Novel piezoelectric fiber transducers for mode selective excitation and detection of lamb waves

One of the most widely applied methods for Structural Health Monitoring of plate like structures, shells and tubes is based on the transmission and reception of guided elastic waves. But, dispersion of various wave modes leads to complex signals which arc difficult to interpret. Piezoelectric fiber patches (PFP) have been developed which can be used to excite and detect Lamb waves. These are of low thickness having the potential to be integrated into structures. This paper deals with a novel method to excite PFP. By this method a Lamb modes can be both excited and detected selectively. In addition, also directivity can be realized. These sensors can be used to simplify the interpretation of the acoustic signals considerably.