Professor Alfred J. Crosby, Polymer Science & Engineering Department, University of Massachusetts Amherst
Nature provides amazing examples of high velocity, high acceleration, impulsive movements that can be repeated numerous times over the course of an organism’s lifetime. Synthetic, or engineered, devices, on the other hand, are often challenged to achieve comparable performance across a wide range of size scales. Common to nature’s examples, including mantis shrimp and trap-jaw ants, is the integration of three essential components for elasticity-assisted movement: an actuator, spring, and latch. Elasticity-assisted motion has been utilized for thousands of years to amplify the power of natural or synthetic actuators; however, the scaling physics of these multi-component systems, especially in light of materials design, have not been widely considered. Here, we discuss our group’s efforts, within a multi-university collaborative team, to lay a foundation for understanding the role that materials properties and structure play in the performance of impulsive systems in nature with an eye toward aiding the development of engineered devices that can overcome current limitations. We first discuss the mechanics of elastic recoil and a set of systematic experiments on a resilin-like synthetic material. The results from this study leads to a common framework for describing the roles of geometry and materials properties for controlling duration, velocity, and acceleration. We then introduce recent advances of using mesoscale polymers, which build upon previously introduced concepts from our group, to develop high rate, large strain, microscale actuators. Collectively, these examples highlight the integrative approach of our group and how we use bio-inspired materials mechanics to inspire new technologies and provide fundamental insight.