Dipartimento di Ingegneria Meccanica e Gestionale, TriboLAB, Politecnico di Bari, V.le Japigia 182, 70126 Bari, Italy.
J R Soc Interface. 2012 Dec 7;9(77):3359-65. doi: 10.1098/rsif.2012.0452. Epub 2012 Sep 12.
We propose a novel design of a biomimetic micro-structured surface, which exhibits controlled strongly direction-dependent adhesion properties. The micro-system consists of parallel elastic wall-like structures covered by a thin layer. Numerical calculations have been carried out to study the adhesive properties of the proposed system and to provide design criteria with the aim of obtaining optimized geometries. A numerically equivalent version of the double cantilever beam fracture experiment is, then, simulated by means of finite element analysis to investigate the anisotropic adhesion of the structure. We find that, because of inherent crack trapping properties of these types of structures, the wall-like geometry allows us to strongly enhance adhesion when the detachment direction is perpendicular to the walls. On the other hand, when the detachment occurs parallel to the walls, the system shows low adhesion. This controlled direction-dependent adhesive property of the proposed structure solves one of the key problems of biomimetic adhesive surfaces, which usually show very strong adhesion, even larger than biological systems, but are not suitable for object manipulation and locomotion, as detachment always occurs at high loads and cannot be controlled.
我们提出了一种仿生微结构表面的新颖设计，该表面具有可控的强烈各向异性粘附特性。微系统由平行的弹性壁状结构组成，这些结构覆盖有一层薄膜。已经进行了数值计算，以研究所提出系统的粘附特性，并提供设计标准，旨在获得优化的几何形状。通过有限元分析模拟了等效于双悬臂梁断裂实验的数值版本，以研究结构的各向异性粘附。我们发现，由于这些类型结构的固有裂纹捕获特性，壁状几何形状允许我们在脱离方向垂直于壁时强烈增强粘附。另一方面，当脱离发生在平行于壁的方向上时，系统表现出低粘附力。所提出结构的这种可控的各向异性粘附特性解决了仿生粘附表面的一个关键问题，即通常表现出非常强的粘附力，甚至比生物系统还要大，但不适合物体操纵和运动，因为脱离总是在高负载下发生，并且无法控制。
