Abstract
Glued timber products are widely used in construction; therefore, it is necessary to develop non-destructive bonding quality assessment methods for long-term structural health monitoring. Air-coupled ultrasound (ACU) inspection is a novel technique, with phenomenal improvements in reproducibility compared to traditional contact ultrasonics, unlimited scanning possibilities, and a high potential for delamination detection in wood products. As part of an ongoing project, glued timber samples of 10 mm thickness with artificial glue line defects were inspected. A normal through-transmission set-up with 120 kHz transducers allowed for successful and accurate imaging of the geometry of glued and non-glued areas in all inspected objects. The influence of wood heterogeneity and the reproducibility of ACU amplitude measurements were analysed in detail, identifying the main sources of variation. Future work is planned for the inspection of more complex glued timber objects.
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Acknowledgments
This research has been supported by the Swiss National Science Foundation under contract 200021-115920. The authors acknowledge the work of Oliver Tolar and Fabian Binkert for the analysis of optical images and processing of ultrasonic data.
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Sanabria, S.J., Mueller, C., Neuenschwander, J. et al. Air-coupled ultrasound as an accurate and reproducible method for bonding assessment of glued timber. Wood Sci Technol 45, 645–659 (2011). https://doi.org/10.1007/s00226-010-0357-z
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DOI: https://doi.org/10.1007/s00226-010-0357-z