Flexural-wave-generation using a phononic crystal with a piezoelectric defect

This paper proposes a method to amplify the performance of a flexural-wave-generation system by utilizing the energy-localization characteristics of a phononic crystal (PnC) with a piezoelectric defect and an analytical approach that accelerates the predictions of such wave-generation performance. The proposed analytical model is based on the Euler-Bernoulli beam theory. The proposed analytical approach, inspired by the transfer matrix and S-parameter methods, is used to perform band-structure and time-harmonic analyses. A comparison of the results of the proposed approach with those of the finite element method validates the high predictive capability and time efficiency of the proposed model. A case study is explored; the results demonstrate an almost ten-fold amplification of the velocity amplitudes of flexural waves leaving at a defect-band frequency, compared with a system without the PnC. Moreover, design guidelines for piezoelectric-defect-introduced PnCs are provided by analyzing the changes in wave-generation performance that arise depending on the defect location.