METHOD OF WOOD STRESS WAVE NONDESTRUCTIVE TEST

摘要

PROBLEM TO BE SOLVED: To provide a method of wood stress wave nondestructive test which calculates a sound velocity and an elastic module by a resonance frequency in the longitudinal direction of a sample, and is applicable for measurement on a production line by improving a conventional rattle noise method.;SOLUTION: A portion near the center on one face of the sample is placed on a guidance system, and slide of the sample is prevented by a frictional force between the guidance system surface and the sample surface, and one end of the sample is knocked by a knocking device. A stress wave generated at the knocking time is transferred to the other end of the sample, and reflection of the stress wave is generated on the other end of the sample, and thereby the generated stress wave is returned to one end where the sample is knocked. The stress wave makes a round trip at the sound velocity between both ends of the sample, and energy of the stress wave is consumed by internal friction of the sample. The change of the frictional force in the guidance system is received by a receiving device connected electrically to the guidance system, and the change of the frictional force is analyzed by an analytical device connected electrically to the receiving device, and the resonance frequency in the longitudinal direction of the sample is detected, to thereby calculate the sound velocity and the elastic module by the resonance frequency.;COPYRIGHT: (C)2004,JPO&NCIPI