scholarly journals Passive vibration control: a structure–immittance approach

Author(s):  
Sara Ying Zhang ◽  
Jason Zheng Jiang ◽  
Simon A. Neild

Linear passive vibration absorbers, such as tuned mass dampers, often contain springs, dampers and masses, although recently there has been a growing trend to employ or supplement the mass elements with inerters. When considering possible configurations with these elements broadly, two approaches are normally used: one structure-based and one immittance-based. Both approaches have their advantages and disadvantages. In this paper, a new approach is proposed: the structure–immittance approach. Using this approach, a full set of possible series–parallel networks with predetermined numbers of each element type can be represented by structural immittances, obtained via a proposed general formulation process. Using the structural immittances, both the ability to investigate a class of absorber possibilities together (advantage of the immittance-based approach), and the ability to control the complexity, topology and element values in resulting absorber configurations (advantages of the structure-based approach) are provided at the same time. The advantages of the proposed approach are demonstrated through two case studies on building vibration suppression and automotive suspension design, respectively.

Author(s):  
Yiqing Yang ◽  
Haoyang Gao ◽  
Wenshuo Ma ◽  
Qiang Liu

The vibration absorber has been effective in vibration control. From the demand of manufacturing structural parts with a deep hole, the design of a turning cutting tool with large length–diameter ratio is presented. An analytical approach of acquiring frequency response of primary structure equipped with typical single-degree-of-freedom vibration absorbers is formulated, and background modes are incorporated with the purpose of achieving an accurate tuning of vibration absorber. Specifically, the three-element type is investigated as the damping element of the vibration absorber embedded in the cutting tool contributes to the stiffness, although it demonstrates medium performance of vibration suppression according to non-dimensional analysis. The experimentally tuned frequency response function of the turning cutting tool with three-element vibration absorber achieves 87.1% reduction on the amplitude of the target mode. Finally, several configurations of internal turning operations are carried out to validate the design of the vibration absorber.


2020 ◽  
Vol 6 (8) ◽  
pp. 1622-1651
Author(s):  
Fatemeh Rahimi ◽  
Reza Aghayari ◽  
Bijan Samali

Given the burgeoning demand for construction of structures and high-rise buildings, controlling the structural vibrations under earthquake and other external dynamic forces seems more important than ever. Vibration control devices can be classified into passive, active and hybrid control systems. The technologies commonly adopted to control vibration, reduce damage, and generally improve the structural performance, include, but not limited to, damping, vibration isolation, control of excitation forces, vibration absorber. Tuned Mass Dampers (TMDs) have become a popular tool for protecting structures from unpredictable vibrations because of their relatively simple principles, their relatively easy performance optimization as shown in numerous recent successful applications. This paper presents a critical review of active, passive, semi-active and hybrid control systems of TMD used for preserving structures against forces induced by earthquake or wind, and provides a comparison of their efficiency, and comparative advantages and disadvantages. Despite the importance and recent advancement in this field, previous review studies have only focused on either passive or active TMDs. Hence this review covers the theoretical background of all types of TMDs and discusses the structural, analytical, practical differences and the economic aspects of their application in structural control. Moreover, this study identifies and highlights a range of knowledge gaps in the existing studies within this area of research. Among these research gaps, we identified that the current practices in determining the principle natural frequency of TMDs needs improvement. Furthermore, there is an increasing need for more complex methods of analysis for both TMD and structures that consider their nonlinear behavior as this can significantly improve the prediction of structural response and in turn, the optimization of TMDs.


Author(s):  
Yiqing Meng ◽  
László E Kollár

The present research proposes two vibration control techniques for attenuating vibration of laboratory-scale suspended cables. The technique is applied to resolve the problems of such high-frequency vibrations as the aeolian vibration. The vibration control device involves an absorber driven by a motor, and the dynamics of the controlled system is investigated numerically considering practical problems. Particular attention is paid to backlash at the driving that influences the effectiveness of control significantly, and to the time response of the controlled system that indicates how quickly the vibration decays after a change in the excitation. One of the proposed controllers involves the implementation of PID technique that enables the significant reduction in the value of cable displacement and acceleration during aeolian vibration, compared to the conventional vibration absorber. An extensive controller has also been proposed based on estimation of cable vibration frequency. The dynamic performance of the controllers is simulated using Simulink. Results also reveals the limitations in the control due to a practical problem like backlash. The main practical benefit from the study is that it provides information about the advantages and disadvantages of the control methodologies, and recommendation may be done for their application without building the controlled system.


Author(s):  
Mark H. Holdhusen ◽  
Kenneth A. Cunefare

A State-Switched Absorber (SSA) is a device capable of instantaneously changing its stiffness, thus it can switch between resonance frequencies, increasing its effective bandwidth as compared to classical tuned vibration absorbers for vibration control. Previous theoretical simulations show that for a system subjected to a multi-harmonic disturbance, using an appropriate logic for switching states, the SSA reduces vibration more effectively than classical tuned vibration absorbers (TVA). This paper considers the experimental performance of the SSA for vibration suppression of an elastically mounted lumped mass base. State switching is achieved using magneto-rheological fluid to connect or disconnect a coil spring in parallel with other coil springs. The stiffness state is controlled by applying or removing a magnetic field across of the MR fluid. Experiments were performed over a range of forcing and tuning frequencies. The SSA system, optimally tuned, outperformed the optimal classical TVA system for all combinations of forcing frequencies.


Author(s):  
Sara Ying Zhang ◽  
Yi-Yuan Li ◽  
Jason Zheng Jiang ◽  
Simon A. Neild ◽  
John H. G. Macdonald

Tuned mass dampers (TMDs), in which a reaction mass is attached to a structural system via a spring–parallel–damper connection, are commonly used in a wide range of applications to suppress deleterious vibrations. Recently, a mass-included absorber layout with an inerter element, termed the tuned mass damper inerter (TMDI), was introduced, showing significant performance benefits on vibration suppression. However, there are countless mass-included absorber layouts with springs, dampers and inerters, which could potentially provide more preferred dynamic properties. Currently, because there is no systematic methodology for accessing them, only an extremely limited number of mass-included absorber layouts have been investigated. This paper proposes an approach to identify optimum vibration absorbers with a reaction mass. Using this approach, a full class of absorber layouts with a reaction mass and a pre-determined number of inerters, dampers and springs connected in series and parallel, can be systematically investigated using generic Immittance-Function-Networks. The advan- tages of the proposed approach are demonstrated via a 3 d.f. structure example.


2017 ◽  
Vol 11 (2) ◽  
pp. 206-214 ◽  
Author(s):  
Ippei Kono ◽  
◽  
Takayuki Miyamoto ◽  
Koji Utsumi ◽  
Kenji Nishikawa ◽  
...  

This study aims to suppress vibration during the machining of long and thin fin parts. Typically, fin parts have low stiffness because fixing the fin is impeded by a end-mill, machine tool or other fins. In this study, multiple tuned mass dampers (TMDs) with the same characteristics were applied to the machining of a fin part measuring 18 mm × 180 mm × 2600 mm. The characteristics of the TMDs were optimized by calculation using a lumped-mass-points system model of the fin part. Then, an impact hammer test and a machining test were conducted on the actual fin part. The dynamic stiffness of the fin part was improved by up to 14 times by using five TMDs, and the amplitude of vibration during machining was decreased by more than 90%.


2013 ◽  
Vol 135 (5) ◽  
Author(s):  
Lei Zuo ◽  
Wen Cui

This paper proposes a novel retrofittable approach for dual-functional energy-harvesting and robust vibration control by integrating the tuned mass damper (TMD) and electromagnetic shunted resonant damping. The viscous dissipative element between the TMD and primary system is replaced by an electromagnetic transducer shunted with a resonant RLC circuit. An efficient gradient based numeric method is presented for the parameter optimization in the control framework for vibration suppression and energy harvesting. A case study is performed based on the Taipei 101 TMD. It is found that by tuning the TMD resonance and circuit resonance close to that of the primary structure, the electromagnetic resonant-shunt TMD achieves the enhanced effectiveness and robustness of double-mass series TMDs, without suffering from the significantly amplified motion stroke. It is also observed that the parameters and performances optimized for vibration suppression are close to those optimized for energy harvesting, and the performance is not sensitive to the resistance of the charging circuit or electrical load.


Sensor Review ◽  
2008 ◽  
Vol 28 (3) ◽  
pp. 233-241 ◽  
Author(s):  
Y‐J. Lin ◽  
Suresh V. Venna

PurposeThe purpose of this paper is to propose an effective and novel methodology to determine optimal location of piezoelectric transducers for passive vibration control of geometrically complicated structures and shells with various curvatures. An industry‐standard aircraft leading‐edge structure is considered for the actuator placement analysis and experimental verification.Design/methodology/approachThe proposed method is based on finite element analysis of the underlying structure having a thin layer of piezoelectric elements covering the entire inner surface with pertinent boundary conditions. All the piezoelectric properties are incorporated into the elements. Specifically, modal piezoelectric analysis is performed to provide computed tomography for the evaluations of the electric potential distributions on these piezoelectric elements attributed by the first bending and torsional modes of structural vibration. Then, the outstanding zone(s) yielding highest amount of electric potentials can be identified as the target location for the best actuator placement.FindingsSix piezoelectric vibration absorbers are determined to be placed alongside both of the fixed edges. An experimental verification of the aluminum leading edge's vibration suppression using the proposed method is conducted exploiting two resistive shunt circuits for the passive damping. A good agreement is obtained between the analytical and experimental results. In particular, vibration suppression around 30 and 25 per cent and Q‐factor reduction up to 15 and 10 per cent are obtained in the designated bending and torsional modes, respectively. In addition, some amount of damping improvement is observed at higher modes of vibration as well.Research limitations/implicationsThe frequency in the proposed approach will be increased slowly and gradually from 0 to 500 Hz. When the frequency matches the natural frequency of the structure, owing to the resonant condition the plate will vibrate heavily. The vibrations of the plate can be observed by connecting a sensor to an oscilloscope. Owing to the use of only one sensor, not all the modes can be detected. Only the first few modes can be picked up by the sensor, because of its location.Practical implicationsThis method can also be used in optimizing not only the location but also the size and shape of the passive vibration absorber to attain maximum amount of damping. This can be achieved by simply changing the dimensions and shape of the piezoelectric vibration absorber in the finite element model on an iterative basis to find the configuration that gives maximum electric potential.Originality/valueThe determination of optimal location(s) for piezoelectric transducers is very complicated and difficult if the geometry of structures is curved or irregular. Therefore, it has never been reported in the literature. Here an efficient FEA‐based electric potential tomography method is proposed to identify the optimized locations for the PZT transducers for passive vibration control of geometrically complicated structures, with minimal efforts. In addition, this method will facilitate the determination of electric potentials that would be obtained at all the possible locations for piezoelectric transducers and hence makes it possible to optimize the placement and configurations of the candidate transducers on complex shape structures.


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