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 (E_x and E_y) and shear moduli (G_xz, G_yz, and G_xy) 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 E_x, E_y, and G_xy 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).

KEYWORDS:

• Cross-laminated timber
• non-destructive evaluation
• plate theory
• global elastic properties
• modal assurance criterion
• industry adoption

Acknowledgements

The authors would like to acknowledge the support of the Queensland Government, Department of Agriculture and Fisheries (DAF) in Brisbane, Australia, the centre for international research and agricultural development in Montpellier, France (CIRAD), and the School of Engineering and built environment at Griffith University on the Gold Coast, Australia. The technical staff, resources and research facilities have been an unmeasurable asset. The support and material provision of industry producer XLam Australia Pty Ltd. have ensured the focus and applicability of the study were maintained. Further acknowledgements are made to the technical expertise of Dr. Henri Bailleres for the contribution to the study and deep knowledge of both the industry and the application of NDE.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Data availability

Data will be made available on request.

Additional information

Funding

The researchers are thankful to the Australian Research Council (ARC) funded Centre for Future Timber Structures [Grant Number CFTS – IH150100030] hub for providing the funding for this project.