Active control of a sandwich plate with reinforced magnetostrictive faces and viscoelastic core, resting on elastic foundation

2021 ◽  
pp. 1045389X2110530
Author(s):  
Ashraf M Zenkour ◽  
Hela D El-Shahrany
Keyword(s):  
Elastic Foundation ◽  
Vibration Suppression ◽  
Vibration Damping ◽  
Laminated Plate ◽  
Control Value ◽  
Aspect Ratios ◽  
Half Wave ◽  
Viscoelastic Core ◽  
Foundation Parameters ◽  
And Control

The current study presents a vibration investigation of a laminated plate considering a viscoelastic core with embedded magnetostrictive layers. The simply-supported plate is supported via Pasternak’s substrate medium. Based on different plate theories and employing Hamilton’s principle, the system of governing differential equations is derived. The mechanical properties of the viscoelastic core are described depend on the time varies based on Kelvin–Voigt model. Actuating magnetostrictive layers are utilized to control the vibration damping process of the system with the assistance of feedback and constant gain distributed control. The analytical solution is obtained to investigate the influence of half wave numbers, thickness ratios, core thickness, aspect ratios, lamination schemes, elastic foundation parameters, damping coefficient, feedback coefficient magnitude, magnetostrictive layers location, on the vibrational behavior of laminated plate. Some observations about the vibration damping process of the present plate are displayed. The results refer to that the vibration suppression rate depends on the thickness of the plate, the feedback control value, the foundation constants, and the viscoelastic structural damping significantly. Moreover, the study can be providing benchmark tests to validate future contributions on the viscoelastic smart structural issues and developing the design of smart viscoelastic structures and control of their vibrations.

Advanced Fringe Analysis Techniques in Circuit Edit

2006 ◽  
Author(s):  
R.K. Jain ◽  
T. Malik ◽  
T.R. Lundquist ◽  
C.-C. Tsao ◽  
W.J. Walecki
Keyword(s):  
Imaging System ◽  
Success Rates ◽  
Endpoint Detection ◽  
Fringe Analysis ◽  
Analysis Techniques ◽  
Aspect Ratios ◽  
Slope Correction ◽  
Trench Area ◽  
And Control ◽  
Thickness Measurements

Abstract Novel Fabry Perot [1] fringe analysis techniques for monitoring the etching process with a coaxial photon-ion column [2] in the Credence OptiFIB are reported. Presently the primary application of these techniques in circuit edit is in trenching either from the front side or from the backside of a device. Optical fringes are observed in reflection geometry through the imaging system when the trench floor is thin and semi-transparent. The observed fringes result from optical interference in the etalon formed between the trench floor (Si in the case of backside trenching) and the circuitry layer beyond the trench floor. In-situ real-time thickness measurements and slope correction techniques are proposed that improve endpoint detection and control planarity of the trench floor. For successful through silicon edits, reliable endpoint detection and co-planarity of a local trench is important. Reliable endpoint detection prevents milling through bulk silicon and damaging active circuitry. Uneven trench floor thickness results in premature endpoint detection with sufficient thickness remaining in only part of the trench area. Good co-planarity of the trench floor also minimizes variability in the aspect ratios of the edit holes, hence increasing success rates in circuit edit.

ACTION MODE, PERSISTENCE AND CONTROL VALUE OF FIPRONIL FOR RICE GRASSHOPPERS OXYA (ORTHOPTERA: CANTANTOPIDAE)

1999 ◽  
Vol 6 (1) ◽  
pp. 62-70 ◽  
Author(s):  
Zhibin Liu ◽  
Mingqing Wu ◽  
Zhiyong Deng ◽  
Qingchuan Wang ◽  
Hanwu Chen ◽  
...  
Keyword(s):  
Control Value ◽  
Action Mode ◽  
And Control

Ultra-thin films effects on vibro-acoustic behaviour of laminated plate including a viscoelastic core

2019 ◽  
Vol 147 ◽  
pp. 121-132 ◽  
Author(s):  
Belaid Bouzouane ◽  
Ameni Ghorbel ◽  
Ali Akrout ◽  
Moez Abdennadher ◽  
Taoufik Boukharouba ◽  
...  
Keyword(s):  
Thin Films ◽  
Laminated Plate ◽  
Acoustic Behaviour ◽  
Viscoelastic Core

Optimal Vibration Control of Membrane Structures with In-Plane Polyvinylidene Fluoride Actuators

2020 ◽  
Vol 20 (08) ◽  
pp. 2050095
Author(s):  
Yifan Lu ◽  
Qi Shao ◽  
Fei Yang ◽  
Honghao Yue ◽  
Rongqiang Liu
Keyword(s):  
Vibration Control ◽  
Polyvinylidene Fluoride ◽  
Vibration Suppression ◽  
Flexible Structures ◽  
Control Force ◽  
Membrane Structures ◽  
Optimization Criteria ◽  
High Flexibility ◽  
And Control ◽  
Actuator Placement

Different kinds of membrane structures have been proposed for future space exploration and earth observation. However, due to the low stiffness, high flexibility, and low damping properties, membrane structures are likely to generate large-amplitude (compared to the thickness) vibrations, which may lead to the degradation of their working performance. In this work, the governing equations are established at first, taking into account the modal control force induced by the polyvinylidene fluoride (PVDF) actuator. The optimal vibration control of the membrane structure is explored subsequently. A square PVDF actuator is attached on the membrane to achieve the vibration suppression. The influence of actuator position and control gains on the vibration control performance are studied. The optimal criteria for actuator placement and energy allocation are developed. Several case studies are numerically simulated to demonstrate the validity of the proposed optimization criteria. The analytical results in this study can serve as guidelines for optimal vibration control of membrane structures. Additionally, the proposed optimization criteria can be applied to active control of different flexible structures.

Sensorless Modal Stabilization for Three-Link Robotic Arm With Elastic Wrist Drive Belt

2001 ◽  
Author(s):  
Martin Hosek
Keyword(s):  
Rigid Body ◽  
Robotic Manipulator ◽  
Vibration Damping ◽  
Rigid Body Dynamics ◽  
Limiting Factor ◽  
Direct Drive ◽  
Stability And Control ◽  
Body Dynamics ◽  
Improved Stability ◽  
And Control

Abstract A control system for a three-link direct-drive robotic manipulator with inherent structural flexibilities is presented. The structural flexibilities introduce undesirable vibration modes which may affect operation of the robot motion controller, resulting in destabilization of the closed-loop system. This represents a major limiting factor for implementation of a conventional controller designed solely for the rigid body dynamics of the robotic manipulator. The fundamental idea in the presented approach is to use a composite controller which consists of a trajectory-tracking section designed for the rigid-body dynamics and a vibration-damping compensator added for attenuation of the dominant flexible dynamics. The vibration damping compensator operates on estimated states of the dominant flexible dynamics obtained from a reduced-order state observer. A mechanism is implemented which allows the robotic manipulator to move through or hold in positions where the dominant flexible dynamics is unobservable and uncontrollable. Results of laboratory tests document that the presented approach leads to improved stability and control performance.

Active Vibration Damping Using an Inertial, Self-Sensing, Electrodynamic Actuator

2005 ◽  
Author(s):  
Christoph Paulitsch ◽  
Paolo Gardonio ◽  
Stephen J. Elliott
Keyword(s):  
Vibration Amplitude ◽  
Vibration Damping ◽  
Induced Voltage ◽  
Current Feedback ◽  
Control Scheme ◽  
Active Vibration Damping ◽  
Active Vibration ◽  
Voltage Feedback ◽  
And Control ◽  
Inertial Actuator

Self-sensing active vibration damping is advantageous if sensors cannot be placed collocated to actuators or these sensors add too much weight or cost. When self-sensing, electrodynamic actuators are used, damping is directly added to the structure where they are attached without the need of electronic integrators or differentiators that could destabilize the system. Inertial actuators have also the advantage that they do not need to react relative to a fixed ground. In this paper self-sensing control with a shunted resistor, current feedback, induced voltage feedback with and without inductance compensation are investigated in simulations and experiments. Experiments with a lightweight, inertial actuator on a clamped plate show that vibration amplitude is decreased between 6dB and 13dB and control bandwidth is doubled when the appropriate control scheme is used.

A Novel Refined Plate Theory for Free Vibration Analyses of Single-Layered Graphene Sheets Lying on Winkler-Pasternak Elastic Foundations

2019 ◽  
Vol 58 ◽  
pp. 151-164 ◽  
Author(s):  
Fatima Boukhatem ◽  
Aicha Bessaim ◽  
Abdelhakim Kaci ◽  
Abderrahmane Mouffoki ◽  
Mohammed Sid Ahmed Houari ◽  
...  
Keyword(s):  
Free Vibration ◽  
Shear Deformation ◽  
Elastic Foundation ◽  
Displacement Field ◽  
Scale Effects ◽  
Plate Theory ◽  
Small Scale ◽  
Graphene Sheets ◽  
Refined Plate Theory ◽  
Foundation Parameters

In this article, the analyses of free vibration of nanoplates, such as single-layered graphene sheets (SLGS), lying on an elastic medium is evaluated and analyzed via a novel refined plate theory mathematical model including small-scale effects. The noteworthy feature of theory is that the displacement field is modelled with only four unknowns, which is even less than the other shear deformation theories. The present one has a new displacement field which introduces undetermined integral variables, the shear stress free condition on the top and bottom surfaces of the plate is respected and consequently, it is unnecessary to use shear correction factors. The theory involves four unknown variables, as against five in case of other higher order theories and first-order shear deformation theory. By using Hamilton’s principle, the nonlocal governing equations are obtained and they are solved via Navier solution method. The influences played by transversal shear deformation, plate aspect ratio, side-to-thickness ratio, nonlocal parameter, and elastic foundation parameters are all examined. From this work, it can be observed that the small-scale effects and elastic foundation parameters are significant for the natural frequency.

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