Passive Vibration Control System Research Articles

Structural vibration mitigation via an inertial amplification mechanism based absorber

This paper proposes a novel passive vibration control system, namely the Inertial Amplification Mechanism-based Absorber (IAM-A), to mitigate unwanted structural vibrations. With the help of the H2 and H∞ optimization methods, closed-form formulas for the design parameters of the proposed IAM-A are obtained. Parametric studies are conducted to evaluate the influence of the design parameters on the vibration mitigation performance of the proposed IAM-A. Finally, numerical simulations are performed to validate the efficiency of the IAM-A. For comparison, time history analyses of a structure with IAM-A, with TMD, and without control under earthquake ground motions are performed. Numerical results confirm that dynamic responses of the primary structure are suppressed when the TMD is introduced. But, the relative displacement responses between the primary structure and the absorber are relatively large. The proposed IAM-A outperforms the TMD. With respect to those of the TMD, dynamic responses of the primary structure with the proposed IAM-A are further suppressed. More importantly, the large relative displacement response of the absorber is reduced by more than half.

Estimating the robust optimal parameters of tuned mass damper

The tuned mass damper (TMD) is one of the oldest and most extensively used passive vibration control systems in dynamically excited buildings. However, the uncertainties or randomness in the loading and the primary structure parameters (i.e., stiffness and damping coefficient) significantly affected the TMD performance. In this framework, Robust Design Optimization (RDO) technique is advantageous, aiming to simultaneously minimize the performance function’s mean and variance. Simulation-based RDO techniques are particularly effective at solving difficult nonconvex and multimodal issues. Therefore, in the present study, a stochastic simulation-based approach is proposed for the RDO of TMD. The performance function’s mean and variance are considered robustness measures. The TMD’s frequency and damping ratios are considered design parameters. TMD attached to a Multiple-Degree-of-Freedom (MDOF) structural system is analyzed to demonstrate the efficacy of the proposed approach. The top floor displacement variance ratio of the protected structural system to that of the unprotected structural system is adopted as the performance function. The simulation results show that the proposed strategy successfully identifies the optimal design for all levels of uncertainty. The necessity of considering the uncertainties is well highlighted. In conclusion, the proposed approach is found to be effective and offers the designer more information for an optimal design decision.

The vibration mitigation of jacket offshore platform based on inerter nonlinear energy sink

The application of the traditional passive vibration control system is limited by the demand for large mass. To ameliorate this situation, the inerter nonlinear energy sink (NES) is introduced and applied, as the substitute for the traditional passive vibration control system, to vibration mitigation of jacket offshore platform under random wave loading, since it has the clear advantage of obtaining apparent vibration control effect through low amounts of added mass. For one thing, the equation of jacket offshore platform including inerter NES is developed considering wave loads. For another, the optimal parameters of inerter NES are obtained through Particle Swarm Optimization (PSO) using numerical simulations. Both analytical and numerical results strongly support that the inerter NES contributes greatly to vibration suppression, compared with traditionally tuned mass dampers (TMD). To explore more practical benefits, further comparison between the vibration mitigation of inerter NES and the optimal TMD system, considering different masses and stiffness, is made right after, which verifies the effectiveness and robustness of inerter NES. Based on the above study and results, it proves valid to conclude that the inerter NES system allows practical application of vibration mitigation for marine structures.

Accuracy Characterization of a MEMS Accelerometer for Vibration Monitoring in a Rotating Framework

Active and passive vibration control systems are of paramount importance in many engineering applications. If an external load excites a structure’s resonance and the damping is too low, detrimental events, such as crack initiation, growth and, in the worst case, fatigue failure, can be entailed. Damping systems can be commonly found in applications such as industrial machines, vehicles, buildings, turbomachinery blades, and so forth. Active control systems usually achieve higher damping effectiveness than passive ones, but they need a sensor to detect the working conditions that require damping system activation. Recently, the development of such systems in rotating structures has received considerable interest among designers. As a result, the development of vibration monitoring equipment in rotating structures is also a topic of particular interest. In this respect, a reliable, inexpensive and wireless monitoring system is of utmost importance. Typically, optical systems are used to measure vibrations, but they are expensive and require rather complex processing algorithms. In this paper, a wireless system based on a commercial MEMS accelerometer is developed for rotating blade vibration monitoring. The proposed system measurement accuracy was assessed by means of comparison with a reference wired measurement setup based on a mini integrated circuit piezoelectric (ICP) accelerometer adapted for data acquisition in a rotating frame. Both the accelerometers were mounted on the tip of the blade and, in order to test the structure under different conditions, the first four blade resonances were excited by means of piezoelectric actuators, embedded in a novel experimental setup. The frequency and amplitude of acceleration, simultaneously measured by the reference and MEMS sensors, were compared with each other in order to investigate the viability and accuracy of the proposed wireless monitoring system. The rotor angular speed was varied from 0 to 300 rpm, and the data acquisitions were repeated six times for each considered condition. The outcomes reveal that the wireless measurement system may be successfully used for vibration monitoring in rotating blades.

A Review Paper on Comparative Analysis on RCC Structure with Energy Dissipation Device and Composite Structure

Abstract: In recent years considerable attention has been paid to research and development of structural vibration control devices with particular emphasis on mitigation of wind and seismic response of buildings. Many vibration-control measures like passive, active, semi-active and hybrid vibration control methods have been developed. Base isolation is a passive vibration control system. The isolator partially reflects and partially absorbs input seismic energy before it gets transmitted to the superstructure. Lead rubber bearing isolators are placed between the superstructure and foundation, which reduces the horizontal stiffness of the system. It thereby increases the time period of the structure and decreases the spectral acceleration of the structure. The superstructure acts like a rigid body, thus inter storey drift is reduced. This study is concerned with the effects of various vertical irregularities on the seismic response of a structure and controls this response using base isolation. The objective of the study is to carry out response spectrum analysis. The predominant lateral loads acting upon building structures are earthquake and wind induced forces. If wind load is much greaterthan earthquake load, the lateral force resisting system required to tackle wind loading may be enough to resist the smaller earthquake load. In this situation, a seismic base isolator will not bring any benefit to the building system. Furthermore, if time period of a building without isolator is greater, incorporation of isolator will not bring much difference to the building behavior with respect to seismic load. Additionally, for buildings with lowerstructural time periods, incorporation of an isolator will greatly alter the seismic behavior

Development of new passive vibration control system in coupled structures with block and tackle

An innovative passive vibration control system employed pulley tackle mechanism (Movable Pulley Damper System: MPDS) in coupled structures is proposed in this paper. A cable can be continuously stretched several times to connect the two buildings through the pulley blocks to amplify the relative displacement and provide the high energy absorption efficiency to the damper linked at the middle of the wire. The principle and the theoretical formulation of the system are initially discussed. Also, the effectiveness of the MPDS is examined through the shaking table tests using a scaled-down building model. The experiments demonstrate the ability of the MPDS to mitigate the building response during earthquake excitations as well as the successful amplification of the damping effect. The validity of the mathematical formulation and the equivalent modeling of the MPDS using the truss elements are confirmed by comparing the analytical and the experimental results.

Enhancing the seismic performance of building structures equipped with composite braces in mega bracing configuration

SummaryIn this research, a new passive vibration control system for building structures is presented. The proposed system improves the seismic performance of non‐moment steel structures using the ultra‐high‐performance concrete‐filled steel tube (UHPCFT) braces. In this system, pre‐tensioned tendons are considered to equalize the tensile and compressive capacity of the brace members which are installed as large scale concentrically braced frames (CBFs) (i.e., mega bracing frames [MBFs]) in order to minimize the induced forces in the other structural elements (i.e., beams, columns and slabs). To investigate the feasibility of the proposed system, three 8‐, 12‐, and 15‐story structures are considered. Also, buckling restrained braced frames (BRBFs) and normal concrete filled steel tube (NCFT) braces are considered for the comparison purposes. Furthermore, the effectiveness of the proposed technique is evaluated considering the performance point values and fragility assessment results calculated using a near‐field pulse‐like earthquake record set. Comparison of the simulation results demonstrates that, for all the considered earthquake records, the proposed system remarkably attenuates the structural demand value and collapse probability for all the considered structures. Also, it has demonstrated that type of the nonlinear analysis affects the damage mode.

Development of Vibration Control Structure on Suspended Ceiling Using Pulley Mechanism

A suspended ceiling system (SCS) is one of the most fragile and non-structural elements during earthquakes. However, effective seismic protection technologies for enhancing the suspended ceiling system have not been developed other than the steel bracing system. An innovative passive vibration control system is proposed in this paper, which equipped a damper-employed pulley amplification mechanism into the indirect suspended ceiling system, named the pulley–damper ceiling system (PDCS). Theoretical formulation and the detailed information on the system were presented first. In addition, a new rotational damper composition consisting of a non-linear viscous damper was developed to follow the large wire-cable stroke. Six types of the full-scale ceiling specimens of a 15.6-square meter area with different configurations were constructed for the preliminary experiments to evaluate the seismic performance and feasibility of PDCS under simulated earthquake motions. The comparative results of the shake table test demonstrated that the application of PDCS is capable of controlling both displacement and acceleration of the ceiling panels. This study also presents the nonlinear time history analyses by modeling a wire-cable as an equivalent truss element to transmit the relative displacement of the ceiling system to the damper. The analytical model accurately simulated the dynamic behavior of PDCS.

Towards a self tuning sliding mass metastructure

Passive vibration control systems are characterized by their simple practical design and independence of external power supplies. However, they are usually hindered by their narrow frequency band that cannot handle variable frequency disturbances. Recent research has demonstrated the capability of passive self-tuning resonators through the use of a sliding mass without the need for any external power sources. This work analytically and experimentally investigates the passive self-tuning of a metastructure consisting of a clamped-clamped beam with a sliding mass. The governing equations of motion show that the slider can be driven by Coriolis and centrifugal forces upon applying the excitation force on the structure. To improve the accuracy of our analytical simulations, we derive the exact instantaneous mode shapes and frequencies of the structure and feed them into an adaptive algorithm, which updates the spatial state of the system. Numerical simulations demonstrate that the proposed resonator can tune itself to the excitation frequency as the slider reaches the equilibrium position. This observation suggests that a significant vibration reduction can be obtained using the proposed resonator over a wide frequency band. Experiments are carried out to validate the analytical findings. The proposed structure can be used in different vibration control applications (i.e., aerospace, automotive, and machining), and its model can further be extended to self-adaptive periodic structures (metamaterials).

Lifetime risk-based seismic performance assessment of buildings equipped with supplemental damping and base isolation systems under probable mainshock-aftershock scenarios

This research attempts to investigate the efficacy of different passive vibration control systems, from both technical and economic points of view, to mitigate the lifetime seismic risk of typical buildings under probable mainshock-aftershocks sequences via a novel probabilistic framework. In this regard, three separate common building models are considered, including 5-, 10-, and 15-story intermediate steel moment-resisting frame buildings. These models are designed optimally with/without passive vibration control systems, including hysteretic damping, linear viscous damping, and base isolation systems as independent alternatives. Next, for the hazard modeling, all active faults located in the greater Tehran area are taken into account to simulate the earthquake scenario. Afterward, probable earthquake scenarios during the 50 years of buildings’ life-spans are generated randomly, including the events, as well as their corresponding synthetic stochastic accelerograms. In the next step, responses of buildings and their cumulative losses are calculated under the whole scenarios considering various damage types such as structural, non-structural, and content-related. In the end, by using the Monte-Carlo simulation method, the seismic risk of different building alternatives is estimated. Interestingly, the application of each of the considered vibration control devices leads to a significant reduction in lifetime losses (both physical and economic). It is revealed that the viscous damper has the highest efficacy among different systems. Importantly, by neglecting aftershocks' effects, the estimated lifetime risk will be underestimated by about 27 to 57% below the expected value. Finally, among the active faults in the greater area of Tehran, the North Tehran, Kahrizak, and Mosha faults have the highest contribution in the estimated lifetime risk of buildings.

An integrated nonlinear passive vibration control system and its vibration reduction properties

A novel integrated nonlinear passive vibration control system with the function of vibration isolation and absorption is proposed by applying a bio-inspired isolator and a nonlinear energy sink (NES). The designed integrated system has excellent vibration isolation capability in the low-frequency bands and can decrease the resonance amplitude simultaneously. The nonlinear dynamic model of the integrated passive vibration control system is established. The displacement transmissibility is employed to evaluate the vibration reduction performance of the integrated system by the harmonic balance method. The coupling mechanism of vibration isolation and absorption is revealed through studying the effects of the parameters on the vibration isolation and absorption performance. It is found that due to the nonlinear weak coupling between the bio-inspired isolator and the NES, they can promote each other in the vibration isolation and absorption. Experiments are conducted to validate the advantageous vibration reduction properties of the system. And the design methodology of the integrated passive vibration control system is also elaborated for practical applications. The integrated nonlinear passive vibration control system would provide an innovative method for vibration control in various engineering practice.

Seismic performance of optimal Multi-Tuned Liquid Column Damper-Inerter (MTLCDI) applied to adjacent high-rise buildings

Conventional vibration absorbers, e.g., a classical tuned mass damper, may be not efficient in simultaneously controlling the seismic response of adjacent high-rise buildings. In this paper, a novel passive vibration control system, denoted as Multi-Tuned Liquid Column Damper-Inerter (MTLCDI), is developed to control the seismic response of adjacent high-rise buildings. Two different configurations of this system, namely inter-story MTLCDI (IS-MTLCDI) and inter-building MTLCDI (IB-MTLCDI), are proposed, and related mathematical models are developed to investigate the seismic performance of MTLCDI. A case study project comprising two adjacent high-rise buildings equipped with the proposed system and subjected to ten earthquake records with various frequency characteristics is considered. Performance-based parametric optimization of the MTLCDI systems is performed through two distinct constrained multi-objective optimization problems via genetic algorithms, wherein peak absolute accelerations and inter-story drift ratios of the two adjacent buildings are selected as performance indexes. The mitigation effects of optimum IS-MTLCDI and IB-MTLCDI on earthquake-induced vibrations are scrutinized, with emphasis placed on the effects of natural frequency ratios between the two host structures. The results indicate that, when the two buildings have distinct natural frequencies, both IS-MTLCDI and IB-MTLCDI outperform inter-building single TLCDI as well as other vibration absorbers in terms of seismic vibration control of absolute acceleration and inter-story drift ratios. Under most natural frequency ratios, the IS-MTLCDI achieves a larger response reduction than IB-MTLCDI. Nevertheless, when the differences between natural frequencies of adjacent buildings are significant, applying an IB-MTLCDI may be preferable due to its satisfactory mitigation effects combined with ease of installation.

Vibration-based structural health monitoring of a RC-masonry tower equipped with non-conventional TMD

This article presents the development and the results of three years of implementation of an automated vibration-based structural health monitoring system for modal tracking the dynamic characteristics of a concrete-masonry Civic Tower in Rieti (Italy) equipped with a passive vibration control system, a Non-Conventional Tuned Mass Damper. The system is based on the data recorded by a small number of high-sensitivity accelerometers set on remote automated modal parameters tracking. The analysis of monitoring data highlights the main characteristics of the response of the tower to operational vibrations and low-return period earthquakes. Despite the low levels of vibration in operational conditions, the system can track the evolution of the structural frequencies along time and successfully capture their dependence from temperature, both daily and seasonally. Moreover, the robustness of the modal identification procedure allowed the detection of anomalous variation from the validated reference dynamics of the structure.

Nonlinear vibration absorbers for ropeway roller batteries control

This work investigates a nonlinear passive control strategy designed to reduce the peak accelerations in ropeway roller batteries systems by deploying an array of nonlinearly visco-elastic vibration absorbers. The control effectiveness is compared with that of an equivalent array made of linearly visco-elastic absorbers. A nonlinear parametric model describing the interactions between the different parts of this mechanical multibody system previously developed by the present authors is here extended to include the passive vibration control system aimed to mitigate the acceleration peaks induced by the vehicles transit at different operational speeds. To this aim, a set of linearly visco-elastic vibration absorbers is first optimized through the Differential Evolution (DE) algorithm seeking to minimize the area below the frequency-response curves of the linear equations of motion. Then, a new group of nonlinearly visco-elastic absorbers, that can be largely tuned (i.e., they can exhibit either softening or hardening behaviors), is proposed to mitigate the accelerations induced in the roller by the vehicle transit. These nonlinearly visco-elastic absorbers are optimized by means of the DE algorithm and comparisons with the control achieved by the linear absorbers are carried out to show the higher performance of the proposed nonlinear device. A possible design of the nonlinearly visco-elastic absorber, based on the hysteresis of a wire rope assembly undergoing flexural cycles, is also proposed and discussed.

An analytical study of transient thermo-viscoelastic responses of viscoelastic laminated sandwich composite structure for vibration control

Viscoelastic laminated sandwich composite structure has been used as a new class of high-efficient structural damping in the passive vibration control systems. This work aims to investigate transient thermo-viscoelastic responses of viscoelastic laminated sandwich composite structure. The effects of fractional order parameters and material constants ratio on the structural transient thermo-viscoelastic responses are evaluated and discussed. For each homogeneous isotropic layer, the governing equations are formulated and solved by Laplace transformation techniques. The results are expected to provide new insights on the vibration control and thermal management of viscoelastic laminated sandwich composite structure under extreme non-isothermal conditions.

Design optimization of magnetorheological damper geometry using response surface method for achieving maximum yield stress

Field controllable magnetorheological (MR) damper has gained prominence as a suitable vibration control device for a wide variety of applications as they offer the combined advantages of high-performance metrics of a fully active vibration control system with the cost metrics of a passive vibration control system. The functional quantity that influences the damping performance of a magnetorheological damper is the yield stress of the magnetorheological fluid across the fluid flow gap when the magnetic field is applied. To achieve maximum damping output from the magnetorheological damper, the geometry of the damper piston needs to be optimized. The main geometrical design parameters of the damper piston are the pole width, magnetorheological fluid flow gap, distance between piston rod and coil and the outer pole thickness. The optimization of the damper geometry is carried over with magnetic field strength and yield stress as response variables in two different iterations. A quadratic polynomial function is considered for both the response variables. The yield stress response variable is found to exhibit a more accurate following through the regression equation and it is selected as the response variable of choice. The individual effect of each of the design variable and the interaction effect of the design variables over the yield stress response variable is studied in this research paper. The optimal values of the piston geometry could be used to fabricate a magnetorheological damper prototype in future study.

Experimental analysis of active–passive vibration control on thin-walled composite beam

In the study presented, active and passive vibration control techniques for a thin-walled composite beam were developed and experimentally analysed. An MFC (Macro Fibre Composite) actuator was used, together with the magnetic forces between two permanent cuboidal magnets (passive vibration control) for vibration damping applications. After the experiments conducted with active vibration control (MFC actuator), it was found that in all cases, the vibration damping of the analysed system was much higher at its resonant frequency. Nevertheless, due to the experimental results, it could be concluded that active and passive vibration control systems were efficient for thin-walled composite beam vibration amplitude control. Methodology for thin-walled composite beam vibration control analysis was developed and presented in the article.

Optimal Damper Slip Force for Vibration Control Structures Incorporating Friction Device with Sway‐Rocking Motion Obtained Using Shaking Table Tests

In this study, a series of shaking table tests were conducted using a specimen that consisted of a superstructure, incorporating a friction device and a sway‐rocking mechanism under the superstructure to determine the optimal damper slip force of a passive vibration control system considering the effects of sway‐rocking motion. The adopted simple friction device, composed of rubber bands and stainless steel plates, allowed the magnitude of the slip force to be easily set. The optimal slip force of the friction device, which minimizes the peak and root‐mean‐square response of the superstructure subjected to earthquakes, was determined from the shaking table tests. Based on the results, the optimal slip force of the friction device was found to vary according to the input level of the ground motions and the sway‐rocking conditions. The obtained results suggest that the effect of sway‐rocking motion should be considered in the design of passive control structures and the determination of their optimal damper slip force.

Nonlinear Behavior of Circular Concrete Storage Tanks: History Pushover and Dynamic Loadings by Providing an Innovative Technique to Reduce the Seismic Response of Semi-Buried Tanks

This study has concentrated on the nonlinear behavior of semi-buried concrete cylindrical storage tanks not subjected to seismic loads such as earthquakes. The support conditions of the tank in this study were investigated in both flexible and rigid conditions. A comparison between the behavior of reinforced concrete and pre-stressed concrete of the tanks has been done for flexible support conditions. Finite Element Method (FE) has been used in order to determine the nonlinear response of cylindrical tanks under dynamic time history analysis and pushover. In addition, in this study a new approach has been provided for tanks with flexible support in order to reduce the seismic response of structures with the seismic rehabilitation method using a passive vibration control system of the viscous damper. it has been shown that using FVD the tank’s response subjected to the seismic loads is reduced. Another achievement of a passive vibration control system of the viscous damper (FVD) in concrete tanks, is the improvement of the system by reducing the cracking of concrete. It can be concluded that flexible-based tanks equipped with FVD can be used as an economical and practical system used in earthquake-prone areas.

Dynamical Analysis Applied to Passive Control of Vibrations in a Structural Model Incorporating SMA‐SE Coil Springs

Mechanical vibrations are severe phenomena of the physical world. These oscillations may become undesirable and may cause temporary and even irreversible damage to the system. There are several techniques to minimizing these vibration effects ranging from passive methods to the use of controllers with smart materials. In this sense, this study aims to analyze a passive vibration control system installed in a structure that simulates two‐floor buildings. This system based on the incorporation of one SMA‐SE (Superelastic Shape Memory Alloys) coil springs configuration for energy dissipation and the addition of damping. Modal analysis was performed using analytical, numerical, and experimental methods. In an experimental basis, response amplitudes were analyzed for free and forced vibrations in different configurations. As compared with the structure configuration with steel spring, the forced vibrations FRF (Frequency Response Function) analysis showed a reduction in displacement transmissibility of up to 51% for the first modal shape and 73% for the second mode in the SMA‐SE coil spring configuration. As for damping, there was a considerable increase in the order of 59% in the first mode and 119% in the second, for the SMA‐SE springs configuration.