抄録
Guided waves can propagate along waveguides with low attenuation. Therefore, guided waves are expected to be used for non-destructive testing especially of wire-ropes. Because of complexity of the wire-rope structure, it has not been known completely how guided waves propagate in wire-ropes. So we conducted two experiments of guided waves transmitted and received by Electromagnetic Acoustic Transducers (EMATs) in order to investigate the characteristics of guided waves propagation in wire-ropes. First, we measured the propagation time of guided waves in a wire-rope, in a core strand, and in an element wire, respectively. From the results, we calculated respective group velocities and compared them with each other. Second, we rotated the magnets of the receiver EMAT for a core strand and measured the amplitude of received waves. Obtained results show that non-axisymmetric distribution of the wave amplitude rotates with the same pitch as the helicity of an element wire. From the experimental results, we verified that L(0,1)-mode can be propagated along the element wires of peripheral strands.
