论文标题
关于不对称弯曲行为的新观点：从叶子学到的教训
New perspectives on asymmetric bending behavior: A lesson learned from leaves
论文作者
论文摘要
设计可以响应对称切换刺激而实现不对称形状转移的材料或结构是提高软执行器/机器人的运动性能的一种有前途的方法。受许多植物细长叶片的几何形状的启发，我们发现带有U形横截面的薄壁梁在弯曲的情况下表现出不对称的变形行为。尽管长期以来一直在某些应用中注意到并使用了这种新型的机械性能，但到目前为止，其机制尚不清楚。在这项研究中，我们将薄壁U形梁的这种不对称弯曲行为归因于弯曲诱导的压缩效应引起的侧壁的屈曲。基于Euler-Bernoulli束理论和Kirchhoff-Love薄板理论，建立了一个简单但有效的模型，以得出以半分析形式的侧壁屈曲的临界力矩。使用有限元分析模拟和实验来验证我们发现的理论基础。我们工作的结果不仅阐明了薄壁U形梁的不对称弯曲行为的基础机制，而且还为高性能软执行器/机器人和其他新型设备的结构设计开辟了新的途径。
Designing materials or structures that can achieve asymmetric shape-shifting in response to symmetrically switching stimuli is a promising approach to enhance the locomotion performance of soft actuators/robots. Inspired by the geometry of slender leaves of many plants, we find that the thin-walled beam with a U-shaped cross section exhibits asymmetric deformation behaviors under bending with opposite orientations. Although this novel mechanical property has been long noticed and utilized in some applications, its mechanism is still unclear so far. In this study, we attribute this asymmetric bending behavior of thin-walled U-shaped beams to the buckling of sidewalls caused by the bending-induced compressive effect. Based on the Euler-Bernoulli beam theory and Kirchhoff-Love thin plate theory, a simple but efficient model is established to derive the critical moment for the sidewall buckling in a semi-analytical form. Finite element analysis simulations and experiments are employed to validate the theoretical foundations of our findings. The results of our work not only shed light on the mechanics underlying the asymmetric bending behavior of thin-walled U-shaped beams, but also open up new avenues for the structure design of high-performance soft actuators/robots and other novel devices.
