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arXiv 2009.01737cond-mat.soft
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通过加载协议调整软介电弹性体的吸合不稳定性

Tuning the pull-in instability of soft dielectric elastomers through loading protocols

Yipin Su, Weiqiu Chen, Michel Destrade

摘要:

当电介质弹性体的厚度急剧减小导致电击穿时,会发生拉入(或机电)不稳定性,这限制了电介质器件的应用。本文通过对驱动系统自由能的分析,导出了电压控制、电荷控制、固定预紧力和固定预拉伸等不同加载方式下驱动系统吸合不稳定性的判据。Hessian准则确定了加载曲线中的最大值,超过该最大值,弹性体将迅速拉伸并失去稳定性,并且可以被视为失效路径。我们提出了数值计算的新胡克理想介电常数,并获得最大允许的致动拉伸的电介质之前,失败的电击穿。我们发现,施加一个固定的预应力或固定的预拉伸到电荷驱动的电介质可能会降低弹性体的拉伸性,这是一种情况下发生的电压驱动的电介质的情况相反。结果表明,通过调节驱动方法,可以实现无吸合不稳定性的介质弹性体的可逆大驱动。

英文摘要:

Pull-in (or electro-mechanical) instability occurs when a drastic decrease in the thickness of a dielectric elastomer results in electrical breakdown, which limits the applications of dielectric devices. Here we derive the criteria for determining the pull-in instability of dielectrics actuated by different loading methods: voltage-control, charge-control, fixed pre-stress and fixed pre-stretch, by analyzing the free energy of the actuated systems. The Hessian criterion identifies a maximum in the loading curve beyond which the elastomer will stretch rapidly and lose stability, and can be seen as a path to failure. We present numerical calculations for neo-Hookean ideal dielectrics, and obtain the maximum allowable actuation stretch of a dielectric before failure by electrical breakdown. We find that applying a fixed pre-stress or a fixed pre-stretch to a charge-driven dielectric may decrease the stretchability of the elastomer, a scenario which is the opposite of what happens in the case of a voltage-driven dielectric. Results show that a reversible large actuation of a dielectric elastomer, free of the pull-in instability, can be achieved by tuning the actuation method.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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