A dimensionally-reduced nonlinear elasticity model for liquid crystal elastomer strips with transverse curvature
A dimensionally-reduced nonlinear elasticity model for liquid crystal elastomer strips with transverse curvature
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DOI：
10.1039/d3sm00664f
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发表时间：
2023-10-23
期刊：
影响因子：
3.4
通讯作者：
Dayal，Kaushik
中科院分区：
文献类型：
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作者：
Logrande，Kevin;Shankar，M. Ravi;Dayal，Kaushik
液晶弹性体（LCE）是一种活性材料，由于其对各种外部刺激（如光和热）的可编程响应而受到关注。当暴露于这些刺激时，材料响应的各向异性由介电指向矢控制，介电指向矢是一个连续参数，定义为液晶相中介晶的平均局部取向。这种向列指向矢可以被编程为在空间中是异质的，从而创造出广阔的设计空间，对于从人工韧带到可展开结构再到自组装机制等应用都很有用。即使专门用于细长条的LCE-这项工作的重点-巨大的设计空间需要使用数值模拟来帮助实验发现。为了减轻全三维数值模拟的计算费用，已经为LCE条开发了几种降维的杆和带模型，但是这些模型没有考虑初始横向曲率的可能性，如木匠的带弹簧。最近的实验表明，横向弯曲的LCE条显示出丰富多样的配置的动机，这项工作推导出一个降维的1-D模型预弯曲的LCE条。1-D模型进行了验证，对全三维有限元计算，它也被证明捕捉实验观察，包括磁带弹簧样的本地化，在激活LCE条。
Liquid crystalline elastomers (LCEs) are active materials that are of interest due to their programmable response to various external stimuli such as light and heat. When exposed to these stimuli, the anisotropy in the response of the material is governed by the nematic director, which is a continuum parameter that is defined as the average local orientation of the mesogens in the liquid crystal phase. This nematic director can be programmed to be heterogeneous in space, creating a vast design space that is useful for applications ranging from artificial ligaments to deployable structures to self-assembling mechanisms. Even when specialized to long and thin strips of LCEs – the focus of this work – the vast design space has required the use of numerical simulations to aid in experimental discovery. To mitigate the computational expense of full 3-d numerical simulations, several dimensionally-reduced rod and ribbon models have been developed for LCE strips, but these have not accounted for the possibility of initial transverse curvature, like carpenter's tape spring. Motivated by recent experiments showing that transversely-curved LCE strips display a rich variety of configurations, this work derives a dimensionally-reduced 1-d model for pre-curved LCE strips. The 1-d model is validated against full 3-d finite element calculations, and it is also shown to capture experimental observations, including tape-spring-like localizations, in activated LCE strips.