Abstract
During recent years structural health monitoring (SHM) systems have gained growing attention. Widely applied methods in SHM are methods based on the ultrasonic Lamb waves (LWs) which are also known as plate waves. LWs may be generated and sensed using different types of transducers and their selection is essential for the SHM systems performance. Among transducers used for generation and sensing of such waves, Interdigital Transducers (IDTs) are ones of the most promising types. Their main advantages are: mode selectivity, high excitation strength, wave directivity, small sizes and relatively low cost. In most cases IDTs are made of piezoceramics or piezoelectric polymers what makes them stiff and fragile. Contrary to the piezoceramic transducers, the ones based on piezocomposites (i.e.: macro-fiber composite) are flexible with the comparable efficiency of piezoelectric effects. The MFC transducers are usually optimized as actuators and they are not designed to any specific frequency. It appears, however, that sparse comb-like electrodes used in interdigital transducers create very interesting properties of mode selectivity. In the paper, after the introduction and short discussion about advantages and disadvantages of the IDTs, a novel type of the interdigital transducer, based on elastic macro-fiber composite, is presented. Next, the results of the numerical and experimental tests of the MFC based IDT designed for the A0 mode excitation in a 4mm-thick aluminium plate is presented. In the final part of the paper advantages and disadvantages of the investigated transducer are discussed.
Published Version
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