标题： 利用不稳定性在介电弹性体中实现大形状变换 显示英文标题

标题： Exploiting Instabilities to Enable Large Shape Transformations in Dielectric Elastomers

摘要： 介电弹性体在从软体机器人到生物医学设备的新技术中具有重要的潜力，这是由于它们能够对电刺激表现出复杂的形状变化。 然而，当前实现的一个重要缺点是，需要较大的电压才能产生有用的驱动应变。 本研究通过理论和数值模拟提出并展示了利用Treloar-Kearsley（TK）不稳定性电机械类比的策略，以实现大而可控的驱动效果。 关键思想是利用TK不稳定性是一种对称性破缺分岔，这意味着在能量景观中存在由对称性驱动的恒定能量区域。 这提供了具有大变形的非线性软模式，可以通过非常小的外部激励来实现，这里通过施加一个小的面内电场来实现。 首先，在均匀变形和电场的理想化情况下，建立了电机械TK不稳定性分岔和分岔后行为的理论。 接下来，基于此，应用有限元分析对具有图案化上下电极的真实几何结构进行分析，以展示由电极间小电压差驱动的大而柔软的形状变化。 显示英文摘要

摘要： Dielectric elastomers have significant potential for new technologies ranging from soft robots to biomedical devices, driven by their ability to display complex shape changes in response to electrical stimulus. However, an important shortcoming of current realizations is that large voltages are required for useful actuation strains. This work proposes, and demonstrates through theory and numerical simulations, a strategy to achieve large and controlled actuation by exploiting the electromechanical analog of the Treloar-Kearsley (TK) instability. The key idea is to use the fact that the TK instability is a symmetry-breaking bifurcation, which implies the existence of a symmetry-driven constant-energy region in the energy landscape. This provides for nonlinear soft modes with large deformations that can be accessed with very small external stimulus, which is achieved here by applying a small in-plane electric field. First, the bifurcation and post-bifurcation behavior of the electromechanical TK instability are established theoretically in the idealized setting of uniform deformation and electric field. Next, building on this, a finite element analysis of a realistic geometry with patterned top and bottom electrodes is applied to demonstrate large and soft shape changes driven by small voltage differences across the electrodes.