| 摘要 |
PURPOSE:To achieve a quantitative detection of any decay defect of a wood pillar or the like accurately by measuring an ultrasonic wave propagation time at the parts on the straight line passing the imaginary center of a measuring section and divided by imaginery lines to determine the shaped and the position of a defect. CONSTITUTION:Ultrasonic probes 2a and 2b are provided at the point P1 and P1' opposite thereto or the like among intersections P1 and P1'-P8 and P8' between imagenery straight lines passing the imagenery center O of the section 5 to be measured of a wood pillar or the like and the propagation time of an ultrasonic wave propagating through the straight line P1 and P1' or the like is measured. In this case, the ultrasonic wave propagates shunting the decayed part H and the comparison between the measured time and the reference propagation time determines the length l1 of the decayed part H. On the other hand, the ultrasonic wave propagation times in parts at 90 deg. or the like divided by the imagenery lines are measured with the probes 2a and 2b provided at the points P1 and P5, P1 and P5', P1' and P5, P1' and P5' and the like and compared with the reference time to calculate the probability of presence of decayed parts thereby determinining the position of decayed parts from the maximum probability. Thus, decay defects of the wood pillar or the like can be accurately detected quantitatively. |
