TY - CHAP A1 - Mahn, J. A1 - Hopkins, C. A1 - Schanda, Ulrich A1 - Krajci, L. T1 - Competitive wooden floor systems - multi-objective optimization based on acoustics improvement T2 - Internoise 2013 N2 - 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 KW - Holzbau KW - Schallmesstechnik Y1 - 2013 ER - TY - JOUR A1 - Schöpfer, F. A1 - Hopkins, C. A1 - Mayr, A. R. A1 - Schanda, Ulrich T1 - Ansätze zur Prognose des Installationspegels im HolzLeichtbau JF - Deutsche Gesellschaft für Akustik e.V. (ed.), Fortschritte der Akustik - DAGA KW - Schallmesstechnik KW - Holzbau KW - Leichtbau Y1 - 2017 ER - TY - JOUR A1 - Schöpfer, F. A1 - Hopkins, C. A1 - Mayr, A. A1 - Schanda, Ulrich T1 - Prediction of noise from machinery in timber-frame buildings using transmission functions JF - Proceedings of ICSV24 N2 - To ensure that building regulations are satisfied, the sound pressure level due to machinery has to be predicted at the design stage of a new building. With the increasing popularity of multistory timber dwellings, prediction becomes an important issue for designers and consultants. At present previous project experience is often used when considering the design of wall and floor constructions and the mounting positions for machinery. Simple tools to calculate the sound pressure levels in rooms based on machinery data and construction details are not currently available. The approach involves two stages: firstly the description of the source and secondly the prediction of vibration transmission across the building and sound radiation into the rooms. In this paper a simple empirical model is proposed for the second stage. This approach is based on measured transmission functions that are defined as the average sound pressure level in a receiving room relative to the injected structure-borne sound power. This is a logical extension of approaches to characterize structure-borne sound sources that also use a power based descriptor (e.g. prEN15657:2016-02: Acoustic properties of building elements and of buildings - Laboratory measurement of structure-borne sound from building service equipment for all installation conditions) and provides a simple method to estimate the sound pressure level in a room. KW - Schallmesstechnik KW - Holzbau Y1 - 2017 ER - 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 -