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Measuring stiffness with sound

As featured at the 2007 Royal Society Summer Science Exhibition (http://www.summerscience.org.uk) The wood produced from sustainably managed forests in countries like the United Kingdom is increasingly being used by the construction industry - particularly for building new houses. Before it can be used by builders, engineers and architects it must be graded to check that it is strong and stiff enough for the intended use. Recently developed technologies allow wood properties to be quickly and reliably measured in a non-destructive manner using sound waves and vibration. This can be done after processing at the sawmill, but there are even greater advantages in using it to measure the properties of logs and trees in the forest - allowing the wood to be sent for processing into the best kind of product and reducing wastage of both timber and energy. There are two main ways of using sound waves (acoustics) to assess wood properties, the "time of flight" method and the "resonance" method. This video shows a demonstration of a resonance method. The tool shown is Fibre-Gen's Director HM200 or "Hitman". You can see more videos like this at http://cte.napier.ac.uk/firrs.

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