The quasi-static coupling coefficients, k/sub 13/ and k/sub 33/, for electrostrictive ceramics are computed analytically. The calculation is based on a three-dimensional constitutive relation that models both electrostriction and nonlinear dielectric behaviors. The results show that the coupling factors depend on the amplitudes of the applied ac field and the dc bias, as well as the mechanical prestress. For an actuator without bias voltage or prestress, the coupling coefficients approach an asymptotic value with increasing electric field. The primary coefficients, k/sub 13/ and k/sub 33/, for a lead magnesium niobate, Pb(Mg/sub 1/3/Nb/sub 2/3/)O/sub 3/-PbTiO/sub 3/BaTiO/sub 3/(PMN-PT-BT), based relaxor ferroelectric are computed as an example. The results show that the coupling coefficients for PMN-PT-BT materials are roughly comparable with those of existing piezoelectrics. These coefficients are important parameters for material section and power source design for transducer devices.
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机译：通过解析计算电致伸缩陶瓷的准静态耦合系数k / sub 13 /和k / sub 33 /。该计算基于对电致伸缩和非线性介电行为建模的三维本构关系。结果表明，耦合因子取决于所施加的交流场和直流偏置的幅度以及机械预应力。对于没有偏置电压或预应力的执行器，随着电场的增加，耦合系数接近渐近值。铌酸铅镁的主要系数k / sub 13 /和k / sub 33 /，Pb（Mg / sub 1/3 / Nb / sub 2/3 /）O / sub 3 / -PbTiO / sub 3 /以BaTiO / sub 3 /（PMN-PT-BT）为基础的弛豫铁电为例。结果表明，PMN-PT-BT材料的耦合系数与现有的压电材料大致相当。这些系数是换能器设备的材料截面和电源设计的重要参数。
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