TMD System Research Articles

A novel design strategy of track‐based asymmetric nonlinear energy sink for seismic response mitigation of structures

AbstractMass dampers, whether linear or nonlinear, rely on resonance with the structure to achieve optimal control performance. However, linear mass dampers require frequency tuning, while nonlinear mass dampers are sensitive to input energy levels, rendering both inadequate for control problems that involve frequency and energy uncertainties. To address this issue, the track asymmetric nonlinear energy sink (TANES) has been developed as a robust mass damper against frequency and energy changes. In this study, a novel design strategy consisting of physical and parameter design was proposed for TANESs. First, TANESs with inverted tracks as the auxiliary mass were proposed, resulting in a significant reduction in the dimensions and weight of the device. The new physical design was then realized, and the mathematical descriptions of the TANES system were validated through experiments on a two‐story frame structure. Subsequently, a parameter design method was proposed to match the frequency variation pattern of the TANES with the given structural and load conditions. Following the design procedure, three TANESs with markedly different track shapes were obtained and compared with existing mass dampers under different types of excitations. Results showed that the frequency responses of the TANES systems subjected to harmonic ground excitations shared great similarity with those of a well‐tuned TMD system at small‐to‐moderate energy levels. As the energy level increased, nonlinear responses such as strongly modulated responses were observed in the TANES systems with decrease structural frequencies, which significantly reduced the resonant peak in the frequency responses. The frequency responses of the TANES systems were consistent with the design objective and could be used to quantitatively predict the robustness performance of the devices under impulsive and seismic excitations. With the reduced dimensions and weight resulting from the inverted‐track configuration and the robustness performance in line with common structural and load conditions, the proposed design strategy of TANESs demonstrated great potential in the seismic response mitigation of engineering structures.

Seismic reduction principle and response analysis of variable damping viscous damper system

PurposeA new type of variable damping viscous damper is developed to meet the settings of different damping parameter values at different working stages. Its main principle and design structure are introduced, and the two-stage and multi-stage controllable damping methods are proposed.Design/methodology/approachThe theoretical calculation formulas of the damping force of power-law fluid variable damping viscous damper at elongated holes are derived, aiming to provide a theoretical basis for the development and application of variable damping viscous dampers. For the newly developed variable damping viscous damper, the dynamic equations for the seismic reduction system with variable damping viscous dampers under a multi-degree-of-freedom system are established. A feasible calculation and analysis method is proposed to derive the solution process of time history analysis. At the same time, a program is also developed using Matlab. The dynamic full-scale test of a two-stage variable damping viscous damper was conducted, demonstrating that the hysteresis curve is complete and the working condition is stable.FindingsThrough the calculation and analysis of examples, the results show that the seismic reduction effect of high and flexible buildings using the seismic reduction system with variable damping viscous dampers is significant. The program developed is used to analyze the seismic response of a broadcasting tower using a variable damping TMD system under large earthquakes. The results indicate that the installation of variable damping viscous dampers can effectively control the maximum inter-story displacement response of TMD water tanks and can effectively consume seismic energy.Originality/valueThis method can provide a guarantee for the safe and effective operation of TMD in wind and vibration control.

Performance of tuned particle impact damper and tuned mass damper seismic control systems considering mainshock-aftershock

Generally, seismic structural design codes have been defined in accordance with a single shock or mainshock. Also, seismic control systems are usually designed and studied based on single events. considering that ground motions in seismic zones are not a single event and usually several remarkable aftershocks accompany a mainshock, the seismic behavior of controlled structures and performance of the seismic control systems are not clear under real seismic sequences. The current study investigates the seismic behavior of a 3D seismic controlled steel structure and the performance of the seismic control systems under seven real mainshock-aftershocks using non-linear implicit analysis. A tuned particle impact damper (TPID) was used that combines a passive TMD and a particle impact damper (PID) to increase efficiency and performance by working out-of-phase with the main structure and increasing energy absorption. The efficiency of the TPID and TMD seismic control systems was studied by comparing the seismic behavior of the TPID-controlled, TMD-controlled and uncontrolled structures under seismic sequences. The parameters of the frequency response, top-story maximum relative displacement, structural damage (residual displacement) and inter-story drift ratio were studied. Additionally, by considering the structural system as a closed adiabatic isolated system with ground motion energy as the only system input energy, the absorbed kinetic and potential (inelastic dissipated energy) energies in seismic control systems were calculated and compared. Results showed that both TPID and TMD seismic control systems are efficient under seismic sequences. But the TPID system is a more efficient seismic control system compared to the TMD system. Also, this case showed that because of the high performance of the TPID and TMD seismic controlled systems, unlike the moment-resisting uncontrolled structures, there is no need to consider seismic sequences in the design of TPID- and TMD-controlled structures.

Study on Vibration Control and Parameters Influence of Cable Inerter Viscous Damping System

In this study, a single-degree-of-freedom (SDOF) model with cable inerter viscous damper (CIVD) is established, and the vibration control equations and frequency response functions are established. Then, the influence of parameters, including inertia mass ratio, additional damping ratio, and stiffness ratio, is studied. Finally, the dynamic time history analysis of SDOF with CIVD under earthquake and fluctuating wind load is carried out to verify the damping performance of CIVD. The research shows that the additional mass and damping of CIVD can be amplified hundreds of times through the rotation, so as to realize the lightweight and high efficiency of the damper and make up for the engineering defects of the traditional TMD system. Meanwhile, when designing CIVD, the inertia mass ratio and additional damping ratio should be reduced as much as possible under the condition of meeting the target damping ratio. The CIVD can significantly suppress the resonance response of the structure and the continuous vibration response in the stable state. The peak displacement can be reduced by 30%–50%. Installing the cable and inerter element can control only the structural vibration, but it cannot reduce the amplitude in the steady state. The CID can control the inertial force output of the original structure, but the rotating speed of the inerter element is high, and the shaking speed of the original structure is fast. Therefore, in order to control the acceleration, velocity, and displacement of the original structure at the same time, we must add the appropriate inerter, additional damping, and additional stiffness.

An innovative methodology for hybrid vibration control (MR+TMD) of buildings under seismic excitations

In this study, the combination of magnetorheological dampers and tuned mass dampers (MR + TMD) as a hybrid control system is investigated on a 15-story shear building where MR damper is attached to the TMD to generate active control force of TMD. The seismic responses of the structure are reduced by employing MR + TMD on rooftop of the structure. The MR damper's control voltage is generated by combining IT2FLC and FOPID. The FOPID + IT2FLC, TMD, and control voltage parameters are optimized using the observer-teacher-learner-based optimization (OTLBO) algorithm to minimize the maximum displacement of the building rooftop under far-field and near-field earthquake excitations. To conduct additional research, the same method was used to mitigate structural responses for PID, FOPID, IT2FLC, and a combination of fuzzy logic type-1 (FLC) and FOPID (FOPID + FLC). All of these controllers' performances in mitigating seismic responses are compared to those of the uncontrolled system and to each other. The results indicate that FOPID + IT2FLC outperforms PID, FOPID, and FOPID + FLC controllers. Additionally, the building's rooftop displacement was reduced by an average of 35.06% using the FOPID + IT2FLC system for sixteen far-field and near-field earthquake records. Moreover, the hybrid MR + TMD system performs better than other conventional controllers. 1 The combined application of the meta-heuristic algorithm and IT2FLC controller along with FOPID controller (FOPID + IT2FLC) to mitigate structural responses. 2 Combined application of MR damper and TMD (MR + TMD) as a hybrid control device. 3 Optimizing FOPID and IT2FLC to generate the control voltage of MR + TMD. 4 Investigating PID, FOPID, FOPID + FLC controllers to compare with the proposed method. 5 Investigating the performance of the suggested method by the aim of energy consumption and 5 novel criteria such as base shear, base moment and etc.

An innovative pendulum-type column-in-column (PCIC) system for structural vibration control induced by seismic ground excitations

Recently, a sliding-type column-in-column (SCIC) system was proposed by the authors to reduce structural response using the TMD concept. The idea of the SCIC design is to split a column into an external and an internal column to form a nonconventional TMD system to control vibrations while not increasing the size nor compromising the load bearing ability of the column. It was found that the control effectiveness of this SCIC system became less effective when a large superstructure acting on the system. To overcome this drawback, the SCIC system is modified by converting the internal column into a pendulum TMD (PTMD) in this paper, i.e., forming a pendulum-type column-in-column (PCIC) system. To investigate the effectiveness of this novel system, the optimum design formulae of the system are firstly derived using the classical ‘fixed point’ theory. Sensitivity analyses are then carried out to validate the robustness of this system with respect to the superstructure mass, stiffness and damping of the PTMD. Nonlinear time history analyses are performed on the commercial software ABAQUS to demonstrate the control effectiveness. Both analytical and numerical results indicate that the proposed PCIC system shows a good robustness and performance in controlling seismic response of tall slender structures.

Vibration control of beam-model using tuned inerter enhanced TMD

Two vibration control devices using the tuned inerter enhanced TMD are introduced to suppress the vibration of Euler–Bernoulli beam-model in this paper. The two tuned inerter enhanced TMD systems are improved on the basis of the classical TMD system by replacing its damper element with the newly developed tuned viscous mass damper (TVMD) and tuned inerter damper (TID), respectively. The equations of motion and frequency response function of the beam-model subjected to harmonic excitation are derived by the theory of Euler–Bernoulli beam-model. Moreover, the H∞ optimization technique and the extended fixed-points theory are employed to obtain the optimal parameters and closed-form solutions of TVMD and TID enhanced TMD systems, and the control performance of two enhanced systems is analyzed compared with the TMD system. The results reveal that TVMD and TID enhanced TMD systems have stronger robustness and wider control range for the resonance response. Furthermore, the enhanced systems have higher control effectiveness at a small mass ratio compared with the TMD system. Finally, the effectiveness of the enhanced systems is verified by a numerical study considering the harmonic and band-limited white noise excitations.

Study on adaptive-passive multiple tuned mass damper with variable mass for a large-span floor structure

Floor structures, especially large-span floor structures, are sensitive to human-induced vibrations, which might cause a serviceability problem. Multiple tuned mass damper (MTMD) system is often used in the vertical vibration control of large-span floor structures. While it is difficult to determine the design parameters of each TMD in an MTMD system, a passive MTMD system still has the detuning shortcoming. In order to overcome this problem, an adaptive-passive variable mass multiple TMD (APVM-MTMD) system is proposed in this study. Each APVM-TMD in the system has a variable mass configuration and a microcontroller system consisting of an accelerometer, a control circuit board, and a driving device. Under ambient excitation, the control circuit board gathers the signals of the accelerometer on the floor, which can identify the dominant natural frequency of the primary structure where this APVM-TMD is located; this is done through the short time Fourier transformation (STFT)-based frequency identification algorithm. Then, each APVM-TMD can automatically control the driving device to retune itself by varying its mass. After retuning steps of all APVM-TMDs, the previous MTMD system becomes a new MTMD system with a different frequency distribution. A large-span floor structure is proposed as a case study. The original finite element model (FEM) is updated according to the in-situ test. In the updated model, an APVM-MTMD system is designed according to the previous model, then the frequency retuning function is verified. Finally, by applying several kinds of human-induced excitations, the vertical vibration control effect of the retuned MTMD system is compared with the mistuned one. The results show that the APVM-MTMD system can retune itself, and the retuned MTMD system has the best vibration control effect compared to the case without control and the mistuned MTMD system case.

Multi-body dynamics modeling and TMD optimization based on the improved AFSA for floating wind turbines

Compared to the onshore or fixed-bottom offshore wind turbines, floating wind turbines experience larger loads and displacements under combined effects of wind and waves. Therefore, it is necessary to control the structural vibration of floating wind turbines. First, a flexible multi-body dynamics model of a spar-type floating wind turbine is established in SIMPACK. Second, to perform the TMD parameter optimization, a simplified model of the wind turbine is constructed, and unknown parameters in the model are estimated using the Levenberg–Marquardt method. Third, the global optimization ability of the artificial fish swarm algorithm (AFSA) is improved to optimize TMD parameters. Fourth, in order to examine the vibration suppression performance of the designed TMD, a new aero-hydro-elastic-servo model of the wind turbine is built to perform simulations. The simulation results show that the optimized TMD system obtained by the improved AFSA has significant vibration control performance for the floating wind turbine.

A new criterion for the prediction of solid-state phase transition in TMDs.

The classical thermodynamic criterion for phase transition predicts whether the phase transition will occur according to whether the nth derivative of the state parameter is discontinuous, and the continuity verification of multi-order derivatives increases the difficulty and complexity of judgment for phase transition to a certain extent. Based on the reverse shifts of the DOS curves near the Fermi level, we propose a new criterion for solid-state phase transition named Conch Criterion, which has been verified in the TMD system. The new criterion can observe the occurrence of phase transition from another perspective besides the thermodynamic properties while mutually confirming the thermodynamic criterion.

Extending the Fatigue Life of Steel Truss Bridges with Tuned Mass Damper Systems

The increasing traffic demand is continuously growing worldwide. Therefore, the life of a large stock of bridges that still exist throughout the world must be extended, ensuring at the same time that safety is not compromised for economic reason. This paper introduces the possibility to control the fatigue life of existing bridges by using a vibration control system. Based on a dynamic optimization analysis, the stresses from traffic on the bridge are obtained. Subsequently, a plate finite element (FE) model of the whole bridge is developed. The equation of motion is presented for a case study bridge, equipped with different tuned mass damper system, and the combination of external loads and train/track interaction with or without the TMD system is developed through own‐developed routines and FEM software. The procedure is showcased for a case study bridge. After gaining the stress states at the critical hotspot, the fatigue crack life is evaluated by using the linear cumulative damage theory. The different TMD solution presented is demonstrated to be able to diminish the stress level in critical hotspots, improving the overall fatigue life of the bridge over an established lifetime.

Effectiveness of Using RFHDS Connected PIP System for Subsea Pipeline Vibration Control

Pipe-in-pipe (PIP) system can be considered as a structure-tuned mass damper (TMD) system by replacing the hard centralizers by the softer springs and dashpots to connect the inner and outer pipes. With properly designed connecting devices, PIP system therefore has the potential to mitigate the subsea pipeline vibrations induced by various sources, such as earthquake or vortex shedding. This study proposes using rotational friction hinge dampers with springs (RFHDSs) to connect the inner and outer pipes. The rotational friction hinge dampers (RFHDs) are used to absorb the energy induced by the external vibration sources and the springs are used to provide the stiffness to the TMD system and to restore the original locations of the inner and outer pipes. To investigate the effectiveness of this new design concept, detailed three-dimensional (3D) finite element (FE) model of the RFHD is developed in ANSYS and the hysteretic behavior of RFHD is firstly studied. The calculated hysteretic loop is then applied to the 3D PIP FE model to estimate the seismic responses. The effectiveness of the proposed system to mitigate seismic induced vibrations is examined by comparing the seismic responses of the proposed system with the conventional PIP system. The influences of various parameters, such as the preload on the bolt, the friction coefficient and the spring stiffness, on the RFHD hysteresis behavior and on the seismic responses of PIP system are investigated and some suggestions on the RFHDS design are made.

Hybrid passive control system of TLD and TMD for seismic response mitigation of Tall Buildings

Using Tuned liquid damper is one of the passive control methods in structures. The system consists of some water tanks that are installed at the highest level of structure. The water turbulence created inside them is used to reduce the seismic oscillation of structure. Therefore, the damper characteristics (tank size and depth of water in it) should be selected in such a way that the frequency of water in the reservoir is tuned with the frequency of structural vibrations. The controlling force to reduce the structural vibrations is created by the pressure difference caused by the difference in surface levels of the liquid in the end chambers which acts as a shear force at the bottom of tanks. It is required to obtain the water surface level at different times to calculate the controlling force caused by tuned liquid dampers. In the present study, the parameters of damper have been simultaneously minimized by Genetic Algorithm (GA) method and based on single-purpose function (displacement of the top story) and multi-purpose functions (displacement and acceleration of the top story). Optimal Pareto Front objective functions are utilized to achieve optimal responses. A 20-story building has been investigated as a numerical example to carry out this study. In this study the comparisons between TLD system and TMD system, i.e. integrated TLD-TMD system is made with the application of Genetic Algorithms. The author codes all the numerical solutions and Genetic Algorithm program.

MULTIPLE TUNED MASS DAMPERS FOR SEISMIC-EXCITED TALL BUILDING

Multiple tuned mass dampers (MTMD) is used for suppressing seismic excitation of tall building. The performance of MTMD is compared with that of a single tuned mass system (TMD). Optimum parameters of TMD/MTMD for minimizing the variance response of the damped primary structure derived by Krenk, Igusa, and Jangid were used. The optimally designed MTMD system is more effective than that of a single TMD system for reducing seismic excitation of a tall building.

Multi-modal Passive-vibration Control of Bridges under General Loading-condition

Application of TMD systems are observed for mitigation of excessive vibration of bridge-structures targeting either wind loading or vehicle loading. Usually, dominant modes in one direction (commonly vertical) are taken in account for such passive control using TMD systems. However, considering modes dominant in one direction may not be considered as a robust practice while any bridge structure is having dominant modes along both the transverse and vertical directions and the same bridge structure is subjected to loading along both the directions. An approach for simultaneous control of major horizontal, vertical and torsional modes is presented in the present study targeting robust vibration control under general loading condition. A modal frequency response function (FRF) based strategy is proposed using the traditional mode-wise control approach. The proposed modal FRF based approach is applied to an existing important large truss bridge (Saraighat Bridge) to carry out an analytical design of TMD system considering general loading conditions. A Good control-performance is observed based on this proposed design methodology under various simulated general loading conditions.

強非線形性要素と大質量比の仮想質量要素を組み合わせた振動制御に関する基礎的研究

The authors have been carrying out numerical studies on the effect of a passive nonlinear absorber system containing a strongly nonlinear stiffness and a large virtual mass (NLVM). In this paper, the performance of this proposed absorber system when used for a base isolated building against harmonic ground motion and impulsive excitation is presented. The NLVM system has the following characteristics. (1) A large virtual mass ratio reduces response acceleration. (2) A strongly nonlinear stiffness avoids a resonance phenomenon and reduces response displacement. We have studied STD, LVM, NLVM, TMD and TMD-VM systems ( shown in Fig. 2 ). The NLVM system is a nonlinear system and the others are linear systems. In order to examine the performance of the NLVM system, the shooting method and the numerical continuation technique are used to examine the resonance curves and also to determine their stability while direct time integration is used to examine the transient behavior of the dynamic system. Firstly, we compared the NLVM system with the STD and LVM systems. As the NLVM has strongly nonlinear stiffness, it makes the peak of the main resonance curve lean in the direction of higher frequencies ( shown in Fig. 3(b) ). Although several stable solutions occur at the same frequencies, we can use the lowest stable solution in the case where initial conditions are zero or small. Therefore, we regard point Z ( shown in Fig. 3(b) ) as the prediction indicator of a maximum amplitude ratio. Even if the initial conditions are large, the probability of converge to the upper periodic solution is reduced while the amplitude ratio becomes large. The NLVM system is shown not to require a large amount of damping even for a large mass ratio. In the case of a sweep excitation, we can neglect resonance phenomena, because it is extremely difficult to generate a resonance phenomenon along the upper periodic solution during a sweep excitation. In the case of a impulsive excitation, the LVM system can reduce the acceleration amplitude ratio drastically. Since the NLVM system is based on LVM, the maximum value of the acceleration amplitude ratio is of the same level with STD( h1 = 20% ). However, both NLVM and LVM systems have a lower limit near the Racc = μ1/(1+μ1). For this reason, an extremely large mass ratio is not recommend. Secondly, we compared the NLVM system with the TMD and TMD-VM systems. Both TMD and TMD-VM are linear systems optimized using the Fixed-point theory. The TMD-VM is equivalent to the TMD except that the additional mass is a virtual mass. The TMD-VM system is more effective than the TMD system at any mass ratio. In the case of a impulsive excitation, the amplitude ratio of NLVM system is of the same level with TMD-VM, whose mass ratio is in the range of μ = 0.5 ∼ 1.0. In this case, the NLVM doesnot have an additional damping while the TMD-VM requires a large amount of damping( h0,opt = 12 ∼ 22% ). In conclusion, the newly proposed NLVM system can avoid a resonance phenomenon and reduce structural response quite effectively.

Study on Seismic Performance of Offshore Platform with Rocking Wall - TMD System

Offshore platform rocking wall system and tuned mass damper are briefly introduced, and the paper integrates the advantages of these two kinds of seismic method, and the TMD is attached to the jacket offshore platform - rocking wall system, using the ANSYS for finite element analysis, and the analysis results are optimized. The results show that compared with the offshore platform - rocking wall system, additional TMD can give full play to the performances of the two kinds of seismic methods, which is remarkable.

1A23 Vibration Control of Variable Stiffness Tuned Mass Damper with Consideration of Time Delay(The 12th International Conference on Motion and Vibration Control)

This study employed a resettable variable stiffness TMD (RVS-TMD) to alleviate detuning effect. The RVS-TMD is composed of a TMD and a resettable variable stiffness device (RVSD), which consists of a resettable element and a controllable stiffness element. By varying the stiffness element of RVSD, the detuning effect can be mitigated. While, by actuating the resettable element, the hysteresis loop of the RVSD can cover all four quadrants in the force-deformation diagram and thus result in more energy dissipation. However, to adjust the stiffness of the TMD system, the problem of time-delay is inevitable. For an active control system, time is consumed in data acquisition, data processing, on-line calculation, and control force execution. There is always a delay between the time at which the control force is assumed to be applied and actually applied, which may cause degradation in control efficiency. Therefore, the control design of a RVS-TMD system should take into account the effect of time delay. This study applied delayed control gains to alleviate the time delay effect based on the LQR optimal output feedback control algorithm. A parametric study was conducted to demonstrate the relationships of delayed gains with intentionally-added delay time. The results of numerical simulation show the application of optimally-delayed gains significantly alleviates the time delay effect and assure the desired control efficacy.

Vibration control of Multi Degree of Freedom structure under earthquake excitation with TMD control and active control force using fuzzy logic method at the highest and the lowest story of the building

In this paper, Control system performance, as a passive and active control on the example building under the Bam earthquake excitation, was studied. In order to passive and active control the structure TMD system mounted on the top floor of the building and FLC method was used, respectively. Active control system first applied to the lowest floor then to the highest point of the structure (applied to the TMD system). Mathematical model of the building is established in MATLAB. Equation of motion was written for high rise building and it was solved by state-space method, the Results are illustrated and compared.

Dynamic Characteristics Research of Structure with Nonlinear TMD System

The dynamic control equations are derived for the mechanical model with two degrees of freedom that the soften spring is considered in the dynamic vibration absorber. In order to facilitate the computation to the equations, through the integral of the dynamic control equations which became a four order ordinary differential equation. The amplitude frequency response curves of the primary structure excited by a harmonic force were drawn with harmonic balance method, the influence of the dynamic characteristics of primary structure about this kind of nonlinear dynamic vibration absorber was discussed.