温度对介电弹性体材料力电耦合变形的影响

EFFECT OF TEMPERATURE ON THE ELECTROMECHANICAL DEFORMATION OF DIELECTRIC ELASTOMER

介电弹性体(Dielectric Elastomer,简称DE)材料是一类在电场激励下可以产生大幅度尺寸或形状变化的新型柔性功能材料.DE材料具有非常宽的温度应用范围,这种宽的温度工作范围和快速大变形性能为各种柔性致动器结构提供了良好的基础,但作为一种粘弹性高分子材料,温度对其性能的影响也是非常明显的.然而到目前为止,所有关于DE材料驱动性能的研究仅局限于室温条件下,温度变化对DE材料力电耦合稳定性的影响几乎没有相关报道.基于此,通过实验研究了温度对最常用的DE材料(VHB 4910,3M)力电耦合变形的影响,结果表明:升高温度可以提高DE材料的力电耦合变形;温度越高,DE材料越容易发生力电耦合失稳.然后,从热力学和粘弹性力学出发,建立了考虑温度影响后的DE材料的粘弹性力电耦合模型,数值模拟理论结果和实验结果定性地吻合.

Dielectric elastomer （DE） is a typical viscoelastic soft material,which is capable of giant deformation under an electric field and can be applied in broad temperature range. Temperature can significantly affect the performance of DE. However, few reports focus on the effect of temperature on the elec tromechanical deformation. In this study, the in-plane deformation of most widely used DE （VHB 4910, 3M） under different temperatures is performed experimentally. The results show that the deformation of the viscoelastic DE increases with the increasing temperature and DE easily occurs electromechanical instability at a high temperature. Subsequently, based on the thermodynamics, we present a viscoelastic model to describe the electromechanical deformation of DE under different temperatures. The numerical results show that DE creeps with time due to the viscoelasticity and has bigger deformation at higher temperature, which show well consistent with the experimental results.