Calculation of quasi-static electromechanical coupling coefficientsfor electrostrictive ceramic materials

摘要

The quasi-static coupling coefficients, k13 andnk33, for electrostrictive ceramics are computed analytically.nThe calculation is based on a three-dimensional constitutive relationnthat models both electrostriction and nonlinear dielectric behaviors.nThe results show that the coupling factors depend on the amplitudes ofnthe applied ac field and the dc bias, as well as the mechanicalnprestress. For an actuator without bias voltage or prestress, thencoupling coefficients approach an asymptotic value with increasingnelectric field. The primary coefficients, k13 and k33n, for a lead magnesium niobate,nPb(Mg1/3Nb2/3)O3-PbTiO3BaTiOn3(PMN-PT-BT), based relaxor ferroelectric are computed as annexample. The results show that the coupling coefficients for PMN-PT-BTnmaterials are roughly comparable with those of existing piezoelectrics.nThese coefficients are important parameters for material section andnpower source design for transducer devices