_Applied_  
_sciences_  
_Article_  
**Dynamic Non-Destructive Evaluation of Piezoelectric Materials to Verify on Accuracy of Transversely Isotropic Material Property Measured by Resonance Method**  
**[PERSON] 1,*\({}^{\copyright}\), [PERSON] 1 and [PERSON] 2**  
1 Department of Mechanical Engineering, National Taiwan University, Taipei 10617, Taiwan; [EMAIL_ADDRESS]  
2 Taiwan Semiconductor Manufacturing Company, Hsinchu 30078, Taiwan; [EMAIL_ADDRESS]  
* Correspondence: [EMAIL_ADDRESS]; Tel.: +886-233662690 check for updates  
Received: 23 June 2020; Accepted: 21 July 2020; Published: 23 July 2020  
**Featured Application: This paper provides the measurement methods and corresponding calculating formulas for piezoelectric material constants. The completely orthotropic material property, i.e., dielectric, piezoelectric, and elastic constants, is obtained and verified by piezoelectric dynamic characteristics. By means of use in anisotropic material property, the mode shape and corresponding natural frequency were determined by finite element numerical calculation. The difference is rare in comparison with the results obtained by optically dynamic vibration measurement. The influence on self-heating phenomenon of soft and hard piezoelectric ceramics is also discussed in the study.**  
In many engineering applications of piezoelectric materials, the design and prediction of the dynamic characteristics depends on the anisotropic electromechanical material property. Through collecting the complete formula in literature and listing all the prepared specimens, transversely isotropic material constants were obtained and verified by dynamic non-destructive evaluation in the paper. The IEEE (Institute of Electrical and Electronics Engineers) resonance method was applied to measure and calculate the orthotropic material constants for piezoelectric ceramics. Five specimens need to be prepared for the measurements using an impedance analyzer, in order to obtain the resonant and anti-resonant frequencies from the modes of thickness extension, length-extension, thickness-shear extension, length-thickness extension, and radial extension. The frequencies were substituted into the formulas guided on the IEEE standard to determine the elastic, dielectric, and piezoelectric constants. The dynamic characteristics of soft and hard piezoelectric ceramics in the results from the finite element method (FEM), which is analyzed from the anisotropic material constants of the resonance method, were verified with the mode shapes and natural frequencies found by experimental measurements. In self-heating, considered as operating on resonant frequencies of piezoelectric material, the resonant frequency and corresponding mode shape calculated by the material constants from resonance method in FEM are more accurate than the material property provided by the manufacturer and literature. When the wide-bandwidth frequency is needed to design the application of piezoelectric ceramics, this study completely provided the measurement method and dynamic verification for the anisotropic electromechanical material property.  
**Keywords: piezoelectric materials; transversely isotropic material; IEEE resonance method; resonant and anti-resonant frequencies; dynamic non-destructive evaluation**