法国巴黎大学Benoît Roman团队研究了非对称弯曲边界层的λ测试。这一研究成果于2025年3月13日发表在《美国科学院院刊》上。

课题组研究了两端非对称带状物的力学行为，描述了粘合附近的弹性连接，并将其概念化为弯曲边界层。虽然这种连接的尺寸随着拉力的增加而减小，但他们观察到结合角作为弯曲刚度的宏观特征的惊人存在。

因此，该结果挑战了忽略薄壳在大拉伸载荷下的弯曲刚度的标准假设。此外，研究组展示了结构的旋转响应如何表现出非线性和普遍的行为，而不管不对称性的比例如何。利用结合角与拉力的独立性，他们最终引入了λ测试——一种通过简单的机械耦合来表征膜的视觉测量技术。

附：英文原文

Title: Asymmetric bending boundary layer: The λ-test

Author: Vani, Nathan, Ibarra, Alejandro, Bico, José, Reyssat, étienne, Roman, Benot

Issue&Volume: 2025-3-13

Abstract: We investigate the mechanics of two asymmetric ribbons bound at one end and pulled apart at the other ends. We characterize the elastic junction near the bonding and conceptualize it as a bending boundary layer. While the size of this junction decreases with the pulling force, we observe the surprising existence of the binding angle as a macroscopic signature of the bending stiffnesses. Our results thus challenge the standard assumption of neglecting bending stiffness of thin shells at large tensile loading. In addition, we show how the rotational response of the structure exhibits a nonlinear and universal behavior regardless of the ratio of asymmetry. Leveraging the independence of the binding angle to the pulling force, we finally introduce the λ-test—a visual measurement technique to characterize membranes through simple mechanical coupling.

DOI: 10.1073/pnas.2426748122

Source: https://www.pnas.org/doi/abs/10.1073/pnas.2426748122