First-principle Calculations Of Piezoelectric Properties And Research On Damping Model Of Piezoelectric Effect-based Composites

The perovskite binary continuous solid solution of PbZrO3 and PbTiO3, known as lead zirconate titanate (PZT), is characterized by high phase transition field intensity, high energy storage capacity and relatively low dielectric constant and dielectric loss. It is applied in capacitors, transducers and damping composites, of which researches by now have been focused on preparation and piezoelectric properties, while the visual representation and modeling of the electromechanical coupling is to be investigated. Based on the theoretical background that the end-point compound PbZrO3(PZ) share some features of PZT near the morphotropic phase boundary (MPB), this paper relied on the open-source quantum chemistry first principle calculation package ABINIT, applying density functional perturbation theory (DFPT) on PbZrO3 crystal (orthorhombic, space group Pbam) to study the piezoelectric properties microscopically. Further investigation of this thesis included the finite element analysis software ANSYS to apply multi-physical field on piezoelectric materials, obtained in the output the strain and voltage related characteristics. The macroscopic result helped to establish the conversion model between the mechanical and electrical energy.Ensuring the convergence of the calculation, we tested to adopt the variable ecut and ngkpt as 8 Hartree and 4×4×4 Monkhorst-Pack grid respectively, and gained graphs of band structure and density of states (DOS). The results showed that PbZrO3 is narrow gap semiconductor with band gap located in R point of the Brillouin zone and the band gap value being underestimated as 0.1ev which is the common case in using the local density approximation (LDA). We also obtained that there is strong hybridization between the d electron of Zr and p electron of O, thence suppresses the short-range repulsive force to stabilize the piezoelectric properties.The elastic tensor C11 calculated was 0.5107036×102GPa, while piezoelectric constant e33 turned out to be-0.00580912 C/m2,from which and the result of intrinsic polarization we found good stiffness in material and consistency with the symmetry of space group Pbam. The research suggests the reliability and efficiency of the first principle calculation in the explanation of micro mechanism of piezoelectricity.Through direct coupling ANSYS simulation, we descript piezoelectric properties of PZT thin films visually:under one-way vibration the maximum displacement of 0.255×10-10m existed in the metal-film interface,while the maximum voltage 58.51mA found in the upper surface of the ceramic film. The displacement and voltage appeared in positive proportion thus constitutes the basis of electromechanical conversion in composites. Further Research makes it possible to explain energy dissipation mechanism in composites fundamentally.