Regulations regarding impact and airborne sound insulation for lightweight timber constructions have become increasingly stringent due in particular to complaints by inhabitants. Accordingly, some building techniques frequently use elastomers at junctions so as to reduce low frequency noise. Development of accurate predictive tools (involving exact material properties) by using numerical methods such as the finite element (FE) method is needed in tackling flanking transmission problems during the design phase of buildings. The present research concerns the characterisation of an elastomer, presenting an accurate method for extracting its material properties from the manufacturer's data sheet (properties there being often linked to such structural effects as shape factors and boundary conditions of samples and tests). The properties were extracted by comparing results obtained by analytical calculations, FE simulations, and mechanical testing, separating geometry and material dependence and ultimately serving as input to commercial FE software for setting up the aforementioned prediction tools.

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One important challenge of the wooden constructions is to achieve a high quality of acoustic insulation, especially decreasing the impact noise in the low-frequency range. In order to avoid over-designed solutions and expensive experimental tests in the design phase, reliable prediction tools are called for. This article is an initial investigation of modeling the ISO standardized tapping machine on a cross-laminated timber floor, using finite element method. The wooden-based floor was first calibrated in terms of its dynamic properties. The influence of the material properties of the cross-laminated timber floor was discussed. The force generated by the tapping machine was then introduced in the established cross-laminated timber model. The model was finally validated by comparing the simulation results with the measured accelerations.

Low frequency impact sound insulation is a challenging task in wooden buildings. Low frequency prediction tools are needed to access the dynamic behavior of a wooden floor in an early design phase to ultimately reduce the low frequency impact noise. However, due to the complexity of wood and different structural details, accurate vibration predictions of wood structures are difficult to attain. Meanwhile, a deterministic model cannot properly represent the real case due to the uncertainties coming from the material properties and geometrical changes. The stochastic approach introduced in this paper aims at quantifying the uncertainties induced by material properties and proposing an alternative calibration method to obtain a relative accurate result instead of the conventional manual calibration. In addition, 100 simulations were calculated in different excitation positions to assess the uncertainties induced by material properties of cross-laminated-timber A comparison between the simulated and measured results was made in order to extract the best combination of Young’s moduli and shear moduli in different directions of the CLT panel.