Measured Lamb wave radiation patterns from <011> Mn-PMN-PZT relaxor ferroelectric disks on an isotropic plate

摘要

Three-dimensional laser Doppler vibrometry is used to quantify the modal composition of the guided plate waves generated by relaxor ferroelectric disk actuators of a 011 poled Mn-Pb(Mg1/3Nb2/3)O-lead zirconate titanate (PZT) single crystal and 100 poled piezoelectric PZT, bonded to an isotropic plate. Disk actuators are excited using a 5.5 cycle Hann-windowed voltage tone-burst at centre frequencies of 100, 200, and 300 kHz. Measured wave fields are processed using a two-dimensional fast Fourier transform to determine the radiation pattern of each contributing mode. For the same applied electric field strength, the single crystal actuators are shown to produce significantly larger wave amplitudes and one additional wave mode, the shear horizontal, as compared with PZT actuators. The wave-mode radiation patterns are shown to be anisotropic, suggesting that the classical theory describing guided-wave modal excitability may need to be revised for these materials. (C) 2018 Author(s).