This study analyzes the finite deformation and the bifurcation behavior associated with the opening (i.e., unbending and eversion) of a bilayered cylinder, with layers made of hyperelastic and incompressible materials. The solution to the finite deformation problem reveals interesting stress states, including the presence of multiple neutral axes, as well as in certain cases the absence of neutral axes. Additionally, we show that the presence of a second layer can significantly impact the bifurcation behavior of the system, when compared to the homogeneous cylinder. The addition of a stiff, thin layer (i.e., coating) both at the tensile as well as at the compressive side can significantly affect when a system loses stability on applying unbending and eversion.

本研究分析了与由超弹性和不可压缩材料制成的双层圆柱体的开口（即，伸直和外翻）相关的有限变形和分叉行为。有限变形问题的解决方案揭示了有趣的应力状态，包括存在多个中性轴，以及在某些情况下不存在中性轴。此外，我们表明，与均质圆柱相比，第二层的存在可以显着影响系统的分叉行为。在拉伸侧和压缩侧添加坚硬的薄层（即涂层）可以显着影响系统在施加不弯曲和外翻时何时失去稳定性。