STRUCTURAL DISCONTINUITY LOCATING BASED ON THE REFLECTION OF GUIDED WAVES

As some guided waves may propagate along the structures in a long distance and occur reflection and transmission at discontinuities, the discontinuities may be located by positioning guided-wave probes along the structure and measuring the reflected and transmitted waves. In this inspection method, the locating accuracy is higly related to the dispersive characteristics of the guided waves. However, although the dispersive characteristics of waves, which is can be estimated by theoretical and numerical methods, some particular types of waves are difficult to excite and measure in experiments, and consequently their dispersive characteristics are difficult to obtain. This paper explores a discontinuity monitoring system for infinite structures using measured wavenumbers. The propagating features of waves, as well as the reflection properties near a discontinuity, were firstly derived to relate the discontinuity location and the wave amplitudes. Meanwhile, the measured diplacements, which are acquired from the probes, are introduced to represent the wave dispersive characteristics to provide a robust discontinuity locating. An experiment on a cracked beam was designed to validate the effectiveness of this method. It's expected that this method can provide an accurate discontinuity detection with the locating error less than 0.2%.