Evaluation of full-sized and thick cross-laminated timber using in-line non-destructive techniques

Abstract

Advancements in non-destructive evaluation systems for predicting mechanical properties of cross-laminated timber appear to have been limited to laboratory scale, reduced sample sizes, or difficult practical solutions for industry implementation. This study has developed classical vibration analysis methods for industry adoption in large-scale, rapid panel characterisation through frequency analysis. The non-destructive method allowed for the prediction of the elastic moduli in both axial directions (Ex and Ey) and shear moduli (Gxz, Gyz, and Gxy) for thin or thick plates. The comparison with the static reference method and non-destructive technique showed a good consistency for predicting the elastic and shear moduli of the cross-laminated timber with mean percentage differences for Ex, Ey, and Gxy of 5.2%, 7.9%, and 18.9%, respectively. An observation was made that the accurate determination of the mechanical properties required enough correctly identified frequencies/modes. Mode shapes generated from experimental data through modal assurance criterion were compared with finite element analysis to confirm the assessment method yielded frequencies specific to the panel, rather than other contributing effects (environment, boundary conditions, panel variability, mesh resolution).