Sunny Jung, Virginia Tech – Applied Mathematics Colloquium

Tea at 3:30 in 330 Phillips Hall

Title: Biomechanics to bio-inspired engineering; tree leaf and diving bird

Abstract: In this talk, I will discuss two bio-inspiration problems of how mechanics principles help us to understand form and function of animals or plants, and how these design ideas from nature can be translated into engineering problems.

The first problem is how tree leaves change their surface structure over the season. In the fall, the wettability of Katsura leaves increases primarily due to the erosion of the second-tier (epicuticular wax) roughness features and the flattening of the first-tier (epidermal cells) surface features. Increased wettability during the fall may accelerate the leaf shedding processes by catching dew or rain droplets. We are currently developing a green technology to extract valuable hydrophobic coating materials from garbaged fallen leaves and to apply them on various surfaces by preserving most advantages that natural leaves have; self-cleaning hydrophobicity and high optical transparency.

The second problem is how several seabirds (e.g. Gannets and Boobies) dive into water at up to 24 m/s without any injuries. This study examines the effects of their beak shape and dense feathers during water entry to reduce or spread the impact force on the body. We found that a specific beak and skull shape helps to minimize the water-entering force. As a bio-inspired engineering system, we are currently developing a deep-ocean projectile. The shape of a projectile is inspired by plunge-diving seabirds to avoid any structural damage, reduce drag, and improve stability in trajectory across the water surface. Also, the projectile can dive deep in the ocean without any propulsive power.