Analysis and Measurement of Adhesive Behavior for Gecko-Inspired Synthetic Microwedge Structure

Synthetic microwedge adhesive inspired by gecko has great advantages in its prominent adhesion property and controllability. Clarifying the adhesion mechanism is significant for designing structure and enhancing performance. However, previous investigations have not given a thorough exposition in the adhesion mechanism of microwedge structure, especially, the complex relationship among shear load, contact area, and normal adhesion. In this paper, aiming to clarify the relationship mentioned above, a novel microwedge adhesive representation combined profile-constructed elastic beam model with a peel zone radius exact-solved cylindrical Johnson–Kendall–Roberts (JKR) model is proposed. First, the contact area can be obtained by reconstructing principal profile to the curved neutral surface based on the elastic beam model under different shear loads. Then the cylindrical JKR model with exact-solved fitting radius of peel zone is formulated to establish the relationship between shear load and normal adhesion of a single microwedge. Further, the effective contact between neighboring microwedges is considered to constrain the single microwedge deformation. Moreover, the microwedge array model takes into account the influence of normal movement, which is expressed with a correction factor based on comparison of theoretical analysis and measurement results. Finally, the model is verified with the simulation and the experimental measurement of two customized apparatuses.