In this study, in order to develop coupled vibration mode piezoelectric devices for Acoustic Emission(abbreviated as AE) sensor application with outstanding displacement and piezoelectric properties have been simulatedby ATILA FEM program. And, From the results of ATILA simulation, the AE sensor specimen, obtained superiorelectromechanical coupling factor and displacement, when the size of specimen is 3.45 mmΦ×3.45 mm with ratio ofdiameter/thickness(Φ/T)= 1.0. Therefore, AE sensor was fabricated by (Na,K,Li)(Nb,Ta) O3(abbreviated as NKL-NT)system piezoelectric ceramics using coupled vibration mode. The piezoelectric properties of NKL-NT ceramics wasexhibited that piezoelectric constant(d33), piezoelectric voltage constant(g33) and electro mechanical coupling factor(kp)have the excellent values of 261[pC/N], 40.10[10-3Vm/N], and 0.44, respectively. The manufactured piezoelectric devicewith ratio of Φ/T= 1.0 indicated the optimum values of resonant frequency(fr)= 556.5[kHz], antiresonant frequency(fa)=631.1[kHz], and effective electromechanical coupling factor(keff)= 0.473. The maximum sensitivity of the coupledvibration mode AE sensor was 55[dB] at the resonant frequency of 75[kHz]. The results show that the coupledvibration mode piezoelectric device is a promising candidate for the application AE sensor piezoelectric device.
