Finding solutions in nature for practical problems is nothing new. However, according to Hisham Abdel-Aal, an associate teaching professor from Drexel University’s College of Engineering, when it comes to the mechanics of friction, examples in nature have been largely overlooked. This, he said, is because the interest in friction has typically been limited either to overcoming or maximizing it for a specific purpose and fades once the issue is resolved.

Abdel-Aal has been studying friction by analyzing snakes for nearly a decade. Through evolution, snakes have adapted to move efficiently and survive in their various habitats immediately. “These environments can be brutal on even our most advanced machinery, so applying what we know about snake texturing could help our technology adapt as well,” he reasoned.

Abdel-Aal collected and studied hundreds of snake skin samples from 40 different species. Source: Drexel UniversityAbel-Aal has analyzed hundreds of shed snakeskins, acquired initially from friends and later from the Philadelphia Zoo and the Academy of Natural Sciences, to learn about their different characteristics and how snakes use friction and movement to navigate their surroundings. His extensive process includes producing an image of each skin with a scanning electron microscope to show the details of its texture. He creates texture profiles that measure the forces of friction exerted by the snake as it moves. By comparing these texture profiles with existing data on the physics of snake movement and measures of the forces of friction exerted by the snakes, Abdel-Aal is able to show the effect of the physical traits on the snake’s mechanics.

Abdel-Aal’s ultimate goal is to develop a reference that allows engineers to compare the characteristics of surfaces with the those of the snakeskins and use that knowledge to manage friction and improve system performance. “For bio-inspired surface design to be effective, we needed to develop a common vocabulary to describe texturing features,” Abdel-Aal wrote.

He has already published his datasets for engineers to use. Examples of how his work is being incorporated into real-world applications include the design and testing of the surface of a prosthetic hip in Colombia, the development of texturing schemes for tool inserts used in dry machining of titanium in the U.K. and the development by German engineers of cylinder liners that minimize friction whether moving forward or backward.

The complete study is available at NCBI PubMed.