TY - JOUR A1 - Hopkins, C. A1 - Filippoupolitis, M A1 - Ferreira, N. A1 - Völtl, R. A1 - Schanda, Ulrich A1 - Mahn, J. A1 - Krajci, L. T1 - Vibroacoustic finite element modelling of the low-frequency performance of a solid timber floor formed from dowel-connected joists JF - Proceedings of Inter-Noise 2016 N2 - This paper investigates the prediction of low-frequency impact sound insulation for a solid timber floor formed from dowel-connected joists with Swiss hardwood. A finite element model was developed for the dynamic response of the floor as it is neither homogeneous nor isotropic and has complex connections. With point force excitation, a FEM model for the dynamic response of the floor was validated using experimental modal analysis in the laboratory. Two different FEM models were developed, one using spring connectors and the other using join connectors. Good agreement between FEM and measurements in terms of the Modal Assurance Criterion (MAC) and eigenfrequencies was achieved for the first 14 modes with the spring connector model and for the first 7 modes with the join connector model. However, for the vibroacoustic analysis it was necessary to use the join connector model due to the computational instabilities of the spring model above 100 Hz when it was coupled to the acoustic medium. With mechanical excitation the radiated sound power from the underside of the timber floor was measured with sound intensity in order to calculate the radiation efficiency. Comparison of measurements and FEM showed reasonable agreement between 20Hz and 200Hz KW - Schallmesstechnik KW - Holzbau Y1 - 2016 ER - TY - CHAP A1 - Buchschmid, M. A1 - Kohrmann, M. A1 - Winter, C. A1 - Müller, G. A1 - Völtl, R. A1 - Schanda, Ulrich T1 - Vibroacoustic Characteristics of Light-Weighted Slabs. Part 2: Measurement-Based Investigation of the Sound Radiation of Suspended Ceilings T2 - Deutsche Gesellschaft für Akustik e.V. (ed.), Fortschritte der Akustik - DAGA N2 - 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. KW - Schallmesstechnik KW - Holzbau Y1 - 2013 ER - TY - CHAP A1 - Völtl, R. A1 - Schanda, Ulrich A1 - Kohrmann, M. A1 - Buchschmid, M. A1 - Müller, G. T1 - Simultaneous operational vibration analysis of different layers of lightweight timber floors T2 - Internoise 2013 N2 - 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 KW - Schallmesstechnik KW - Holzbau Y1 - 2018 ER - TY - CHAP A1 - Schanda, Ulrich A1 - Tröbs, H.-M. A1 - Völtl, R. A1 - Becker, P. T1 - Semi-empirical model of the impact force of a walking person in the time domain and generated impact sound spectra T2 - Internoise 2013 KW - Schallmesstechnik KW - Holzbau Y1 - 2018 ER - TY - CHAP A1 - Kohrmann, M. A1 - Buchschmid, M. A1 - Müller, G. A1 - Völtl, R. A1 - Schanda, Ulrich T1 - Numerical models for the prediction of vibroacoustical characteristics of light-weighted ceilings T2 - Internoise 2013 N2 - 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. KW - Schallmesstechnik KW - Holzbau Y1 - 2013 ER - TY - CHAP A1 - Tröbs, H.-M. A1 - Schanda, Ulrich A1 - Völtl, R. T1 - Measurement of the radiation efficiency of suspended ceilings at low frequencies using swept sine excitation and high-frequency resolution T2 - Internoise 2013 N2 - 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. KW - Schallmesstechnik KW - Holzbau Y1 - 2013 ER - TY - CHAP A1 - Völtl, R. A1 - Franzen, T. A1 - Schanda, Ulrich T1 - Experimental investigations on the sound transmission of drywall constructions at low frequencies T2 - Deutsche Gesellschaft für Akustik e.V. (ed.), DAGA KW - Schallmesstechnik KW - Trockenbau Y1 - 2009 ER -