磁头精定位控制中压电致动特征的解析解

AN ANALYTICAL SOLUTION OF ELECTRO-MECHANICCHARACTERISTIC TO A PIEZOELECTRIC ACTUATOR WITHSPLIT ELECTRODES IN THE CONTROL OF PRECISIONPOSITION OF MAGNETIC HEAD

利用压电弹性介质的二维本构关系,对于分割电极片状压电致动器在恒定的反平行电场作用下的电-力致动特性,在对自由端边界作圣维南意义下的放松处理后,采用弹性力学的半逆求解方法,导出了其力-电耦合的静态位移和应力分布的解析解.通过将所得解析解与没有简化假设的有限元数值解进行比较,结果表明:所得解析解的致动特性（即自由端位移随外加电压的变化特征）与数值解的结果几乎完全重合,表明其二维解析解是有效和可靠的.

With the rapid development of information technology, the track densities and data rates in magnetic recording devices become higher. To achieve high track density, the develop-ment of dual-stage actuators using conventional voice coil motor as a primary stage and some sort of microactuator device located between the pivot of the voice coil and the read/write head has continued in both industry and academia. The devices have varied in their method for electrical to mechanical energy conversion and in their location in the mechanical structure of actuator sys-tem. One of methods of energy conversion from electrical energy to mechanical one is based on piezoelectric effects. Researchers have been trying to design large displacement and high band-width piezoelectric actuators for high densities magnetic disk drives, so the research on their electromechanical-coupled characteristics is very important.Based on the two-dimensional constitutive equations of piezoelectric and elastic materials, this article presents an analytical solution of displacements and stresses to the electro-mechanical in-teraction of a piezoelectric actuator with split electrode under the static anti-parallel electric fields after the boundary conditions at free end are dealt with by means of the Saint-Venant's assump-tion, and the semi-inverse method of solution to an elastic body is employed. By comparing the obtained analytical solution with one of numerical solutions, e.g., a finite element solution, to the problem without using the Saint-Venant's assumption, i.e., the numerical solution to the prob-lem with the point-by-point satisfied boundary conditions, it is found that the characteristics of electro-displacements at the free end from the analytic solution is almost coincident with those from the finite element solution, which shows that the analytic solution presented in this paper is efficient and reliable.