Multiple Tuned Mass Dampers Research Articles

Seismic Vibration Control on Reinforced Concrete Structure with Multiple Tuned Mass Damper Considering SSI Effects

An earthquake causes a great deal of damage to the structure, that’s why many researchers work on the vibration of the structures caused by the earthquake. A fifteen-story reinforced concrete structure with MTMD (multiple tuned mass dampers) is modeled with a fixed and flexible base in SAP 2000. And also deals with the analysis of the structure and the comparison of the Natural periods, Storey displacement, and Base shear of building values under the dynamic condition considering SSI effects. The paper concluded that the natural periods increase when the soil-structure interaction effect is considered as compared to the assumption of fixed support and the story displacements increase when the soil-structure interaction effect is considered as compared to the assumption of fixed support. The analysis of this structure yielded better results under the conditions used by the multi-tuned mass damper. Keywords: Reinforced concrete structures, Earthquake, Multiple Tuned mass dampers, Soil-Structure Interaction (SSI), SAP2000. DOI: 10.7176/CER/13-2-05 Publication date: April 30 th 2021

Gradient-based multi-hazard optimization of MTMDs for tall buildings

Past research has shown that, from a long-term damage perspective, a multi-hazard approach should often be considered for the design of tall buildings. This also stands for the design of supplemental dissipation devices such as multiple tuned mass dampers (MTMDs). Although MTMDs present several advantages over conventional TMDs, their design is a rather complex process. Thus, an efficient optimization algorithm is necessary to design large-scale MTMDs. This paper presents a powerful multi-hazard optimization-based methodology for the design of MTMDs attached to tall buildings. The total added mass is minimized, while the multi-hazard life-cycle cost (LCC) is taken as a constraint. To enable an efficient optimization of large-scale MTMDs, a gradient-based algorithm is developed, supported by a sensitivity analysis of the PEER-based multi-hazard LCC formulation. Material interpolation techniques are used to provide distinct design alternatives. The methodology is applied to a realistic tall building. First, a small-scale problem is used to compare the new methodology with classic evolutionary algorithms. The proposed framework required less than 2% of the function evaluations executed by the benchmark algorithms to deliver competitive solutions. Subsequently, large-scale problems using different formulations are presented. Solving problems with 133 TMDs, the optimized solutions allow to reduce the multi-hazard LCC by 35%, adding 0.69–0.86% of the building mass. The results show that the algorithm can provide economic designs at acceptable computational costs, and the methodology can capture consistently the multi-hazard behavior.

Formula omitted] optimization of multiple tuned mass dampers for multimodal vibration control

In this paper, a new computational method for the purpose of multimodal vibration mitigation using multiple tuned mass dampers is proposed. Classically, the minimization of the maximum amplitude is carried out using direct H∞ optimization. However, as shall be shown in the paper, this approach is prone to being trapped in local minima, in view of the nonsmooth character of the problem at hand. This is why this paper presents an original alternative to this approach through norm-homotopy optimization. This approach, combined with an efficient technique to compute the structural response, is shown to outperform direct H∞ optimization in terms of speed and performance. Essentially, the outcome of the algorithm leads to the concept of all-equal-peak design for which all the controlled peaks are equal in amplitude. This unique design is new with respect to the existing body of knowledge.

Use of Added Damping Devices with Special Emphasis on Multiple Tuned Mass Dampers : A Review

Dampers are significant part of structure in the highlight increment seismic opposition. As they increment the life of structure, toughness and flexiblity. In various power condition the conduct of damper assumes a significant job, which shows the need of damper .So it is important to concentrate to make its utilization in better manner.

Optimization of Multiple Tuned Mass Damper (MTMD) Parameters for a Primary System Reduced to a Single Degree of Freedom (SDOF) through the Modal Approach

The research paper presents a novel approach toward constructing motion equations for structures with attached MTMDs (multiple tuned mass dampers). A primary system with MDOF (multiple dynamic degrees of freedom) was reduced to an equivalent system with a SDOF (single degree of freedom) through the modal approach, and equations from additional MTMDs were added to a thus-created system. Optimization based on ℌ2 and ℌ∞ for the transfer function associated with the generalized displacement of an SDOF system was applied. The research work utilized GA (genetic algorithms) and SA (simulated annealing method) optimization algorithms to determine the stiffness and damping parameters for individual TMDs. The effect of damping and stiffness (MTMD tuning) distribution depending on the number of TMDs was also analyzed. The paper also reviews the impact of primary system mass change on the efficiency of optimized MTMDs, as well as confirms the results of other authors involving greater MTMD effectiveness relative to a single TMD.

Passive control of jacket–type offshore wind turbine vibrations by single and multiple tuned mass dampers

Vibration control is gaining focuses in the field of offshore wind turbines (OWTs) in recent years as the turbine tower becomes taller and more slender. Although a number of research works have been carried out to control the OWT vibrations, using tuned mass damper (TMD) and multiple tuned mass dampers (MTMDs) to control the jacket–type OWT vibrations is rarely reported, especially for the MTMDs, of which the application in the field of OWTs is still in the initial stage. This study focuses on the performance of TMD and MTMDs in controlling the tower vibrations of the jacket–type OWT subjected to the combined wind, wave and current loads, which are the most common external vibration resources for OWTs. The control effectiveness is numerically investigated and evaluated by the reductions of the standard deviation displacement (σ(d)) and the standard deviation acceleration (σ(a)) of the tower top. After the installation of TMD, σ(d) and σ(a) are reduced by 32% and 29% respectively. Larger TMD mass ratios lead to better control effectiveness, but the improvement becomes less obvious as the mass ratios constantly increase. The control effectiveness of the MTMD system is slightly decreased compared with a single large TMD. However, the robustness of MTMDs is superior since the OWT vibrations can still be controlled effectively even if some TMDs do not function. The control effectiveness of the MTMD system can also be affected by the change in the positions of malfunctioned TMDs.

Optimization of Multiple Tuned Mass Dampers for Road Bridges Taking into Account Bridge‐Vehicle Interaction, Random Pavement Roughness, and Uncertainties

Road bridge designs are based on technical standards, which, to date, consider dynamic loading as equivalent static loads. Additionally, the few engineers who perform a dynamic analysis typically do not consider the effects of bridge‐vehicle interaction and also simplify the road’s irregularity profile. Moreover, often, even when a simplified dynamic analysis is carried out and shows that there will be a high dynamic amplification factor (DAF), designers prefer to solve this problem by adopting high safety factors and thereby oversizing the bridge, rather than using energy dissipation devices that would allow reducing the amplitude of vibration. In this context, the present work proposes a complete methodology to minimize the dynamic response of road bridges by optimizing multiple tuned mass dampers (MTMD), taking into account the bridge‐vehicle interaction, the random profile of pavement irregularities, and the uncertainties present in the coupled system and in the excitation. For illustrative purposes, the coupled vibration problem of a regular truck traveling on a random road profile over a typical Brazilian bridge is analyzed. Three different scenarios for the MTMD are considered. The proposed optimization problem is solved by employing the Whale Optimization Algorithm (WOA). The results showed the excellent ability of the proposed methodology, reducing the bridge’s DAF to acceptable values for all analyzed cases, considering or not the uncertainties present in the system. Furthermore, the results obtained by the proposed methodology are compared with results obtained using classical tuned mass damper (TMD) design methods, showing the best performance of the proposed optimization method. Thus, the proposed method can be employed to optimize MTMD, improving bridge design.

Simplified design procedure for nonconventional multiple tuned mass damper and experimental validation

SummaryA simplified design procedure, for nonconventional multiple tuned mass damper (TMD) (NC‐MTMD) system, was proposed. This system entails targeted tuning of each TMD by considering several mechanical factors (e.g., seismic excitation, TMD mass, and location). Subsequently, all TMDs are tuned to their corresponding modes by a group of semi‐empirical design formulae based on previous theoretical studies on MTMD systems, in the tuning phase. The procedure was then calibrated by numerical optimization results of an actual existing thermal power plant structure and validated in both comparative numerical study and a shaking table test. The experimental model was designed based on the thermal power plant structure configuration. Springs and eddy current dampers were adopted to model the resistance and energy dissipation of TMDs. A numerical comparative study was carried out between a traditional design method and the proposed design scheme. Six representative NC‐MTMD mass cases were investigated in the shaking table test to study the robustness of the method. The seismic mitigation efficiency was evaluated by comparison study on frequency, peak, and root mean square responses. The NC‐MTMD design was proved to be effective to help reduce seismic responses of the structure.

Closure to “Effect of Multiple Tuned Mass Dampers for Vibration Control in High-Rise Buildings” by Lekshmi Suresh and K. M. Mini

Closure to “Effect of Multiple Tuned Mass Dampers for Vibration Control in High-Rise Buildings” by Lekshmi Suresh and K. M. Mini

Discussion of “Effect of Multiple Tuned Mass Dampers for Vibration Control in High-Rise Buildings” by Lekshmi Suresh and K. M. Mini

Discussion of “Effect of Multiple Tuned Mass Dampers for Vibration Control in High-Rise Buildings” by Lekshmi Suresh and K. M. Mini

Life-cycle cost-based optimization of MTMDs for tall buildings under multiple hazards

Tall buildings are especially prone to damage caused by winds and earthquakes. In practice, only a single hazard is assumed to dominate the design and is adopted for structural verifications. This is also the case when supplemental damping devices such as tuned mass dampers (TMDs) are adopted. Nevertheless, previous research has shown that from a life-cycle cost (LCC) perspective the dominant hazard concept is misleading, and a multi-hazard approach is necessary. This article proposes a methodology for multi-objective optimization-based design of multiple TMDs (MTMDs) attached to tall buildings subjected to both winds and earthquakes. The LCC related to damage on non-structural components is taken as one of the objective functions to join consistently these hazards. The MTMDs initial cost is selected as the second objective function. The results of these multi-objective optimization problems are Pareto fronts of optimized solutions that may be of interest to stakeholders, including non-technical decision makers. A genetic algorithm is adopted as solution strategy. A realistic case study is presented, and the optimization results are compared with classic literature solutions.

Optimal Location of Multiple Tuned Mass Dampers in Regular and Irregular Tall Steel Buildings Plan

Tuned mass dampers are one of the most common devices for the passive control of structures subjected to earthquakes. The structure of these dampers consists of three main parameters: mass, damping, and stiffness. Tuned mass dampers reduce the amplitude of the responses affecting on a mode. In most cases, only a single TMD (tuned mass damper) or a few dampers at several points above the building height are installed on the roof of the building, requiring considerable mass and space in some parts of the structure as overhead. It is also more important to predict the elements that will meet the required mass. In this research, the performance of multiple tuned mass dampers (MTMDs) is investigated in L- and U-shaped regular and irregular tall steel buildings with 10 and 20 floors, under the near- and far-field records. Nonlinear time history analysis is also applied to evaluate the multiple tuned mass dampers effects on the seismic responses of the structures. The SAP2000 API and MATLAB genetic algorithm are used to determine the optimal location of the MTMDs in the roof plans of the buildings. The results show the effects of multiple tuned mass dampers in reducing the seismic response of acceleration, displacement, and base shear up to 50, 40, and 40% in average, respectively. The results of determining the optimum location of MTMDs in the models indicate the importance of the symmetry of the dampers relative to the centre of mass of the building.

Seismic performances of a structure equipped with a large mass ratio multiple tuned mass damper

SummaryThis paper focuses on improvement of structural seismic performance under earthquakes of different intensities using a large mass ratio multiple tuned mass damper (LMTMD). A thermal power plant was taken as the example, and the plant was modeled using the finite element software ABAQUS. Coal buckets, which comprised 29.2% of the total mass of the structure, were used as the mass of the LMTMD. Thus, a large mass ratio was easily achieved without adding any extra mass. Incremental dynamic analysis was used to investigate the seismic fragility of the structures, and the seismic performances of the structure equipped with the LMTMD and the original structure were compared. The damping effectiveness and the control reliability of the LMTMD were evaluated. The fragility curves show that under rare earthquakes, the LMTMD reduced the probability of the moderate damage limit state by 43.9%, and under extremely rare earthquakes, the LMTMD exhibited good control robustness and reduced the probability of the severe damage limit state by 25.1%. Furthermore, the LMTMD could control the deformation pattern of the structure and effectively reduced concentrated damage, especially under high‐intensity ground motions; specifically, it reduced the average value of the interstory drift ratio by 1.2%–12% and reduced the standard deviation of the interstory drift ratio by 15%–62%. These results indicate that the LMTMD significantly improved the seismic performance of the structure with satisfactory reliability.

Vibration control of a pentapod offshore wind turbine under combined seismic wind and wave loads using multiple tuned mass damper

The dynamic characteristics and coupling mechanisms of a bottom fixed offshore wind turbine (OWT) with a pentapod substructure under combined seismic, wind, and wave conditions are analyzed. A passive control method of a tuned mass damper (TMD) is then applied. The influence of the TMD parameters on the control effects of the OWT is investigated, and the feasible parameters for the vibration mitigation are recommended. Then, a multiple tuned mass damper (MTMD) with abundant tuning frequencies is developed in view of the limitation of the TMD on the vibration control. Both the local and global responses of the OWT can be significantly decreased by the MTMD, validating its wide applicability relative to the TMD. Furthermore, suggestions for designing the MTMD for an OWT under the seismic cases are summarized.

Tuned Mass Dampers for Response Reduction of a Reinforced Concrete Chimney Under Near-Fault Pulse-Like Ground Motions

The article investigates response mitigation of a reinforced concrete (RC) chimney subjected to pulse-like near-fault ground motions using tuned mass damper (TMD) schemes. The total height of the chimney is 250 m with a mass of 11109 ton. Three TMD schemes are used: single tuned mass damper (STMD), multiple TMDs having equal stiffness (w-MTMDs) and multiple TMDs having equal masses (e-MTMDs). The STMD is tuned to the fundamental frequency of the chimney while both w-MTMDs and e-MTMDs have three TMDs for controlling each of the first and second modes (total of 6 TMDs) of vibration. Response of the uncontrolled and controlled structures is calculated for 69 recorded ground motions containing a dominant velocity pulse. Displacement and acceleration at top node of the RC chimney are the response of interest for performance assessment. It is found that e-MTMDs are more effective and robust than other schemes. It is also found that the pulse period of ground motion plays a very important role in how effective the control schemes are. There is a large variability in the reduction of response across these ground motions, and optimization methods independent of ground motion are not robust. There is a need for more advanced optimization methods incorporating information about local seismic sources.

Effectiveness of Location and Number of Multiple Tuned Mass Damper for Seismic Structures

Tuned mass dampers (TMD) are one of the most reliable devices to control the vibration of the structure. The optimum mass ratio required for a single tuned mass damper (STMD) is evaluated corresponding to the fundamental natural frequency of the structure. The effect of STMD and Multiple tuned mass dampers (MTMD) on a G+20 storey structure are studied to demonstrate the damper’s effectiveness in seismic application. The location and number of tuned mass dampers are studied to give best structural performance in maximum reduction of seismic response for El Centro earthquake data. The analysis results from SAP 2000 software tool shows damper weighing 2.5% of the total weight of the structure effectively reduce the response of the structure. Study shows that introduction of 4-MTMD at top storey can effectively reduce the response by 10% more in comparison to single tuned mass damper. The use of MTMD of same mass ratio that of STMD is more effective in seismic response.

Three-dimensional vibration control of offshore floating wind turbines using multiple tuned mass dampers

Offshore floating wind turbines (FWT) subjected to misaligned wind and wave loadings experience extreme three-dimensional vibrations which will increase the fatigue loadings on the structure and mooring cables. The present study uses a three-dimensional pendulum tuned mass damper (3d-PTMD) and dual linear pounding tuned mass dampers (2PTMDs) to mitigate the three-dimensional vibrations of a spar-type FWT under wind and wave loadings. An analytical model of a spar-type FWT coupled with the 3d-PTMD and 2PTMDs is established using Euler-Lagrangian equation. Blade Element Momentum method is utilized to determine the aerodynamic loading and Morison equation is used to compute the hydrodynamic loading. Mooring cables are modeled using an open source module MoorDyn. The optimal design of the 2PTMD is determined using a numerical search approach. Performance of the proposed controlling devices in reducing the three dimensional vibrations of the spar FWT is evaluated via using the NREL 5 MW OC3-Hywind spar buoy wind turbine. Results show that a well-designed 3d-PTMD and 2PTMDs can effectively reduce the three-dimensional vibrations of the tower and the platform. More importantly, it is shown that the proposed 2PTMDs experiences a smaller stroke which is 50% smaller than that of traditional linear TMDs. This is of significant value for practical applications.

Applying multiple tuned mass dampers to control structural loads of bottom-fixed offshore wind turbines with inclusion of soil-structure interaction

Using structural control methods to suppress structural loads of offshore wind turbines is an economical and feasible solution. Note that the dynamic responses of offshore wind turbines are generally analyzed under the parked condition, and the blades are usually modeled with a lumped mass. Actually, the geometrical properties and rotational speed of blades can significantly affect the wind turbine performances. Therefore, these simplifications may result in inaccurate evaluation for the wind turbine dynamic responses, and then further influence the evaluation of the load mitigation effect of a control system. Moreover, the vibration behaviors and structural responses of the wind turbine can be influenced by soil-structure interaction. In this work, the structural responses of a bottom-fixed offshore wind turbine that suffers combined wind and wave excitations are explored. The blade model is explicitly established and soil-structure interaction is also taken into account. The dynamic responses of the wind turbine as well as the vibration mitigation effects of a single tuned mass damper (STMD) and a multiple TMDs (MTMD) system are examined. Furthermore, the sensitivity analysis for the TMD tuning frequency and the robustness of the MTMD system are investigated under the assumption that some TMDs in MTMD do not work properly.

Tuned mass dampers in wind response control of wind turbine with soil-structure interaction

The efficiency of tuned mass dampers (TMDs) in along-wind response mitigation of a wind turbine with consideration of blade coupling and soil-structure interaction (SSI) is investigated. The wind turbine tower is modeled as a multi-degree of freedom (MDOF) with three blades are connected as a MDOF system to the tower. The along-wind drag forces are generated using Shinozuka method. The effect of SSI is considered using frequency independent parameters. The equation of motion for the coupled system is numerically solved in time domain using the Newmark Beta method. In order to observe the changes in response of the system, the blades are subjected to rotating wind field to include the effects of the blade-tower interaction and rotor movement. The peak displacement, peak acceleration, root mean square (RMS) displacement, RMS acceleration, and power spectral density (PSD) of the wind turbine are the response quantities considered for comparative studies. Single TMD (STMD) and distributed multiple TMDs (d-MTMDs) are used to mitigate the wind response of the tower. Parametric studies are conducted to find the most suitable parameters (such as mass ratio, frequency bandwidth, and damping ratios) of the TMD schemes to increase the effectiveness of the strategy in the mitigation of the wind response of wind turbine with/without consideration of SSI. It is concluded that wind response of the wind turbine is amplified with inclusion of the SSI, blade-tower interaction, and rotor movement. In addition, it is concluded that the d-MTMDs are more effective and robust in wind response control of the wind turbine as compared to the STMD.

The Multiple Tuned Mass Damper for Passive Control of Structures by Cuckoo Algorithm

Adjustable mass dampers are recently used to reduce seismic vibrations of engineering structures. Function of these types of systems requires a suitable setting of their parameters. In this study, a practical method to design Multiple Tuned Mass Dampers (MTMD) has been proposed to minimize the maximum displacement of roof, acceleration of roof and TMDs displacement to reduce the seismic response of structures. To solve the problem Cuckoo Optimization Algorithm (CMOA) has been used. The results of numerical simulations for a shear frame of ten floors exposed to earthquakes demonstrate that CMOA is able to present appropriate solutions in the form of Parato charts for setting optimal parameters of MTMD, caused by creating a proper compromise between the objective functions in conflict with each other. Eventually, MTMD desirably reduces seismic responses of structures. Also, MTMD performance depends on input quake, TMD mass ratio and the number of TMDs.