CAREER: Modulation of Propagating Instabilities in Deployable Shell Structures

About This Grant

This Faculty Early Career Development (CAREER) award will support research focused on understanding the prevailing conditions for propagating instabilities and creating methods for regulating their behavior in deployable shell structures. Highly deformable thin shells can be elastically stowed and self-deployed while exhibiting superior stiffness to mass ratios when compared to other shape changing mechanisms. However, excessively tight packaging causes prolonged and disordered motion during deployment. This is driven by propagating instabilities consisting of the buckled formation and travel of localized folds. The underlying factors that cause multiple fold propagations, including interaction behaviors between folds, remain fundamentally unexplained. If left unregulated, the resulting motion could cause incomplete deployment and damage due to collision or entanglement. This award will support research focused on elucidating the mechanics of propagating instabilities that inform the robust design and packaging of deployable shell structures. The outcomes are anticipated to include new design principles for future deployable and adaptive structures that will advance the frontiers of space exploration, robotics, and morphing vehicles. Furthermore, this award will spark early interest in STEM and motivate students to pursue STEM careers through lab internships for high school students, research opportunities for undergraduate students, and exhibitions at local STEM events and museums. The main objective of this research award is to characterize the structural, dynamic, and packaging parameters that govern multiple fold propagation behaviors in deployable shell structures. A computational framework will produce response maps that visualize the motion and interaction of these deformations while strain energy stability landscapes will explain the underlying mechanisms. Novel fold interaction behaviors will be fundamentally understood including convergence, merging, reflections, divergence, and bifurcation. Experimental validation of the deployment paths will be provided by discrete, full-field, and embedded measurement techniques. The second objective is to investigate packaging and design methods that modulate multiple propagating instabilities in composite shells by (1) increasing the stability level of packaged folds that interact with and dissipate the energetic propagation of highly unstable folds, and (2) altering the local shape and layup in the traveling path of folds to manipulate their movement. The generated knowledge will be of the fold arrangements and localized changes to the shell that effectively suppress excessive deployment motion. This will be extended to more complex shell profiles and 3D shell formations, which will help explain how propagating instabilities behave and are modulated in kinematically coupled and variable curvature shell structures. 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.