Average sound radiation model for orthotropic cross laminated timber plates.

Cross Laminated Timber (CLT) engineered solid wood panels, that consist of an odd number of layers of timber beams glued together orthogonally, have become increasingly popular in building construction over the last two decades. The material provides good structural properties and is costcompetitive compared for example to masonry and concrete. However, due to the low volume density and its relative high stiffness, it cannot count on its mass to provide the sufficient acoustic performance required in buildings. Therefore it is important to investigate its vibro-acoustic behavior in order to develop proper acoustic measures to improve these structures. In this paper, which is part of an extensive analysis on sound radiation from CLT plates, we present a numerical model to predict the average radiation efficiency for CLT plates. The model is based on the simple assumption of thin orthotropic plate behaviour. Unlike for homogeneous isotropic thin plates, CLT’s apparent stiffness depends on the angle of wave propagation in the material as well as on frequency. This is mainly caused by the layered structure of CLT. In order to consider all these effects, the proposed radiation model uses measured bending wavenumbers as input data.