Park Ji-Sung, Kim Junseong, Lee Anna, Kim Ho-Young
Department of Mechanical Engineering, Seoul National University, Seoul 08826, Korea.
Department of Mechanical Engineering, Pohang University of Science and Technology, Pohang 37673, Korea.
Soft Matter. 2023 Nov 1;19(42):8213-8220. doi: 10.1039/d3sm01020a.
Snap-through buckling instability of elastic shells can provide a variety of biological and artificial mechanical systems with an efficient strategy to generate rapid and powerful actuation. However, snapping spherical shells studied to date have typically been shallow and thus are dominantly prone to axisymmetric inversions. Here, we study diffusion-swelling stimulated snap-through inversion of bilayer shells of a wide range of depth to cover non-axisymmetric as well as axisymmetric modes. We first establish an analytical model of strain energy stored in axisymmetrically swelling shells, in order to predict the snap-through conditions based on energy minimization. Confirming that the strain energy can indicate the critical conditions for snap-through, we compare the conditions of axisymmetric and non-axisymmetric snap-through inversion using both experiments and numerical simulations. We find that differentially swelling bilayer shells snap-through with a time-lagged but increased energy release during inversion when buckled non-axisymmetrically rather than axisymmetrically.
弹性壳的突变屈曲不稳定性可为各种生物和人工机械系统提供一种高效策略，以产生快速而强大的驱动。然而，迄今为止所研究的突变球形壳通常较浅，因此主要易于发生轴对称反转。在此，我们研究了广泛深度的双层壳在扩散膨胀作用下的突变反转，以涵盖非轴对称以及轴对称模式。我们首先建立了轴对称膨胀壳中储存的应变能的解析模型，以便基于能量最小化来预测突变条件。在确认应变能可指示突变的临界条件后，我们通过实验和数值模拟比较了轴对称和非轴对称突变反转的条件。我们发现，当非轴对称而非轴对称屈曲时，差异膨胀的双层壳在反转过程中会以时间延迟但能量释放增加的方式发生突变。
