Document Type

Conference Proceeding


Review of Progress in Quantitative Nondestructive Evaluation

Publication Date



Kingston, RI


Due to the porous nature of wood and natural fiber based products, conventional fluid or gel coupled ultrasonic inspection is unsuitable. Air‐coupled ultrasonic transmission scanning, being non‐contact, is ideally suited for inspecting lumber, wood and natural fiber based products. We report here several successful applications of air‐coupled ultrasound for the inspection of wood. Air‐coupled ultrasonic scan at 120 kHz can easily detect “sinker‐stock” lumber in which bacterial damage of ray tissue cells had occurred during anaerobic pond storage. Channels in ash lumber board caused by insect bore were imaged in transmission scan. Delamination and material inhomogeneities were mapped out in manufactured wood and natural fiber products including medium density fiberboards, compression molded shredded waste wood with formaldehyde resin, and acoustic panels molded with kenaf fibers. The study has demonstrated some of the capabilities of air‐coupled ultrasound in the NDE of forest products.


Copyright 2010 American Institute of Physics. This article may be downloaded for personal use only. Any other use requires prior permission of the author and the American Institute of Physics.

This article appeared in AIP Conference Proceedings 1211 (2010): 1533–1540 and may be found at

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American Institute of Physics




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