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Numrering	Referens	Omslagsbild	Hitta
1.	Forssén, Jens, 1968, et al. (författare) Thick barrier noise-reduction in the presence of atmospheric turbulence: Measurements and numerical modelling 2002 Ingår i: Applied Acoustics. - 0003-682X .- 1872-910X. ; 63:2, s. 173-187 Tidskriftsartikel (refereegranskat)abstract Atmospheric turbulence causes scattering of sound, which can reduce the performance of sound barriers. This is an important inclusion in prediction models to obtain a correct picture of the sound reduction at higher frequencies. Here a prediction method is applied that uses the strengths of the wind and temperature turbulence to estimate the scattered power into the shadow zone of a barrier. The predictions are compared to full-scale measurements on a thick barrier, where both acoustic and meteorological data were recorded simultaneously under both calm and windy conditions. Comparison between the measurements and the predictions indicate that the method gives reasonably accurate results for mid to high frequencies and a slight overestimation at very high frequencies.
2.	Horoshenkov, K. V., et al. (författare) The sound speed and attenuation in loose and consolidated granular formulations of high alumina cements 2003 Ingår i: Applied Acoustics. - 0003-682X .- 1872-910X. ; 64:2, s. 197-212 Tidskriftsartikel (refereegranskat)abstract Clinkers of high alumina cements are separated into three granular formulations with particle sizes in the range 0.6-0.71 mm, 0.71-1.18 mm and greater than 1.18 mm. These are used to manufacture consolidated samples of porous concrete in an autoclave. The acoustic and microscopic properties of loose and consolidated porous samples of concrete are investigated using both experimental methods and mathematical modelling. Values of porosity, flow resistivity, tortuosity and parameters of the pore size distribution are determined and used to predict closely the sound speed, acoustic attenuation and normal incidence absorption coefficient of these materials. It is shown that high alumina cements do not require additional binders for consolidation and that the structural bonds in these cements are developed quickly between individual clinkers in the presence of water. The hydration product build-up during the consolidation process is insignificant which ensures good acoustic performance of the consolidated samples resulting from a sufficient proportion of the open pores. The value of porosity in the consolidated samples was found to be around 40%, which is close to that measured in some commercial acoustic absorbers. This work provides a foundation for the development of acoustically efficient and structurally robust materials, which can be integrated in environmentally sustainable concrete and masonry structures. © 2002 Elsevier Science Ltd. All rights reserved.
3.	Johansson, Carin (författare) Design and evaluation of an impact noise laboratory 1994 Ingår i: Applied Acoustics. - 0003-682X .- 1872-910X. ; 42:1, s. 75-84 Tidskriftsartikel (refereegranskat)abstract An acoustic laboratory has been constructed in order to measure sound transmission through floors. It has been erected inside an existing building. Apart from the costs being considerably less than if a new building had been constructed, this has meant that several other advantages have been obtained. The design and location of the laboratory have been partially governed by activities already existing in the building. This article presents the construction from the point of view of building technique and of acoustics. In an effort to eliminate flank transmission in the frequency range 100–3150 Hz the construction has been dimensioned with vibration dampers having a natural frequency fo = 10 Hz. For the same reason and in order to increase the sound insulation the walls and ceiling have been lined with radiation reducing material. Comparative calculations and measurements have been carried out which show how the results have been affected by this procedure. The radiated effect from the various surfaces is shown in the form of graphs. The ratios of the receiving room dimensions are chosen so that the natural frequencies in the low-frequency region 100, 125 and 160 Hz are spaced fairly uniformly Despite the economic limitations and a limited amount of space the laboratory meets the requirement set by the International Standards ISO 140 with a good margin.
4.	Johansson, Carin, et al. (författare) Development of a lightweight wooden joist floor with high impact noise insulation 1994 Ingår i: Applied Acoustics. - 0003-682X .- 1872-910X. ; 43:1, s. 67-79 Tidskriftsartikel (refereegranskat)abstract This article describes the results of a project for the development of a lightweight wooden joist floor. The work has been carried out by the optimization of each of the variables which are important for sound insulation and has resulted in the construction of a framing of joists which has good impact sound insulation, small dimensions, can be constructed in a simple way at low cost and can be assembled in an easy and safe way. Forty-five different constructions and combinations were tested in the laboratory. The optimal construction was finally tested in several blocks of flats. In order for the construction to meet the Swedish Building Standards for sound insulation, the impact noise index Ii must not exceed 63 dB. The final construction had an index Ii of 52 dB in the laboratory and 53–58 dB in the field, and was thus approximately 10 dB better that the standard limit for impact noise between adjoining flats. The total weight of the construction is only 60 kg/m2 and the total thickness is 342 mm. Furthermore the framing of joists is economical and practical to manufacture in factories, is easy to transport without deformation and is easy to install in the building on the site.
5.	Johansson, Carin (författare) Low-frequency impact sound insulation of a light weight wooden joist floor 1995 Ingår i: Applied Acoustics. - 0003-682X .- 1872-910X. ; 44:2, s. 133-147 Tidskriftsartikel (refereegranskat)abstract This article describes the results of a project for the development of a lightweight wooden joist floor. The project concerns the further development of an earlier joist construction, in which very good laboratory and field results were obtained in the frequency range 100–3150 Hz. The work was carried out to investigate how impact sound at frequencies under 100 Hz is affected if the construction is made more rigid by various means. Attention was concentrated on the effect of increasing the rigidity of joists and boards. The report cover laboratory experiments as well as measurements in the field.
6.	Johansson, Örjan, et al. (författare) Source characterization of the lower front-end of a diesel engine 1996 Ingår i: Applied Acoustics. - 0003-682X .- 1872-910X. ; 49:4, s. 383-404 Tidskriftsartikel (refereegranskat)abstract The lower front end of a diesel engine is a major noise source. Describing the source mechanisms of this area is problematic as it consists of a rotating torsional vibration damper in front of the timing transmission cover and the oil sump. This experimental study focuses on the acoustic interaction phenomena between the damper and the structure behind it. To describe the source mechanisms a test series of different modifications by conventional lead wrapping technique is performed. The vibration behaviour of each substructure is determined by operational deflection shape measurements and the source strength for each modification is determined by near-field sound intensity measurements. The results show the contributions from different substructures and describes the interference effects due to coherent radiation. It is concluded that the radiation is dominated by the timing transmission cover structure behind the damper. At some frequencies though, the torsional vibration damper in combination with the timing transmission cover behind it, causes the high radiation. This effect is mainly due
7.	Ljunggren, Fredrik, et al. (författare) Development of a new damper to reduce resonant vibrations in lightweight steel joist floors 2002 Ingår i: Applied Acoustics. - 0003-682X .- 1872-910X. ; 63:11, s. 1267-1280 Tidskriftsartikel (refereegranskat)abstract Floor vibrations annoying to humans often occur in lightweight constructions. A number of methods to solve the problem of resonant vibrations are reported in the literature. Tuned mass damper, semi-active tuned vibration absorber and active control system are all examples of existing methods. A new method has been tested in laboratory environment on a prefabricated floor containing a resilient ceiling with a size up to 6.8×4.8 m2. The method takes advantage of small pieces of visco-elastic material connected between the ceiling joists and the primary beams. A finite element model is used to calculate the correct amount of visco-elastic material. The new damper is especially effective in damping mode shapes where the ceiling oscillates out of phase relative to the floor but shows improvements for other mode shapes as well.
8.	Sandberg, Ulf, 1946- (författare) Road traffic noise : The influence of the road surface and its characterization 1987 Ingår i: Applied Acoustics. - : Elsevier. - 0003-682X .- 1872-910X. ; 21:2, s. 97-118 Tidskriftsartikel (refereegranskat)abstract Unacceptable errors in the prediction of traffic noise occur in some cases when the road surface is largely different from that on which the prediction model is based. The reason is that tyre/road noise has appeared to be the dominating component of the noise from free-flowing traffic and that this noise is to a substantial extent dependent on the road surface.The mechanisms for tyre/road noise generation and its relation to road characteristics are described. Relevant road surface characterization methods are suggested. The major method is the measurement of the road texture profile and subsequent spectral analysis of the profile curve. Supplementary methods concern the measurement of acoustical and mechanical impedances. It is concluded that the road surface effect on traffic noise is extremely complicated and that it is very difficult to generalize any simple relations.For free-flowing traffic it is shown that the tested road surface types and conditions may influence the traffic noise by up to 11 dB(A). This calls for a correction term for the road surface in the prediction models. Despite the complicated relations, it appears feasible—within stringent limitations—to use a table where the correction term is a variable of vehicle type, vehicle speed as well as road surface type and condition.
9.	Shi, Wanqing, et al. (författare) An investigation of the characteristics of impact sound sources for impact sound insulation measurement 1997 Ingår i: Applied Acoustics. - 0003-682X .- 1872-910X. ; 51:1, s. 85-108 Tidskriftsartikel (refereegranskat)abstract At the assessment of the impact sound insulation of a construction, a standard tapping machine is used as sound source. However, the current standard tapping machine has been criticised especially for measurement of wooden joist floors since the sounds generated by a tapping machine differ from those generated by actual footfall. This study has investigated the waveform and frequency spectra of human footfall (walking, running and jumping), of sand balls, sand bags and dropped tires, and of the standard tapping machine. It is shown that the frequency spectra differ between the standard tapping machine and actual footfall, especially at low frequencies. Results from other excitation sources such as a sand ball falling from a certain height showed concordance with actual footfall. This means that a sand ball drop as an impact source provides a better representation of actual human footfall than the standard tapping machine.
10.	Shi, Wanqing, et al. (författare) Assessment of the sound insulation of a wood joist construction due to different types of impact sources 1996 Ingår i: Applied Acoustics. - 0003-682X .- 1872-910X. ; 48:3, s. 195-203 Tidskriftsartikel (refereegranskat)abstract The ISO standard tapping machine was specified as an impact source to assess the sound insulation of floors. The problem is that the noise spectrum produced by the tapping machine does not give similar spectra to that produced by an actual footfall. There are not enough low frequency components in the noise spectrum generated by the tapping machine and it does not, therefore, accurately reflect low frequency noise from the construction being measured. This study presents the impact sound power radiation from a wooden joist construction while applying different impact sources, actual footfall and the standard tapping machine. The sound power radiation obtained from the construction when the tapping machine is applied contains large discrepancies when compared with measurements obtained from an actual footfall at the lower frequency. Comparison of the sound power radiation from the wood joist construction generated by different impact sources showed very good agreement between an actual footfall and a sand ball falling from a certain height. This means that the use of the sand ball drop is a better method of assessing the low frequency impact sound insulation of a construction than using the standard tapping machine.
11.	Ågren, Anders, et al. (författare) Experimental study of repeatability errors in 3D sound intensity measurements in narrow frequency bands 1994 Ingår i: Applied Acoustics. - 0003-682X .- 1872-910X. ; 43:2, s. 95-111 Tidskriftsartikel (refereegranskat)abstract When investigating the 2D or 3D intensity of complex ‘real life’ noise sources, rather than the intensity normal to a surface, to obtain more detailed information about the radiated sound field great care has to be taken both in measuring and in interpreting the results. In this study it is shown that in measurements of 3D intensity for fixed points and in narrow frequency bands, large errors can be expected for a well-defined simple source if the positioning is imprecise and for a complex source even if the positioning device and the probe are of highest quality. Comparisons have been made between a two-microphone and a six-microphone probe, hand-held and robot-controlled. The comparisons show that, except for the case of an ideal measurement with a simple source and a high-precision robot, significant errors can be expected for all the tested measurement cases. The measurements also show that the positioning of the microphone is of major importance for the repeatability accuracy. The accuracy obtained with a 3D-probe is notably better than with a 1D-probe. The errors when measuring the complex source with a robot-controlled 3D-probe, however, are still so high, especially for the non-dominant directions, that interpretations have to be made with great care. Under non-ideal measurement conditions, the errors are found to be exponentially dependent upon the sound field pressure/intensity relationship (the pI-index).
12.	Ågren, Anders (författare) The design and evaluation of a semi-anechoic engine test room 1992 Ingår i: Applied Acoustics. - 0003-682X .- 1872-910X. ; 37:2, s. 151-161 Tidskriftsartikel (refereegranskat)abstract A low-cost hemi-anechoic laboratory for study of diesel engine emissions has been constructed. The laboratory has been equipped for research in acoustics as well as on exhaust emissions. The facilities for acoustic research are described. A low-budget wall absorber with durable, inexpensive and easily exchangeable wedges has been designed. Various ways of evaluating the acoustic properties of hemi-anechoic rooms are investigated. Finally, measurements are presented that show sound level decay with distance from a source and the standard deviation for sound level when the source and microphone are rotated in a so-called carousel measurement. For sound level decay measurements a special extremely low loudspeaker must be used to avoid interfering floor reflections. Carousel measurements give good results even for a standard loudspeaker. Our carousel measurements show that the absorbers are as appropriate as other more expensive absorbers for measurements up to 2 m from a sound source.
13.	Alberdi-Muniain, Ane, et al. (författare) Indirect energy flow measurement in magneto-sensitive vibration isolator systems 2013 Ingår i: Applied Acoustics. - : Elsevier BV. - 0003-682X .- 1872-910X. ; 74:4, s. 575-584 Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract The indirect energy flow measurement method is extended to cover highly nonlinear, frequency, amplitude and magnetic field dependent magneto-sensitive natural rubber isolators applied in a real vibration isolation system. Energy flow is an effective measure of vibration isolation while being a single quantity that considers both force and velocity. The use of the indirect technique is of interest while requiring only accelerometers since it is usually difficult to directly measure the force in a real application. The vibration isolation system is composed of four magneto-sensitive rubber isolators that are inserted under a vibrating source consisting of a solid aluminium mass excited by an electro-dynamic shaker. Magneto-sensitive rubber isolators are more useful than conventional rubber isolators since the dynamic stiffness varies with the application of an external magnetic field, thus resulting in more effective vibration isolation. Various approximations regarding the indirect technique are investigated, concluding that average stiffness of magneto-sensitive isolators can be used and auto-spectrum of the foundation velocity ignored. In addition, various error analyses are performed. Finally, the indirect measurement of the energy flow is validated by direct measurements, showing very good agreement.
14.	Baro, Simone, et al. (författare) Modelling of a lined tyre for predicting cavity noise mitigation 2019 Ingår i: Applied Acoustics. - : ELSEVIER SCI LTD. - 0003-682X .- 1872-910X. ; 155, s. 391-400 Tidskriftsartikel (refereegranskat)abstract Tyre cavity resonance can significantly affect vehicle interior noise at frequencies around 200 Hz. The insertion of a sound absorbing liner inside the tyre is known to be an efficient countermeasure, in fact nowadays tyre manufacturers are already producing tyres implementing this kind of solution. The present work, through analytical and numerical models, supported by material testing, provides a methodology for predicting the dag performance of a lined tyre, taking into account tyre/lining geometry and sound absorbing material properties. The results reported in the paper show that for fixed material characteristics, the attenuation of the cavity resonance is mostly influenced by the volume of the lining treatment. Moreover, the numerical model developed for discontinuous treatments, suggests that for fixed volume and material properties, the cavity resonance attenuation can be increased by choosing a proper layout. Elsevier Ltd. All rights reserved.
15.	Bosser, Lennart, et al. (författare) Target echo calculations using the OpenGL graphics pipeline 2021 Ingår i: Applied Acoustics. - : Elsevier BV. - 0003-682X .- 1872-910X. ; 181 Tidskriftsartikel (refereegranskat)abstract This paper presents a novel approach to using modern graphics card capabilities for predicting the hydroacoustic target echo strength of an object. The key feature of this method is to inject code in the fragment shader stage of the OpenGL graphics pipeline, in effect transforming the optics reflection problem of computer graphics to an acoustic reflection problem. This is exemplified with the simple situation of an acoustically hard body and the monostatic detection case. Numerical accuracy is compared with Kirchhoff theory for simple bodies. Some suggestions for further work are proposed. (C) 2021 Elsevier Ltd. All rights reserved.
16.	Braat-Eggen, Ella, et al. (författare) Auditory distraction in open-plan study environments : Effects of background speech and reverberation time on a collaboration task 2019 Ingår i: Applied Acoustics. - : Elsevier. - 0003-682X .- 1872-910X. ; 154, s. 148-160 Tidskriftsartikel (refereegranskat)abstract Previous research has shown that semantic-based tasks are negatively influenced by semantic aspects in background speech. Collaboration is an important task in open-plan study environments and is a semantic task which might be disrupted by background speech. Therefore, the aim of this study was to analyze the influence of irrelevant background speech on student-collaboration. Participants worked in pairs to solve spot-the-difference puzzles, by using the 'DiapixUK' collaboration task, while they were exposed to different background sound scenarios. The composed sound scenarios varied in semantic content (mother tongue and foreign language background speech)and reverberation time (short vs long), the latter affecting speech intelligibility. Although a longer reverberation time decreases the intelligibility of background speech and a foreign language decreases meaningfulness of speech, no significant changes in performance were found. On the other hand, the data show an increased perceived disturbance for a longer reverberation time, which we interpret as an increased difficulty of interpersonal communication in the collaboration task due to the increased level of the background speech. The quiet reference condition was the most preferred sound condition which is in line with both the effect of a low background sound level and the absence of semantic interference.
17.	Cameron, Christopher John, et al. (författare) Prediction of NVH behaviour of trimmed body components in the frequency range 100-500 Hz 2010 Ingår i: Applied Acoustics. - : Elsevier BV. - 0003-682X .- 1872-910X. ; 71:8, s. 708-721 Tidskriftsartikel (refereegranskat)abstract The work within this paper focuses on the application and validation of numerical methods for predicting the acoustic and structural NVH behaviour of trimmed body components in an automotive context. In particular, the level of modelling refinement and accuracy necessary to establish a reliable finite element analysis model for comparative purposes in the development of alternative designs is investigated. Specifically, the roof structure of a passenger car was investigated from various performance aspects, using both structural and acoustic excitation. The roof was initially tested in situ, with and without interior lining, to provide a reference for subsequent component tests. It was then detached from the car, mounted in a stiff frame and tested in a transmission window using both acoustic and structural excitation. A finite element model of the detached component was developed using shell and solid elements for the structure and solid elements for the interior lining. Predictions were carried out to evaluate the STL as well as the vibrational frequency response due to a force applied to the structure. Special attention was given to the modelling of the headliner as well as the air gap separating the headliner from the outer sheet metal. A sensitivity study of various headliner properties was performed in addition to a comparison between solutions calculated using standard Nastran elements and augmented poro-elastic elements via the software package CDH/EXEL. The main objective of the current work has been to establish a datum reference for alternative designs. From this aspect, the validation of the numerical modelling methodology, in particular the level of detail and accuracy used, was a crucial step. It was found that the predictions agreed very well with the measured data. As an additional, very interesting result, it was also found that the in situ testing correlated well with the transmission suite testing.
18.	Conrady, Kristina, et al. (författare) Amplitude modulation of wind turbine sound in cold climates 2020 Ingår i: Applied Acoustics. - : Elsevier. - 0003-682X .- 1872-910X. ; 158 Tidskriftsartikel (refereegranskat)abstract Amplitude modulation is assumed to be a major annoyance factor of wind turbine sound. However, studies on the generation of amplitude modulation and the impact of atmospheric conditions on amplitude modulation are limited, especially in cold climates. Long-term acoustic and meteorological measurements in the vicinity of a wind farm in northern Sweden show a dependence of the occurrence of amplitude modulation on wind direction and atmospheric stability. The occurrence of amplitude modulation is highest for crosswinds from southwest, compared with the other wind directions. Moreover, the occurrence of amplitude modulation is clearly linked to atmospheric stability and highest for very stable conditions. The impact of atmospheric stability is supported by analyses of wind shear, the wind speed gradient close to the surface and the bulk Richardson number. Amplitude modulation is more likely during winter than during summer and more likely during night and early morning than during noon and early afternoon.
19.	Dickson, Crispin, et al. (författare) Continuous judgment by category-ratio scaling of aircraft noise 2014 Ingår i: Applied Acoustics. - : Elsevier BV. - 0003-682X .- 1872-910X. ; 84, s. 3-8 Tidskriftsartikel (refereegranskat)abstract A continuous judgment by category-ratio (CJCR) scaling method was used to evaluate the instantaneous annoyance of original and modified aircraft sounds. The result from the proposed method resulted in a temporal stream of annoyance levels for the whole flyover sequence that could be further analyzed. The test subjects were continuously rating their instantaneous annoyance on a Borg CR 100 scale (R) during the playback of 10 flyover sequences. Using a category-ratio (CR) scale instead of a category (C) scale, mathematical operations such as calculations of average were enabled but gave also advantages in terms of higher resolution in the responses. The results showed differences in perception in the time segment where the sound had been modified. The temporal stream of annoyance was also converted into overall judgments of the sounds, these estimations showed consistency with previous results obtained using the semantic differential and paired comparison method.
20.	Estévez Mauriz, Laura, 1982, et al. (författare) Dynamic traffic noise assessment tool: A comparative study between a roundabout and a signalised intersection 2018 Ingår i: Applied Acoustics. - : Elsevier BV. - 0003-682X .- 1872-910X. ; 130, s. 71-86 Tidskriftsartikel (refereegranskat)abstract Considering traffic flow as a steady noise source is common practice when studying traffic alternatives and its impact on the sound environment. However, vehicle dynamics have a strong influence on both transport behaviour and noise emission. One of the most relevant elements of traffic design is the intersection, where replacement of crossing intersections with roundabouts is common. In order to understand the features of these two traffic configurations, microscopic approaches are needed, making it possible to study time-pattern fluctuations relevant for the urban sound environment perception. A model based on individual-vehicle characteristics as function of time is developed and implemented in a real case study at a development stage. The model incorporates state-of-art microscopic traffic simulation software combined with the recent noise emission model, CNOSSOS-EU, applied through an in-house developed dynamic traffic noise tool, including both internal combustion engine and all-electric vehicles at different traffic flows. The tool is described in general terms incorporating the randomisation of source power. The propagation considers a flat-city configuration up to 100 m range. The tool enables study of different statistical indicators, including descriptors of probability density functions, calm periods through the novel indicator Centre of Mass Time (CMT) and noise events. The outcomes are presented through graphs and maps explaining traffic disruptions, acceleration effects, vehicle configurations and flows, source strengths, contribution and difference maps. Among the results, it is shown that, for the signalised crossing, the acceleration of the simulated traffic has a large effect on the source strength. It is however also shown that, for an unbalanced roundabout intersection leading to congestions, it can become noisier than the signalised crossing. It is furthermore shown that, when reducing the traffic flow, the two intersection types behave more similarly; however the roundabout having the best performance for the majority of the studied analysis. Further results are shown, e.g. for removing heavy vehicles, removing also medium heavy vehicles and assuming only all-electric light vehicles, including analysis from using various indicators. A discussion about the presented tool, the current results and ideas for future work concludes the paper. The present paper goes along a series of studies with the overall intention to provide a more solid basis for justifying decisions in traffic planning regarding the outdoor sound environment.
21.	Feng, Leping, et al. (författare) Engineering methods to predict noise levels at reference points with known source properties 2015 Ingår i: Applied Acoustics. - : Elsevier BV. - 0003-682X .- 1872-910X. ; 96, s. 68-74 Tidskriftsartikel (refereegranskat)abstract Two engineering methods are proposed to predict the sound pressure levels at a given point when the sound power level of a noise source is known and the transfer function between the source and the reference point can be obtained. The first method is applicable when the source is surrounded by many reflectors, or inside a box-like structure. A single monopole with average transfer function is suggested for this situation. For a source with a strong directivity placed in an essentially free space, the "box-source" method is recommended to take into account of the source directivity. The total sound power is in this case divided into five independent noise sources which are obtained via ordinary sound power measurement methods. Experimental verifications are made for several cases in laboratory. Satisfactory results are obtained for both methods.
22.	Feng, Leping (författare) Modified impedance tube measurements and energy dissipation inside absorptive materials 2013 Ingår i: Applied Acoustics. - : Elsevier BV. - 0003-682X .- 1872-910X. ; 71:12, s. 1480-1485 Tidskriftsartikel (refereegranskat)abstract Impedance tube is an important tool to measure acoustic properties of a material, for which two methods have been standardized. The methods for a "modified" impedance tube have been developed recently to measure material properties in the condition of an anechoic termination. Instead of commonly used two-load or two-source methods, a method with direct and inverted configuration in cooperation with the single-microphone method is suggested in this paper. With the help of transfer matrix method, combined effect of several materials placed in series can be predicted from individual properties. A simple recurrence formula is obtained to relate the acoustic properties of a multilayer structure with the reflection and transmission coefficients of each layer. Very good agreements are obtained between the prediction and the direct measurements. Energy dissipations inside porous materials for different situations are studied and compared.
23.	Forssén, Jens, 1968, et al. (författare) Auralization model for the perceptual evaluation of tyre–road noise 2018 Ingår i: Applied Acoustics. - : Elsevier BV. - 0003-682X .- 1872-910X. ; 132, s. 232-242 Tidskriftsartikel (refereegranskat)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.
24.	Forssén, Jens, 1968, et al. (författare) Effects of urban morphology on traffic noise: A parameter study including indirect noise exposure and estimated health impact 2022 Ingår i: Applied Acoustics. - : Elsevier BV. - 0003-682X .- 1872-910X. ; 186 Tidskriftsartikel (refereegranskat)abstract Noise exposure has been calculated and analysed for 31 different urban morphologies in an urban setting. For five of the urban morphologies also vegetation surfaces on facades and roofs were studied. Facade exposures were analysed for both smaller (single-sided) flats and larger (floor-through) flats, considering the direct exposure from the roads as well as the indirect exposure at noise-shielded positions like inner yards. Also, grid map area exposures at ground level were calculated and analysed for both sidewalk and yard areas. The facade exposure levels, using indicators Lden and Lnight, were used to estimate annoyance and sleep disturbance as well as disease burden in terms of DALY (Disability-Adjusted Life Years) per person. In all urban morphology cases, single-sided flats showed overall better performance (i.e. lower DALY) than larger, floor-through flats; however, the inclusion of a bonus for additional facade elements having a lower noise exposure gave the large flats a similar or better predicted overall performance compared with the small flats. Among the building types studied, for small flats and constant building density, the use of perimeter blocks with closed inner yards, slightly open yards and U-shaped buildings showed results of relatively better overall performance compared with I-shaped, L-shaped and point buildings. When the yards grow in size, the performance of closed inner yards dropped. As general trends, perimeter blocks were shown to perform better than morphologies with less enclosed yards and densification with constant traffic flow was shown to result in improved performance. However, building types with slightly open yards may provide an attractive compromise solution due to its relatively good noise shielding at the same time as enabling solutions to air pollution and corner-flat layouts. In addition, complementing the perimeter blocks with towers was shown to enable improvement. Furthermore, traffic concentration by locating all local traffic to a single road was shown to be beneficial, increasingly so by widening the road. Predicted effects of vegetation surfaces on facades and roofs showed significant overall improvement, where closed inner yards benefit from vegetated roofs. The area exposure results showed that when the building blocks are successively less enclosed the levels are reduced on the side-walks and increased in the yards. Also, the benefit of facade vegetation is shown for the area exposures. (C) 2021 The Author(s). Published by Elsevier Ltd.
25.	Forssén, Jens, 1968, et al. (författare) Modelling the interior sound field of a railway vehicle using statistical energy analysis 2012 Ingår i: Applied Acoustics. - : Elsevier BV. - 0003-682X .- 1872-910X. ; 73:4, s. 307-311 Tidskriftsartikel (refereegranskat)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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