引張応力下におけるワイヤーケーブルのガイド波伝播特性

抄録

Wire cables are widely used for mechanical and structural components. There are problems that the rupture accident can be caused by corrosion, frictional wear, etc. Therefore, the method for heath monitoring of wire cable is important. It is possible to evaluate efficiently, if guided wave and acoustic emission can be used for monitoring. However, characteristic of propagation in wire cables can not be calculated because wire cables consist of complicated twisted threads. In this study, wire cable that consist of two strand was used in order to simplify propagation path. Then, we measured the guided wave propagation in wire cable under tensile stress. A guided wave was produced by a Q-switched YAG pulse laser and was detected by PZT transducers. Guided wave excitation utilizes the adiabatic expansion at the irradiated position. We found that propagation mode of guided wave on an excited strand was similar to longitudinal mode of a rod, according to group velocity dispersion curve and the wavelet contour maps of the detected waves. As the tensile force increased, the arrival time of longitudinal mode was delayed. We identified that velocity of longitudinal mode is important, when guided wave were analyzed.