THUNDER元件热机电耦合动力学分析

针对THUNDER型压电驱动器这一类特殊结构形式,提出一种包含4个位移节点,8个温度节点和2个电势节点的热机电耦合混合有限元模型,并基于虚功原理推导了热机电耦合有限元方程。针对物理属性截然不同的冷却阶段、再极化阶段和驱动阶段开展了动力学研究,并利用初始位移这一变量将它们有机地联结起来;系统地分析了该类驱动器的热机电耦合问题。数值算例表明:该混合有限元模型具有良好的计算精度;THUNDER型压电驱动器的驱动性能与其制造过程密切相关,且其驱动位移与外载荷的凹曲线关系使其具有良好的综合驱动性能;在实际应用中,当温度发生变化时,热应变对驱动性能具有重大影响,而焦电效应的影响相对较小但仍十分明显,体现出对THUNDER型压电驱动器开展热机电耦合动力学研究的重要性。

Piezothermoelastic dynamic analysis of THUNDER actuators

For THUNDER actuator’s special structure, a mixed piezothermoelastic finite element model including 4 displacement nodes, 8 temperature nodes and 2 potential nodes is presented. A general piezothermoelastic finite element equations for THUNDER actuators are deduced by use of the principle of virtual work. From manufacture to application, the thermal deformation in cooling process, the deformation due to repolarization in repoling process and the piezothermoelastic coupling effect in actuating process are studied respectively, and their dynamic analysis are organically linked together through the variable of initial strain. Numerical results show: the mixed finite element model has good precision; it is the relationship of concave curve between the actuating displacement and loads that makes a THUNDER actuator having a good combination property on driving displacement and bearing loads; when temperature is varied in engineering application, thermal strains have a great effect and the pyroelectric effect has relatively small but still noticeable effect on dome height, which reflects the piezothermoelastic dynamic analysis is necessary for a THUNDER actuator to be used more effectively and accurately in engineering application.