Polydomain liquid crystalline (nematic) elastomers exhibit unique mechanical properties such as soft elasticity, where the material largely deforms at nearly constant stress, due to microstructural evolution. In this paper, we numerically study the effect of such remarkable soft behavior on the surface instability of a half-space polydomain nematic elastomer, which is uniformly compressed parallel to the interface under a plane-strain condition. We compare the creasing instability of nematic elastomers with that of neo-Hookean elastomers by presenting bifurcation diagrams, stress and strain development in the elastomers, energy relaxation, and surface morphology at the creased state. Our results reveal that soft elasticity stabilizes nematic elastomers in plane-strain compression. Remarkably, the critical strain and stress at which the crease nucleates depend nonlinearly on the degree of anisotropy in nematic elastomers. Moreover, we find that the morphology of the creased surface in nematic elastomers exhibits the universal cusp shape previously observed in neo-Hookean elastomers.

中文翻译：

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压缩时多域向列弹性体的不稳定性增加


多域液晶（向列型）弹性体表现出独特的机械性能，例如软弹性，由于微观结构的演变，材料在几乎恒定的应力下大部分会变形。在本文中，我们数值研究了这种显著的软行为对半空间多域向列弹性体表面不稳定性的影响，该弹性体在平面应变条件下平行于界面均匀压缩。我们通过提供分叉图、弹性体中的应力和应变发展、能量松弛和折痕状态下的表面形态，比较了向列弹性体与新胡克弹性体的折痕不稳定性。我们的结果表明，软弹性在平面应变压缩中稳定了向列弹性体。值得注意的是，折痕成核的临界应变和应力非线性地取决于向列弹性体的各向异性程度。此外，我们发现向列弹性体中折痕表面的形态表现出先前在新胡克弹性体中观察到的通用尖头形状。