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Journal ArticleDOI

Stiffness control of cylindrical shells under axial compression using piezocomposite actuators—An experimental investigation

TL;DR: In this article, the effects of surface-bonded microfiber composite actuator patches on cylindrical shells subjected to axial compression are studied experimentally, and the actuators are placed such that the distance separating them is less than the observed axial and circumferential buckling wavelengths.
Abstract: The present study explores the modification and control of prebuckling stiffness of cylindrical shells for their potential use in smart structures. The effects of surface-bonded microfiber composite actuator patches on cylindrical shells subjected to axial compression are studied experimentally. The actuators are placed such that the distance separating them is less than the observed axial and circumferential buckling wavelengths. Strain gauge sensors are used to measure the axial strains at discrete locations on the cylindrical shell. Experimental results indicate that the actuation effect can reduce the local strains as well as improve the overall stiffness of the structure. The results obtained in this study potentially have a significant impact in space applications.
Citations
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Journal ArticleDOI
TL;DR: This research presents a new generation of soft robotic grippers inspired by the adhesion capability of gecko’s toe and adaptability, which have the potential to revolutionise the field of grippers.
Abstract: Soft robotic grippers have gained much attention in recent years owing to their advantages of easy fabrication, flexibility, and adaptability. Inspired by the adhesion capability of gecko’s toe and...

9 citations

Journal ArticleDOI
TL;DR: In this article, the effects of various parameters on friction performance of wet brake under different working conditions were studied through numerical analysis on the temperature rise and stress condition of the wet brake.
Abstract: To study the effects of various parameters on friction performance of wet brake under different working conditions, this paper, through the numerical analysis on the temperature rise and stress cha...

3 citations

Journal ArticleDOI
TL;DR: The ability to control equilibrium trajectory to buckling via uniform/non-uniform prebuckling stresses introduced using piezoelectric actuators creates interesting possibilities for designing smart actuators.
Abstract: The ability to control equilibrium trajectory to buckling via uniform/non-uniform prebuckling stresses introduced using piezoelectric actuators creates interesting possibilities for designing smart...

3 citations


Cites background from "Stiffness control of cylindrical sh..."

  • ...The experimental studies on thin cylindrical shells using patch actuators were focused only on the enhancement of the initial stiffness of the structure [22]....

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Journal ArticleDOI
TL;DR: In this paper, a shape memory alloy (SMA) driven actuator is proposed for active stiffness control of thin-walled cylindrical shells with a new SMA actuator.
Abstract: Thin-walled cylindrical shells have been widely used as key components in various engineering applications. The stiffness of the thin-walled cylindrical shell is an important factor affecting its working performance. This study aims to investigate the active stiffness control of thin-walled cylindrical shells with a new SMA (shape memory alloy) driven actuator. The configuration of the actuator is designed first according to the circumferential and axial modal characteristics of the cylindrical shell. Geometric parameters of the actuator are optimized based on the statics and modal analysis of the system. SMA tubes are used as the driving sources of the actuator and their mechanical performance, including compressive mechanical property and recovery mechanical property are tested. The active stiffness control experiments are carried out on a simply supported thin-walled cylindrical shell. The control performance of the actuator is indicated by the enhancement ratio of natural frequencies of different modes. The influences of actuator number and actuation time on the control performance are also investigated. The results demonstrate that the proposed actuator can significantly improve the stiffness of the thin-walled cylindrical shell by nearly 30%.

2 citations

Journal ArticleDOI
TL;DR: In this paper, the authors demonstrate the feasibility of creating adaptive multimodal surface patterns on an otherwise featureless cylindrical shell surface with the help of surface-bonded piezoelectric a...
Abstract: The present study demonstrates the feasibility of creating adaptive multimodal surface patterns on an otherwise featureless cylindrical shell surface with the help of surface-bonded piezoelectric a...

1 citations

References
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Journal ArticleDOI
TL;DR: In this paper, the results of an experimental investigation of axial crushing modes and energy absorption properties of quasi-statically compressed aluminium alloy tubes are presented, and the influence of tube length on these properties is discussed and quantified.

387 citations

Journal ArticleDOI

100 citations


"Stiffness control of cylindrical sh..." refers background in this paper

  • ...The earliest work reported in the literature on buckling control of structures using piezoelectric actuators was carried out by Meressi and Paden [1]....

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Journal ArticleDOI
TL;DR: In this paper, a finite-element model is developed for the active buckling control of laminated composite plates using piezoelectric materials, which can be surface bonded or embedded and can be either continuous or segmented.
Abstract: A finite-element model is developed for the active buckling control of laminated composite plates using piezoelectric materials. The finite-element model is based on the first-order shear deformation plate theory in conjunction with linear piezoelectric theory. The piezoelectric sensors and actuators can be surface bonded or embedded and can be either continuous or segmented. The dynamic buckling behavior of the laminated plate subjected to a linearly increasing uniaxial compressive load is investigated. The sensor output is used to determine the input to the actuator using a proportional control algorithm. The forces induced by the piezoelectric actuators under the applied voltage fields enhance the critical buckling load. Finite-element solutions are presented for composite plates with clamped and simply supported boundary conditions and the effectiveness of piezoelectric materials in enhancing the buckling loads is demonstrated.

99 citations


"Stiffness control of cylindrical sh..." refers background or result in this paper

  • ...This result is in contradiction with other structures like columns and plates where orienting the actuators towards the center of the shell can result in maximum enhancement in buckling characteristics [2, 3]....

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  • ...Ever since then, a number of works have been reported on the active control of buckling [2, 3]....

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Book
30 Dec 2013
TL;DR: In this article, the authors focus on smart materials, structures and systems, which are also referred to as intelligent, adaptive, active, sensory and metamorphic, and the purpose of these materials from the perspective of smart systems is their ability to minimize life-cycle cost and/or expand the performance envelope.
Abstract: The twenty-first century could be called the 'Multifunctional Materials Age' The inspiration for multifunctional materials comes from nature, and therefore these are often referred to as bio-inspired materials Bio-inspired materials encompass smart materials and structures, multifunctional materials and nano-structured materials This is a dawn of revolutionary materials that may provide a 'quantum jump' in performance and multi-capability This book focuses on smart materials, structures and systems, which are also referred to as intelligent, adaptive, active, sensory and metamorphic The purpose of these materials from the perspective of smart systems is their ability to minimize life-cycle cost and/or expand the performance envelope The ultimate goal is to develop biologically inspired multifunctional materials with the capability to adapt their structural characteristics (such as stiffness, damping and viscosity) as required, monitor their health condition, perform self-diagnosis and self-repair, morph their shape and undergo significant controlled motion over a wide range of operating conditions

72 citations

Journal ArticleDOI
TL;DR: In this paper, the nonlinear relationship between the piezoelectric shear coefficient and applied ac field is represented as a polynomial curve fit, and a rate feedback control law is implemented which feeds back the higher harmonics of the time rate of change of strain in the azimuthal direction.
Abstract: Governing equations are obtained for helicopter rotor blades with surface bonded piezoceramic actuators using Hamilton's principle. The equations are then solved for dynamic response using finite element discretization in the spatial and time domains. A time domain unsteady aerodynamic model is used to obtain the airloads. The nonlinear relationship between the piezoelectric shear coefficient and applied ac field is represented as a polynomial curve fit. The nonlinear effects are investigated by applying a sinusoidal voltage to the helicopter rotor blade. The rotor blade is modeled as a two-cell box section with piezoelectric layers surface bonded to the top and bottom of the box beam. Comparison of results with linear and nonlinear shear coefficients is presented. Use of a nonlinear relationship (compared to linear) to achieve targeted reductions in strains or displacements results in a reduction in the requirement of applied amplitude of the sinusoidal field. A rate feedback control law is implemented which feeds back the higher harmonics of the time rate of change of strain in the azimuthal direction. The sensed voltage is then applied to the rotor blade, resulting in a vibration reduction of approximately 43% for a four-bladed, soft-in-plane hingeless rotor in forward flight.

49 citations