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Meso-Structural Considerations of Ultrasonic Propagation in Wood

Feeney B., Chivers R., Barnard G.

Molecular and Quantum Acoustics

2001

Vol. 22

57-68

To date most reports on the propagation of ultrasonic waves in wood have assumed that it is an homogeneous orthotropic material. Results are summarized from four experimental investigations of the variation of the mechanical and ultrasonic properties of wood on dimensional scales of the order of 1 mm or less (a meso-structural level).

Macroscopic Cosiderations of Ultrasonic Propagation in Wood - Attenuation

Feeney B., Chivers R.

Molecular and Quantum Acoustics

2001

Vol. 22

45-56

Measurement of ultrasonic longitudinal and transverse transmittion loss have been made on specimens of Horse Chesnut, Maple and Norway Spruce. Five frequencies between 100kHz and 1.5MHz were chosen, while the direction of propagation of the waves was varied in seven equal steps between the principals axes of the wood in each of the three principal planes. The problem of mode conversion, interference, transduction, and phase cancellation require the measurements along the principal axes to be interrupted with grat care, while the lack of pure mode propagation off-axis can enhance these problems.Nevertheless differing frequency and angular responses were foung for the different species, with the loss increasing with frequent being typically in the range 12-30 (or more) dB/cm in this frequency range.

Macroscopic Considerations of Ultrasonic Propagation in Wood - Velocity

Feeney B.

Molecular and Quantum Acoustics

2000

Vol. 21

319-326

Meosurements of ultrasonic longitudinal and transverse wave velocities have been made on specimens of Horse Chestnut, Maple and Norway Spruce. Five frequencies between J 00 kHz and 1.5 MHz were chosen, while the direction of propagation ofthe waves was varied in seven equal steps between the principal axes of the wood specimens. Differing angular and frequency responses are found for the different species, with clear evidence of dispersion being found in many ofthe results. There is some indication that these bulk wave measurements may reflect the microstructure of the wood.