On force- and moment mobilities of a timber joist floor
- In wood framed buildings, floors are formed by fastening wood sheathing to joists spaced at a regular interval. The sheathing is typically fastened to the joist using screws so the resulting system is a complicated periodic point-connected plate-rib structure. It is shown that the point force mobility varies significantly with position. A machine installation generally is close to discontinuities, such as at: floor edges, joist-screw locations, joints between the sheathing plates, and due to workmanship. In such cases, moment excitation might become important at some frequencies and the neglect of moments a priori can ead to inaccurate prediction of the total emission. This paper presents measured point moment mobilities with respect to the distance to discontinuities for a timber joist floor where a single layer of chipboard forms the sheathing. It is shownthat the measured point moment mobility indicates an infinite plate behaviour. This includes for positions above a joist but between screw positions. To determine the relative contribution of moments and perpendicular forces to the total structure-borne sound power, case studies of two sources, a fan unit and a whirlpool bath, are described, for various locations on a timber joist floor.
Author: | Andreas R. Mayr, Barry Gibbs, Heinz Martin Fischer |
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Parent Title (English): | 35th German Annual Conference on Acoustics (DAGA), Rotterdam, March 2009. |
Document Type: | Conference Proceeding |
Language: | English |
Publication Year: | 2009 |
Tag: | Force- and moment mobilities; Timber joist floor |
faculties / departments: | Fakultät für Angewandte Natur- und Geisteswissenschaften |
Dewey Decimal Classification: | 5 Naturwissenschaften und Mathematik / 53 Physik |