AEROSPACE ENGINEERING

Abstract

The field of multi-stable metastructures has been steadily growing due to a wide range of potential applications including morphing structures, energy harvesting, MEMS, and mechanical logic. This work focuses on utilizing elastic energy trapping and snap-through phenomena of bistable unit cells to design a latticed, hierarchical multi-stable cylinder that can articulate up to 30 degrees from its center axis. The employment of bistable elements is hypothesized to reduce the total strain energy required to articulate the cylinder and yield faster responses with the snap-through phenomenon. Modeling results show that the strain energy of an articulating cylinder can be minimized with the use of multi-stability and that a multi-stable cylinder can require nearly an order of magnitude smaller loads to maintain desired articulation compared to a mono-stable structure. These findings can lead to future works on optimizing the articulating cylinder by varying the geometric parameters of the unit cells. In addition, this study can yield methodologies for designing arbitrarily morphing skins beyond just cylindrical geometries. Additionally, the multi-stable articulation can be actuated using active materials and structures, which have been the focus of research for several decades due to their applications spanning fields from aerospace to biomedicine. In recent years, multi-field actuated composites utilizing two active materials have been studied in order to deform simple structures into more complex geometries. These deformations can be achieved with active materials such as electro-active and magneto-active polymers, which can be deformed under externally applied electric and magnetic fields, respectively. Some of these materials gain their active properties from micro-mechanical interactions of particles, which have been modeled using electrodynamics and nonlinear elasticity.  Theoretical analyses of the mechanics of heterogenous active systems have shown that these materials can be tailored to desired properties or responses by modifying the orientations of particles via processing methods.

Speaker

Dr. Anil Erol

A National Research Council post-doctoral Research Associate at the Air Force Research Laboratory at Wright-Patterson AFB, OH. He earned his Ph.D. in mechanical engineering from the Pennsylvania State University, with a thesis on modeling the nonlinear mechanics of electro- and magneto-active polymers. His postdoctoral research explores unique cross-disciplinary approaches to morphing structures, particularly focusing on leveraging multi-stability, mechanical instabilities, and active materials.