ORYOKUSOKUTEIHOHO

摘要

PURPOSE:To enable a stress measurement using an ultrasonic wave by a method wherein a phase difference-stress characteristic is prepared beforehand and a characteris tic curve is determined by actual measurement for an object to be measured to obtain a cyclic deviation in the characteristic curve as phase difference of a reference wave. CONSTITUTION:A characteristic curve A1 is determined to indicate a size of a reflected ultrasonic wave with respect to a position of an ultrasonic wave when the ultrasonic wave is radiated to a specified object and a reference stress works thereon and a characteristic curve A2 as obtained when other stresses work thereon under the same condition is determined by a theoretical analysis or a model actual measurement. Then, the cycles of the curves A1 and A2 are compared using a reference wave A3 with a specified frequency as reference to determine a cycle deviation between points P1 and P2 as phase difference of the reference wave A3 thereby preparing a phase difference-stress characteristic. Then, a characteristic curve of an object is measured actually when an unknown stress works and a cyclic deviation of an actual measure ment curve from the cycle of the characteristic curve A1 determined by the theoretical analysis is obtained as a phase difference of the reference wave A3. This enables the determination of a stress based on the phase difference-stress characteristic previous ly made from the phase difference.