Investigations of the guided wave data analysis capabilities in structural health monitoring of composite objects

Abstract

Ultrasonic guided waves are widely used for non-destructive testing of composite objects. Low frequency guided waves propagate long distances, so they can be used in structural health monitoring systems. However, in order to increase efficiency of guided waves usage in structural health monitoring systems, deep analysis of the measured signals is required. Usually non-destructive testing systems exploit the signals measured different positions of the object under investigation. In structural health monitoring systems the amount of measurement positions is limited and analysis of guided wave signals is more complicated.

The objective of this work was to investigate which guided wave parameters can be measured and monitored during the bending tests of composite plates. The analysis of the experimental signals showed that using embedded transducers it is possible to measure group velocity of the fastest wave, directivity pattern of ultrasonic transducers and even to estimate the anisotropy of group velocity. The investigation also revealed that identification of other guided wave modes requires a numerical model which simulates the wave propagation in the object under investigation. Detailed analysis of experimental signals showed that precise measurements of delay times and amplitudes enable to estimate relatively small changes of the object properties.

http://dx.doi.org/10.5755/j01.u.66.3.651