The Biomimetic Shark Skin Optimization Design Method for Improving Lubrication Effect of Engineering Surface

Nature has long been an important source of inspiration for mankind to develop artificial ways to mimic the remarkable properties of biological systems. In this work, a new method was explored to fabricate a biomimetic engineering surface comprising both the shark-skin, the shark body denticle, and rib morphology. It can help reduce water resistance and the friction contact area as well as accommodate lubricant. The lubrication theory model was established to predict the effect of geometric parameters of a biomimetic surface on tribological performance. The model has been proved to be feasible to predict tribological performance by the experimental results. The model was then used to investigate the effect of the grid textured surface on frictional performance of different geometries. The investigation was aimed at providing a rule for deriving the design parameters of a biomimetic surface with good lubrication characteristics. Results suggest that: (i) the increase in depression width ratio $Λ$ decreases its corresponding coefficient of friction, and (ii) the small coefficient of friction is achievable when $Λ$ is beyond 0.45. Superposition of depth ratio Γ and angle's couple under the condition of $Λ$ < 0.45 affects the value of friction coefficient. It shows the decrease in angle decreases with the increase in dimension depth $Γ$⁠.