TITLE:
Non-Contact Velocity Measurement of Japanese Cedar Columns Using Air-Coupled Ultrasonics
AUTHORS:
Masumi Hasegawa, Misaki Mori, Junji Matsumura
KEYWORDS:
Air-Coupled Ultrasonics, Velocity, Non-Contact Method, Nodestructive Evaluation, Japanese Cedar
JOURNAL NAME:
World Journal of Engineering and Technology,
Vol.4 No.1,
February
5,
2016
ABSTRACT: The ultrasonic wave velocities of Japanese cedar columns were measured using a non-contact method. An air-coupled ultrasonic wave was propagated through the axial and lateral directions of wood. The velocities in the axial direction (VL) showed the minimum values around the pith. The averaged VL increased from 3600 m/s towards the outside of measurement area and attained the maximum values (=4010 m/s). The velocities in the lateral direction (VRT ) showed no tendency among measurement points. The averaged VRT was 1450 m/s. The velocities obtained using the non-contact method showed a significant positive relationship with those obtained using the contact method. The averaged ratio of VL to VRT was measured to be approximately 2.2 to 2.8. These ratios were in agreement with those from a contact method. These findings suggest that it is possible to measure the velocity in Japanese cedar columns with the non-contact method by using air-coupled ultrasonics.