Higher-order modal parameter estimation and verification of cross-laminated timber plates for structural-acoustic analyses

Cross-Laminated Timber (CLT) is a wood composite that is popular due to its favourable stiffness-to-mass-density ratio and environmental benefits, among other positive attributes. This paper presents the estimation of higher-order modal parameters and their use in the verification and validation of an Equivalent Single-Layer (ESL) CLT model. The eigenvectors, eigenfrequencies, and modal damping ratios of 20 out-of-plane vibration modes were experimentally determined. The experimentally determined eigenfrequencies and eigenmodes were correlated and compared to those derived from a numerical model. The modal damping ratios were compared to damping loss factors derived from the power injection method. A broadband frequency view is also considered, with the comparison of experimental and numerical forced response models. As part of the verification and validation process, a framework of key indices and respective criteria is suggested and discussed in this contribution. Over the course of the paper, an ESL CLT model which derives its properties from a layerwise basis is validated in detail against experimental measurements. The results are intended to be of relevance to both structural and acoustic domains.