发表机构
SISSA - International School for Advanced Studies; School of Mathematical and Statistical Sciences, University of Galway; School of Materials and Mechanical Engineering, University College Dublin; Biomedical Design, School of Mechanical Engineering, Technological University Dublin; School of Engineering, University of Galway（国际高等研究院; 高威大学数学与统计科学学院; 都柏林大学学院材料与机械工程学院; 都柏林理工大学机械工程学院生物医学设计; 高威大学工程学院）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
该研究分析受拉伸双层圆柱的拉伸不稳定性，发现薄膜泊松比影响褶皱出现时机，采用 auxetic 薄膜开展模拟与实验，虽模拟预测褶皱形成，但实验因振幅小难以观测。
AI 中文摘要
我们研究由不可压缩芯体和薄可压缩薄膜构成的双层圆柱的近表面拉伸不稳定性。理论上，圆柱受拉伸时外表面可能出现带有轴向波前的周向褶皱。我们通过建模、数值计算、有限元模拟及受控实验分析这些不稳定性，发现褶皱振幅和波长取决于薄膜的泊松比以及薄膜与基体的剪切模量之比；薄膜泊松比越低，受拉伸时褶皱出现得越早。这一发现促使我们在有限元模拟和实验中使用具有定制微结构的 auxetic 薄膜（负泊松比材料）。实验中，我们制备了带有刚性 auxetic 外层的 3D 打印软圆柱并对其施加轴向载荷，尽管模拟预测会形成明显褶皱，但由于褶皱振幅较小，实验观测更难实现。
英文摘要
We study near-surface tension instabilities in bilayered cylinders composed of an incompressible core coated with a thin compressible film. In theory, circumferential wrinkles with axial wavefronts may appear on the outer surface when the cylinder is stretched. We analyze these instabilities through modelling, numerics, finite element simulations, and controlled experiments. We show that the wrinkle amplitude and wavelength depend on the Poisson ratio of the coating and the ratio of the film and substrate shear moduli. We find that the lower the film's Poisson ratio, the earlier the wrinkles emerge under tension. This observation motivates us to use auxetic films (with negative Poisson ratios) with bespoke microstructures in the finite element simulations and the experiments. For the latter, we fabricated 3D-printed soft cylinders with stiff auxetic outer layers and subjected them to axial loading. Although simulations predicted clear wrinkle formation, experimental observation proved more elusive due to the small amplitude of the wrinkles.
