@inproceedings{TroebsSchandaVoeltl2013, author = {Tr{\"o}bs, H.-M. and Schanda, Ulrich and V{\"o}ltl, R.}, title = {Measurement of the radiation efficiency of suspended ceilings at low frequencies using swept sine excitation and high-frequency resolution}, series = {Internoise 2013}, booktitle = {Internoise 2013}, year = {2013}, abstract = {It is common for timber ceiling constructions to include a suspended ceilings made of plasterboard. In order to minimize the radiation from impact excitation, especially in the low frequency range below 100 Hz, a detailed analysis of the vibration behaviour was necessary. An experimental modal analysis was carried out and the radiated sound power from the suspended ceiling was measured using a sweep sine excitation by a shaker connected to the top layer of the timber floor construction. Since the experimental modal analysis was conducted using a high frequency resolution and with a non-stationary sound field, it was necessary to check the validity of the intensity measurements by comparing it with 1/3-octave band measurements. The results show very good agreement. By this means the radiation efficiency can be measured simultaneously with an experimental modal analysis of a structure.}, language = {en} } @inproceedings{MahnHopkinsSchandaetal.2013, author = {Mahn, J. and Hopkins, C. and Schanda, Ulrich and Krajci, L.}, title = {Competitive wooden floor systems - multi-objective optimization based on acoustics improvement}, series = {Internoise 2013}, booktitle = {Internoise 2013}, year = {2013}, abstract = {The objective of this research project is the design of lightweight timber floor systems which have similar thicknesses to those of concrete floors but which perform better than concrete in terms of their environmental life cycle impact and in terms of airborne and impact sound insulation. The availability of superior lightweight acoustic designs will increase the share of timber based floors within the Swiss construction market and will contribute to higher wood utilization in general. A program for systematically developing validated finite element models for the development of lightweight timber floor systems has been proposed. The use of Swiss hardwoods in floor systems will be studied and implemented where possible. Keywords: lightweight timber, sound transmission, impact noise}, language = {en} } @inproceedings{BuchschmidKohrmannWinteretal.2013, author = {Buchschmid, M. and Kohrmann, M. and Winter, C. and M{\"u}ller, G. and V{\"o}ltl, R. and Schanda, Ulrich}, title = {Vibroacoustic Characteristics of Light-Weighted Slabs. Part 2: Measurement-Based Investigation of the Sound Radiation of Suspended Ceilings}, series = {Deutsche Gesellschaft f{\"u}r Akustik e.V. (ed.), Fortschritte der Akustik - DAGA}, booktitle = {Deutsche Gesellschaft f{\"u}r Akustik e.V. (ed.), Fortschritte der Akustik - DAGA}, year = {2013}, abstract = {In this contribution a method for the prediction of the radiated sound out of the velocity field of a vibrating ceiling is presented. The numerical method was validated via measurements on a real structure using a pp-probe. It is based on Integral Transform techniques and can be applied in the postprocessing of a FEM simulation (harmonic analysis) [1]. The method was verified by measurements on the real structure and can be used for parametrical studies. Rounding off the Parts 1 and 2 of this publication nomograms, based on dimensionless parameters, can be developed to predict the sound radiation of light weight slabs. Hereby different sets of geometry as well as different configurations of ceilings can be studied in order to describe the acoustical and dynamical behaviour of wooden ceilings.}, language = {en} } @inproceedings{KohrmannBuchschmidGreimetal.2013, author = {Kohrmann, M. and Buchschmid, M. and Greim, A. and M{\"u}ller, G. and Schanda, Ulrich}, title = {Vibroacoustic Characteristics of lightweighted Slabs. Part 1: Aspects of Numerical Modeling, Model Updating and Parametric Studies using the Buckingham π -Theorem}, series = {Deutsche Gesellschaft f{\"u}r Akustik e.V. (ed.), AIA-DAGA}, booktitle = {Deutsche Gesellschaft f{\"u}r Akustik e.V. (ed.), AIA-DAGA}, year = {2013}, abstract = {In order to set up guidelines for the design of light-weighted ceilings for timber constructions to be used by engineers in practice, investigations based on both measurements and numerical models have been carried out [1, 2, 3]. The setup and the calibration of the numerical model of the structure are outlined briefly. A semi-analytical approach for the prediction of radiated sound is presented, which is based on Integral Transform Methods. The method can be applied in the post processing of a Finite Element computation. Thus as a first step the structure, consisting of a timber slab, a floating floor and a suspended ceiling, is built up in a Finite Element model, where the material properties of wood and the characteristics of the system are considered. The model is parameterized in order to enable computations with varying geometry and material parameters and calibrated with the help of measurements using model updating techniques. The velocity pattern resulting out of the FEM computation is transformed from the spatial into the wavenumber domain and from the time into the frequency domain using Fourier Transform Methods. Applying this velocity pattern as a boundary condition to the Helmholtz Equation, which results out of the Fourier Transform of the wave equation, the wavenumbers, which fulfil the radiation condition, can be selected and the pressure field in the adjacent acoustic fluid can be computed. Due to the properties of the Fourier-Transform the radiated sound power can be calculated efficiently in the transformed domain out of pressure and velocity. In a second part of the contribution the model for the air cushion in the suspended ceiling is discussed, where a FSI-model for the acoustic fluid and the structure is compared against engineering approaches using simplifications concerning mass distribution and transfer impedances between the individual nodes at the interface}, language = {en} } @inproceedings{KohrmannBuchschmidMuelleretal.2013, author = {Kohrmann, M. and Buchschmid, M. and M{\"u}ller, G. and V{\"o}ltl, R. and Schanda, Ulrich}, title = {Numerical models for the prediction of vibroacoustical characteristics of light-weighted ceilings}, series = {Internoise 2013}, booktitle = {Internoise 2013}, year = {2013}, abstract = {In order to set up guidelines for the design of light-weighted ceilings for timber constructions to be used by engineers in practice, investigations based on both measurements and numerical models have been carried out within the cooperative research project "VibWood". In this contribution the setup and the calibration of the numerical model of the structure as well as the prediction of radiated sound are discussed, where a special focus is set on a dimensionless description in order to deduce information for a wide range of system's specifications. The structure, consisting of a timber slab, a floating floor and a suspended ceiling, is built up in a Finite Element model, where the material properties of wood and the characteristics of the system (e.g.support conditions, contact phenomena dynamic properties of individual parts) are considered. The model is parameterized in order to enable computations with varying geometry and material parameters. After calibrating the FE-model with the help of measurements using model updating techniques dimensionless parameters are defined based on the Buckingham-π- Theorem and computations are carried out in order to specify guidelines for various systems. The radiation of sound is computed in a post processing using Integral Transform Methods.}, language = {en} } @inproceedings{VoeltlSchandaKohrmannetal.2013, author = {V{\"o}ltl, R. and Schanda, Ulrich and Kohrmann, M. and Buchschmid, M. and M{\"u}ller, G.}, title = {Simultaneous operational vibration analysis of different layers of lightweight timber floors}, series = {Internoise 2013}, booktitle = {Internoise 2013}, year = {2013}, abstract = {Within the scope of the research project "VibWood", operational vibration analyses of timber floor constructions were carried out. In order to understand the vibration behaviour of and the sound transmission through the layers of the constructions the coupling between them was investigated. The transfer function from the point of excitation to a pattern of receiving positions located on each of the layers of the construction was measured using a swept sine excitation. As a result, the frequency range of decoupling between the base floor and the floating floor and between the base floor and the suspended ceiling could be identified and the individual vibration behavior analyzed. The measurements also included the radiated sound power from the suspended ceiling. There is indication that there is not necessarily a correlation between the eigenmodes of the suspended ceiling and the maxima of the radiated sound power}, language = {en} } @inproceedings{SchandaTroebsVoeltletal.2013, author = {Schanda, Ulrich and Tr{\"o}bs, H.-M. and V{\"o}ltl, R. and Becker, P.}, title = {Semi-empirical model of the impact force of a walking person in the time domain and generated impact sound spectra}, series = {Internoise 2013}, booktitle = {Internoise 2013}, year = {2013}, language = {en} } @article{RaboldBacherSchandaetal.2013, author = {Rabold, Andreas and Bacher, Stefan and Schanda, Ulrich and Mayr, Andreas R. and Sch{\"o}pfer, Fabian}, title = {Schallschutz von Holzbalkendecken - Planungshilfen f{\"u}r die Altbausanierung. Teil 1: Direktschalld{\"a}mmung}, series = {Bauphysik}, journal = {Bauphysik}, number = {35(4)}, publisher = {Ernst \& Sohn}, address = {Berlin}, pages = {280 -- 285}, year = {2013}, abstract = {Die Altbausanierung nimmt im gesamten Baubereich eine immer bedeutendere Stellung ein. Falls die geplanten Sanierungsmaßnahmen nicht unter den Bestandsschutz von Baudenkm{\"a}lern fallen, sind die Anforderungen der zum Zeitpunkt der Sanierung baurechtlich eingef{\"u}hrten Normen zu ber{\"u}cksichtigen. Das Bauteil, das bei der Sanierung eine besonders sorgf{\"a}ltige Planung erfordert, ist die Wohnungstrenndecke, die in Altbauten h{\"a}ufig als Holzbalkendecke ausgef{\"u}hrt wurde. Die vorhandenen Planungsgrundlagen f{\"u}r den Schallschutznachweis von Holzbalkendecken sind sowohl in der Normung als auch in der Literatur sehr l{\"u}ckenhaft. Um bessere Planungsdaten zu erhalten, wurde deshalb am ift Rosenheim zun{\"a}chst ein Forschungsvorhaben durchgef{\"u}hrt, in dem die Luft- und Trittschalld{\"a}mmung typischer Altbaudecken und deren Verbesserungen durch unterschiedliche Sanierungsmaßnahmen unter Laborverh{\"a}ltnissen ohne Flanken{\"u}bertragung untersucht wurden [1], [2]. In einem weiteren Forschungsvorhaben [3] wurde in Kooperation mit der Hochschule Rosenheim die Flanken{\"u}bertragung bei unterschiedlichen Mauerwerkstypen und Deckeneinbindungen ermittelt. Der vorliegende Beitrag beschreibt den Einfluss der Deckenkonstruktion auf die Schalld{\"a}mmung und die Ermittlung der Planungswerte f{\"u}r die direkte {\"U}bertragung {\"u}ber die Decke. In einem noch folgenden zweiten Beitrag werden Planungsdaten f{\"u}r die Flanken{\"u}bertragung bei Altbaukonstruktionen behandelt.}, language = {de} } @article{SchandaMayrSchoepferetal.2013, author = {Schanda, Ulrich and Mayr, Andreas R. and Sch{\"o}pfer, Fabian and Rabold, Andreas and Bacher, Stefan}, title = {Schallschutz von Holzbalkendecken - Planungshilfen f{\"u}r die Altbausanierung. Teil 2: Flankenschalld{\"a}mmung}, series = {Bauphysik}, journal = {Bauphysik}, number = {35(6)}, publisher = {Ernst \& Sohn}, address = {Berlin}, pages = {392 -- 398}, year = {2013}, abstract = {Die Altbausanierung nimmt im gesamten Baubereich eine immer bedeutendere Stellung ein. Falls die geplanten Sanierungsmaßnahmen nicht unter den Bestandsschutz von Baudenkm{\"a}lern fallen, sind die Anforderungen der zum Zeitpunkt der Sanierung baurechtlich eingef{\"u}hrten Normen zu ber{\"u}cksichtigen. Das Bauteil, das bei der Sanierung eine besonders sorgf{\"a}ltige Planung erfordert, ist die Wohnungstrenndecke, die in Altbauten h{\"a}ufig als Holzbalkendecke ausgef{\"u}hrt wurde. Die vorhandenen Planungsgrundlagen f{\"u}r den Schallschutznachweis von Holzbalkendecken sind sowohl in der Normung als auch in der Literatur sehr l{\"u}ckenhaft. Um bessere Planungsdaten zu erhalten, wurde deshalb zun{\"a}chst ein Forschungsvorhaben [1] durchgef{\"u}hrt, in dem die Luft- und Trittschalld{\"a}mmung typischer Altbaudecken und deren Verbesserungen durch unterschiedliche Sanierungsmaßnahmen unter Laborverh{\"a}ltnissen ohne Flanken{\"u}bertragung untersucht wurden. Die Ergebnisse wurden in einem ersten Beitrag [2] ver{\"o}ffentlicht. Im vorliegenden zweiten Beitrag werden die Ergebnisse eines weiteren Forschungsvorhabens [3] vorgestellt. Der Fokus lag hierbei auf der Ermittlung der Flanken{\"u}bertragung bei unterschiedlichen Mauerwerkstypen und Deckeneinbindungen. Die Ergebnisse werden als Planungsdaten f{\"u}r die Flanken{\"u}bertragung bei Altbaukonstruktionen dargestellt und die Anwendung des erarbeiteten Rechenmodells sowie die Validierung anhand von Baumessungen erl{\"a}utert.}, language = {de} }