介电型电活性聚合物(EAP)驱动器失效行为分析

Failure Analysis of Dielectric Electroactive Polymer(EAP) Actuator

介电型电活性聚合物(EAP)驱动器在工作过程中,边界条件及驱动电压的改变经常导致EAP薄膜发生起皱现象以及介电击穿,致使驱动器失去工作能力。为了保障驱动器的正常工作,避免失效行为的发生,对EAP驱动器的失效行为进行了研究。针对锥形驱动器,计算出不同驱动电压下驱动器EAP薄膜的变形情况以及其中的应力、应变和电场强度的分布情况。利用薄膜起皱判别方法,对驱动器的起皱行为进行预测,同时分析了预拉伸倍数对驱动器失效的影响。试验结果表明,EAP驱动器的理论临界起皱电压与理论分析比较吻合,预拉伸可以提高薄膜的机电稳定性能。研究结果可用于预测介电型EAP驱动器发生失效的临界电压,有利于保障驱动器的安全工作。

During the working process of a dielectric electroactive polymer（EAP） actuator,variations of boundary conditions and actuation voltages often lead to wrinkling and dielectric breakdown of the EAP membrane and result in the failure of the actuator.To avoid this and assure the safety of the actuator,its failure behavior is investigated.The deformation is obtained of the EAP membrane of a conically-shaped dielectric EAP actuator,together with the distribution of its principal stress,the principal stretch ratio and electrical field in the membrane under different voltages,This is used to predict the failure of a dielectric EAP actuator based on the failure criterion of the membrane.How the prestretch ratio of an EAP membrane affects the failure of the actuator is also explored.Finally,the experiment results of the critical wrinkle voltage of the EAP actuator agree well with the theoretical analysis,and the experiments show that prestretch can improve the electromechanical stability of an EAP membrane.The work of this paper can be used to predict the critical voltage of a dielectric EAP actuator when the failure occurs and guarantee its safe working.