Active Wing Shaping Control Concept Using Composite Lattice-Based Cellular Materials

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Towards Continuous Production of Shaped Honeycombs

Copyright © 2018 ASME. Honeycomb sandwich panels are widely used for high performance parts subject to bending loads, but their manufacturing costs remain high. In particular, for parts with non-flat, non-uniform geometry, honeycombs must be machined or thermoformed with great care and expense. The ability to produce shaped honeycombs would allow sandwich panels to replace monolithic parts in a number of high performance, spaceconstrained applications, while also providing new areas of research for structural optimization, distributed sensing and actuation, and on-site production of infrastructure. Previous work has shown methods of directly producing shaped honeycombs by cutting and folding flat sheets of material. This research extends these methods by demonstrating work towards a continuous process for the cutting and folding steps of this process. An algorithm for producing a manufacturable cut-And-fold pattern from a three-dimensional volume is designed, and a machine for automatically performing the required cutting and parallel folding is proposed and prototyped. The accuracy of the creases placed by this machine is characterized and the impact of creasing order is demonstrated. Finally, a prototype part is produced and future work is sketched towards full process automation

Fabrication and characterization of folded foils supporting streamwise traveling waves

© 2019 Elsevier Ltd A body of work has grown around the use of small amplitude traveling waves on aerodynamic and hydrodynamic surfaces for boundary layer control. In particular, when the traveling wave speed exceeds the free stream velocity, significant drag reductions have been shown in simulation. Building viable prototypes to test these hypotheses, however, has proven challenging. In this paper, we describe a candidate system for constructing structural airfoils and hydrofoils with embedded electromagnetic actuators for driving high velocity traveling waves. Our approach relies on the fabrication of planar substrates which are populated with electromagnetic components and then folded into a prescribed three dimensional structure with actuators embedded. We first specify performance characteristics based on hydrodynamic requirements. We then describe the fabrication of fiber-reinforced polymer composite substrates with prescribed folding patterns to dictate three dimensional shape. We detail the development of a miniaturized single-phase linear motor which is compatible with this approach. Finally, we compare the predicted and measured force produced by these linear motors and plot trajectories for a 200 Hz driving frequency