Numerical investigation of squeeze film lubrication on bioinspired hexagonal patterned surface

Purpose This paper aims to investigate the squeeze film lubrication properties of hexagonal patterned surface inspired by the epidermis structure of tree frog's toe pad and numerically explore the working mechanism of hexagonal micropillar during the acquisition process of high adhesive and friction for wet contacts. Design/methodology/approach A two-dimensional elastohydrodynamic numerical model is employed for the squeezing contacts. The pressure distribution, load carrying capacity and liquid flow rate of the squeeze film are obtained through a simultaneous solution of the two-dimensional Reynolds equation and elasticity deformation equations. Findings Higher pressure is found to be longitudinally distributed across individual hexagonal pillar, with pressure peak emerging at the center of hexagonal pillar. Expanding the area density and shrinking the channel depth or initial film thickness will improve the magnitude of squeezing pressure. Relatively lower pressure is generated inside interconnected channels, which reduces the load carrying capacity of the squeeze film. Meanwhile, the introduction of microchannel is revealed to downscale the total mass flow rate of squeezing contacts. Originality/value This paper provides a good proof for the working mechanism of surface microstructures during the acquisition process of high adhesive and friction for wet contacts.

Automated summary

This study investigates the lubrication properties of a hexagonal patterned surface inspired by the epidermis structure of a tree frog's toe pad and explores the working mechanism of hexagonal micropillars in acquiring high adhesive and friction in wet contacts. The results reveal that higher pressure is longitudinally distributed across individual hexagonal pillars, with a pressure peak at the center. Increasing density and decreasing channel depth or initial film thickness improves the squeezing pressure magnitude. Lower pressure is generated in interconnected channels, reducing the load carrying capacity. The introduction of microchannels downscales the total mass flow rate.