooth tyres, while block resonances are not expected to be located in the frequency range in which tyre/road noise is important.
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| 14. |
- Andersson, Patrik, 1974, et al.
(author)
-
High Frequency Dynamic Behaviour of Smooth and Patterned Passenger Car Tyres
- 2004
-
In: Acta Acustica united with Acustica. - 1610-1928 .- 1861-9959. ; 90:3, s. 445-456
-
Journal article (peer-reviewed)abstract
- Most traditional tyre models concern the low and middle frequency ranges. For improved accuracy in tyre/roadinteraction models it is necessary to include higher frequencies. Often only the radial direction is included, althoughthe tangential direction may be important, especially studying stick slip motion in the contact between tyreand road surface. Designing accurate and efifcient models requires insight into the behaviour of the tyre structureat higher frequencies to make the models as complete as necessary without creating tools that are computationallytoo costly. To add insight to this area, experimental studies were done on four different tyres with the sameinternal design but with different tread patterns. Point mobilities were measured and compared with two differenttyre models, a two-layer plate model based on the elastic field equations and an orthotropic plate model. Theresults of this study underline the importance of the local deformation when there are forces that act with smallexcitation areas on the tread. Adequate consideration of the tread properties in the tyre/road interaction modelsis thus of extreme importance to obtain the correct local contact force distribution. This is most important for thetangential driving point mobility. Tread patterns are shown mainly to modify the flexural stiffness in comparisonto smooth tyres, while block resonances are not expected to be located in the frequency range in which tyre/roadnoise is important.
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| 15. |
- Andersson, Patrik, 1974, et al.
(author)
-
Investigation of Driving Point and Transfer Mobilities of Simple Tread Blocks on a Tyre
- 2001
-
In: 17th International Congress on Acoustics, Rome, Italy, 2001.
-
Conference paper (peer-reviewed)abstract
- An important issue when modeling noise generation from rolling tyres using the orthotropic plate tyre model [1] is to find accurate Green’s functions for the responses of the tyre. These Green’s functions are used to solve the tyre/road contact problem of the rolling tyre in the time domain. For tyres with tread blocks, it is important to consider the influence of the tread blocks on the response. It has previous been suggested that the tread blocks could be modeled as mass-spring systems [2]. Measurements of mobilies on a tyre with simple and regular tread blocks shows that this approach is unnecessary when modelling the response in radial direction of the tyre in the frequency range between 0 and 2500 Hz. Instead the tyre may be modeled, using a plate tyre model, as a soft plate with slightly higher local deformation. The tread pattern may be modeled in the tyre/road contact model as a macro roughness, where points at the blocks may be in contact with the road while forces at points in the groves are set to zero.
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| 16. |
- Andersson, Patrik, 1974, et al.
(author)
-
Numerical Modelling of Tyre/Road Interaction
- 2012
-
In: Scientific Bulletin, Automotive Series. - 1453-1100. ; 22
-
Journal article (peer-reviewed)abstract
- From November 2012 all passenger car tyres, light truck tyres and heavy duty vehicle tyres sold on the aftermarket in the European Union must have a label classifying the external rolling noise, the fuel efficiency, and the wet grip. This regulation puts a focus on optimisation of the tyre design with respect to all these parameters at once. Up to today these three parameters have been treated rather independently. There is little to no detailed information available on the relationship between rolling noise generation, rolling resistance, and grip of car tyres besides empirical data based on measurements. Today, simulation models that can simulate all these effects at once have just started to emerge. This paper gives a brief presentation of the past and the most resent development of numerical tyre/road interaction models with focus on external noise, rolling resistance, and grip. Today, the simulation models can be used to gain fundamental knowledge about the tyre/road interaction process and the resulting noise, rolling resistance, and grip. Models for combined optimisation of rolling resistance and noise emissions exists, and are just about to be used in preliminary investigations. Models that in addition give results for grip are still under development.
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| 17. |
- Andersson, Patrik, 1974, et al.
(author)
-
Numerical Modelling of Tyre/Road Interaction
- 2011
-
In: Exploratory Workshop: Modern Methods of Vibro-Acoustic Studies With Automotive Applications, University of Pitesti, Romania, November 24-25, 2011.
-
Conference paper (other academic/artistic)abstract
- From November 2012 all passenger car tyres, light truck tyres and heavy duty vehicle tyres sold on the aftermarket in the European Union must have a label classifying the external rolling noise, the fuel efficiency, and the wet grip. This regulation puts a focus on optimisation of the tyre de- sign with respect to all these parameters at once. Up to today these three parameters have been treated rather independently. There is little to no detailed information available on the relationship between rolling noise generation, rolling resistance, and grip of car tyres besides empirical data based on measurements. Today, simulation models that can simulate all these effects at once have just started to emerge. This paper gives a brief presentation of the past and the most resent develop- ment of numerical tyre/road interaction models with focus on external noise, rolling resistance, and grip. Today, the simulation models can be used to gain fundamental knowledge about the tyre/road interaction process and the resulting noise, rolling resistance, and grip. Models for combined opti- misation of rolling resistance and noise emissions exists, and are just about to be used in preliminary investigations. Models that in addition give results for grip are still under development.
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| 18. |
- Andersson, Patrik, 1974, et al.
(author)
-
Rapid tyre/road separation: An experimental study of adherence forces and noise generation
- 2009
-
In: Wear. - : Elsevier BV. - 0043-1648. ; 266:1-2, s. 129-138
-
Journal article (peer-reviewed)abstract
- Adhesion forces in the tyre/road contact interface significantly influence the contact dynamics and resulting noise generation for certain tyre/road combinations. Hence, an experimental setup was built where tyre tread samples are loaded and rapidly unloaded in the direction normal to a wearing course sample from an ISO10844-road. Time records of contact forces and sound pressures are acquired during the separation. The separation process in terms of the contact forces and noise generation is described and interpreted. There is good repeatability in the general character of the time signals for a given geometry, but variations occur requiring statistical analysis, as the initial conditions (on smaller length scales) are only approximately repeated. The measured adherence force depends strongly on load, load duration, and unloading rate, in a way supported by theories for contact of rough surfaces. The total sound pressure level of the noise generated during separation is directly related to the level of the adherence force, but the distribution of energy in 1/3-octave bands cannot be estimated from the adherence force record alone, as they also depend on the exact contact geometry. The details of the contact geometry are also very decisive for the magnitude of the adherence force.
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| 19. |
- Andersson, Patrik, 1974, et al.
(author)
-
Time domain contact model for tyre/road interaction including nonlinear contact stiffness due to small-scale roughness
- 2008
-
In: Journal of Sound and Vibration. ; 318:1-2, s. 296-312
-
Journal article (peer-reviewed)abstract
- Rolling resistance, traction, wear, excitation of vibrations, and noise generation are all attributes to consider in optimisation of the interaction between automotive tyres and wearing courses of roads. The key to understand and describe the interaction is to include a wide range of length scales in the description of the contact geometry. This means including scales on the order of micrometres that have been neglected in previous tyre/road interaction models. A time domain contact model for the tyre/road interaction that includes interfacial details is presented. The contact geometry is discretised into multiple elements forming pairs of matching points. The dynamic response of the tyre is calculated by convolving the contact forces with pre-calculated Green's functions. The smaller-length scales are included by using constitutive interfacial relations, i.e. by using nonlinear contact springs, for each pair of contact elements. The method is presented for normal (out-of-plane) contact and a method for assessing the stiffness of the nonlinear springs based on detailed geometry and elastic data of the tread is suggested. The governing equations of the nonlinear contact problem are solved with the Newton–Raphson iterative scheme. Relations between force, indentation, and contact stiffness are calculated for a single tread block in contact with a road surface. The calculated results have the same character as results from measurements found in literature. Comparison to traditional contact formulations shows that the effect of the small-scale roughness is large; the contact stiffness is only up to half of the stiffness that would result if contact is made over the whole element directly to the bulk of the tread. It is concluded that the suggested contact formulation is a suitable model to include more details of the contact interface. Further, the presented result for the tread block in contact with the road is a suitable input for a global tyre/road interaction model that is also based on the presented contact formulation.
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| 20. |
- Beckenbauer, Thomas, et al.
(author)
-
A mixed physical and statistical approach for the prediction of tyre/road noise
- 2013
-
In: Proceedings of AIA-DAGA 2013 Conference on Acoustics, Meran, Italy, March 18-21, 2013.
-
Conference paper (peer-reviewed)abstract
- The hybrid approach is intended to make a tool available for both analysis of tyre/road noise depending on road surface characteristics and synthesis of low noise road surfaces. However, the model does not claim applicability for the development of low noise tyres. Basic physical models for the calculation of non linear contact forces and tyre vibrations as well as an empirical model for the aerodynamic tyre/road noise generation have been implemented in order to feed a multiple regression model with problem specific input quantities. The model is able to predict absolute coast-by noise levels in terms of third octave bands between 315 Hz and 2 kHz within a wide speed range from 50 km/h up to 120 km/h separately for different noise generation mechanisms. Despite the fact that the model does not perform better than +/- 1 dB concerning the difference between calculated and measured overall noise levels and +/- 5 dB for spectral level differences it provides relevant information on the distribution of sound energy due to mechanical and aerodynamic processes within the tyre/road contact. This affords opportunity to characterize and develop road surfaces yielding reduced excitation of rolling noise which is presented by means of practically relevant examples.
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| 21. |
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| 22. |
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| 23. |
- Beckenbauer, Thomas, et al.
(author)
-
Tyre/road noise prediction: A comparison between the SPERoN and HyRoNE models, Part 1
- 2008
-
In: 7th European Conference on Noise Control 2008, EURONOISE 2008; Paris; France; 29 June 2008 through 4 July 2008. - 2226-5147. ; , s. 2933-2938
-
Conference paper (peer-reviewed)abstract
- The SPERoN and HyRoNE models predict the pass-by tyre/road noise of a passenger car from intrinsic characteristics of the road surface. Both models are hybrid: they combine statistical laws with physical models. With a computing time of a few minutes (very quick compared to full physical models), they provide operational tools for tyre/road noise prediction. Particular fields of interest are road surface optimisation with respect to noise at the laboratory scale, conformity of production of a new surface and acoustic monitoring of roads. They are now implemented as user-friendly stand-alone applications. The presentation will address the principles of the models, their performances and their respective main fields of application. Part 1 will address the philosophy and the principles of the models.
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| 24. |
- Bein, Thilo, et al.
(author)
-
Integrated Solutions for Noise & Vibration Control in Vehicles
- 2012
-
In: Procedia - Social and Behavioral Sciences. - : Elsevier BV. - 1877-0428. ; 48, s. 919-931
-
Journal article (peer-reviewed)abstract
- A strong issue on the development of new vehicles is the weight reduction, required for the reduction of the fuel consumption and the CO2 emissions. The current vehicles have already a structure optimised to have low weight without reducing the required performances. However, there are some components of the structure that can be further reduced in weight still matching the resistance, crash and fatigue performances, but giving a poor performance in terms of noise and vibrations and increasing both the structure-borne and air-borne sound transmission.In the European FP7 project Green City Car, flexible, integrated passive and active solutions are developed permitting noise and vibration attenuation in vehicles equipped with the next generation of highly fuel-efficient two- or three cylinder internal combustion engines (ICE). Among others, shunted piezoelectric patches and electro-magnetic actuation as well as smart Helmholtz resonators are considered. Additionally, dedicated active noise control systems for the control of broadband rolling noise are developed. Besides, Green City Car addresses and implements novel damping materials and acoustic treatments as well as design approaches for tyres which are an important acoustic source for exterior and interior noise. This holistic approach should lead to a reduction in noise and vibrations levels in the order of 10 dB(A) and more measurable in the city car provided (not on component level). Currently, Green City Car finished its second year and first results are presented and discussed in this paper.
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| 25. |
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| 26. |
- Buckers, C., et al.
(author)
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Analysis of the acoustic characteristics and optimization potential of road surfaces - One focus within the project "Quiet Road Traffic 3"
- 2012
-
In: 41st International Congress and Exposition on Noise Control Engineering 2012, INTER-NOISE 2012; New York, NY; United States; 19 August 2012 through 22 August 2012. - 9781627485609 ; 6
-
Conference paper (peer-reviewed)abstract
- The development of silent road surfaces demands a detailed analysis of the tire/road interaction mechanisms basically determining the noise radiation of flowing traffic. Such an analysis is of significant importance to identify and characterize the relevant effects which affect the acoustic properties of the pavements. This paper reviews the approaches pursued within the interdisciplinary research project "Quiet Road Traffic 3" including an adequate expansion of the SPERoN model for the quantitative prediction of the tire/road noise. A variety of novel materials and road constructions is investigated to validate the model, to design optimized pavements, and to explore their application potential. The practical use of the results will be finally checked by implementing and monitoring test tracks. The research activities cover asphalt as well as concrete construction techniques and focus in particular on measures to reduce the noise nuisance in agglomerations. In total, the approaches within the project "Quiet Road Traffic 3" are intended to lower the road traffic noise level by 4 to 6 dB(A) as compared to the current state of the art.
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| 27. |
- Coja, Michael, 1977-
(author)
-
Effective vibro-acoustical modelling of rubber isolators
- 2005
-
Doctoral thesis (other academic/artistic)abstract
- This thesis, gathering four papers, concerns the enhancement in understanding and modelling of the audible dynamic stiffness of vibration rubber isolators including experimental measurements. Paper A studies the performances of three different types of vibration isolator using an indirect measurement technique to estimate the blocked dynamic transfer stiffness of each specimen. The measurements are performed over a wide audible frequency range of 200 to 1000 Hz in a specially designed test rig enabling the investigation of arbitrary preload influences. Paper B addresses the modelling of the audible-frequency stiffness of the rubber conical mount experimentally appraised in Paper A accounting for preload effects. The model is based on a simpliflied waveguide approach approximating the nonlinearities attributed to the predeformations by adopting shape factor considerations. The carbon black filled rubber is assumed incompressible, displaying a viscoelastic behavior based on a fractional derivative Kelvin-Voigt model efficiently reducing the number of required material parameters. In Paper C the focus is on the axial dynamic stiffness modelling of an arbitrary long rubber bushing within the audible frequency range. The problems of simultaneously satisfying the locally non-mixed boundary conditions at the radial and end surfaces are solved by adopting a waveguide approach, using the dispersion relation for axially symmetric waves in thick-walled infinite plates, while fulfilling the radial boundary conditions by mode-matching. The results obtained are successfully compared with simpliflied models but display discrepancies when increasing the diameter-to-length ratios since the influence of higher order modes and dispersion augments. Paper D develops an effective waveguide model for a pre-compressed cylindrical vibration isolator within the audible frequency domain at arbitrary compressions. The original, mathematically arduous problem of simultaneously modelling the preload and frequency dependence is solved by applying a novel transformation of the pre-strained isolator into a globally equivalent homogeneous and isotropic configuration enabling the straightforward application of a waveguide model to satisfy the boundary conditions. The results obtained present good agreement with the non-linear finite element results for a wide frequency range of 20 to 2000 Hz at different preloads.
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| 28. |
- Colomo González, Miguel, et al.
(author)
-
Influence of bolted items on modal analysis performed on a car body
- 2008
-
In: 7th European Conference on Noise Control 2008, EURONOISE 2008; Paris; France; 29 June 2008 through 4 July 2008. - 2226-5147. ; , s. 5475-5480
-
Conference paper (peer-reviewed)abstract
- When performing Modal Analysis testing on a BIP (Body-in-Prime), some bolted items are included to better take into account their inuence on body stiffness. However, their contribution to the stiffness is not relevant in the frequency range accessible for modal analysis (usually up to 70 Hz on a BIP). On the other hand, these bolted items increase the dispersion between results obtained for nominally identical test objects. The question which arises is whether the items should be included in the BIP definition to perform modal analysis and, in this case, which is their inuence on the results? MIMO (Multi-Input-Multi-Output) measurements were carried out over three, nominally identical, BIPs. Several configurations were measured for each BIP, starting from the complete body the bolted items were progressively removed. A version of LMS PolyMAX method was programmed by Matlab to analyze the measured data. Conclusions about bolted items inuence are drawn based on the study of stabilization diagrams and modal parameters. The poles selection by the stabilization diagrams is one of PolyMAX method keys. The method understanding obtained from programming allows studying the ins and outs of poles selection. Polynomial order plays an important role in physical poles identification, especially for closely spaced modes. Results are shown to highlight its relevance.
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| 29. |
- Diapoulis, Georgios, 1981, et al.
(author)
-
Person identification from walking sound on wooden floor
- 2018
-
In: Euronoise 2018. - 2226-5147. ; , s. 1727-1732
-
Conference paper (peer-reviewed)abstract
- Human activities in building structures may vary to a great extend and daily mobility may be the cause of noise and vibrations. We focused on walking sound to identify different individuals based on airborne sound recordings. Our aim was to provide a description of high-level acoustical features that corresponds to walking sound and person identification. We present two levels of abstraction. The first level builds upon principal component analysis and provides the main sound characteristics of walking activity. For the second level of abstraction we provide higher-level acoustical features that better describe person identification.
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| 30. |
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| 31. |
- Dinkova, Penka, 1977, et al.
(author)
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Modeling the vibrational response of truck tyres
- 2006
-
In: 6th European Conference on Noise Control: Advanced Solutions for Noise Control, EURONOISE 2006; Tampere; Finland; 30 May 2006 through 1 June 2006.
-
Conference paper (peer-reviewed)abstract
- When modelling structures, one key question is to have access to proper input data. In the case of tyres this is a very complicated task having in mind the complex design of the structure. In addition the data might be load and temperature depended as well as varying with frequency.Obtaining data on a detailed level (i.e. for individual cords, wires, rubber compounds) is not sufficient since, models (e.g. Finite Element Models) on this level will be computational very costly in the frequency range of interest (in our case up to 4kHz). In addition the detailed structure is not of importance for wave propagation in this frequency range. Instead global material data are needed.In this paper measurements are presented which help model and to identify key parameters such as bending stiffness, pre-stress, and damping. The measurements are carried out at a freely suspended truck tyre with a slick tread.The response in normal direction to the surface is measured on the tread surface and on the sidewall. From these measurements animations can be created enlightening the vibrational behaviour of the tyre. From the measurements conclusions can be made on the different types of propagating waves, their speed and attenuation. The extracted material data are applied in a model for truck tyres.
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| 32. |
- Estévez Mauriz, Laura, 1982, et al.
(author)
-
Incorporation of the quiet side in noise maps
- 2014
-
In: TECNIACUSTICA 2014. 45st SPANISH CONGRESS ON ACOUSTICS. 8 th IBERIAN CONGRESS ON ACOUSTICS. EUROPEAN SYMPOSIUM ON SMART CITIES AND ENVIRONMENTAL ACOUSTICS. - 2340-7441. - 9788487985256 ; , s. 123-130
-
Conference paper (peer-reviewed)abstract
- Nowadays noise maps are focused on the noise level at the most exposed façade, leading to underestimations on the shielded areas. Previous research showed that quiet areas have positive effects for the inhabitants' quality of life. To solve this problem, an engineering method was developed within the QSIDE project. This method aims to improve noise maps in terms of multiple reflections in an efficient way. Two different terms, attenuation due to the barrier and the canyon will be incorporated. In this paper, the suggested model from QSIDE has been further developed for its inclusion in noise map calculations.
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| 33. |
- Estévez Mauriz, Laura, 1982, et al.
(author)
-
Isolating key features in urban traffic dynamics and noise emission: a study on a signalized intersection and a roundabout
- 2016
-
In: Proceedings of the INTER-NOISE 2016 - 45th International Congress and Exposition on Noise Control Engineering: Towards a Quieter Future.
-
Conference paper (peer-reviewed)abstract
- Urban planning and transport network are considered as major urban systems with great impact on the sound environment. Most of the work done in transport management and traffic design to improve the quality of both outdoor and indoor sound environment relies on conventional noise mapping software outcomes. This type of tool is based on macroscopic traffic modelling, considering traffic flow as a steady noise source. A commonly implemented practice intended to reduce noise in urban areas is the transformation of a signalised crossing into a roundabout. However, the individual vehicle behaviour becomes relevant in these decisions, where high time-pattern fluctuations are responsible for changes in the quality of the urban sound environment and of human activity. The present paper studies a set of indicators from isolated key features in these two road traffic configurations and their possible variations (acceleration, heavy vehicles, etc.). A VISSIM microscopic traffic simulation model combined with the CNOSSOS-EU noise emission model is used to test cases based on real situations, now in development stage. The approach presented aims to provide stronger basis in the reasoning behind why different road traffic configurations adopted in the urban planning practice give certain effects in relation to the urban sound environment.
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| 34. |
- Estévez Mauriz, Laura, 1982, et al.
(author)
-
Let the Children Listen: A First Approximation to the Sound Environment Assessment of Children through a Soundwalk Approach
- 2020
-
In: International Journal of Environmental Research and Public Health. - : MDPI AG. - 1661-7827 .- 1660-4601. ; 17:12, s. 1-18
-
Journal article (peer-reviewed)abstract
- The urban sound environment is one of the layers that characterizes a city, and several methodologies are used for its assessment, including the soundwalk approach. However, this approach has been tested mainly with adults. In the work presented here, the aim is to investigate a soundwalk methodology for children, analyzing the sound environment of five different sites of Gothenburg, Sweden, from children's view-point, giving them the opportunity to take action as an active part of society. Both individual assessment of the sound environment and acoustic data were collected. The findings suggested that among significant results, children tended to rank the sound environment as slightly better when lower levels of background noise were present (LA90). Moreover, traffic dominance ratings appeared as the best predictor among the studied sound sources: when traffic dominated as a sound source, the children rated the sound environment as less good. Additionally, traffic volume appeared as a plausible predictor for sound environment quality judgments, since the higher the traffic volume, the lower the quality of the sound environment. The incorporation of children into urban sound environment research may be able to generate new results in terms of children's understanding of their sound environment. Moreover, sound environment policies can be developed from and for children.
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| 35. |
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| 36. |
- Estévez Mauriz, Laura, 1982, et al.
(author)
-
SONORUS Urban sound planning project and test sites: an example within the planning stage
- 2016
-
In: Proceedings of the INTER-NOISE 2016 - 45th International Congress and Exposition on Noise Control Engineering: Towards a Quieter Future.
-
Conference paper (peer-reviewed)abstract
- SONORUS Urban sound planning project looks towards a proactive planning for improved sonic environments, coupled with the variables influencing the quality of life in cities. The project embraces a holistic urban planning approach, involving acoustics at the planning stage as another variable capable to enrich the built environment. To connect the research carried out with practical implementations, SONORUS incorporates four real case studies with different characteristics and a common demand on the improvement of the sound environment at different stages. This paper focuses mainly on Frihamnen test site (Gothenburg, Sweden), considered a strategic city project with the intention to transform the space into a dense mixed-use area. The paper goes through a general introduction framing the holistic approach in urban sound planning at four test sites. The discussion is centred in the research within Frihamnen and the workshop carried out with SONORUS members and city representatives, with the intention to analyse the acoustic situation and understand the impact of future developments on the sound environment. Finally, the work discusses about the consequences and possibilities that the holistic approach might have in urban sound planning and the entire urban planning process as a driving force to improve the liveability of spaces.
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| 37. |
- Estévez Mauriz, Laura, 1982, et al.
(author)
-
Soundwalks in Gothenburg
- 2016
-
Reports (other academic/artistic)abstract
- The present report presents the results of a series of soundwalks carried out in the city of Gothenburg as part of the “Framtidsveckan 2015” activities. The study was developed inside the EC project SONORUS Urban Sound Planning in collaboration with the Environmental Office of the city of Gothenburg.The goal is to analyse the sound environment at different locations from the citizens’ point of view through a series of questions while at the same time, sound recordings and acoustical indicator data is obtained. Thereby, thecitizens’ will have the opportunity to contribute to the present and future urban development, including urban sound planning, in the planning agenda. Moreover, the intention is to increase awareness among citizens in terms of noise exposure and sound quality, in addition to make them part of the study of their city. The soundwalks took place in October 2015.
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| 38. |
- Estévez Mauriz, Laura, 1982, et al.
(author)
-
Traffic dynamics, road design and noise emission: a study case
- 2015
-
In: Euronoise 2015, 10th European Congress on Noise Control Engineering.
-
Conference paper (peer-reviewed)abstract
- Traffic management and traffic design have been issued as the main solutions to reduced problems related to mobility. In relation with noise mapping, traffic simulation is usually based on macroscopic modelling, with e.g. mean speed and flow as output. However, dynamics in terms of acceleration have a strong influence on noise emission. In the current paper, road traffic noise emission is calculated with dynamic traffic as input. A real case, now in planning stage, is used as a setting containing several traffic design alternatives. The resulting total noise emission is calculated for the different traffic and road design solutions by using a microscopic traffic simulation model (VISSIM) combined with a model for noise emission (CNOSSOS-EU). The qualities of the resulting traffic and noise situations are discussed.
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| 39. |
- Estévez Mauriz, Laura, 1982, et al.
(author)
-
Urban space and the sound environment: Transport system, urban morphology, quiet side and space users in the SONORUS project
- 2016
-
In: Proceedings of the INTER-NOISE 2016 - 45th International Congress and Exposition on Noise Control Engineering: Towards a Quieter Future. ; , s. 2928-2938
-
Conference paper (peer-reviewed)abstract
- Awareness on urban environmental quality is leading the built environment resilience and sustainability vision, highlighting the importance of a multidisciplinary framework on urbanization processes. A main concern is the negative impact of outdoor noise due to road traffic, determined largely by the source strength, i.e. the vehicles. This paper summarizes the work within the optimization of urban areas inside the SONORUS Urban sound planning project. The purpose is to provide urban planning tools focusing on interacting approaches through the traffic planning and buildings as instruments supporting a better urban environment, with noise as the main indicator. First, the prediction modelling for quiet sides based on the Qside model is implemented and tested on cases measured in situ. Second, a microscopic road traffic modelling tool gives useful output for noise level predictions as function of time, opening the possibility to calculate noise indicators and test traffic configurations. Discussion extends towards the study of urban morphology diversification, considered a key strategy to increase liveability of spaces, its interaction with the transport system and the impact on the sound environment. Finally, interest focuses on space users modelling their environment beyond noise control, using the soundwalk as a tool to study urban sound experience.
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| 40. |
- Fabre, François, et al.
(author)
-
Sound Radiation from Railway Wheels including Ground Reflections: A half-space formulation for the Fourier Boundary Element Method
- 2021
-
In: Journal of Sound and Vibration. - : Elsevier BV. - 1095-8568 .- 0022-460X. ; 493
-
Journal article (peer-reviewed)abstract
- Current models for the acoustic radiation from railway wheels assume free field radiation. However, slab tracks are increasingly used for new railway lines. The acoustically hard surface of those tracks makes a re-evaluation of the free field assumption relevant, as such a surface can affect the radiation efficiency of an acoustic radiator. The wheel as the acoustic radiator is most conveniently described in a cylindrical coordinate system, thus making use of its axisymmetry. While this is a viable solution for the structural vibrations, for instance by using the curved Waveguide Finite Element formulation, the axisymmetry breaks when including a reflective plane in the calculation of the acoustic radiation. A convenient method to include an infinitely large, reflective plane is by using half-space Green’s functions in combination with the Boundary Element method. This method can be formulated in cylindrical coordinates using the Fourier series BEM (FBEM). However, the FBEM has not yet been combined with half-space Green’s functions. This paper provides a half-space formulation for the FBEM, which enables e.g. the evaluation of sound radiation of railway wheels over reflective surfaces. Finally, it is shown that the assumption of free field radiation for railway wheels is valid, as there is no major contribution of the reflective plane to the radiation efficiency of the wheel. The developed method is validated against laboratory measurements as well as analytical models.
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| 41. |
- Forssén, Jens, 1968, et al.
(author)
-
A model study of low-frequency noise exposure indoors due to road traffic
- 2023
-
In: Building Acoustics. - 1351-010X .- 2059-8025. ; 30:1, s. 3-24
-
Journal article (peer-reviewed)abstract
- Indoor low-frequency noise levels due to road traffic has been modelled for facade examples consisting of a lightweight steel facade, a concrete facade and two types of windows. Possible audibility of heavy vehicles passing by has been investigated as well as the dependence of the exposure level on driving speed and distance to road. The results show that pass-by events may be audible at low frequencies for cases complying with building standards and noise guideline values exemplified by Swedish regulation. Moreover, the A-weighted levels may be dominated by low frequency noise, and the frequency of occurrence of pass-by traffic noise events may be sufficiently high to create disturbance for typical traffic situations. Furthermore, it is shown that the contribution of pass-by events to the equivalent level indoors may increase when the driving speed is lowered.
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| 42. |
- Forssén, Jens, 1968, et al.
(author)
-
Auralization model for the perceptual evaluation of tyre–road noise
- 2018
-
In: Applied Acoustics. - : Elsevier BV. - 0003-682X .- 1872-910X. ; 132, s. 232-242
-
Journal article (peer-reviewed)abstract
- Due to improvements in combustion-engines and use of electric-engines for cars, tyre noise has become the prominent noise source also at lower speeds. Models exist that simulate the noise produced by a rolling tyre, as do models that auralize different traffic situations from basic data. In this paper, a novel auralization method is introduced, with the purpose to enable synthesis of useful car pass-by sound signals for various situations. The method is based on an established model for tyre noise levels (SPERoN) that is combined with a validated auralization tool (LISTEN). In the LISTEN approach, source signals for tyre–road interaction and propulsion are produced from data based on recorded pass-by sounds. In the combined model, the tyre–road interaction data is shaped by the spectra estimated in SPERoN and synthesized back into a pass-by signal. The combined model is made to agree spectrally with measurements for a receiver at 7.5 m distance. Psychoacoustic judgments were used to compare the modelled signals with recorded signals, and the pass-by sounds for a given listener position showed promising quality and accuracy with respect to perceived pleasantness.
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| 43. |
- Forssén, Jens, 1968, et al.
(author)
-
How can we plan for a good urban sound environment, focusing on road traffic noise?
- 2020
-
In: IOP Conference Series: Earth and Environmental Science. - : IOP Publishing. - 1755-1307 .- 1755-1315. ; 588:5
-
Conference paper (peer-reviewed)abstract
- The sound environments in our cities are affected by unwanted sounds, i.e. noise, to an extent that is largely undesired, affecting health and wellbeing. The World Health Organization (WHO) has estimated the burden of disease from traffic-related noise within the western part of Europe and concluded that we each year lose at least one million disability-adjusted life years (DALYs) and that only air pollution has a larger disease burden among environmental factors. The burden of environmental noise is mainly sleep disturbance and annoyance. And the dominant source is road traffic. Methods. This paper describes the mechanisms behind road traffic noise and how we can use them in an urban sound planning perspective to improve the sound environment, as an integral part of sustainable cities and communities. The results are based on calculations and measurements made in previous and ongoing projects. Results. Treatments at source consider tyre, road, engine (whether electric or combustion), driving speed and acceleration, and further vehicle restrictions. Methods for reduction of noise during propagation and more general urban planning aspects include low-height barriers and ground treatments; acoustically absorbing facades and roofs of buildings, e.g. including vegetation; and building morphology and quiet side. Quantitative reductions, in decibels, as well as qualitative aspects are presented. Conclusions. The described possible improvements to the urban sound environment, with focus on road traffic noise as the dominant impairing factor, inform us about how a good urban sound environment can be reachable. However, to reach a good sound environment in reality, the work process of applied urban sound planning demands work across disciplines, also at early-stage planning, instead of traditional noise control applied late in the planning process.
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| 44. |
- Forssén, Jens, 1968, et al.
(author)
-
Introduction to traffic noise abatement
- 2014
-
In: Environmental Methods for Transport Noise Reduction. - : CRC Press. ; , s. 1-18
-
Book chapter (other academic/artistic)abstract
- Presents Evidence-Based Guidance on Noise Abatement Methods Solutions for reducing the noise impact of road and rail traffic can be found in the use of natural elements in combination with artificial elements in urban and rural environments. Ground and road surface treatments; trees, forests, and tall vegetation; and the greening of buildings and other surfaces can contribute to powerful and cost-effective noise reduction. Environmental Methods for Transport Noise Reduction presents the main findings of the Holistic and Sustainable Abatement of Noise by optimized combinations of Natural and Artificial means (HOSANNA) research project. This project involved experts from seven countries, and assessed noise reduction in terms of sound level reductions, perceptual effects, and cost–benefit analysis. It considered a number of green abatement strategies, and aimed to develop a toolbox for reducing road and rail traffic noise in outdoor environments. Combines Theory with Practice Broad in both theory and application and based on leading-edge research, the book brings together the findings and their practical use. It details assessment methods for perceived noise, and outlines noise prediction methods that can be integrated with noise mapping software. It also explores the economic benefits and positive effects on urban air quality and CO2 levels. The material is this book: Includes up-to-date results on noise mitigation using vegetation and ground treatments Contains relevant results on innovative noise barrier designs Presents data on acoustic performance of vegetation and soil substratum Provides perceptual and cost–benefit analyses of noise mitigation methods Environmental Methods for Transport Noise Reduction is a helpful guide for noise consultants, city planners, architects, landscape architects, and researchers.
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| 45. |
- Forssén, Jens, 1968, et al.
(author)
-
Modelling the interior sound field of a railway vehicle using statistical energy analysis
- 2012
-
In: Applied Acoustics. - : Elsevier BV. - 0003-682X .- 1872-910X. ; 73:4, s. 307-311
-
Journal article (peer-reviewed)abstract
- The sound field in train compartments, treated as a series of connected air cavities, is modelled using statistical energy analysis, SEA. For the case under study, with five cavities in series and the source in the second cavity, a closed-form solution is obtained. An adjusted SEA model is used to predict the rate of spatial decay within a cavity. The SEA model is validated using results from a ray tracing method and from scale model measurements. For the octave bands 500-4000 Hz, good agreement is shown between the results from measurements, the ray tracing and the SEA model, for the two saloons closest to the source cavity (a vestibule). The SEA model was shown to slightly underestimate the rate of spatial decay within a cavity. It is concluded that a reasonable cause is the additional diffusion due to the seating.
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| 46. |
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| 47. |
- Garcia-Andrés, Xavier, et al.
(author)
-
REDUCING ROLLING NOISE IN RAILWAY WHEELS WITH CONSTRAINED LAYER DAMPING TREATMENTS CONSIDERING COMPREHENSIVE VISCOELASTIC MODELS
- 2023
-
In: Proceedings of the International Congress on Sound and Vibration. - 2329-3675.
-
Conference paper (peer-reviewed)abstract
- In this work, the reduction of radiated sound power of a railway wheel incorporating a constrained layer damping treatment is modelled and studied in detail. Such vibration control mechanism consists of an arrangement of a viscoelastic material between a constraining layer and the wheel web, and has been proven as an effective method of reducing rolling noise. The modelling of these devices presents many challenges due to the non-linear and frequency-dependent nature of the viscoelastic material behaviour, as well as the interaction between the wheel and the different layers of material. Thus, the model developed in the present work considers the viscoelastic behaviour of the polymer through a number of material models that include the frequency dependence of the main properties, such as the Burgers and Zener approaches. The variation of radiated rolling noise for a wheel with different configurations of constrained layer damping is later compared, analysing their suitability for minimising sound radiation.
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| 48. |
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| 49. |
- Gidlöf-Gunnarsson, Anita, 1957, et al.
(author)
-
Ljudlandskap för bättre hälsa. Resultat och slutsatser från ett multidisciplinärt forskningsprogram : Soundscape Support to Health. Final Report.
- 2008
-
Reports (other academic/artistic)abstract
- Vikten av tillgång till goda ljudlandskap för vår hälsa och vårt välbefinnande, vad som kännetecknar sådana goda ljudlandskap, hur man mäter kvalitén och hur man åstadkommer goda ljudlandskap i och kring bostäder och i rekreationsområden har varit centrala frågor för forskningsprogrammet Ljudlandskap för bättre hälsa. Genom samarbetet mellan forskare inom miljömedicin, miljöpsykologi och akustik har programmet skapat förutsättningar för bred kunskapsutveckling och framtagning av helhetslösningar som i grunden baseras på påverkan av ljud/buller på hälsa och välbefinnande. De viktigaste resultaten finns sammanfattade i denna rapport som finns att ladda ned som en pdf-fil under www.ljudlandskap.acoustics.nu
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| 50. |
- Grau, Loïc, et al.
(author)
-
Influence of the ground/structure interaction on the calculation of the force at the wheel/rail contact
- 2016
-
In: Proceedings of the INTER-NOISE 2016 - 45th International Congress and Exposition on Noise Control Engineering: Towards a Quieter Future. ; , s. 2086-2097
-
Conference paper (peer-reviewed)abstract
- The prediction of ground vibration from railway traffic represents a major challenge for railway operators, especially with regard to the increasing number of new lines built close to residential buildings. In this context, it becomes essential to have a model that accounts on the one hand for ground/structure interaction and on the other hand for wheel/rail interaction. In this paper, such a model is developed by combining two existing models. The model for ground/structure interaction, SIPROVIB, is an analytical model of a slab with Kirchhoff-Love hypothesis coupled to the ground in 3D. The model for wheel/rail interaction is a computationally efficient time-domain model, where vehicle and track are represented by pre-calculated Green's functions. The wheel/rail contact is modelled as 3D, non-linear and non-Hertzian. Both models are combined by replacing the track Green's function by a Green's function representing the ground and slab coupled to a simplified rail model. Numerical results showed that the influence of slab and ground on the dynamic wheel/rail contact forces increases for thinner slabs and softer grounds, but is generally of secondary importance. Deviations in contact force did not exceed 2 dB for frequencies up to 200 Hz. © 2016, German Acoustical Society (DEGA). All rights reserved.
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