Stiffness Shaping for Zero Vibration Fluidic Flexible Matrix Composites

2008 ◽  
Author(s):  
Amir Lotfi-Gaskarimahalle ◽  
Ying Shan ◽  
Suyi Li ◽  
Christopher D. Rahn ◽  
Charles E. Bakis ◽  
...  
Keyword(s):  
Equations Of Motion ◽  
Active Vibration Control ◽  
Variable Stiffness ◽  
Matrix Composites ◽  
Mass System ◽  
Apparent Stiffness ◽  
Active Vibration ◽  
3D Elasticity ◽  
High Bulk ◽  
Orifice Valve

This paper studies semi-active vibration control using Fluidic Flexible Matrix Composites (F2MC) as variable stiffness structures. The apparent stiffness of F2MC tubes can be changed using a variable orifice valve. With fiber reinforcement, the volume inside the tube may change with external load. With an open valve, the liquid is free to move in or out of the tube, so the apparent stiffness will not changed. When the valve is closed, the high bulk modulus liquid is confined, which resists the volume change and causes the apparent stiffness of the tube to increase. The equations of motion of an F2MC-mass system is derived using a 3D elasticity model and the energy method. A reduced order model is then developed for fully-open or fully-closed valves. A Skyhook valve that cycles the valve between open and closed, asymptotically decays the vibration. A Zero Vibration (ZV) Stiffness Shaping technique is introduced to suppress the vibration in finite time. A sensitivity analysis of the ZV Stiffness Shaper studies the robustness to parameteric uncertainties.

Switched Stiffness Vibration Controllers for Fluidic Flexible Matrix Composites

2009 ◽  
Author(s):  
Amir Lotfi-Gaskarimahalle ◽  
Christopher D. Rahn
Keyword(s):  
Equations Of Motion ◽  
Active Vibration Control ◽  
Flexible Structures ◽  
Variable Stiffness ◽  
Flow Coefficient ◽  
Step Response ◽  
Semiactive Control ◽  
Matrix Composites ◽  
Mass System ◽  
3D Elasticity

This paper investigates semi-active vibration control using Fluidic Flexible Matrix Composites (F2MC) as variable stiffness components of flexible structures. The stiffness of F2MC tubes can be dynamically switched from soft to stiff by opening and closing an on/off valve. Fiber reinforcement of the F2MC tube changes the internal volume when externally loaded. With an open valve, the fluid in the tube is free to move in or out of the tube, so the stiffness is low. When the valve is closed, the high bulk modulus fluid resists volume change and produces high stiffness. The equations of motion of an F2MC-mass system is derived using a 3D elasticity model and the energy method. The stability of the unforced dynamic system is proven using a Lyapunov approach. To capture the important system parameters, nondimensional full order and reduced order models are developed. A Zero Vibration (ZV) state switch technique is introduced that suppresses vibration in finite time, and is compared to conventional Skyhook semiactive control. The ITAE performance of the controllers is optimized by adjusting the open valve flow coefficient. Simulation results show that the optimal ZV controller outperforms the optimal Skyhook controller by 13% and 60% for impulse and step response, respectively.

Active Vibration Control for the Closed Loop Flexible Mechanisms Combined the Feedback and Feed-Forward Strategy: Part 2 — Control Design and Simulation

2000 ◽  
Author(s):  
Zhang Xianmin ◽  
Chao Changjian
Keyword(s):  
Equations Of Motion ◽  
Active Vibration Control ◽  
Elastic Vibration ◽  
Linkage Mechanism ◽  
Control Laws ◽  
Feed Forward ◽  
Feed Forward Control ◽  
Active Vibration ◽  
Four Bar Linkage ◽  
Flexible Mechanisms

Abstract On the basis of the complex mode theory and the equations of motion of the flexible mechanisms developed in part 1, a hybrid independent modal controller is presented, which is composed of state feedback and disturbance feed-forward control laws. As an illustrative example, the strategy is used to control the elastic vibration response of a four-bar linkage mechanism. The imitative computational result shows that the vibration is efficiently suppressed.

Active Vibration Control of Smart Hull Structure Using Piezoelectric Composite Actuators

2008 ◽  
Vol 47-50 ◽  
pp. 137-140 ◽  
Author(s):  
Jung Woo Sohn ◽  
Seung Bok Choi
Keyword(s):  
Vibration Control ◽  
Fiber Composite ◽  
Equations Of Motion ◽  
Active Vibration Control ◽  
Piezoelectric Composite ◽  
Governing Equations ◽  
Linear Quadratic ◽  
Element Analysis ◽  
Hull Structure ◽  
Active Vibration

In this paper, active vibration control performance of the smart hull structure with Macro-Fiber Composite (MFC) is evaluated. The governing equations of motion of the hull structure with MFC actuators are derived based on the classical Donnell-Mushtari shell theory. Subsequently, modal characteristics are investigated and compared with the results obtained from finite element analysis and experiment. The governing equations of vibration control system are then established and expressed in the state space form. Linear Quadratic Gaussian (LQG) control algorithm is designed in order to effectively and actively control the imposed vibration. The controller is experimentally realized and control performances are evaluated.

Active Vibration Control of Beams By Combining Precompressed Layer Damping and ACLD Treatment: Theory and Experimental Implementation

2011 ◽  
Vol 133 (6) ◽  
Author(s):  
Sanjiv Kumar ◽  
Rakesh Sehgal ◽  
Rajiv Kumar
Keyword(s):  
Equations Of Motion ◽  
Active Vibration Control ◽  
Flexible Structures ◽  
Constrained Layer Damping ◽  
Linear Quadratic ◽  
Active Constrained Layer Damping ◽  
Active Vibration ◽  
Passive Technique ◽  
Failure Conditions ◽  
Passive Constrained Layer Damping

By attaching initially stressed poly vinyl chloride (PVC) layers on the flexible structures, necessary passive damping can be provided. Using passive constrained layers on these PVC layers, the efficiency can be made even better than ordinary passive constrained layer damping (PCLD) treatment. By using stressed PVC layers, a rich performance in case of circuit failure conditions is always available. An active constraining layer further enhances the damping performance of this passive technique. Precompressed layer damping treatment augmented with active constrained layer damping (ACLD) treatment has been suggested, which has many desirable features as compared to existing pretensed layer damping treatment. Such enhancement in damping performance is not possible by conventional ACLD as well as PCLD techniques. The effect of initial strain (compressive or tensile) and other parameters of the PVC layers on the vibration characteristics of flexible structure have been investigated. The Hamilton principle in conjunction with finite element method is used to derive the differential equations of motion. Using proportional feedback controllers, the complex closed loop eigenvalue problem is developed and solved numerically. The effectiveness of the proposed technique has been validated experimentally using a digital linear quadratic Gaussian controller.

Combined Piezoelectric-Hydraulic Actuator Based Active Vibration Control for Rotordynamic System

1993 ◽  
Author(s):  
Punan Tang ◽  
Alan Palazzolo ◽  
Albert Kascak ◽  
Gerald Montague ◽  
Wenduan Li
Keyword(s):  
Vibration Control ◽  
Active Vibration Control ◽  
Control Force ◽  
Hydraulic Actuator ◽  
Low Leakage ◽  
Actuator System ◽  
Active Vibration ◽  
Transmission Fluid ◽  
Controlled Structure ◽  
High Bulk

Abstract Previous research by the authors concentrated on using piezoelectric actuators for active vibration control (AVC) of rotating machinery. The current work extends this by positioning the piezoactuator remotely from the controlled structure and transmitting the control force via a hydraulic line and two pistons. Liquid plastic is employed as a transmission “fluid” to obtain a high bulk modulus and low leakage. The paper presents results for bulk moduli measurement, and bench and rig tests for the entire actuator system. These results show the high effectiveness of the hybrid actuator for controlling vibrations on a laboratory rotor test rig.

Architectural Synthesis and Analysis of Dual-Cellular Fluidic Flexible Matrix Composites for Multifunctional Metastructures

2015 ◽  
Vol 137 (4) ◽  
Author(s):  
Suyi Li ◽  
K. W. Wang
Keyword(s):  
Cellular Structure ◽  
Large Scale ◽  
Equations Of Motion ◽  
Variable Stiffness ◽  
Cell Stiffness ◽  
Matrix Composites ◽  
Vibration Absorption ◽  
Design And Synthesis ◽  
Mechanical Constraints ◽  
The Rich

Recently, a cellular structure concept based on fluidic flexible matrix composites (F2MCs) was investigated for its potential of concurrently achieving multiple adaptive functions. Such structure consists of two fluidically connected F2MC cells, and it has been proven capable of dynamic actuation with enhanced authority, variable stiffness, and vibration absorption. The purpose of the research presented in this paper is to develop comprehensive design and synthesis tools to exploit the rich functionality and versatility of this F2MC based system. To achieve this goal, two progressive research topics are addressed: The first is to survey unique architectures based on rigorous mathematical principles. Four generic types of architectures are identified for the dual-cellular structure based on fluidic and mechanical constraints between the two cells. The system governing equations of motion are derived and experimentally tested for these architectures, and it is found that the overall structural dynamics are related to the F2MC cell stiffness, internal pressure difference, and static flow volume between the two cells according to the architectural layout. The second research topic is to derive a comprehensive synthesis procedure to assign the F2MC designs so that the cellular structure can simultaneously reach a set of different performance targets. Synthesis case studies demonstrate the range of performance of the F2MC based cellular structure with respect to different architectures. The outcome of this investigation could provide valuable insights and design methodologies to foster the adoption of F2MC to advance the state of art of a variety of engineering applications. It also lays the foundation for a large-scale “metastructure,” where many pairs of fluidically connected F2MC can be employed as modules to achieve synergetic global performance.

Passive and Switched Stiffness Vibration Controllers Using Fluidic Flexible Matrix Composites

2012 ◽  
Vol 134 (2) ◽  
Author(s):  
Amir Lotfi-Gaskarimahalle ◽  
Lloyd H. Scarborough ◽  
Christopher D. Rahn ◽  
Edward C. Smith
Keyword(s):  
Passive Control ◽  
Axial Strain ◽  
Damping Ratio ◽  
Equations Of Motion ◽  
Absolute Error ◽  
Step Response ◽  
Axial Stiffness ◽  
Matrix Composites ◽  
Mass System ◽  
Valve Orifice

This paper investigates passive and semi-active vibration control using fluidic flexible matrix composites (F2MC). F2MC tubes filled with fluid and connected to an accumulator through a fixed orifice can provide damping forces in response to axial strain. If the orifice is actively controlled, the stiffness of F2MC tubes can be dynamically switched from soft to stiff by opening and closing an on/off valve. Fiber reinforcement of the F2MC tube kinematically relates the internal volume to axial strain. With an open valve, the fluid in the tube is free to move in or out of the tube, so the stiffness is low. With a closed valve, however, the high bulk modulus fluid resists volume change and produces high axial stiffness. The equations of motion of an F2MC-mass system are derived using a 3D elasticity model and the energy method. The stability of the unforced dynamic system is proven using a Lyapunov approach. A reduced-order model for operation with either a fully open or fully closed valve motivates the development of a zero vibration (ZV) controller that suppresses vibration in finite time. Coupling of a fluid-filled F2MC tube to a pressurized accumulator through a fixed orifice is shown to provide significant passive damping. The open-valve orifice size is optimized for optimal passive, skyhook, and ZV controllers by minimizing the integral time absolute error cost function. Simulation results show that the optimal open valve orifice provides a damping ratio of 0.35 compared with no damping in closed-valve case. The optimal ZV controller outperforms optimal passive and skyhook controllers by 32.9% and 34.2% for impulse and 34.7% and 60% for step response, respectively. Theoretical results are confirmed by experiments that demonstrate the improved damping provided by optimal passive control F2MC and fast transient response provided by semi-active ZV control.

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