Lamb Wave Detection Using PZT and Fiber Optic Sensor

The surface mounted piezoceramic transducers and fiber optic sensor can detect signals in both symmetric and antisymmetric Lamb wave modes. Hanning windowed sine torn bursts were used for the piezoceramic transducer excitation signals. In order to overcome the difficulties in the signal processing of the simultaneous modes, the symmetric and antisymmetric modes were separated by using the two sensors bonded on the opposite surfaces at the same planer location. Spectral analyses of the separated symmetric and antisymmetric Lamb waves showed that each mode propagated with different frequency characteristics in the exciting frequency band range. In case of a fiber optic sensor, its geometric characteristics induce sensing directivity of Lamb wave. In this paper, the directivity of a fiber optic sensor was investigated using EFPI (extrinsic Fabry-Perot interferometer) sensor.