Dept. of Materials Science and Engineering Fall Seminar Series: Shu Yang

Description

Shu Yang, professor of engineering and applied science and chair of Materials Science & Engineering at the University of Pennsylvania, will give a talk titled "Snapping of Liquid Crystal Elastomer Looped Fibers and Knots for Diverse Motions and Sustainability" for the Department of Materials Science and Engineering.

Abstract:

Snapping instability is common in nature as seen in Venus flytrap and hummingbird to catch insects mid-flight where the animals and plants use this mechanism to store the elastic energy and release it as kinetic energy for rapid motions. Here, I will discuss how we explore spontaneous snap-through instabilities in looped fibers and knots made from liquid crystal elastomers (LCE) upon contact with a hot surface. When LCE fibers are connected into lobed loops, where each fiber is geometrically constrained by the neighboring ones, they demonstrate autonomous, self-regulated, and repeated synchronization. By adding a rigid bead on the fiber, we can fine-tune the actuation direction and speed, demonstrating various gait-like locomotion patterns using the loops as the soft robot's legs. By exploiting the knot topology and materials elasticity, I will discuss our effort to program the stored elastic energy within the knots, demonstrating ultrafast, ultrahigh leaping behaviors with variable flying patterns. Lastly, I will discuss their potential applications for seed dispersals and self-burial seeding for sustainability.