High-speed airflow influence on adhesion performance of fibrillar adhesive

Bio-inspired adhesives have been widely studied in various fields, including attachment and grasping technologies in sea, land, air, and space. However, current research primarily focuses on static and quasi-static scenarios, necessitating further exploration in achieving adhesion on high-speed moving objects, such as railroads and automobiles. In this study, we explore a representative adhesive system comprising a fibrillar adhesive layer and a backing structure contacting with a smooth substrate in high-speed airflow. The investigation into adhesion performance was conducted by FEA (finite element analysis), theoretical analysis, and experimental approaches. Our findings indicate that the impact of high-speed airflow on microfiber structure deformation primarily manifests within the initial 1~2 rows on the windward side, yet remains insufficient to significantly influence adhesion. The adhesion capacity of the adhesive composite in high-speed airflow is mainly determined by the elastic modulus of the backing structure and the deformation offset, exhibiting a straightforward linear relationship with their product. Moreover, an optimization strategy of adding a cowling to the adhesive composite with soft backing was proposed to preserve its high loading capacity. These findings present a comprehensive understanding of the loading mechanism of fibrillar adhesive composite in high-speed airflow and provide new insights into robust reversible adhesion design for related technologies.