Crumple Dynamics and Interactions Mediating Elastic Deformations of Structures

Board Of Regents, Nshe, Obo University Of Nevada, Reno, Reno NV

Investigators

Abstract

The elastic deformation of thin plate and shell structures at many length scales, from cell membranes to clothing to aircraft panels to storage tanks, is characterized by the localization of stretching and bending. This is often simply called “crumpling,” and the small regions of large deformations “crumples.” Crumples are observed to play an important role in enabling the large-scale deformations of thin structures, often through rapid transient dynamic behavior that is currently not well documented or understood. This award will facilitate the study of these fundamental deformation processes through experiments on a simple model system and two different theoretical approaches. Insights from this work will aid in the modeling and control of complex phenomena in multi-scale elastic systems that are prohibitively complex to simulate in real time through the development of reduced-order models, e.g., the aero-thermo-elastic phenomena in aerospace applications. Results will also be applicable to other branches of structural mechanics, compliant mechanisms, soft robotics, and some biological systems. The award will support a postdoctoral researcher and train a group of graduate and undergraduate students in advanced structural mechanics, with the latter involving international exchanges with collaborators. The PI and students will also co-develop an education module for a summer science and engineering program in local middle and high schools. The objective of this award is to quantify and model the meso-scale mechanics of localized elastic regions (crumples) in deforming plates, focusing on the role these localized crumples play in mediating global deformations through both quasistatic and rapid transient dynamics. The work builds on preliminary experiments demonstrating phenomena such as sequences of ordered patterns, nucleation of individual crumples, and crumple-crumple or crumple-boundary interactions. Two theoretical approaches will be employed. One will leverage ideas from structural mechanics and pattern-forming systems, where “snaking” transitions occur between localized patterns in continua. Another will take a novel particle-level description of crumples as individual discrete entities that can interact with a background curvature field, with each other, and with boundaries. These approaches will be accompanied by quantitative experimental measurements of forces on, and curvatures of, buckled sheets. 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.