Effects of Internal Hole-Defects Location on the Propagation Parameters of Acoustic Wave in the Maple Wood

To detect the effects of internal hole-defects location on the propagation parameters of acoustic wave in the wood, forty maple wood samples used as the study objects are tested by using PLG (Portable Lumber Grader) instrument in this paper. The propagation velocity and vibration frequency of acoustic wave in intact wood and defective wood were compared, and then the correlation between the propagation velocity or vibration frequency and the elastic modulus were discussed respectively. The analysis results showed that: (1) there were significant positive correlations between the propagation velocity or vibration frequency of acoustic wave and the elastic modulus of the intact and defective maple wood samples; (2) the propagation velocity and vibration frequency of acoustic wave in defective wood samples were lower than those of intact wood samples; and (3) the changes of acoustic wave propagation parameters were different when the location of internal hole-defects of wood samples were different.