抄録
We have developed the finite element simulation program for the vibration and stress analysis of three-dimensional electrostrictive materials such as ceramics. Mechanical forces are caused through the electro-mechanical coupling, which depends on the polarization in the materials. In the above program, the materials are assumed to be fully polarized in a certain direction. This is not the case in general. In order to polarize the materials, high electric field must in advance be applied through the electrodes suitably arranged and the residual polarization remains after the electric field is removed. In this paper, the polarization process in ferro-electric materials or ceramics is considered. The process of nonlinear electrical field is solved by the use of the finite element method coupled with the Newton-Raphson iteration algorithm for D-E (flux density-electric field strength) relation. The procedure is similar to that of the magnetization process in ferro-magnetic materials. The procedure has already been examined for the two-dimensional models. In the present paper, extension is made to the three-dimensional case, for which the formulation is made using eight-node isoparametric elements. The polarization is demonstrated for some simple model and the vibration problem is also considered making use of this result. Incomplete polarization affects the vibration characteristic so that it must be included for evaluation in advance.
