CAREER: Patterning Hard Interlocking Particles to Achieve Soft Materials and Structures

This Faculty Early Career Development Program (CAREER) award will be used to study the mechanics of interlocking granular materials that consist of hard, interlocking elements assembled into soft, deformable materials, and their ability to enable shape-shifting structures. Soft materials have been essential to innovations in tissue engineering, soft robotics, stretchable electronics, among many other applications; however, their mechanical behavior is hard to tune and scaling them for nano- to meter-scale applications (e.g., from miniaturized medical devices to meter-scale reconfigurable structures) is challenging. Since the underlying structure of interlocking granular materials can be precisely tailored using optimization and advanced manufacturing, they have higher potential to be engineered for targeted behavior than traditional soft materials. This research will address the key challenge of understanding the fundamental deformation and failure mechanisms of interlocking granular materials and develop computational models for design and analysis purposes. Furthermore, a partnership between the research team and a workforce development program at Georgia Tech will enable long-term immersion of high-school students into the research and provide a platform to pilot educational materials related to interlocking granular materials for release to the broader engineering education community. Interlocking granular materials lie at the intersection of traditional architected materials (e.g., truss lattices) with rigidly connected constituents and traditional granular materials (e.g., gravels) with disconnected constituents. Their mechanics differs from the former in that they can “flow” via relative movement of their particles and from the latter in that their ability to “flow” is limited by collision of the particles in tension as well as in compression. Topological interlocking is the key distinguishing feature that prompts a different theoretical and numerical treatment than in these other well-studied systems. Experimentation and expensive discrete element simulations have dominated the limited studies on interlocking granular materials, but a well-founded theoretical and computational mechanics description that facilitates integration of interlocking granular materials into methodical design strategies is not yet established. Inspired by continuum mechanics of soft materials, a two-potential approach will capture the effects of particle-level contact, deformation, and failure as a function of particle and network topology parameters, in a homogenized view of the discrete system, which will enable strategic patterning of interlocking granular materials into optimized structures with shape-shifting capabilities. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria. NSF Award ID: 2542321 | Program: 01002627DB NSF RESEARCH & RELATED ACTIVIT | Principal Investigator: Emily Sanders | Institution: Georgia Tech Research Corporation, ATLANTA, GA | Award Amount: $662,045 View on NSF Award Search: https://www.nsf.gov/awardsearch/show-award/?AWD_ID=2542321 View on Research.gov: https://www.research.gov/awardapi-service/v1/awards/2542321.html