电极非对称对压电材料驱动性能的影响

Influences of Electrode Asymmetry on the Actuation Performance of Piezoelectric Materials

采用有限元法分析了外加电压分别作用于交叉指型电极(IDE)压电纯陶瓷材料和压电纤维复合材料时的静电场分布,研究了IDE非对称及非对称的程度对某一厚度压电材料驱动性能的影响,讨论和比较了非对称程度由小变大对不同厚度压电材料驱动性能的影响,以及其变化对压电材料电场集中和应力集中的影响。研究结果表明,对于压电纯陶瓷材料,在厚度较小时,电极非对称对驱动性能的影响不明显。随着厚度的增加,电极非对称程度越大,对驱动性能的影响越大,总体是使驱动应变下降。不管压电材料的厚度如何变化,在增大电极非对称的程度时,电场的不均匀性总是呈增大趋势。电极非对称程度的提高对厚度较小的压电材料的驱动应力提高明显,且应力集中程度无明显增大。对于压电纤维复合材料,电极与压电纤维之间夹层厚度越大,则非对称程度增大的影响越大。

The electrostatic field distribution of inter-digital electrode （IDE） piezoceramies and piezoelectric fiber composite were analyzed by finite element method separately. The impact of the inter-digital electrode asymmetry on the actuation performance of piezoelectric actuators with a certain interlayer thickness was studied. The influence of the inter-digital electrode asymmetry on the actuation performance, stress concentration and electrostatic field con eentration with different interlayer thicknesses were also discussed and compared. For piezoceramies, the results showed that the actuation performance could be influenced little by increasing the degree of the excursion with a rela- tively thin interlayer thickness. As the interlayer thickness increased, the actuation performance could be influenced much by increasing the degree of the asymmetry. And it resulted in the decrease of the longitudinal free strain over- all. Regardless of how the thickness of the piezoelectric material changed, the electric field became increasingly uneven as the degree of the asymmetry increased. The actuated stress could be improved evidently by increasing the degree of the asymmetry with a relatively thin interlayer thickness while the stress concentration was not increased ap- parently. For PFCs, the thicker the thickness between the electrode and the fiber, the greater the actuation per- formance would be influenced by the asymmetry.