In order to increase our knowledge of the sound transmission and radiation processes of lightweight wall and oor structures, theoretical models are needed. Detailed models may form a valuable tool. In lightweight oor structures, impact sound insulation is perhaps the most important property to consider. This thesis presents an overview of various solution strategies that may be useful in finding a theoretical model for impact sound insulation. Expressions for the point mobility of infinite plates driven by a rigid indenter are derived. These expressions are needed when determining the deformation close to the excitation area, which is important when studying impact noise to properly describe the interaction between the source and the oor. A detailed three-dimensional thick-plate analysis is used. The excitating pressure is found by means of a variational formulation. The point mobility is calculated by means of numerical integration. The excitation force provided by the ISO tapping machine is examined, partly in relation to the three-dimensional deformation analysis. Results found in the literature are reviewed and reconsidered. Low-frequency asymptotes are derived. A more general impact force description is derived, suited for arbitrary frequencydependent mobilities of the oor structure. The frequency-dependency of the mobility can be due to local effects, investigated by means of thick-plate theory, and/or global effects, investigated by means of a spatial Fourier transform method. A theoretical model for a point-excited simple lightweight oor is presented. The model is used for the prediction of impact noise level. A comparison between numerical computations and measurements found in the literature is performed. A relatively good correspondence between measurements and calculations can be achieved. Lightweight walls (and oors) are often designed as a framework of studs with plates on each side. The studs can be seen as walls in the cavity, thus introducing finiteness. A prediction model for airborne sound insulation including these effects is presented. Due to variabilities, no structure can be perfectly periodic. The effects of near-periodicity are studied by means of transform technique and the expectation operator. The near-periodicity leads to an increase of the damping (if material damping is present). Resilient devices are commonly used in lightweight structures to decrease the sound transmission in a broad frequency band. Applications of such devices may be found, for example, in resiliently mounted ceilings in aeroplanes, ships and buildings. A measurement method to characterise the two-port acoustic properties of resilient devices is presented.
TräGuiden tillhandahåller information om trä och träbyggande. Webbsidan drivs av Svenskt Trä, en del av Skogsindustrierna, och utgör med sina nära en miljon besökare per år ett viktigt informationsnav för byggande i Sverige.
TräGuiden beskriver tekniska lösningar för träbyggande samt innehåller information om trämaterialets egenskaper. TräGuidens innehåll av illustrationer och konstruktionslösningar kan fritt skrivas ut eller delas med andra.
Det finns också nedladdningsbara ritningar i CAD-format på TräGuiden.
Du vet väl att du kan spara sidor till senare. Samla här pins för de sidor du besöker ofta och enkelt vill kunna återkomma till.
Ett enkelt sätt att spara dina pins är att maila dem
Du har nu skickat dina pins!
Något gick fel. Kontrollera e-postadressen och prova igen.