Layered Jamming Functional Polymer-Based Composite Structures

With the ever-increasing usage of lightweight, high strength, and high stiffness per unit weight polymer-composite-based structural components combined with sensitive electronic components in land and air vehicles, there has been a growing need to develop composite structures that have integrated EMF shielding, as well as reliable detection and quantification of composite fatigue damage. Of particular importance for damage detection are the damage precursors that are initiated during early stages of structural fatigue life. While existing techniques, such as the acoustic emission (AE) and ultrasonic pitch-catch, etc. have been quite useful, those techniques only provide damages at the bulk level, missing the precursors generally created at microstructural level. Additionally, there have been increasing threats in damage and detection of platform by electromagnetic (EM) radiation. To address these challenges and also to develop structurally compatible noninvasive techniques, there is a need to develop composite structures with functional materials that can be used for sensing damage, morphing, shape sensing, and even EM shielding, potentially using non-contacting techniques. To realize these structures, we have employed “layered jamming” principles, where we can combine layers of different materials with various functionalities whose response can be controlled via different mechanisms, such as vacuum pressure. We have designed and fabricated a prototype-layered jamming functional polymer-based composite structure that behaves like a shape memory material using bistable composites for morphing capabilities combined with metal layers with carbon-coated paper that be used for flexural sensing, as well as paper layers to control the mechanical properties of the structure. Results indicate that it is viable to realize fatigue-tolerant structures with morphing, shape sensing, and structural health-monitoring capabilities through the combination of bistable composites and layered jamming structures.