Predicting sound radiation and sound transmission in orthotropic cross-laminated timber panels

Abstract

In the last decades, new materials and new technologies which satisfy sustainability and energy efficiency demands have been developed for the building construction market. Lightweight structures are becoming increasingly popular, but it has been proved that they cannot provide satisfactory sound insulation. Therefore a proper acoustic treatment needs to be specifically designed, considering both airborne and structure-borne sound sources. Cross-laminated timber (CLT) elements, for example, have had great success in the last twenty years, both in Europe and North America. CLT plates, due to their peculiar sub-structure, exhibit an orthotropic behavior; they have different stiffness properties along their two principle directions. This paper investigates prediction models for orthotropic plates designed to evaluate sound radiation due to mechanical excitation, and sound transmission due to acoustic excitation. Particular attention is paid to the influence on sound radiation of non-resonant vibration, or near-field vibration, in the case of mechanical excitation. The purpose of these simplified models is to be an efficient tool for acousticians, architects and engineers, helpful in the design process for new buildings and retrofitting of existing ones. The validation of numerical results with experimental data are reported. The applicability of the models and their limitation are finally discussed.