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 11.

Effect of frequency on attenuation coefficients $α_{ij} = - \frac{1}{d}$ $\alpha_{{ij}} = -\frac{1}{d}$ ln A/Ao (in Nepers/cm) and velocities (in m/s) in curly maple and common spruce, measured in wood anisotropic axes with the sinusoidal burst transmission technique and longitudinal and transverse waves. Velocity in m/s. (Note: 1 dB/10² m = 8.69 Np/10⁻² m). d – the size of the specimen for path wave measurement [43].

Wood species	Wave type	Parameters	Frequency of excitation

			0.10 MHz	0.25 MHz	0.50 MHz	1.0 MHz	1.5 MHz
Curly maple	P wave	α11	1.55	1.62	1.62	1.75	1.90
		V₁₁	4332	4409	4540	4706	4559
		α22	2.30	2.25	2.29	2.47	2.63
		V₂₂	2285	2270	2279	2325	2340
		α33	2.82	2.82	3.03	3.22	3.22
		V₃₃	1254	1291	1321	1316	1345

	S wave	α44	1.64	1.85	1.85	2.32	2.47
		V₄₄	869	966	918	918	–
		α55	1.68	1.77	2.10	2.47	2.39
		V₅₅	1214	1350	1394	1428	1399
		α66	1.77	1.94	2.05	2.27	2.34
		V₆₆	1342	1552	1566	1602	1580

Spruce	P wave	α11	2.17	2.07	2.10	2.29	2.47
		V₁₁	4458	4847	5343	5327	5401
		α22	2.83	3.02	3.22	3.22	–
		V₂₂	1612	1741	1832	1832	–
		α33	2.71	3.02	3.02	3.02	3.22
		V₃₃	1283	1400	1321	1325	1346

	S wave	α44	No signal
		V₄₄	No signal
		α55	1.62	1.62	1,85	2.06	2.17
		V₅₅	1310	1320	1356	1383	1372
		α66	1.64	1.71	1.71	2.17	2.36
		V₆₆	1250	1372	1383	1822	1839

Notes. 1 dB/10⁻² m = 8.69 Np/10⁻² m.

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