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  • 1.
    Burström, Lage
    et al.
    Luleå tekniska universitet.
    Nilsson, Christer
    Luleå tekniska universitet.
    Ågren, Anders
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Operation, Maintenance and Acoustics.
    Manöverrum i stålindustrin: Delrapport 4 : Krav och riktlinjer1981Report (Other academic)
  • 2.
    Burström, Lage
    et al.
    Luleå tekniska universitet.
    Ågren, Anders
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Operation, Maintenance and Acoustics.
    Nilsson, Christer
    Luleå tekniska universitet.
    Manöverrum i stålindustrin: Delrapport 6, Referensrum SSAB Luleå, Slutrapport1981Report (Other academic)
  • 3.
    Giessman, Ray
    et al.
    Luleå tekniska universitet.
    Ågren, Anders
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Operation, Maintenance and Acoustics.
    Structural modifications of A 9 litre diesel engine to decrease noise radiation: A, Text B, Appendices1992Report (Other academic)
  • 4.
    Grane, Camilla
    et al.
    Luleå University of Technology, Department of Business Administration, Technology and Social Sciences, Human Work Science.
    Normark, Carl Jörgen
    Luleå University of Technology, Department of Business Administration, Technology and Social Sciences, Innovation and Design.
    Lundkvist, Andre
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Operation, Maintenance and Acoustics.
    Alm, Håkan
    Ågren, Anders
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Operation, Maintenance and Acoustics.
    Broström, Robert
    Volvo Car Corporation, Sverige.
    Davidsson, Staffan
    Volvo Car Corporation.
    Project: EFESOS - Environmental Friendly efficient Enjoyable and Safety Optimized Systems2012Other (Other (popular science, discussion, etc.))
    Abstract [sv]

    EFESOS is a Swedish Vehicle HMI (Human Machine Interaction) FFI research project. The overall ambition is to make driving of future cars more environmental friendly, enjoyable and safer by means of optimized systems. The project is managed by Volvo Car Corporation (VCC) and it is a collaboration between VCC and seven other research partners including Luleå University of Technology.

  • 5.
    Göhler, Martin
    et al.
    Luleå tekniska universitet.
    Ågren, Anders
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Operation, Maintenance and Acoustics.
    Noise radiation from a diesel engine: noise control investigations on the timing cover1991Report (Other academic)
  • 6.
    Isaksson, M.
    et al.
    Luleå tekniska universitet.
    Johansson, Carin
    Luleå tekniska universitet.
    Ågren, Anders
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Operation, Maintenance and Acoustics.
    Comparison of measured and FE-calculated sound pressure levels in a room induced by roof vibration1994In: Proceedings of Nordic Acoustical Meeting - [NAM 94], Danish technological institute , 1994Conference paper (Refereed)
  • 7.
    Johansson, Carin
    et al.
    Luleå tekniska universitet.
    Leth, Siv
    Luleå tekniska universitet.
    Ågren, Anders
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Operation, Maintenance and Acoustics.
    Buller vid stränggjutning: preliminär rapport1985Report (Other academic)
  • 8.
    Johansson, Carin
    et al.
    Luleå tekniska universitet.
    Ågren, Anders
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Operation, Maintenance and Acoustics.
    An investigation of low frequency vibration modes of a lightweight wooden joist floor structure1995Report (Other academic)
  • 9.
    Johansson, Carin
    et al.
    Luleå tekniska universitet.
    Ågren, Anders
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Operation, Maintenance and Acoustics.
    Analysis of the vibration modes of light weight wooden joist floors1994In: Proceedings of Nordic acoustical meeting, NAM 94 / [ed] Henrik S. Olesen, Aarhus: Danish technological institute , 1994Conference paper (Refereed)
  • 10.
    Johansson, Carin
    et al.
    Luleå tekniska universitet.
    Ågren, Anders
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Operation, Maintenance and Acoustics.
    Behaviour of a light weight wooden joist floor at low frequencies: analysis of the vibration modes1994In: Noise - quantity and quality: proceedings / The 1994 International Congress on Noise Control Engineering, Inter-Noise 94 ; Yokohama, Japan, August 29 - 31, 1994, Poughkeepsie, NY: Noise control foundation , 1994, p. 1555-1558Conference paper (Refereed)
  • 11.
    Johansson, Carin
    et al.
    Luleå tekniska universitet.
    Ågren, Anders
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Operation, Maintenance and Acoustics.
    Development of a lightweight wooden joist floor with high impact noise insulation1994In: Applied Acoustics, ISSN 0003-682X, E-ISSN 1872-910X, Vol. 43, no 1, p. 67-79Article in journal (Refereed)
    Abstract [en]

    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.

  • 12.
    Johansson, Carin
    et al.
    Luleå tekniska universitet.
    Ågren, Anders
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Operation, Maintenance and Acoustics.
    Development of a light-weight wood-joist floor with high impact sound insulation1989In: Engineering for environmental noise control: Inter-Noise 89 Proceedings / [ed] George C. Maling, Jr., Poughkeepsie, N.Y: Noise control foundation , 1989, p. 621-624Conference paper (Refereed)
    Abstract [en]

    When building small and medium size houses for more than one tennant the demands for good sound insulation are high. In Sweden it has become more and more popular to build these kind of houses in lightweight timber constructions. A disadvantage then is that problems with bad sound insulation increases. For a building enterprise that build prefabricated wooden houses there is normally no problem in designing partitioning walls to fulfill these demands

  • 13.
    Johansson, Carin
    et al.
    Luleå tekniska universitet.
    Ågren, Anders
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Operation, Maintenance and Acoustics.
    Bergenudd, Lennart
    Luleå tekniska universitet.
    Lätta träbjälklag med hög stegljudsisolering1990Report (Other academic)
  • 14.
    Johansson, Carin
    et al.
    Luleå tekniska universitet.
    Ågren, Anders
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Operation, Maintenance and Acoustics.
    Sundbäck, Ulrik
    Luleå tekniska universitet.
    Stränggjutning, bullerdämpning vid skärmaskin: förstudie1983Report (Other academic)
  • 15.
    Johansson, R.
    et al.
    Luleå tekniska universitet.
    Ågren, Anders
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Operation, Maintenance and Acoustics.
    Prediction of point and tendencies of the presure waveform from crankshaft speed measurements2000In: Proceedings of ISMA 25, 2000 International Conference on Noise and Vibration Engineering: 2000 September 13 - 15, [Leuven] / [ed] Paul Sas, Leuven: Katholieke universiteit , 2000Conference paper (Refereed)
  • 16. Johansson, Örjan
    et al.
    Kahn, M.S.
    Luleå tekniska universitet.
    Ågren, Anders
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Operation, Maintenance and Acoustics.
    Sound quality assessment of a diesel engine due to structure modifications1996In: Noise control - the next 25 years: proceedings, St Albans: Institute of Acoustics , 1996Conference paper (Refereed)
  • 17. Johansson, Örjan
    et al.
    Ågren, Anders
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Operation, Maintenance and Acoustics.
    A study of the interaction effects between the torsional vibration damper and engine structure by gated measurements1994In: Noise - quantity and quality: proceedings / The 1994 International Congress on Noise Control Engineering, Inter-Noise 94 ; Yokohama, Japan, August 29 - 31, 1994, Poughkeepsie, NY: Noise control foundation , 1994, p. 395-398Conference paper (Refereed)
  • 18. Johansson, Örjan
    et al.
    Ågren, Anders
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Operation, Maintenance and Acoustics.
    Noise radiation from a torsional vibration damper in a diesel engine1993In: People versus noise: proceedings of the 1993 International congress on noise control engineering, Inter-Noise 93 / [ed] Pierre Chapelle; Gerrit Vermeir, Poughkeepsie, NY: Noise control foundation , 1993Conference paper (Refereed)
  • 19. Johansson, Örjan
    et al.
    Ågren, Anders
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Operation, Maintenance and Acoustics.
    Noise radiation from the torsional damper in a diesel engine: an investigation of the interaction effect between the torsional damper and the timing cover1992Report (Other academic)
  • 20. Johansson, Örjan
    et al.
    Ågren, Anders
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Operation, Maintenance and Acoustics.
    The use statistical methods to predict the noise radiation from a torsional vibration damper in a diesel engine1993Report (Other academic)
  • 21. Johansson, Örjan
    et al.
    Ågren, Anders
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Operation, Maintenance and Acoustics.
    Lindberg, W.
    Luleå tekniska universitet.
    Principal components and partial least squares modelling of sound intensity measurements1995In: Proceedings of the 15th international congress on acoustics: Trondheim, Norway, 26-30 June 1995, Trondheim: Tapir Akademisk Forlag, 1995Conference paper (Refereed)
  • 22. Johansson, Örjan
    et al.
    Ågren, Anders
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Operation, Maintenance and Acoustics.
    Sundbäck, Ulrik
    Luleå tekniska universitet.
    Klopotek, Manfred
    Luleå tekniska universitet.
    Source characterization of the lower front-end of a diesel engine1996In: Applied Acoustics, ISSN 0003-682X, E-ISSN 1872-910X, Vol. 49, no 4, p. 383-404Article in journal (Refereed)
    Abstract [en]

    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

  • 23. Johnsson, Roger
    et al.
    Tingvall, Bror
    Ågren, Anders
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Operation, Maintenance and Acoustics.
    Predicitng interior factory noise with ray-tracing modelling: an example of hardening plant2000In: Proceedings: Inter.Noise 2000 : August 27 - 30, 2000, Nice, France / [ed] Didier Cassereau, Paris: SFA , 2000, p. 1595-1599Conference paper (Refereed)
  • 24. Johnsson, Roger
    et al.
    Ågren, Anders
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Operation, Maintenance and Acoustics.
    Cylinder pressure reconstruction from vibration and speed measurements on IC engines2004In: Noise and vibration engineering: proceedings of ISMA 2004 / [ed] P. Sas, Heverlee: Katholieke Univ. Leuven , 2004, p. 965-974Conference paper (Refereed)
    Abstract [en]

    Knowledge of the in-cylinder pressure pulse in IC engines is of main importance in order to fulfill the requirements on low fuel consumption, exhaust emissions and noise. Direct measurements of the in-cylinder pressure are not suitable outside the laboratory environment due to a number of drawbacks. In this paper a combined indirect method for the measurement of the cylinder pressure pulse is developed and verified. The method is based on linear transfer functions between cylinder pressure and engine vibration and crankshaft speed, respectively. The combined method shows better results than achieved by either method separately. The low frequency part of the pressure pulse is reconstructed from crankshaft speed measurements while the high frequency part is reconstructed from vibration measurements. However, there is still a frequency region between the methods where neither method gives a reliable prediction.

  • 25.
    Johnsson, Roger
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Operation, Maintenance and Acoustics.
    Ågren, Anders
    Localisation of the TDC-position from crankshaft speed fluctuation measurements2002In: Proceedings of the Sixth International Conference on Rotor Dynamics, IFT o MM / [ed] E.J. Hahn; R.B. Randall, Sydney: International Federation for the Theory of Machines and Mechanisms , 2002, p. 265-272Conference paper (Refereed)
  • 26. Johnsson, Roger
    et al.
    Ågren, Anders
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Operation, Maintenance and Acoustics.
    Prediction of points and tendencies of the pressure waveform from crankshaft speed measurements2000In: Proceedings of ISMA 25, 2000 International Conference on Noise and Vibration Engineering: 2000 September 13 - 15, [Leuven / [ed] P. Sas, Leuven: Katholieke universiteit , 2000, p. 907-12Conference paper (Refereed)
    Abstract [en]

    Direct measurements of the pressure inside the engine have a number of limitations that makes the method expensive and only good for laboratory measurements. Therefore an indirect method to measure the pressure is of main interest. In this study a method based on the crankshaft angular speed fluctuation using neural network has been developed. Two points on the pressure pulse have been reconstructed maximum pressure (Pmax) and start of combustion (SOC). Pmax is predicted with an accuracy of 7.7 MPa and SOC with an accuracy of 1.3 degrees.

  • 27.
    Lennström, David
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Operation, Maintenance and Acoustics.
    Johnsson, Roger
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Operation, Maintenance and Acoustics.
    Nykänen, Arne
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Operation, Maintenance and Acoustics.
    Ågren, Anders
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Operation, Maintenance and Acoustics.
    Determination of radiated sound power from an electric rear axle drive in-situ and its contribution to interior noise2013In: SAE technical paper series, ISSN 0148-7191, Vol. 6, no 3, p. 1554-1563Article in journal (Refereed)
    Abstract [en]

    System and component target setting for noise and vibration are important activities within automotive product development. New challenges arise when electric motors are introduced into cars traditionally powered by combustion engines. The emitted noise from an electric traction motor for hybrid electric vehicles is characterized by high frequency tonal components from the dominating magnetic harmonics which can be perceived as annoying. Sound power is frequently used for quantifying the airborne noise from rotating electrical machines. This paper describes the process of determining the radiated sound power from an automobile electric rear axle drive in-situ and its contribution to interior cabin noise for a prominent rotor order. The sound power was calculated by combining the average stator surface vibration velocity together with an estimate of the radiation efficiency. To model the radiation efficiency, the vibration shape of the cylindrically shaped stator shell was determined by means of operational deflection shapes. The acoustic transfer functions between the source and receiver positions close to a passenger's ear, were defined as the ratio of sound pressure and sound power. By combining the acoustic transfer functions with the calculated operational sound power, the airborne interior noise can be predicted. The calculated interior noise levels were found to be in accordance, within approximately 3 dB, with the measured airborne noise from the stator shell. This indicated that the method is valid and could be helpful for calculating allowed radiated power from interior noise targets and acoustic transfer functions.

  • 28.
    Lennström, David
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Operation, Maintenance and Acoustics.
    Johnsson, Roger
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Operation, Maintenance and Acoustics.
    Ågren, Anders
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Operation, Maintenance and Acoustics.
    Nykänen, Arne
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Operation, Maintenance and Acoustics.
    The influence of the acoustic transfer functions on the estimated interior noise from an electric rear axle drive2014In: SAE International Journal of Passenger Cars - Mechanical Systems, ISSN 1946-3995, E-ISSN 1946-4002, Vol. 7, no 1, p. 413-422Article in journal (Refereed)
    Abstract [en]

    In the vehicle development process, targets are defined to fulfill customers' expectations on acoustic comfort. The interior complete vehicle acoustic targets can be cascaded down to system and component targets, e.g. insulation properties and source strengths. The acoustic transfer functions (ATFs) from components radiating airborne noise play a central role for the interior sound pressure levels. For hybrid vehicles fitted with an electric traction motor, the contribution of high frequency tonal components radiated from the motor housing needs to be controlled. The interior sound pressure due to an airborne motor order can be estimated by surface velocities and ATFs. This study addresses the ATFs measured from a large number of positions located around an electric rear axle drive (ERAD) and their influence on estimated interior noise. First, the magnitude variation between the individual ATFs and how it clearly can be visualized was presented. Displaying all ATFs in a color map revealed the magnitude at each geometrical location of the respective microphone. Secondly, the influence of the ATF's spatial resolution on estimated interior sound pressure was investigated. This was done for theoretical models of the stator shell source shape and also for measured surface velocities. By reducing the spatial resolution from 0.05 to 0.10 m between each microphone, the difference in noise contribution is typically within three decibels with a 12th octave smoothing filter applied to the narrow-band data. The findings from this work provide insight in the risks of compromising with the number of ATF's needed for contribution analysis.

  • 29.
    Lennström, David
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Operation, Maintenance and Acoustics.
    Ågren, Anders
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Operation, Maintenance and Acoustics.
    Nykänen, Arne
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Operation, Maintenance and Acoustics.
    Sound quality evaluation of electric cars: preferences and influence of the test environment2011In: Aachener Akustik Kolloquium 2011: proceedings, 2011Conference paper (Other academic)
  • 30. Ljunggren, Fredrik
    et al.
    Wang, Junye
    Luleå tekniska universitet.
    Ågren, Anders
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Operation, Maintenance and Acoustics.
    Human perception thresholds when exposed to vibrations of single and double frequency components2004In: Proceedings - Inter-Noise 2004, the 33rd International Congress and Exposition on Noise Control Engineering: Prague, Czech Republic, August 22 - 25 / [ed] Josef Novák, Prague: International institute of noise control engineering , 2004Conference paper (Refereed)
  • 31. Ljunggren, Fredrik
    et al.
    Wang, Junye
    Luleå tekniska universitet.
    Ågren, Anders
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Operation, Maintenance and Acoustics.
    Human vibration perception from single- and dual-frequency components2007In: Journal of Sound and Vibration, ISSN 0022-460X, E-ISSN 1095-8568, Vol. 300, no 1-2, p. 13-24Article in journal (Refereed)
    Abstract [en]

    This paper covers three different studies with respect to human perception of vertical vibrations. Although the amplitudes and frequencies throughout the experiments are set to match those that might occur in lightweight floor constructions, the results can be seen as general. A motion simulator generates signals from 5 to 31.5 Hz and the test subjects receive the vibrations sitting on a wooden chair. In the first study, the absolute threshold values from sinusoidal signals are determined. The results agree reasonably well with those found from other similar studies. In study number two, threshold values are determined in the presence of an 8 Hz base component. The threshold values were generally found to be higher than those obtained in the first study, except in the case of 10 Hz which due to beating effect gave an even lower threshold level than when the signal was played alone. The third study is about annoyance from dual sinusoidal vibrations, always including a base signal of 8 Hz at fixed amplitude. In similarity with study two, test persons reported to be more annoyed as the second signal component gets close to the base frequency and, naturally, they also got more annoyed as the amplitude increased.

  • 32.
    Ljunggren, Fredrik
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Operation, Maintenance and Acoustics.
    Ågren, Anders
    Acoustics in wooden buildings. State of the art 2008: Vinnova project 2007-016532008In: Acoustics in wooden buildings. State of the art 2008, Stockholm: SP Sveriges Tekniska Forskningsinstitut , 2008Chapter in book (Other academic)
  • 33.
    Ljunggren, Fredrik
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Operation, Maintenance and Acoustics.
    Ågren, Anders
    Development of a new damper to reduce resonant vibrations in lightweight steel joist floors2002In: Applied Acoustics, ISSN 0003-682X, E-ISSN 1872-910X, Vol. 63, no 11, p. 1267-1280Article in journal (Refereed)
    Abstract [en]

    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.

  • 34.
    Ljunggren, Fredrik
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Operation, Maintenance and Acoustics.
    Ågren, Anders
    Dynamic and subjective analysis of a lightweight/semi-heavyweight floor in a laboratory2009In: Collected Papers in Building Acoustics: Sound Transmission, Brentwood: Multi-Science Publishing, 2009, p. 79-96Chapter in book (Other academic)
  • 35.
    Ljunggren, Fredrik
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Operation, Maintenance and Acoustics.
    Ågren, Anders
    Dynamic and subjective analysis of a lightweight/semi-heavyweight floor in a laboratory2006In: Building Acoustics, ISSN 1351-010X, Vol. 13, no 4, p. 255-272Article in journal (Refereed)
    Abstract [en]

    A lightweight steel framed floor was tested in a laboratory for eight configurations: continuous/lumped main support, support/unsupported free long sides and concrete/plasterboard as top. The dynamic properties were revealed by modal analysis and subjective evaluations in terms of body perception and perception of vibrating articles. The results showed that the tested parameter that affects the floor most was the top layer. The semi-heavy weight floor with concrete layer was in general judged to be of higher acceptance than the lightweight floor having plaster-boards on the top. Additionally, the lightweight floor was used in a series of experiments where the effect of modified support and the effect of adding line loads of various degree of mechanical connection were tested. This part aims to simulate how the dynamics of a floor stepwise might change going from a bare floor to a floor installed inside a real building. The results show that the line load, mass and stiffness influence the floor in terms of changed natural frequencies. Depending on where on the floor the loads are located, different modes were affected and, depending on how the loads were connected to the floor, the gained stiffness varied slightly

  • 36.
    Ljunggren, Fredrik
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Operation, Maintenance and Acoustics.
    Ågren, Anders
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Operation, Maintenance and Acoustics.
    Elastic layers to reduce sound transmission in lightweight buildings2013In: Building Acoustics, ISSN 1351-010X, Vol. 20, no 1, p. 25-42Article in journal (Refereed)
    Abstract [en]

    To obtain satisfactory sound insulation is a challenging task when designing lightweight buildings. Poor performance at low frequencies as well as severe flanking transmission has traditionally often been more pronounced compared to heavier constructions. In the present casestudy based paper, various aspects of using elastic layers to improve sound insulation in lightweight buildings are considered.The effect on impact and airborne sound insulation by using two different kinds of vibration insulators between floor plans was examined together with the effect of using glues of various degree of elasticity in the construction. In situ measurements were performed inside a four-storey wooden frame based residential building and statistically significant variations in sound insulation were found.The efficiency of the two vibration insulators was further evaluated by vibration reduction measurements over the junctions. The difference in vibration reduction was found to be nearly constant in the frequency range 50-1000 Hz while the improvement of impact sound insulation increased by frequency.Along term test of elastic glues was also conducted, during three years, for stability over time. The best glues preserved a significantly higher damping ratio over time compared to the main part of the glues.

  • 37. Ljunggren, Fredrik
    et al.
    Ågren, Anders
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Operation, Maintenance and Acoustics.
    How to improve impact sound insulation in a lightweight module based building system2007Conference paper (Refereed)
    Abstract [en]

    This paper covers the initial work in a project where the focus is to improve impact sound insulation for a lightweight module based building system. The size of each module could typically be a small apartment (one room student apartment) or a part of a larger apartment (like two bedrooms or a living room). Modules are prefabricated in a factory, indoors, and are then assembled together at the building yard to form a complete multi-storey building up to fives floors.This building technique often suffers from poor impact sound insulation, especially at low frequencies. A number of parameters that potentially affect the impact sound have undergone experimental testing performed on a setup of two modules, one upper and one lower. Examples of tested parameters: single vs. double layer of floor plaster boards, grey rag boards vs. underlayer foam under the parquet flooring, varying load (weight) on the module and varying kind of vibration insulation in between the modules.

  • 38.
    Ljunggren, Fredrik
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Operation, Maintenance and Acoustics.
    Ågren, Anders
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Operation, Maintenance and Acoustics.
    How to match building acoustic measurements with subjective judgments2012In: Inter-Noise 2012, 2012, Vol. 11, p. 8922-8996Conference paper (Other academic)
    Abstract [en]

    The Swedish research program AkuLite deals with various aspects regarding sound and vibration within lightweight buildings. As the popularity of lightweight block of flats increases it has been noticed that standardised (ISO) measurements, like airborne and impact sound insulation, tend to show different correlation with subjective experiences compared with concrete buildings. It is therefore of importance to either develop existing evaluation methods or to find new measurement parameters for better correspondence. In the project, series of sound and vibration measurements are carried out in various types of buildings. The measurements include extended frequency range and various sources as well as increased number of extracted parameters compared to existing standards. In parallel, questionnaires are distributed to the tenants, in the same buildings, where they give answer to questions regarding the experienced sound annoyance in their flat. Statistical analysis of the correlation between the objective measurement parameters and the subjective opinions from the tenants will be carried out.

  • 39. Ljunggren, Fredrik
    et al.
    Ågren, Anders
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Operation, Maintenance and Acoustics.
    Minor construction measures that influence vibrations in lightweight floors2003In: Proceedings of the 10th International Congress on Sound and Vibration (ICSV10): Stockholm, July 7-10, 2003 / [ed] A. Nilsson; H. Bodén, Institute of Acoustics , 2003, p. 4579-4586Conference paper (Refereed)
    Abstract [en]

    The minor construction measures that influence vibration in lightweight floors were presented. A lightweight steel framed floor equipped with a resilient ceiling was used as test object under laboratory conditions. The ceiling joist stiffness was analyzed by a finite element model where both thickness of material and position of the mounting screws were considered. Two different kinds of joists were tested on a floor section. The effect of a visco-elastic material in conjunction with the joists, to increase the damping, were also shown.

  • 40. Ljunggren, Fredrik
    et al.
    Ågren, Anders
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Operation, Maintenance and Acoustics.
    Potential solutions to improved sound performance of volume based lightweight multi-storey timber buildings2011In: Applied Acoustics, ISSN 0003-682X, E-ISSN 1872-910X, Vol. 72, no 4, p. 231-240Article in journal (Refereed)
    Abstract [en]

    Lightweight building systems in general suffer from poor sound insulation, especially in the low frequency region. Since no reliable mathematical models that can predict the impact sound pressure level exists, the lightweight building design is to a high extent based upon previous experience and upon measurements. A special difficulty is related to experimental measurements since the variation among identical units must not be neglected. A modern volume based lightweight wooden buildingn concept has here been tested by numerous well controlled measurements, in laboratory as well as in more field like conditions. The volume construction technique offers new possibilities and challenges to improve sound insulation in light weight timber construction. The main purpose was to investigate how different constructional solutions in the floor, like plaster board, mineral wool, elastic glue, dividing board, floating floor etc., affect the sound insulation. Many of the tested modifications resulted in only marginally changed impact sound pressure level but parameters that substantially can improve the sound insulation were found in using elastic glue to mount the floor boards, to install extra board layers and to use floating floors.

  • 41. Ljunggren, Fredrik
    et al.
    Ågren, Anders
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Operation, Maintenance and Acoustics.
    Using visco-elastic damper to reduce resonant vibrations in a lightweight steel joist floor equipped with resilient ceiling2002In: Proceedings of Inter-Noise 2002, the 2002 International Congress and Exposition on Noise Control Engineering [and] additional proceedings: SQS 2002, Dearborn, Michigan, USA, August 22, 2002 [and] additional information: technical activities of INCE/USA and International INCE, Dearborn, Mich: Institute of noise control engineering , 2002Conference paper (Refereed)
  • 42.
    Ljunggren, Fredrik
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Operation, Maintenance and Acoustics.
    Ågren, Anders
    Wang, J.
    Luleå tekniska universitet.
    Knutsson, H.
    Luleå tekniska universitet.
    Reduction of light weight floor vibrations through a visco-elastic damper solution and through addition of building structure elements2002In: 3rd European Congress on Acoustics, 2002Conference paper (Refereed)
  • 43. Mosharrof, Mohammad Sazzad
    et al.
    Brunskog, Jonas
    Acoustic Technology, Department of Electrical Engineering, Technical University of Denmark.
    Ljunggren, Fredrik
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Operation, Maintenance and Acoustics.
    Ågren, Anders
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Operation, Maintenance and Acoustics.
    An improved prediction model for the impact sound level of lightweight floors: Introducing decoupled floor-ceiling and beam-plate moment2011In: Acta Acoustica united with Acustica, ISSN 1610-1928, E-ISSN 1861-9959, Vol. 97, no 2, p. 254-265Article in journal (Refereed)
    Abstract [en]

    To better understand the complex acoustic behaviour of lightweight building structures both experimental and theoretical approaches are necessary. Within the theoretical approach developing theoretical models is of great importance. The aim here is to further develop an existing method to predict the impact sound pressure level in a receiving room for a coupled floor structure where floor and ceiling are rigidly connected by beams. A theoretical model for predicting the impact sound level for a decoupled floor structure, which has no rigid mechanical connections between the floor and the ceiling, is developed. An analytical method has been implemented, where a spatial Fourier transform method as well as the Poisson's sum formula is applied to model transformed plate displacements. Radiated sound power was calculated from these displacements and normalized sound pressure levels were calculated in one-third octave frequency bands. The predicted results from the model are compared with the results from the experiments on the decoupled floor-ceiling construction. The results gave agreements in line with comparisons regarding previous model. The effect of introducing beam-plate moment in the model is studied and is found to be dependent on frequency, showing significant improvement in predicting impact sound level at high frequency region.

  • 44. Mosharrof, Mohammad Sazzad
    et al.
    Ljunggren, Fredrik
    Ågren, Anders
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Operation, Maintenance and Acoustics.
    Brunskog, Jonas
    Prediction model for the impact sound pressure level of decoupled lightweight floors2009In: 38th International Congress and Exposition on Noise Control Engineering 2009: INTER-NOISE 2009 ; Ottawa, Canada, 23 - 26 August 2009 / [ed] J. Stuart Bolton, Red Hook, NY: Curran Associates, Inc., 2009, p. 2038-2046Conference paper (Refereed)
    Abstract [en]

    Prediction of impact sound insulation in timber buildings is difficult since the constructions are complex, non isotropic and show large variances. There are earlier publications on precise models of simplified structures and simplified models of complex structures, where so far, none is considered as an acceptable simplified engineering model tool. The goal of our research is to develop methodology for such a simplified engineering tool. The starting focus is to model impact sound in a simple floor model of two plates that are realistically coupled via beams. The floor structure in Nordic countries is mostly decoupled, meaning there is either no structural connection or an elastic connection between the plates and the beams. In this paper, an improved floor model is proposed where as a first step there is no physical connection between the plates and beams, and where each plate is stiffened by separate beams. Hence the construction becomes more realistic as only coupling between the plates via air trapped inside the cavity is taken into account. Next step will be to introduce resilient coupling between the respective beams. The modelling show promising results with reasonable sound insulation improvements.

  • 45.
    Nilsson, Siv
    et al.
    Luleå tekniska universitet.
    Johansson, Carin
    Luleå tekniska universitet.
    Ågren, Anders
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Operation, Maintenance and Acoustics.
    Buller i mineralberedningsverk: slutrapport1984Report (Other academic)
  • 46.
    Normark, Carl Jörgen
    et al.
    Luleå University of Technology, Department of Business Administration, Technology and Social Sciences, Innovation and Design.
    Tretten, Phillip
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Operation, Maintenance and Acoustics.
    Grane, Camilla
    Luleå University of Technology, Department of Business Administration, Technology and Social Sciences, Human Work Science.
    Ågren, Anders
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Operation, Maintenance and Acoustics.
    Lundkvist, Andre
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Operation, Maintenance and Acoustics.
    Nykänen, Arne
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Operation, Maintenance and Acoustics.
    Project: Human Factors LAB2014Other (Other (popular science, discussion, etc.))
  • 47. Nybacka, Mikael
    et al.
    Larsson, Tobias
    Jeppsson, Peter
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Product and Production Development.
    Ågren, Anders
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Operation, Maintenance and Acoustics.
    Karlsson, Lennart
    Rantatalo, Matti
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Operation, Maintenance and Acoustics.
    Lindgren, Per
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Construction Engineering.
    Andren, Henrik
    Engström, Niclas
    Larsson, Roland
    Fransson, Lennart
    Hyyppä, Kalevi
    Fredriksson, Håkan
    Eriksson, Johan
    van Deventer, Jan
    Tingvall, Bror
    Project: CASTT - Centre for Automotive Systems Technologies and Testing2007Other (Other (popular science, discussion, etc.))
    Abstract [sv]

    Through the Centre for Automotive Systems Technologies and Testing, Luleå University of Technology aims to first of all support automotive winter testing in Northern Sweden. This means to support the local automotive test entrepreneurs and through them their customers: the car manufacturers and their suppliers. To succeed in this task, the center relies on the university's areas of leading research and most importantly on the cooperation between those areas.

  • 48.
    Odelius, Johan
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Operation, Maintenance and Acoustics.
    Johansson, Örjan
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Operation, Maintenance and Acoustics.
    Ågren, Anders
    Communication quality for students with hearing impairment: a study evaluating speech intelligibility and annoyance2005In: Proceedings Forum Acusticum, Scientific society for optics, acoustics, motion picture and theater technology , 2005, p. 2709-2714Conference paper (Refereed)
    Abstract [en]

    New pedagogical views on assistive listening devices have enlightened the technology's impact on communication patterns among students with a hearing impairment. The objective of this study was to find methods to evaluate assistive listening devices supporting a more dialogue-oriented and participatory learning environment. With this approach a three-dimensional communication quality definition was proposed. The dimensions are: 1) Speech intelligibility 2) Ambient sounds; annoyance and feeling of presence 3) Parameters concerning the students' performance given the aim and task of the pedagogical situation. In this experiment dimensions 1 and 2 were evaluated, where dimension 2 concerned annoyance. Speech intelligibility was assessed using just-follow-conversation (JFC) tasks performed by normal hearing subjects. The task consisted of adjusting the level of a masker until the listener felt he or she just could understand what was being said. In conjunction with the JFC task, the subjects were asked to estimate the annoyance of the masking signal on an eleven-point scale. The speech and masking signals were filtered by impulse responses generated in a room acoustic model. Design variables were: A) Room acoustic model; two acoustic properties B) Distance between speech source and microphone; 0.75 m or 1.5 m C) Noise masker; speech-spectrum random noise or structure-borne noise D) Microphone directivity; omni-directional or delay-and-sum beamformer E) Amplifier; linear or compression.

  • 49.
    Odelius, Johan
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Operation, Maintenance and Acoustics.
    Johansson, Örjan
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Operation, Maintenance and Acoustics.
    Ågren, Anders
    Effects on speech intelligibility using a binaural assistive listening device2006In: Proceedings of the Baltic-Nordic Acoustic Meeting: BNAM, 2006Conference paper (Refereed)
  • 50.
    Shi, Wangqing
    et al.
    Luleå University of Technology.
    Ågren, Anders
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Operation, Maintenance and Acoustics.
    Wang, Junye
    Luleå University of Technology.
    Modelling of impact sound insulation of lightweight steel framing floors2001Report (Other academic)
    Abstract [en]

    It is valuable for the house designer to be aware of a structure's acoustic performance from its material properties at the design stage. A simplified calculation procedure is necessary for this purpose. This report concerns the application of a homogeneous plate prediction model in determining the impact sound insulation for the lightweight steel framing floors. The method is a further development of a prediction method for timber floors. In order to calculate driving point impedance of the lightweight steel framing floor, an equivalent method is used in this study to obtain the parameters of the composite lightweight steel framing floor, e.g. floor height, material density and elasticity to replace a composite floor with a homogeneous single plate. The main advantages of this method will be its simplicity and improve the understanding of the impact sound insulation of the lightweight steel framing floors. This method can also give brief information about the acoustic performance of the structure at an earlier design stage.

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