Chapter 6 Flexible Energy Harvesting/Storage Structures for Flapping Wing Air Vehicles Alex Holness, Hugh A. Bruck, and Satyandra K. Gupta Abstract Morphing structures are needed for many challenging missions for flapping wing air vehicles (FWAVs), but they will increase electrical power consumption in order to drive actuation systems and will require additional support systems to deliver and control the power. These power demands and associated support systems will comprise the ability of FWAVs to operate for longer periods of time without opportunities for refueling. Harvesting energy, such as solar, and increasing energy storage capacity appears to be an attractive solution to address this challenge. Although research has been conducted on integrating powering existing into aerospace components such as the body, tail and wings, they are typical rigid and can reduce performance because of parasitic mass. We envision compliant multifunctional skins with built-in capabilities for harvesting and storing energy can be used in highly compliant aerospace components, such as morphing wings. These skins will be able to deform and conform to the underlying structure, much like the way skins have evolved to work with components of biological actuation systems such as muscle and bone. They will increase the range of operation by utilizing readily available solar energy to increase electrical power and also increase storage capacity for excess electrical power conversion. Compliant multifunctional structure-energy harvesting-power concepts, once completely developed, may have an enormous impact not only on FWAVs, but on the field of UAVs in general, because of the current energy limitations that exist for these flight platforms. Once energy sources are no longer limited, the field of UAVs, especially Micro Air Vehicles (MAVs), should be able to expand exponentially. Keywords Multifunctional wing structures • Flexible solar cells • Flexible batteries • Multifunctional performance analysis 6.1 Introduction Skin materials can provide an interface for an underlying structure to interact with the surrounding environment. In aerospace applications, skins are made out of materials that have the appropriate friction, corrosion, and isolation characteristics that optimize durability and flight performance, while minimizing mass. Skin thicknesses are selected to ensure they provide adequate thermomechanical performance, since they are typically subjected to significant thermomechanical strain due to their location on the structure surface. Challenging air force missions are requiring electrically-powered systems to operate for longer period of times without opportunities for refueling. Harvesting solar energy and increasing energy storage capacity appears to be an attractive solution to address this challenge. Although research has been conducted into using batteries and solar cells in existing aerospace components such as the body, tail and wingspan, simply attaching solar cells and batteries to these rigid structures does not necessarily improve system performance. We envision multifunctional skins with built-in capabilities for harvesting and storing energy can cover or replace highly compliant aerospace components, such as morphing wings, while enhancing system performance. The compliant skins will be able to deform and conform to the underlying structure, and will increase the range of operation by utilizing readily available solar energy to increase electrical power and also increase storage capacity for excess electrical powerconversion. A. Holness • H.A. Bruck ( ) Department of Mechanical Engineering, University of Maryland, College Park, MD, USA e-mail: bruck@umd.edu S.K. Gupta Department of Mechanical and Aerospace Engineering, University of Southern California, Los Angeles, CA, USA © The Society for Experimental Mechanics, Inc. 2018 J. Carroll et al. (eds.), Fracture, Fatigue, Failure and Damage Evolution, Volume 7, Conference Proceedings of the Society for Experimental Mechanics Series, DOI 10.1007/978-3-319-62831-8_6 35
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