scholarly journals Vibration Suppression of a Large Beam Structure Using Tuned Mass Damper and Eddy Current Damping

2014 ◽  
Vol 2014 ◽  
pp. 1-10 ◽  
Author(s):  
Jae-Sung Bae ◽  
Jai-Hyuk Hwang ◽  
Dong-Gi Kwag ◽  
Jeanho Park ◽  
Daniel J. Inman
Keyword(s):  
Eddy Current ◽  
Smart Materials ◽  
Vibration Suppression ◽  
Constrained Layer Damping ◽  
Structural Vibrations ◽  
Beam Structure ◽  
Tuned Mass Dampers ◽  
Large Structures ◽  
Eddy Current Damping ◽  
Actuator Constraints

For a few decades, various methods to suppress the vibrations of structures have been proposed and exploited. These include passive methods using constrained layer damping (CLD) and active methods using smart materials. However, applying these methods to large structures may not be practical because of weight, material, and actuator constraints. The objective of the present study is to propose and exploit an effective method to suppress the vibration of a large and heavy beam structure with a minimum increase in mass or volume of material. Traditional tuned mass dampers (TMD) are very effective for attenuating structural vibrations; however, they often add substantial mass. Eddy current damping is relatively simple and has excellent performance but is force limited. The proposed method is to apply relatively light-weight TMD to attenuate the vibration of a large beam structure and increase its performance by applying eddy current damping to a TMD. The results show that the present method is simple but effective in suppressing the vibration of a large beam structure without a substantial weight increase.

Modeling of a New Active Eddy Current Vibration Control System

2008 ◽  
Vol 130 (2) ◽  
Author(s):  
Henry A. Sodano ◽  
Daniel J. Inman
Keyword(s):  
Magnetic Field ◽  
Vibration Control ◽  
Electric Fields ◽  
Eddy Current ◽  
Eddy Currents ◽  
Vibration Suppression ◽  
Frequency Doubling ◽  
Damping Force ◽  
Theoretical Derivation ◽  
Eddy Current Damping

There exist many methods of adding damping to a vibrating structure; however, eddy current damping is one of few that can function without ever coming into contact with that structure. This magnetic damping scheme functions due to the eddy currents that are generated in a conductive material when it is subjected to a time changing magnetic field. Due to the circulation of these currents, a magnetic field is generated, which interacts with the applied field resulting in a force. In this manuscript, an active damper will be theoretically developed that functions by dynamically modifying the current flowing through a coil, thus generating a time-varying magnetic field. By actively controlling the strength of the field around the conductor, the induced eddy currents and the resulting damping force can be controlled. This actuation method is easy to apply and allows significant magnitudes of forces to be applied without ever coming into contact with the structure. Therefore, vibration control can be applied without inducing mass loading or added stiffness, which are downfalls of other methods. This manuscript will provide a theoretical derivation of the equations defining the electric fields generated and the dynamic forces induced in the structure. This derivation will show that when eddy currents are generated due to a variation in the strength of the magnetic source, the resulting force occurs at twice the frequency of the applied current. This frequency doubling effect will be experimentally verified. Furthermore, a feedback controller will be designed to account for the frequency doubling effect and a simulation performed to show that significant vibration suppression can be achieved with this technique.

scholarly journals Vibration Suppression of a Cantilever Plate Using Magnetically Multimode Tuned Mass Dampers

2018 ◽  
Vol 2018 ◽  
pp. 1-13 ◽  
Author(s):  
Jae-Sung Bae ◽  
Jung-Sun Park ◽  
Jai-Hyuk Hwang ◽  
Jin-Ho Roh ◽  
Bong-do Pyeon ◽  
...  
Keyword(s):  
Vibration Suppression ◽  
Structural Vibration ◽  
Design Parameters ◽  
Cantilever Plate ◽  
Solar Panels ◽  
Tuned Mass Dampers ◽  
Torsion Mode ◽  
Bending Mode ◽  
Mass Damper ◽  
Eddy Current Damping

For a few decades, various methods of suppressing structural vibration have been proposed. The present study proposes and exploits an effective method of suppressing the vibration of cantilever plates similar to the solar panels of a satellite. Magnetically tuned mass dampers (mTMDs) are a tuned mass damper (TMD) with eddy current damping (ECD). We introduce the mTMD concept for the multimode vibration suppression of the cantilever plate. The design parameters of the mTMD are determined based on the parametric study of the theoretical four-degree-of-freedom model, which was derived for a cantilever plate with TMDs. Two TMDs are optimized for the first bending mode and first torsion mode of the plate, and they are verified analytically and experimentally. To increase the damping performance of the TMDs, ECD is introduced. Its damping ratios are estimated analytically and verified experimentally.

Concurrent Vibration Suppression and Energy Harvesting Using Ferrofluids: An Experimental Investigation

2014 ◽  
Author(s):  
Saad F. Alazemi ◽  
Amin Bibo ◽  
Mohammed F. Daqaq
Keyword(s):  
Magnetic Field ◽  
Power Generation ◽  
Energy Harvesting ◽  
Vibration Suppression ◽  
Design Parameters ◽  
Structural Vibrations ◽  
Rectangular Container ◽  
Fluid Damper ◽  
Magnetized Ferrofluid ◽  
Experimental Response

This paper presents an experimental study which examines the design parameters affecting the performance characteristics of a Tuned Magnetic Fluid Damper (TMFD) device designed to concurrently mitigate structural vibrations and harvest vibratory energy. The device which is mounted on a vibrating structure, consists of a rectangular container carrying a magnetized ferrofluid and a pick-up coil wound around the container to enable energy harvesting. Experiments are performed to investigate the three-way interaction between the vibrations of the structure, the sloshing of the fluid, and the harvesting circuit dynamics. In particular, the tuning and optimization is examined for several design parameters including magnetic field spatial distribution and intensity, winding direction, winding location, winding density, and ferrofluid height inside the tank. The experimental response of the device is compared against the conventional TMFD at different excitation levels and frequencies. Results demonstrating the influence of the significant parameters on the relative performance are presented and discussed in terms of vibration suppression and power generation capabilities.

Hybrid Control of Rotating Beams Using Pattern Search Based Optimization Technique

2018 ◽  
Author(s):  
Rajiv Kumar Vashisht ◽  
Qingjin Peng
Keyword(s):  
Smart Materials ◽  
Optimization Technique ◽  
Flexible Structures ◽  
Pattern Search ◽  
Feedback Controller ◽  
Structural Vibration ◽  
Flexible Beam ◽  
Constrained Layer Damping ◽  
Rotating Beams ◽  
Passive Constrained Layer Damping

Rotating beams are quite common in rotating machinery e.g. fans of compressors in an airplane. This paper presents the experimental, hybrid, structural vibration control of flexible structures to enhance the vibration behavior of rotating beams. Smart materials have been used as sensors as well as actuators. Passive constrained layer damping (PCLD) treatment is combined with stressed layer damping technique to enhance the damping characteristics of the flexible beam. To further enhance the damping parameters, a closed form robust feedback controller is applied to reduce the broadband structural vibrations of the rotating beam. The feed forward controller is designed by combing with the feedback controller using a pattern search based optimization technique. The hybrid controller enhances the performance of the closed loop system. Experiments have been conducted to validate the effectiveness of the presented technique.

Damping Characteristics of a Cantilever Plate Using Permanent Magnetic Constrained Layer Damping Strip Treatment

2012 ◽  
Vol 450-451 ◽  
pp. 466-471
Author(s):  
Ming Li ◽  
Hui Ming Zheng
Keyword(s):  
Ritz Method ◽  
Constrained Layer Damping ◽  
Structural Vibrations ◽  
Torsional Mode ◽  
Calculation Of Parameters ◽  
New Class ◽  
Damping Characteristics ◽  
Special Cases ◽  
Cantilever Rectangular Plate ◽  
Passive Constrained Layer Damping

Significant improvement of damping characteristics can be achieved by using the new class of magnetic constrained layer damping treatment (MCLD). This paper presents the damping properties of the first and second torsional mode for a five-layer cantilever rectangular plate treated with partial MCLD. The Rayleigh-Ritz method and Hamilton’s principle are employed in the analysis. We have chosen both single and segmented patches with different sizes. It can be observed that for the two modes single-patched MCLD treatment induces less improvement of damping characteristics especially for the short patch. The effects of calculation of parameters like placement strategies of discrete patches, the length of patches are analyzed and discussed. The results obtained from analytical show that the optimum location of the patch, for the torsional mode, is at edge of the plate. Favorable comparisons with the conventional passive constrained layer damping treatment (PCLD) on various special cases of the problem are obtained. The results demonstrate MCLD treatment still improvements over PCLD in damping structural vibrations.

Vibration Reduction of Flexible Structures Using Extended Input Shaper and Smart Materials

2001 ◽  
Author(s):  
G. Song ◽  
B. Kotejoshyer ◽  
J. Fei
Keyword(s):  
Smart Materials ◽  
Vibration Suppression ◽  
Flexible Structures ◽  
Flexible Beam ◽  
Smart Sensor ◽  
New Approach ◽  
Active Vibration Suppression ◽  
Command Input ◽  
Active Vibration ◽  
Smart Actuator

Abstract This paper presents a new approach of integrating the method of command input shaping and the technique of active vibration suppression for vibration reduction of flexible structures during slew operations. The control object is a flexible composite beam driven by a high torque DC motor with the presence of nonlinearities such as backlash and stick-slip type of friction. Two piezoelectric patches are bonded on the surface of the flexible beam near its cantilevered end and are used as the smart actuator and the smart sensor respectively. In this new approach, the method of command input shaping is used to modify the existing command so that less vibration will be caused by the command itself. To overcome the nonlinearities associated with the DC motor, an extended shaper is designed. The technique of active vibration suppression using smart materials is used to actively control the vibration during and after the slew. With this pair of smart actuator and smart sensor, a strain rate feedback (SRF) controller is designed for active vibration suppression. With the extended Zero Vibration Derivative (ZVD) shaper and the SRF controller, the proposed new approach can effectively reduce the vibration of the flexible beam during slew operations.

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