Laser Ultrasonic Experimental Study on the Propagation of Acoustic Emission Signals in Steel Wires

To form the basis for acoustic emission(AE) monitoring of bridge cables, laser ultrasonic study on steel wires is conducted in this paper. Ultrasonic testing is first performed on a single wire. The experimental dispersion curves are then compared with those derived using elastic wave propagation theory in a rod, and good agreement is found, suggesting the potential of this experimental technique for investigating acoustic emission in steel wires particularly for cases when the analytical solution is not available. Hence subsequent experiments are conducted on two contacted wires where the variation of propagation properties of guided waves caused by the interaction between the two strand wires is focused. With the help of improved two-dimensional Fourier Transform, the results reveal new modes of guided waves in two strand wires in contact, which means the two strand wires become a new waveguide different from a single wire because of the close contact.