Shape Memory Alloy Actuated Ribbon Fin

I have always been fascinated by marine life. I remember going to the aquarium and being in awe of how gracefully these creatures glided through the water. This prompted me to study biomimetic aquatic propulsion. I spent a semester leading a team of four in the development of a shape memory actuator biomimitic ribbon fin. This fin consisted of five rays, each connected to a set artificial muscles. As the muscles bend, a sin wave propagates down the fin pushing water along with it generating forward motion.  Our final version was capable of delivering roughly 0.06 N of thrust.

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Artificial Muscles

Each muscle consists of three components: a delrin core, SMA actuator wire, and a silicone overmold. The delrin core provides structure and elasticity to the fin, allowing it to return after actuation. The SMA wire contracts 5% along its length when heated, serving as the muscle for the system. The rubber overmold protects the SMA actuator, insulating it from the cold aqueous environment.