A Feasibility Study to Control Airfoil Shape Using Thunder
A Feasibility Study to Control Airfoil Shape Using Thunder

Author: National Aeronautics and Space Administration (NASA)

Publisher: Createspace Independent Publishing Platform

Published: 2018-06-28

Total Pages: 30

ISBN-13: 9781721999811

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The objective of this study was to assess the capabilities of a new out-of-plane displacement piezoelectric actuator called thin-layer composite-unimorph ferroelectric driver and sensor (THUNDER) to alter the upper surface geometry of a subscale airfoil to enhance performance under aerodynamic loading. Sixty test conditions, consisting of combinations of five angles of attack, four dc applied voltages, and three tunnel velocities, were studied in a tabletop wind tunnel. Results indicated that larger magnitudes of applied voltage produced larger wafer displacements. Wind-off displacements were also consistently larger than wind-on. Higher velocities produced larger displacements than lower velocities because of increased upper surface suction. Increased suction also resulted in larger displacements at higher angles of attack. Creep and hysteresis of the wafer, which were identified at each test condition, contributed to larger negative displacements for all negative applied voltages and larger positive displacements for the smaller positive applied voltage (+102 V). An elastic membrane used to hold the wafer to the upper surface hindered displacements at the larger positive applied voltage (+170 V). Both creep and hysteresis appeared bounded based on the analysis of several displacement cycles. These results show that THUNDER can be used to alter the camber of a small airfoil under aerodynamic loads. Pinkerton, Jennifer L. and Moses, Robert W. Langley Research Center RTOP 505-63-50-13...

Smart Composites
Smart Composites

Author: Rani Elhajjar

Publisher: CRC Press

Published: 2013-12-14

Total Pages: 432

ISBN-13: 1439895910

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Smart Composites: Mechanics and Design addresses the current progress in the mechanics and design of smart composites and multifunctional structures. Divided into three parts, it covers characterization of properties, analyses, and design of various advanced composite material systems with an emphasis on the coupled mechanical and non-mechanical behaviors. Part one includes analyses of smart materials related to electrically conductive, magnetostrictive nanocomposites and design of active fiber composites. These discussions include several techniques and challenges in manufacturing smart composites and characterizing coupled properties, as well as the analyses of composite structures at various length and time scales undergoing coupled mechanical and non-mechanical stimuli considering elastic, viscoelastic (and/or viscoplastic), fatigue, and damage behaviors. Part two is dedicated to a higher-scale analysis of smart structures with topics such as piezoelectrically actuated bistable composites, wing morphing design using macrofiber composites, and multifunctional layered composite beams. The analytical expressions for characterization of the smart structures are presented with an attention to practical application. Finally, part three presents recent advances regarding sensing and structural health monitoring with a focus on how the sensing abilities can be integrated within the material and provide continuous sensing, recognizing that multifunctional materials can be designed to both improve and enhance the health-monitoring capabilities and also enable effective nondestructive evaluation. Smart Composites: Mechanics and Design is an essential text for those interested in materials that not only possess the classical properties of stiffness and strength, but also act as actuators under a variety of external stimuli, provide passive and active response to enable structural health monitoring, facilitate advanced nondestructive testing strategies, and enable shape-changing and morphing structures.

Proceedings of the 5th IEEE/IFToMM International Conference on Reconfigurable Mechanisms and Robots
Proceedings of the 5th IEEE/IFToMM International Conference on Reconfigurable Mechanisms and Robots

Author: Fengfeng (Jeff) Xi

Publisher: ReMAR2021

Published: 2021-08-12

Total Pages: 828

ISBN-13: 1774170434

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The 5th IEEE/IFToMM International Conference on Re-configurable Mechanisms and Robots (ReMAR 2021) was held in Toronto, Canada on August 12-14, 2021 at Ryerson University. The conference proceedings include more than 70 papers on three main subjects, 1) Reconfigurable Mechanisms and Robotics, 2) Variable Topology and Morphing Mechanism, and 3)Origami and Bio-inspired mechanisms.

Piezoelectric and Acoustic Materials for Transducer Applications
Piezoelectric and Acoustic Materials for Transducer Applications

Author: Ahmad Safari

Publisher: Springer Science & Business Media

Published: 2008-09-11

Total Pages: 483

ISBN-13: 0387765409

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The book discusses the underlying physical principles of piezoelectric materials, important properties of ferroelectric/piezoelectric materials used in today’s transducer technology, and the principles used in transducer design. It provides examples of a wide range of applications of such materials along with the appertaining rationales. With contributions from distinguished researchers, this is a comprehensive reference on all the pertinent aspects of piezoelectric materials.