Abstract: The movement mode of snakes is crawling, and the living environment of snakes with numerous branches and stones will cause plenty of wear for the snake scales. There are plenty of surface structures and morphology on snake scales to avoid severe wear. Among them, the research towards the keeled structure on snake scales is missing. Therefore, in this research, the wear resistance improvement of the keeled structure on the snake scales and the overlapped distribution of snake scales are investigated. The keeled and smooth snake scales were 3D printed and they were distributed on the substrate in the overlapped or paralleled ways. Besides these four samples with keeled/smooth scales and overlapped/paralleled distributed, there is also a reference sample with the same thickness. Based on the tribology test, the number of grooves of samples with the keeled structures is higher than that of samples with smooth surfaces, which indicates that the keeled structure dramatically enhances the wear resistance of snake scales, especially during the wear in the vertical direction. The experiment on surface morphology greatly compromised the result of the tribology test. In addition, the bottom portion of the keeled snake scales can be protected by the keeled structure. Besides, the overlapped distribution can protect the central region of snake scales and provide double-layer protection of the snake body. Overall, the keeled structure and the overlapped distribution play a significant part in the improvement of wear resistance of the snake skin. These findings can enhance the knowledge of the reptiles-mimic surface structure and facilitate the application of military uniforms under high-wear conditions.

Key words: Biomimetic , · Snake scales , · Keeled structure , · Overlapped distribution , · Wear resistance