Semi-active Tuned Mass Damper Research Articles

Experimental study of the semi-active mass damper under impulse excitation.

Mass dampers usually aim to control the steady state vibration of harmonic excitation, but few efforts have focused on suppressing the transient vibration caused by impulse excitation. To obtain the optimum tuning parameters of the semi-active tuned mass damper (TMD) under impulse, optimization analysis of the transient vibration response is carried out. The analytical solutions of transient response are obtained. The transient response of the primary system is attenuated effectively by optimizing three parameters of the TMD, namely, the stiffness, initial displacement, and initial velocity. Three experimental setups are built to achieve different values of the parameters to verify the simulation results. The stiffness of the TMD is modeled analytically and experimentally, and the vibration magnitude denotes that there are several fluctuations when the stiffness of the TMD changes. The results also show that initial displacement and initial velocity of the TMD can lead to different transient vibration magnitudes for the primary system. The optimum parameters of the semi-active TMD can be obtained by the proposed method, and the transient response can be controlled by optimizing the stiffness, initial displacement, and initial velocity of the TMD.

Dynamic response assessment of an offshore jacket platform with semi-active fuzzy-based controller: A case study

The present study investigates the dynamic responses of offshore jacket platforms using a passive and semi-active tuned mass damper (TMD, SATMD), where the control action is achieved by a fuzzy logic controller (FLC) under environmental (i.e., wind, water waves, sea currents) and seismic loadings. Since the studied structure failed to meet recent codes requirements adequately, the suppressing effect of a SATMD is considered as a way to retrofit structural performances under hydrodynamic loadings. After extraction of the dynamic properties of the jacket-type structure, simulations of an installation system with and without a TMD have been performed, and the effectiveness of TMD is quantified.In order to exploit the potential of the structure to overcome all types of excitations, the SATMD comes complete with a fuzzy-algorithm-controller, acknowledging that the use of a passive TMD is only a preliminary attempt to reduce the structure's dynamic responses. Comparison of the results indicates a significant response value reduction in acceleration, base shear, overturning moment, velocity and lateral displacement of a case study of steel jacket platforms.

Nonlinear soil-pile-structure interaction for midrise STMD buildings

One of the effective vibration control systems used for structures is the semi active tuned mass damper (STMD), which is popular since it is reliable and simple. STMD characteristics in the design for piled foundations are usually obtained by modelling the foundation raft only to incorporate the soil structure interaction (SSI). However, as it proposed in the recent studies the role of SSI and simulation of piled raft in the analyses proved to be very important in the determination of the STMD parameters. Hence, in this study, efficiency of STMD with respect to the control of seismic response of the structure, is studied by considering the soil-pile-structure interaction (SPSI). Nonlinear time history analysis is applied for a three-layered soil profile including pile foundations by using the well-known substructure (spring) model under two different ground motion records. In order to increase the accuracy of the results, soil profile with piles and building structure with STMD are considered all at once in a single model under the action of seismic loading, named as direct method. P-Y curves which are suggested by American Petroleum Institute (API) are used in the spring method for simulating soil-pile-structure interaction. The results showed that, adjusting the STMD characterizations on piled structures without considering the soil-pile-structure interaction may result to ineffective control of the seismic vibration and in the worst case may lead to amplification of the vibration of buildings.

Application of Semi-active TMD to Tilted High-Rise Building Structure Subjected to Seismic Loads

Application of Semi-active TMD to Tilted High-Rise Building Structure Subjected to Seismic Loads

Mitigation of Vortex-Induced Vibration in Bridges Using Semiactive Tuned Mass Dampers

With increases in the span length, the vortex-induced vibration (VIV) in bridges often occurs at modest wind velocities. The tuned mass damper (TMD) is very effective in mitigating the VIV, while robustness is a major concern for the TMD control with a small mass ratio. To improve the robustness, a magnetorheological TMD (MRTMD) instead of the TMD is used to mitigate the VIV with slowly time-varying frequency. A control strategy considering VIV characteristics is proposed for realizing the real-time tuning and mass stroke limitation simultaneously, including the control force design, control command determination, and frequency estimation. Numerical simulations of a long-span continuous bridge subjected to the VIV are presented to validate the feasibility of the control strategy and the superiority of the MRTMD control. Numerical results show that the MRTMD control is more robust against the resonant frequency change than the TMD control, and the maximum mass stroke is less than a preset stroke in both tuned and mistuned cases.

Vibration suppression of structures using tuned mass damper technology: A state-of-the-art review

To date, considerable attention has been paid to the development of structural vibration suppression techniques. Among all vibration suppression devices and techniques, the tuned mass damper is one of the most promising technologies due to its mechanical simplicity, cost-effectiveness, and reliable operation. In this article, a critical review of the structural vibration suppression using tuned mass damper technology will be presented mainly focused on the following four categories: (1) tuned mass damper technology and its modifications, (2) tuned mass damper technology in discrete and continuous structures (mathematical modeling), (3) optimization procedure to obtain the optimally designed tuned mass damper system, and (4) active tuned mass damper and semi-active tuned mass damper with the practical realization of the tuned mass damper technologies.

Lateral soil pile structure interaction assessment for semi active tuned mass damper buildings

Using Lateral load-displacement curves (p-y curves) which is recommended by American Petroleum Institute (API) guideline, is typically used as a design approach for analysis of soil-pile-structure interaction due to its simplicity. The soil-pile structure interface has two separate parts of interaction; kinematic and inertial interaction. Both types of interaction must be measured accurately for the structures with dampers to determine the optimum parameters for design. For structures equipped with semi active tuned mass damper (STMD) on deep foundation, determination of the optimum STMD characterizations are completely related to the dynamic attitude of the structure. Hence, in this study, first the accuracy of general p-y equation for buildings with STMD which have short period on deep foundations are evaluated. Then, three dimensional continuum method (finite element method) is used and the general equation of API are updated to provide compatibility. The results showed that the accuracy of spring method (p-y curves method) is very poor in estimation of dynamic response of the structure. A modified API equation is proposed to improve the accuracy and reduce the degree of error for the data set provided. However, it is concluded that the three dimensional continuum method is still a more trustworthy approach for the type of problem investigated in this paper.

Acceleration based ground-hook control of an electromagnetic regenerative tuned mass damper for automotive application

Due to the absence of power demands and yet effective performances, the semi-active tuned mass dampers (STMDs) have been broadly investigated. However, there is still a gap between the theoretical simulations and practical implementation of controlled tuned mass dampers. Moreover, using displacement and velocity sensors make such control systems less cost-effective, less reliable, and more complex. In this paper, the acceleration-based ground-hook semi-active control (ABGH) was proposed for an electromagnetic regenerative tuned mass damper (ERTMD). In this manner, a prototype of a compact back iron-based ERTMD was manufactured. The concept of a controllable system with switched transistor was utilized for the proposed ERTMD. Comparative simulations between the controlled and passive ERTMD was conducted and then validated by experimental results of the ERTMD prototype implemented in a protected mass test-bench similar to a typical vehicle unsprung mass. This paper concluded that the proposed control policy can be utilized for the ERTMD to increase the regenerative ability of the fabricated ERTMD under random excitations.

Automated synthesis of controlled cable-stayed footbridges with S-shaped deck

Curved cable-stayed bridges (CSB) have been increasingly used in the past years. There are currently 42 operational CSB registered in the Structurae database, 37 of which have been built in the last two decades. The minimum cost design of curved S-Shaped pedestrian CSB with external pylons satisfying the static and dynamic code requirements (Eurocodes and Setra guidelines in this work) are found by using an optimization algorithm with polynomial convergence time. Dampers cannot be located at the pylon-deck connection because it does not exists, the structure being controlled by passive and semi-active tuned mass dampers. The sensitivity analysis considers the non-linear dynamic behaviour of the semi-active device. Two optimal solutions are sought using semi-active (S1) and passive (S2) dampers. The results show that both solutions have different geometries and cross sections. The pylon height is markedly higher for structure S2 because this improves the dynamic behaviour of the bridge. The results reveal that the pylon acts like a dynamic leverage arm magnifying the vertical response of the deck. Better results are obtained from performing structural-optimization and determination of control procedure simultaneously rather than separately.

Robust H∞ Control of STMDs Used in Structural Systems by Hardware in the Loop Simulation Method

This paper investigated the performance of a semi-active tuned mass damper (STMD) on a multi-degree of freedom (MDOF) building model. A magnetorheological (MR) damper was used as a control element that provided semi-activity in the STMD. The Hardware in the Loop Simulation (HILS) method was applied to mitigate the difficulty and expense of experimental studies, as well as to obtain more realistic results from numerical simulations. In the implementation of this method for the STMD, the MR damper was set up experimentally, other parts of the system were modeled as computer simulations, and studies were carried out by operating these two parts simultaneously. System performance was investigated by excitation with two different acceleration inputs produced from the natural frequencies of the MDOF building. Additionally, a robust H ∞ controller was designed to determine the voltage transmitted to the MR damper. The results showed that the HILS method could be applied successfully to STMDs used in structural systems, and robust H ∞ controls improve system responses with semi-active control applications. Moreover, the control performance of the MR damper develops with an increase in the mass of the STMD.

Development of Seismic Response Simulation Model for Building Structures with Semi-Active Control Devices Using Recurrent Neural Network

A structural analysis model to represent the dynamic behavior of building structure is required to develop a semi-active seismic response control system. Although the finite element method (FEM) is the most widely used method for seismic response analysis, when the FEM is applied to the dynamic analysis of building structures with nonlinear semi-active control devices, the computational effort required for the simulation for optimal design of the semi-active control system can be considerable. To solve this problem, this paper used recurrent neural network (RNN) to make a time history response simulation model for building structures with a semi-active control system. Example structures were selected of an 11-story building structure with a semi-active tuned mass damper (TMD), and a 27-story building having a semi-active mid-story isolation system. A magnetorheological damper was used as the semi-active control device. Five historical earthquakes and five artificial ground motions were used as ground excitations to train the RNN model. Two artificial ground motions and one historical earthquake, which were not used for training, were used to verify the developed the RNN model. Compared to the FEM model, the developed RNN model could effectively provide very accurate seismic responses, with significantly reduced computational cost.

On‐line system identification of structures using wavelet‐Hilbert transform and sparse component analysis

AbstractA new wavelet‐Hilbert transform based sparse component analysis (WHT‐SCA) method is presented for online system identification in indeterminate conditions. The instantaneous phase ratios of output signals are obtained by using a wavelet‐Hilbert transform based filter; and the out‐of‐phase data, that causes errors in identification accuracy, is detected and eliminated. Then, modal parameters of the structure are identified through existing relationships between the dispersion of filtered data in the frequency domain. Subsequently, to demonstrate the capability of the online identification, a new controller is introduced by combining the WHT‐SCA and a semi‐active tuned mass damper (STMD), resulting in creation of smart structures. The performance of the proposed method and controller is investigated through examples. The results demonstrate that, modal parameters of structures are identified accurately even with noise contamination and limited number of sensors. Also, the STMD is effectively robust against any variations in modal parameters of the structure.

Further steps towards the tuning of inertial controllers for broadband‐frequency‐varying structures

There is a large number of slender structures which are prone to vibrate due to pedestrian loads. The well-known Tuned Mass Damper (TMD) is increasingly used in practice, but this device may detune under several circumstances drastically reducing its expected performance. A Semi-active TMD (STMD) provides more robustness under structure uncertainties than the passive one and may be recommended for use when several vibration modes are in the excitation range and/or when the mode to cancel has uncertainty or varies over time. The tuning of the semi-active device for these cases cannot be the same as the passive one. This paper presents a methodology for the tuning of an STMD under broad frequency-band uncertainties using an ON/OFF phase control law. This control law is experimentally implemented considering interesting practical aspects, such as the estimation of the inertial mass velocity from the measured acceleration, or a low-pass filter to avoid unnecessary control actions, among others. An optimization process using a proposed performance index is carried out. Thus, it has been demonstrated that the optimal STMD is achieved for much lower damping and higher tuned frequency than the passive one. Finally, the proposed methodology is validated with experimental results.

Multiple failure criteria-based fragility curves for structures equipped with SATMDs

In this paper, a procedure to develop fragility curves of structures equipped with semi-active tuned mass dampers (SATMDs) considering multiple failure criteria has been presented while accounting for the uncertainties of the input excitation, structure and control device parameters. In this procedure, Latin hypercube sampling (LHS) method has been employed to generate 30 random SATMD-structure systems and nonlinear incremental dynamic analysis (IDA) has been conducted under 20 earthquakes to determine the structural responses, where failure probabilities in each intensity level have been evaluated using Monte Carlo simulation (MCS) method. For numerical analysis, an eight-story nonlinear shear building frame with bilinear hysteresis material behavior has been used. Fragility curves for the structure equipped with optimal SATMDs have been developed considering single and multiple failure criteria for different performance levels and compared with that of uncontrolled structure as well as structure controlled using passive tuned mass damper (TMD). Numerical analysis has shown the capability of SATMDs in significant enhancement of the seismic fragility of the nonlinear structure. Also, considering multiple failure criteria has led to increasing the fragility of the structure. Moreover, it is observed that the influence of the uncertainty of input excitation with respect to the other uncertainties is considerable.

An investigation on the impacts of passive and semiactive structural control on a fixed bottom and a floating offshore wind turbine

AbstractThe application of structural control to offshore wind turbines (OWTs) using tuned mass dampers (TMDs) has shown to be effective in reducing the system loads. The parameters of a magnetorheological (MR) damper modeled by the Bouc‐Wen model are modified to utilize it as a damping device of the TMD. Rather than showcasing the intricate design policy, this research focuses on the availability of the MR damper model on TMDs and its significance on structural control. The impact of passive and semiactive (S‐A) TMDs applied to both fixed bottom and floating OWTs is evaluated under the fatigue limit state (FLS) and the ultimate limit state (ULS). Different S‐A control logics based on the ground hook (GH) control policy are implemented, and the frequency response of each algorithm is investigated. It is shown that the performance of each algorithm varies according to the load conditions such as a normal operation and an extreme case. Fully coupled time domain simulations are conducted through a newly developed simulation tool, integrated into FASTv8. Compared with the passive TMD, it is shown that the S‐A TMD results in higher load reductions with smaller strokes under both the FLS and the ULS conditions. The S‐A TMD using displacement‐based GH control is capable of reducing the fore‐aft and side‐to‐side damage equivalent loads for the monopile by approximately 12% and 64%, respectively. The ultimate loadings at the tower base for the floating substructure are reduced by 9% with the S‐A TMD followed by inverse velocity‐based GH control (IVB‐GH).

Energy‐based predictive algorithm for semi‐active tuned mass dampers

SummaryThere are various control strategies proposed and implemented for the protection of structures against different types of dynamic excitations. Currently, semi‐active control devices are very popular due to their adaptability and low power requirement. In this paper, a novel energy‐based predictive (EBP) algorithm is proposed, and its effectiveness is studied when applied to semi‐active tuned mass damper (SATMD). The mechanical energy of the primary structure is taken as the key parameter to be used by the algorithm to predict a suitable value of the manipulated variable, the damping of the tuned mass damper (TMD). The choice of the damping is made such that the damping used at a time interval leads to the least possible mechanical energy of the primary structure. The efficacy of the proposed control algorithm is studied by employing the EBP algorithm on single‐story and multistory structures equipped with the SATMD. The performance of the proposed algorithm when applied to the SATMD is also compared with that with the passive TMD for similar parameters. The results of the study show that the implementation of the EBP algorithm leads to significantly reduced dynamic response as compared with the passive TMD. Furthermore, numerical studies are conducted to gain insight into the effect of various parameters such as the mass ratio, the TMD damping ratio, and the flexibility of the structure.

Optimised semi-active tuned mass damper with acceleration and relative motion feedbacks

Abstract This paper presents a semi-active tuned mass damper (STMD) with acceleration and relative motion feedbacks that is optimised in the frequency domain to ensure the same vibration damping efficiency as the Den Hartog’s tuned mass damper (TMD) of up to seven times larger mass. The proposed STMD has attractive features. Firstly, its effectiveness under harmonic excitation is equivalent – also in the case of frequency detuning – to the TMD with K-times larger mass, where K, ranging from 2 to 7, is the main design parameter of the STMD. Secondly, its maximal displacement is not greater than for the TMD having the same mass. Finally, its structure is almost as simple as that of the TMD and it is formed by replacing a viscous damper in the TMD with a controllable damper, for example a magnetorheological damper. The paper presents the tuning of the feedback gains that are introduced along with their correction factors aiming at minimisation of the adverse effect of clipping the active forces. Finding the optimal correction factors together with their polynomial approximations are reported. Due to the practical importance of the proposed STMD, its complete numerical validation as well as in-depth characterisation are provided.

Optimal Step-by-Step Tuning Method for Variable Stiffness Semiactive Tuned Mass Dampers

AbstractA new method, optimal step-by-step tuning (OSST), is presented for the frequency adjustment of variable stiffness semiactive tuned mass dampers (SATMDs). In this method, the external excita...

Use of semi-active tuned mass dampers to control footbridges subjected to synchronous lateral excitation

Tuned mass dampers (TMDs) have been an extensively used technology to control harmonic induced vibrations. These devices have been successfully employed in a wide range of applications, with particular focus on the areas of civil and mechanical engineering. The control of the synchronous lateral excitation in footbridges has been a recent concern, with the use of TMDs being one of the most employed solutions to mitigate this problem. However, this type of devices is very sensitive to the tuning properties and exhibits a clear performance downgrade when detuning occurs. By adding a semi-active damper in the connection between the structure and TMD, it is possible to mitigate the detuning effect, making this feature one of the most interesting advantages of semi-active tuned mass dampers (SATMDs). In this paper, the application of SATMDs to control synchronous lateral excitations in footbridges (also known as ‘lock-in’) is addressed. A numerical procedure is proposed to evaluate its effectiveness and to compare it to passive TMDs. Two example structures are studied: the first corresponds to a practical example of a footbridge with one mode of vibration, which represents a common scenario in footbridge design; the second is a real footbridge with three modes of vibration within the critical lateral resonance range. The results demonstrate a higher efficiency for the SATMD when compared to passive TMDs, particularly regarding to the lower detuning sensitivity, which leads to a substantially lower inertial mass of the device.

Nonlinear structural control using integrated DDA/ISMP and semi-active tuned mass damper

In the recent decade, the robustness, reliability and operability of semi-active tuned mass dampers (STMD) against frequency changes in linear structures has primarily been investigated in the frequency domain. Under severe environmental excitations such as strong earthquakes or winds, structures are expected to respond in the nonlinear range due to material nonlinearity or occurrence of damage which necessitates time domain analyses. In this study, a new proposed STMD controller is presented based on integrating damage detection and semi-active control strategies. The variable stiffness of the STMD is provided by a semi-active independently variable stiffness (SAIVS) device. The stiffness variation of the SAIVS device is implemented by adapting the frequency of the STMD to the fundamental frequency of the bare structure (without STMD), which is obtained using real-time tracking of the damage in the structure based on the measured dynamic responses of the coupled main structure and the STMD system. In this paper, the structural parameters of the bare structure are estimated using the damage detection algorithm based on identified system Markov parameters (DDA/ISMP) method. The effectiveness of the proposed scheme is evaluated via numerical analysis of a nonlinear ten-story building considering seven performance criteria under real earthquakes. In comparison to the passive case, the results reveal that the proposed STMD controller is robust against any structural frequency variations which effectively mitigates damages and nonlinear dynamic responses of the structure under strong ground motions.