A Study of the Thermal Effects in a Smart Structure Helicopter Rotor
A Study of the Thermal Effects in a Smart Structure Helicopter Rotor

Author:

Publisher:

Published: 1999

Total Pages: 0

ISBN-13:

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One concept being considered for active noise and vibration control of helicopter rotors is a trailing edge flap design driven by a high-displacement piezoelectric actuator device. The proposed device requires an 800-V power supply and draws a current on the order of .3 A. Thus, depending on the duty cycle and efficiency of the mechanism, some portion of the 240 W of electrical input energy will be converted to heat. This study provides an initial estimate of the temperatures that may be encountered if no provisions are made for cooling the actuator. Also included are a discussion of the heat transfer calculation, assuming conduction and radiation as the dominant modes, and a description of HEAT 8, the computer code used.

Rotor/body Aerodynamic Interactions
Rotor/body Aerodynamic Interactions

Author: Mark D. Betzina

Publisher:

Published: 1983

Total Pages: 44

ISBN-13:

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A wind-tunnel investigation was conducted in which independent, steady-state aerodynamic forces and moments were measured on a 2.24-m-diam, two- bladed helicopter rotor and on several different bodies. The objective was to determine the mutual interaction effects for variations in velocity, thrust, tip-path-plane angle of attack, body angle of attack, rotor/body position, and body geometry. the results of the investigation show that the body longitudinal aerodynamic characteristics are significantly affected by the presence of a rotor and hub, and that the hub interference may be a major part of such interaction. This report presents the effects of various parameters on the interactions and discusses the difficulties encountered in determining the effect of the body on the rotor performance.

Smart Structures Technology: Innovations and Applications to Rotorcraft Systems
Smart Structures Technology: Innovations and Applications to Rotorcraft Systems

Author:

Publisher:

Published: 2000

Total Pages: 93

ISBN-13:

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The status of a number of rotorcraft research tasks supported under the Army Research Office "Smart Structures URI" program is reported herein for the reporting period from 1 January 1992 to 31 December 1997. For each task, the task objectives, the approach taken, and the final status of the research, and pertinent abstracts of journal articles or conference papers published as result of the research conducted under the task. Copies of all journal papers and conference papers that were produced under this program were forwarded to the U.S. Army Research Office in 1998, at the completion of the program, and are available upon request. The tasks are varied and cover many aspects of smart helicopter rotor development at the University of Maryland, including: (1) Development of a smart rotor using trailing edge flaps, and a controllable twist rotor blade, (2) Active tuning of composite shaft using shape memory alloy wires, (3) Active/passive damping for helicopter rotor stability augmentation, (4) Rotor acoustics control and analysis, (5) Health monitoring and damage detection, and (6) Elements of smart structures.

Smart Civil Structures
Smart Civil Structures

Author: You-Lin Xu

Publisher: CRC Press

Published: 2017-04-11

Total Pages: 548

ISBN-13: 1315351919

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A smart civil structure integrates smart materials, sensors, actuators, signal processors, communication networks, power sources, diagonal strategies, control strategies, repair strategies, and life-cycle management strategies. It should function optimally and safely in its environment and maintain structural integrity during strong winds, severe earthquakes, and other extreme events. This book extends from the fundamentals to the state-of-the-art. It covers the elements of smart civil structures, their integration, and their functions. The elements consist of smart materials, sensors, control devices, signal processors, and communication networks. Integration refers to multi-scale modelling and model updating, multi-type sensor placement, control theory, and collective placement of control devices and sensors. And the functions include structural health monitoring, structural vibration control, structural self-repairing, and structural energy harvesting, with emphasis on their synthesis to form truly smart civil structures. It suits civil engineering students, professionals, and researchers with its blend of principles and practice.

Smart Helicopter Rotors
Smart Helicopter Rotors

Author: Ranjan Ganguli

Publisher: Springer

Published: 2015-12-16

Total Pages: 264

ISBN-13: 3319247689

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Exploiting the properties of piezoelectric materials to minimize vibration in rotor-blade actuators, this book demonstrates the potential of smart helicopter rotors to achieve the smoothness of ride associated with jet-engined, fixed-wing aircraft. Vibration control is effected using the concepts of trailing-edge flaps and active-twist. The authors’ optimization-based approach shows the advantage of multiple trailing-edge flaps and algorithms for full-authority control of dual trailing-edge-flap actuators are presented. Hysteresis nonlinearity in piezoelectric stack actuators is highlighted and compensated by use of another algorithm. The idea of response surfaces provides for optimal placement of trailing-edge flaps. The concept of active twist involves the employment of piezoelectrically induced shear actuation in rotating beams. Shear is then demonstrated for a thin-walled aerofoil-section rotor blade under feedback-control vibration minimization. Active twist is shown to be significant in reducing vibration caused by dynamic stall. The exposition of ideas, materials and algorithms in this monograph is supported by extensive reporting of results from numerical simulations of smart helicopter rotors. This monograph will be a valuable source of reference for researchers and engineers with backgrounds in aerospace, mechanical and electrical engineering interested in smart materials and vibration control. Advances in Industrial Control aims to report and encourage the transfer of technology in control engineering. The rapid development of control technology has an impact on all areas of the control discipline. The series offers an opportunity for researchers to present an extended exposition of new work in all aspects of industrial control.