Abstract:Due to the good direction sensing characteristic of piezoelectric fiber to Lamb wave, the piezoelectric fiber sensor, which is similar to the strain rosette, is adopted to achieve the detection of the Lamb wave propagation direction. Aiming at commonly used 4 structure configurations of 45°rectangular, 135°rectangular, 60°delta and 120°delta, the theoretical, simulation and experiment studies are conducted to find out the influences of various piezoelectric fiber sensor configurations on the identification accuracy of Lamb wave propagation direction in this paper. According to the piezoelectric equation and attenuation characteristic of Lamb wave propagation, the sensing response equation of piezoelectric fiber to A0 mode Lamb wave under narrowband excitation is theoretically derived. The error function of the response amplitudes of three piezoelectric fibers is defined and used to estimate the Lamb wave propagation direction. The ANSYS software was adopted to conduct the piezoelectric coupling simulation analysis and obtain the response signals of different piezoelectric fiber sensors, and corresponding experiment tests were carried out. The matching pursuit algorithm was applied to perform the signal decomposition and extract the response amplitudes. The Lamb wave propagation directions were identified according to the error function and the response signals. The simulation and experiment results are compared, the causes of simulation and experiment errors are discussed. The analysis results show that the identification errors of the Lamb wave direction detection for four different configurations of the piezoelectric fiber depend on the length of the piezoelectric fiber, configuration angle, excitation frequency, the adhesion condition of the piezoelectric fiber, and etc. In terms of overall error, the 135°rectangular configuration is the best, the error is less than 4%; the 60°delta configuration is slightly better than the 45°rectangular configuration, its error is less than 8%; due to the large size, the 120°delta configuration presents the largest error. This study could provide a theoretical basis for piezoelectric fiber sensor structure design.