Active and passive control of the aeroelastic response of helicopter rotors using smart materials to tailor the blade root flexibility

1995 ◽  
Author(s):  
Fred Nitzsche
Keyword(s):  
Smart Materials ◽  
Passive Control ◽  
Helicopter Rotors ◽  
Aeroelastic Response ◽  
Blade Root

scholarly journals Dynamical Analysis Applied to Passive Control of Vibrations in a Structural Model Incorporating SMA-SE Coil Springs

2018 ◽  
Vol 2018 ◽  
pp. 1-15 ◽  
Author(s):  
Yuri J. O. Moraes ◽  
Antonio A. Silva ◽  
Marcelo C. Rodrigues ◽  
Antonio G. B. de Lima ◽  
Rômulo P. B. dos Reis ◽  
...  
Keyword(s):  
Smart Materials ◽  
Passive Control ◽  
Structural Model ◽  
Physical World ◽  
Forced Vibrations ◽  
Dynamical Analysis ◽  
Modal Shape ◽  
Irreversible Damage ◽  
Second Mode ◽  
Structure Configuration

Mechanical vibrations are severe phenomena of the physical world. These oscillations may become undesirable and may cause temporary and even irreversible damage to the system. There are several techniques to minimizing these vibration effects ranging from passive methods to the use of controllers with smart materials. In this sense, this study aims to analyze a passive vibration control system installed in a structure that simulates two-floor buildings. This system based on the incorporation of one SMA-SE (Superelastic Shape Memory Alloys) coil springs configuration for energy dissipation and the addition of damping. Modal analysis was performed using analytical, numerical, and experimental methods. In an experimental basis, response amplitudes were analyzed for free and forced vibrations in different configurations. As compared with the structure configuration with steel spring, the forced vibrations FRF (Frequency Response Function) analysis showed a reduction in displacement transmissibility of up to 51% for the first modal shape and 73% for the second mode in the SMA-SE coil spring configuration. As for damping, there was a considerable increase in the order of 59% in the first mode and 119% in the second, for the SMA-SE springs configuration.

Control of Sound Radiation of an Active Constrained Layer Damping Plate/Cavity System Using the Structural Intensity Approach

2002 ◽  
Vol 8 (6) ◽  
pp. 903-918 ◽  
Author(s):  
Mohamed S. Azzouz ◽  
J. Ro
Keyword(s):  
Smart Materials ◽  
Passive Control ◽  
Sound Radiation ◽  
Constrained Layer Damping ◽  
Acoustic Cavity ◽  
Structural Intensity ◽  
Vibrating Plates ◽  
Active Constrained Layer Damping ◽  
Cavity System ◽  
Active Constrained Layer

Considerable attention has been devoted to actively and passively controlling the sound radiation from vibrating plates into closed cavities. With the advent of smart materials, extensive effort has been exerted to control the vibration and sound radiation from flexible plates using smart sensors/actuators. The Active Constrained Layer Damping (ACLD) treatment has been used successfully for controlling the vibration of various flexible structures. The treatment provides an effective means for augmenting the simplicity and reliability of passive damping with the low weight and high efficiency of active controls to attain high damping characteristics over broad frequency bands. This study investigates a numerically simulated example consisting of an ACLD treated plate/acoustic cavity system excited by a point harmonic force. In this study, an ACLD treated plate/acoustic cavity coupled finite element model is utilized to calculate the structural intensity and sound pressure radiated by the vibrating plates. In the passive control, the optimum placement of ACLD patches is determined by the structural intensity of ACLD treated plates and compared to the results obtained by using the strain energy approach. The influence on the structural intensity of the plate due to the damping treatment is investigated.

An Investigation of the Electroaeroelastic Behavior of a Locally Resonant Piezoelectric Metastructure

2018 ◽  
Author(s):  
Gabriel B. Schiavon ◽  
Joao H. R. Dainezi ◽  
Carlos De Marqui
Keyword(s):  
Control Systems ◽  
Smart Materials ◽  
Passive Control ◽  
Flexible Substrates ◽  
Aerodynamic Loads ◽  
Unsteady Aerodynamic ◽  
Control Schemes ◽  
Piezoelectric Layers ◽  
Rotary Wings ◽  
Resonant Shunt

The literature of aeroelasticity includes the use of smart materials to modify the aeroelastic behavior of fixed or rotary wings. In some cases, they are employed as actuators in active control systems while in others the use of smart materials in passive control schemes is investigated. In this work a different approach is investigated. The aeroelastic behavior of a locally resonant electromechanical metastructure made from flexible substrates with piezoelectric layers connected to resonant shunt circuits is investigated. An electromechanically coupled finite element plate model is employed for predicting the electroelasatic behavior of the wing. The unsteady aerodynamic loads are obtained from the doublet lattice model. By combining the structural and aerodynamic models, the aeroelastic behavior of the metastructure over a range of airflow speeds is studied.

scholarly journals Experimental results for active control of multimodal vibrations by optimally placed piezoelectric actuators

2018 ◽  
Vol 211 ◽  
pp. 20001 ◽  
Author(s):  
Andrea Rossi ◽  
Fabio Botta ◽  
Roberto Maiozzi ◽  
Andrea Scorza ◽  
Salvatore Andrea Sciuto
Keyword(s):  
Cantilever Beam ◽  
Smart Materials ◽  
Potential Distribution ◽  
Passive Control ◽  
Piezoelectric Actuators ◽  
Vibration Damping ◽  
Active Systems ◽  
Electrodynamic Shaker ◽  
And Performance ◽  
And Control

Vibration damping is an effective strategy to enhance the life-cycle and performance of mechanical components. In this regard passive control systems involve lower costs and are easier to implement but their bandwidth is limited, whereas active systems provide larger bandwidth and higher adaptability to dynamic loads but higher costs and complexity are required. The recent advances in smart materials promoted the development of smart structures suitable for vibration damping and control. Between them the piezoelectric systems seem to be the most promising, however their efficiency relies on their placement. In a previous work the authors proposed and validated an analytical method to detect the optimal location of piezoelectric plates to control the multi-modal vibrations of a cantilever beam. Recent findings show that, if all actuators are activated simultaneously, the optimization problem can be traced back to the determination of the optimal potential distribution on all the piezoelectric actuators. In this paper the above method is taken into account and applied to a cantilever beam with 13 pairs of surface mounted PZT plates under the excitation provided by an electrodynamic shaker. The experimental damping of two flexural modes combinations has been performed by means of a special-purpose workbench and the assessment of the damping efficiency has been measured by means of a micro I.C.P. accelerometer. The results showed that the multimode vibrations of the cantilever beam can be efficiently damped if the potential distribution on all the PZT plates is optimized.

Passive Control of the Vibration and Sound Radiation from Submerged Shells

2002 ◽  
Vol 8 (4) ◽  
pp. 425-445 ◽  
Author(s):  
J. Oh ◽  
M. Ruzzene ◽  
A. Baz
Keyword(s):  
Smart Materials ◽  
Passive Control ◽  
Sound Radiation ◽  
Structural Vibration ◽  
Finite Element Models ◽  
Constrained Layer Damping ◽  
Noise Radiation ◽  
Experimental Validations ◽  
Vibration And Sound Radiation ◽  
Passive Constrained Layer Damping

Vibration and noise radiation from fluid-loaded cylindrical shells are controlled using multiple stiffeners and Passive Constrained Layer Damping treatment. Dynamic and fluid finite element models are developed to study the fundamental phenomena governing the interaction between the stiffened shell, with and without damping, and the fluid domain surrounding it. The models are used to predict the response of the shell and to evaluate the effect of the stiffening rings and damping treatment on both the structural vibration and noise radiation in the fluid domain. The prediction of the models are validated experimentally and against the predictions of a commercial FE software package (ANSYS). It is shown that stiffening of the shell reduces the amplitude of the vibration and noise radiation, particularly for high order lobar modes. The attenuation of the shell response and sound radiation can be significantly increased through the application of Passive Constrained Layer Damping treatment on the inner surface of the stiffening rings. The numerical and experimental validations demonstrate the accuracy of the developed models and emphasize its potential extension to the application of smart materials for active control of vibration and noise radiation from fluid-loaded shells.

Effect of Crowning of Dovetail Joints on Turbine Blade Root Damping

2007 ◽  
Vol 347 ◽  
pp. 317-322 ◽  
Author(s):  
Marco Allara ◽  
Stefano Zucca ◽  
Muzio M. Gola
Keyword(s):  
Theoretical Model ◽  
Fatigue Damage ◽  
Passive Control ◽  
Structural Integrity ◽  
Resonant Vibrations ◽  
Blade Root ◽  
Centrifugal Load ◽  
Turbomachinery Blades ◽  
Contact Surfaces ◽  
First Time

Stresses due to resonant vibrations induce fatigue damage in turbomachinery blades jeopardizing their structural integrity. Damping plays a fundamental role in passive control of resonant stresses. In the present work the effect of ‘crowning’ of dovetail joints on blade-root friction damping is for the first time investigated. In detail, the damping of a simplified blade is measured under varying centrifugal load for two different joint geometries: a customary dovetail attachment and a ‘crowned’ one. A theoretical model is developed to quantify the damping generated at the contact surfaces. Experimental results and analytical predictions are compared.

A Method of Rapidly Estimating Propeller Moment

1954 ◽  
Vol 58 (520) ◽  
pp. 299-301
Author(s):  
P. R. Payne
Keyword(s):  
Fundamental Equation ◽  
Major Axis ◽  
Dynamic Phenomenon ◽  
Total Moment ◽  
Helicopter Rotors ◽  
Variable Pitch ◽  
Blade Root

Propeller moment is the name given to a dynamic phenomenon which causes considerable trouble in the design of variable pitch propellers and helicopter rotors. The development of the fundamental equation has not previously been published, to the author's knowledge, and for this reason the steps leading up to it are given. The propeller moment on any section tends to place its major axis in the plane of rotation, and the fundamental equation is equation. Its use to determine the total moment at a blade root results in lengthy calculations, with the possibilities of delays and errors.

4D printing technology, modern era: A short review

2020 ◽  
pp. 92-111
Author(s):  
Khodadad Mostakim ◽  
Nahid Imtiaz Masuk ◽  
Md. Rakib Hasan ◽  
Md. Shafikul Islam
Keyword(s):  
Smart Materials ◽  
Computer Aided Design ◽  
Short Review ◽  
Stimuli Responsive ◽  
4D Printing ◽  
Space Applications ◽  
Printing Technology ◽  
Practical Applications ◽  
Biomedical Technologies ◽  
Novel Material

The advancement in 3D printing has led to the rapid growth of 4D printing technology. Adding time, as the fourth dimension, this technology ushered the potential of a massive evolution in fields of biomedical technologies, space applications, deployable structures, manufacturing industries, and so forth. This technology performs ingenious design, using smart materials to create advanced forms of the 3-D printed specimen. Improvements in Computer-aided design, additive manufacturing process, and material science engineering have ultimately favored the growth of 4-D printing innovation and revealed an effective method to gather complex 3-D structures. Contrast to all these developments, novel material is still a challenging sector. However, this short review illustrates the basic of 4D printing, summarizes the stimuli responsive materials properties, which have prominent role in the field of 4D technology. In addition, the practical applications are depicted and the potential prospect of this technology is put forward.

Passive Control of a Hydraulic Valve

1989 ◽  
Author(s):  
John D. Charlton ◽  
James J. Brickley
Keyword(s):  
Passive Control ◽  
Hydraulic Valve
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