By Ranjan Ganguli, Dipali Thakkar, Sathyamangalam Ramanarayanan Viswamurthy
Exploiting the homes of piezoelectric fabrics to reduce vibration in rotor-blade actuators, this publication demonstrates the potential for clever helicopter rotors to accomplish the smoothness of experience linked to jet-engined, fixed-wing airplane. Vibration regulate is effected utilizing the techniques of trailing-edge flaps and active-twist. The authors’ optimization-based strategy exhibits the benefit of a number of trailing-edge flaps and algorithms for full-authority regulate of twin trailing-edge-flap actuators are offered. Hysteresis nonlinearity in piezoelectric stack actuators is highlighted and compensated through use of one other set of rules. the belief of reaction surfaces offers for optimum placement of trailing-edge flaps.
The idea of lively twist includes the employment of piezoelectrically brought about shear actuation in rotating beams. Shear is then confirmed for a thin-walled aerofoil-section rotor blade lower than feedback-control vibration minimization. energetic twist is proven to be major in decreasing vibration brought on by dynamic stall. The exposition of principles, fabrics and algorithms during this monograph is supported by way of vast reporting of effects from numerical simulations of shrewdpermanent helicopter rotors.
This monograph could be a priceless resource of reference for researchers and engineers with backgrounds in aerospace, mechanical and electric engineering drawn to clever fabrics and vibration control.
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Extra resources for Smart Helicopter Rotors: Optimization and Piezoelectric Vibration Control
146]. 50 at 5/rev excitation frequencies. In , a Vlasov based bar analysis was used to derive a specialized, computationally efficient, one dimensional finite element, to model the nonrotating actuator beam. This was a two-node, 12-degree-of-freedom element with bending, torsion, and in-and out-of-plane warping degrees of freedom and induced strain capability. Results obtained by FEM (Finite Element Method) were validated by experiments for two cases. Good correlation was obtained with experimental data.
A finite element formulation was used to implement the coupled theory. After the induced-velocity coefficients were obtained, the aerodynamic, inertial, and centrifugal forces along the blade span were integrated to calculate the rotor vibratory loads. For maximum efficiency, the distribution of the actuator locations must be closely related to the region of high strain rate of the vibration modes. Elements 1 (root area where maximum strain rate occurs, blade length is divided into 10 elements) and 5 represent optimal actuator locations for the control of the second flapping mode and elements 1, 3, 4, 9, and 10 represent the most effective locations for the third flapping mode.
Vertica 11(1/2), 109–122 (1987) 53. : Design and first tests of individual blade control actuators. In: Proceedings of the 16th European Rotorcraft Forum, Glasgow, Scotland, UK (1990) 54. : Vibratory loads reduction testing of the NASA/Army/MIT active twist rotor. J. Am. Helicopter Soc. 47(2), 123–133 (2002) 55. : New developments in vibration reduction with actively controlled trailing edge flaps. Math. Comput. Model.