Ultrasound and Wood Science at the Forestry Research Centre in Nancy, France, for a period of twenty years, between 1979 and 1999

Topical Issue - Development of European Acoustics in 20th Century

Open Access

Table 14.

Wood anisotropy expressed by the ratio of ultrasonic attenuation coefficients as a function of frequency for air dried specimens of horse chestnut [42].

Waves type	Anisotropy	Frequency (MHz)					Dispersion
Waves type	Anisotropy	0.1	0.25	0.50	1.0	1.5	Δ from 0.1 to 1.5 MHz

		Ratio of attenuation coefficients					%
P waves	α₁₁/α₂₂	0.137	0.169	0.260	0.067	0.380	+63.3
	α₂₂/α₃₃	0.417	0.444	0.089	0.249	0.110	−73.6
	α₁₁/α₃₃	0.087	0.088	0.022	0.017	0.042	−51.7

S waves	α₆₆/α₄₄ at 90°	0.037	0.039	0.026	0.022	0.014	−62.1
	α₆₆/α₅₅ at 0°	0.679	0.333	0.418	0.333	0.375	−44.7
	α₆₆/α₅₅ at 90°	0.249	0.452	0.222	0.249	0.283	+3.4

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