scholarly journals Seismic Assessment of 10-Story Building Using Tuned Mass Damper

2020 ◽  
Author(s):  
Mohammad Aghajani Delavar
Keyword(s):  
Frequency Tuning ◽  
Damping Ratio ◽  
Equations Of Motion ◽  
Tuned Mass Dampers ◽  
Earthquake Excitation ◽  
Optimum Parameters ◽  
Seismic Records ◽  
Structural Responses ◽  
Lateral Displacements ◽  
Shear Building

In this paper, optimum parameters of Tuned Mass Dampers (TMD) are considered to control the responses of 10-story shear building under harmonic loading and 22 set of seismic records of FEMA-P695. The criterion used to obtain the optimum parameters is to select mass ratio, the frequency (tuning) and damping ratio that would result in smallest lateral displacements. State-space equations of motion are presented to compute the structural responses by developing a MATLAB file. A 10-story shear building is presented as a case study to assess the effects of TMDs on the multi-story structures. The results indicate that using TMD can reduce structural responses up to the average 20% under earthquake excitation and up to 90% under harmonic loadings. TMDs are not always effective under any type of ground motion; therefore, being aware of the given location is significant to design TMDs properly.

PERFORMANCE OF DUAL-LAYER MULTIPLE TUNED MASS DAMPERS FOR STRUCTURES UNDER GROUND EXCITATIONS

2006 ◽  
Vol 06 (04) ◽  
pp. 541-557 ◽  
Author(s):  
CHUNXIANG LI
Keyword(s):  
Natural Frequencies ◽  
Vibration Mode ◽  
Frequency Tuning ◽  
Tuned Mass Damper ◽  
Tuned Mass Dampers ◽  
Optimum Parameters ◽  
Generalized System ◽  
Magnification Factors ◽  
Mass Damper ◽  
Multiple Tuned Mass Dampers

The dual-layer multiple tuned mass dampers (DL-MTMD) with a uniform distribution of natural frequencies are proposed, which consist of one large tuned mass damper (L-TMD) and an arbitrary number of small tuned mass dampers (S-TMD). The structure is represented by a generalized system corresponding to the specific vibration mode to be controlled. The criterion for assessing the optimum parameters and effectiveness of the DL-MTMD is based on the minimization of the minimum values of the maximum dynamic magnification factors (DMF) of the structure installed with the DL-MTMD. Also considered is the stroke of the DL-MTMD. The proposed DL-MTMD system is demonstrated to show higher effectiveness and robustness to the change in frequency tuning, in comparison to the multiple tuned mass dampers (MTMD) with equal total mass ratios. It is also demonstrated to be more effective than the dual tuned mass dampers (DTMD) with one large and one small tuned mass damper, but they maintain the same level of robustness to the change in frequency tuning. The DL-MTMD system can be easily manufactured as the optimum value for the linking dashpots between the structure and L-TMD is shown to be zero.

OPTIMUM MULTIPLE TUNED MASS DAMPERS FOR BASE-EXCITED DAMPED MAIN SYSTEM

2004 ◽  
Vol 04 (04) ◽  
pp. 527-542 ◽  
Author(s):  
S. V. BAKRE ◽  
R. S. JANGID
Keyword(s):  
Damping Ratio ◽  
Tuned Mass Damper ◽  
Frequency Bandwidth ◽  
Tuned Mass Dampers ◽  
Explicit Formulas ◽  
Optimum Parameters ◽  
Main System ◽  
Mass Damper ◽  
Tuning Frequency ◽  
Multiple Tuned Mass Dampers

The optimum parameters of multiple tuned mass dampers (MTMD) for suppressing the dynamic response of a base-excited damped main system are investigated by a numerical searching technique. The criterion selected for the optimality is the minimization of the steady state displacement of the main system under harmonic base acceleration. The parameters of the MTMD that are optimized include: the damping ratio, the tuning frequency ratio and the frequency bandwidth. The optimum parameters of the MTMD system and corresponding displacement are obtained for different damping ratios of the main system and different mass ratios of the MTMD system. The explicit formulas for the optimum parameters of the MTMD (i.e. damping ratio, bandwidth and tuning frequency) are then derived using a curve-fitting scheme that can readily be used in engineering applications. The error in the proposed explicit expressions is investigated and found to be negligible. The effectiveness of the optimally designed MTMD system is also compared with that of the optimum single tuned mass damper. It is observed that the optimally designed MTMD system is more effective for vibration control than the single tuned mass damper. Further, the damping in the main system significantly influences the optimum parameters and the effectiveness of the MTMD system.

Pendulum tuned mass dampers and tuned mass dampers: Analogy and optimum parameters for various combinations of response and excitation parameters

2021 ◽  
pp. 107754632110034
Author(s):  
Payam Soltani ◽  
Arnaud Deraemaeker
Keyword(s):  
Transfer Functions ◽  
Tuned Mass Damper ◽  
Tuned Mass Dampers ◽  
Earthquake Excitation ◽  
Optimum Parameters ◽  
Mass Damper ◽  
Different Types ◽  
Host Structure ◽  
Mass Spring ◽  
Tuning Rules

This study deals with the optimisation of pendulum tuned mass damper parameters for different types of excitations and responses of the host structure to which it is attached. The study considers force excitation and base excitation with different types of output quantities to be minimised on the host structure. It also considers both harmonic motion with H ∞ optimisation of the different transfer functions and random white noise excitation where the variance of the output signal is minimised, leading to H2 optimisation. Although a lot of work has been done on optimisation of tuned mass dampers, there exists in the literature only a few solutions for optimisation of the pendulum tuned mass dampers not covering all possible types of loads and output quantities. The analogy between the mass spring tuned mass damper and pendulum tuned mass damper presented in this study allows to use all the tuning rules developed for tuned mass dampers in the case of pendulum tuned mass dampers. In addition, the existing tuning rules for tuned mass dampers are extended to cases which were not previously solved in the literature for H2 optimisation and validated by comparing with numerical optimisation. Finally, a discussion is presented where the different tuning rules are compared, and the performance degradation is assessed when the wrong tuning rule is used. This is representative of the case where, for example, both wind and earthquake excitation exist on the structure, and the pendulum tuned mass damper is tuned for just wind excitation.

On the Vibration Suppression and Energy Harvesting of Building Structures Using an Electromagnetic-Inerter-Absorber

2018 ◽  
Author(s):  
Eshagh F. Joubaneh ◽  
Oumar R. Barry ◽  
Lei Zuo
Keyword(s):  
Energy Harvesting ◽  
Vibration Suppression ◽  
Damping Ratio ◽  
Equations Of Motion ◽  
Optimization Technique ◽  
Building Structures ◽  
Earthquake Excitation ◽  
Mechanical Coupling ◽  
Rlc Circuit ◽  
Tuning Ratio

This paper studies the performance of an electromagnetic resonant shunt tuned mass-damper-inerter (ERS-TMDI) in terms of simultaneously suppressing unwanted vibration and harvesting energy in a vibrating building. The ERS-TMDI is attached to a building, which is subjected to an earthquake excitation. An inerter is connected between the TMD and the ground. The electromagnetic transducer and associated circuit, which replaces the viscous damping in the classical tuned mas-damper (TMD), is assumed to be an ideal transducer shunted with a resistor, an inductor, and a capacitor (RLC) circuit. Two RLC circuit configurations are investigated: one in series and another in parallel. The governing equations of motion are presented and H2 optimization technique is employed to derive explicit expressions for the optimal mechanical tuning ratio, electrical damping ratio, electrical tuning ratio, and electromagnetic mechanical coupling coefficient. The validity of the obtained closed-form expressions is examined using Matlab optimization toolbox. Parametric studies are carried out to investigate the effect of the mass and inertance ratios on the obtained optimal parameters. Numerical examples are also conducted to demonstrate the role of key design variables on vibration mitigation and energy harvesting performances. Also, the performance of a parallel RLC circuit configuration is compared to that of a series configuration.

Development of stiffness-adjustable tuned mass dampers for frequency retuning

2018 ◽  
Vol 22 (2) ◽  
pp. 473-485 ◽  
Author(s):  
Zhihao Wang ◽  
Hui Gao ◽  
Hao Wang ◽  
Zhengqing Chen
Keyword(s):  
Magnetic Force ◽  
Frequency Tuning ◽  
Equations Of Motion ◽  
Tuned Mass Damper ◽  
Significant Loss ◽  
Negative Stiffness ◽  
Experimental Investigations ◽  
Tuned Mass Dampers ◽  
Engineering Structures ◽  
Mass Damper

Tuned mass damper is an attractive strategy to mitigate the vibration of civil engineering structures. However, the performance of a tuned mass damper may show a significant loss due to the frequency detuning effect. Hence, an inerter-induced negative stiffness (apparent mass effect) and magnetic-force-induced positive/negative stiffness are proposed to integrate a stiffness-adjustable vertical tuned mass damper and pendulum tuned mass damper for frequency retuning, respectively. Based on the established differential equations of motion for a vertical tuned mass damper coupled with an inerter and a pendulum tuned mass damper integrated with a magnetic-force-induced positive-/negative-stiffness device, the frequency retuning principles of a vertical tuned mass damper and a pendulum tuned mass damper are, respectively, demonstrated. The frequency retuning strategies for both the vertical tuned mass damper and the pendulum tuned mass damper are confirmed and clarified by model tests. Furthermore, the performance of a retuned vertical tuned mass damper for mitigating vibration of a linear undamped single-degree-of-freedom primary structure is discussed, and the effects of the amplitudes of the pendulum tuned mass damper on magnetic-force-induced stiffness as well as the frequency of the pendulum tuned mass damper are also investigated. Both theoretical analysis and experimental investigations show that the proposed frequency tuning methodologies of tuned mass dampers are efficient and cost-effective with relatively simple configurations.

scholarly journals OPTIMUM MULTIPLE TUNED MASS DAMPERS FOR THE WIND EXCITED BENCHMARK BUILDING / OPTIMALŪS MASĖS SLOPINTUVAI VĖJO VEIKIAMUOSE AUKŠTYBINIUOSE PASTATUOSE

2011 ◽  
Vol 17 (4) ◽  
pp. 540-557 ◽  
Author(s):  
Veeranagouda B. Patil ◽  
Radhey Shyam Jangid
Keyword(s):  
Equations Of Motion ◽  
Tuned Mass Damper ◽  
Performance Criteria ◽  
Governing Equations ◽  
Tuned Mass Dampers ◽  
Optimum Parameters ◽  
Mass Damper ◽  
Mass Ratios ◽  
Space Formulation ◽  
Multiple Tuned Mass Dampers

The performance of multiple tuned mass dampers (MTMD) installed at the top floor of the wind excited benchmark building under across wind loads is investigated. The performance of MTMD is compared with that of single tuned mass damper (TMD) having same total mass. The governing equations of motion of the building with MTMD/ TMD are solved by employing state space formulation. Initially, the TMD is installed at the top floor of the benchmark building and the optimum parameters of the damper for the minimization of various performance criteria of the building are obtained for different mass ratios. Later on, the MTMD is installed at the top floor of the building and the optimum parameters are obtained for the minimization of various performance criteria of the building for different mass ratios and number of dampers. As it is easier to maintain the same stiffness of dampers, the stiffness of each damper in MTMD is maintained as constant. From the study, it is found that the MTMDs are quite effective and robust in the vibration control of the benchmark building. Santrauka Straipsnyje tiriamas kelių masės slopintuvų (KMS), įrengtų aukštybinio pastato, kurį veikia vėjo apkrovos, viršutiniame aukšte, poveikis konstrukcijai. Šis KMS poveikis lyginamas su vieno masės slopintuvo (VMS) poveikiu, teigiant, kad abiem atvejais suminės masės reikšmė yra ta pati. Pagal KMS ir VMS sudarytos judėjimo lygtys išspręstos pritaikius erdvinio būvio formuluotę. Iš pradžių VMS įrengiamas viršutiniame pastato aukšte ir šiam atvejui suskaičiuojami optimalus slopintuvo parametrai, minimizuojant įvairius darbo kriterijus ir įvertinant skirtingus masės koeficientus. Po to KMS įrengiami viršutiniame pastato aukšte ir optimalūs parametrai apskaičiuojami šiam atvejui, įvertinant skirtingus masės koeficientus ir skirtingą slopintuvų skaičių. Kiekvieno slopintuvo standumas KMS atveju nekinta. Daroma išvada, kad KMS įrengimas – gana efektyvi ir veiksminga priemonė siekiant išvengti vibracijų aukštybiniuose pastatuose.

The Dynamic Behaviour of Passively Compensated, Hydrostatic Journal Bearings with Various Numbers of Recesses

1976 ◽  
Vol 18 (6) ◽  
pp. 292-302 ◽  
Author(s):  
P. B. Davies
Keyword(s):  
Dynamic Behaviour ◽  
Damping Ratio ◽  
Equations Of Motion ◽  
Steady State Solution ◽  
Flow Equation ◽  
External Excitation ◽  
Signal Flow Graphs ◽  
Flow Compensation ◽  
Circular Functions ◽  
Flow Graphs

A previously established small-perturbation analysis is developed to express the unsteady-state continuity-of-flow equation for an isolated recess in a passively compensated, multirecess, hydrostatic journal bearing in terms of generalized co-ordinates. The concise form of this equation enables motion of the shaft about the concentric position to be described by equations which are derived in closed form for bearings with orifice, capillary or constant flow compensation and any number of recesses. These equations of motion, and hence the expressions for the receptances which describe the response of a bearing to external excitation, are shown to be of exactly the same form for all bearings of the type considered. Furthermore, the damping ratio and natural frequency in any particular case are determined by a single dynamic constant which is shown to be equal to a linear combination of circular functions and a limited number of coefficients which may be found explicitly by routine use of signal flow graphs. The results of the analysis, which is exact within the stated assumptions, are compared with those of other workers and the steady-state solution of the equations of motion is shown to give an expression for static stiffness which is useful for design purposes. Numerical values of the dynamic constant for bearings with between 3 and 20 recesses are given graphically.

Optimal Design of Vibration Absorber Systems Supported by Elastic Base

1991 ◽  
Author(s):  
Hashem Ashrafiuon
Keyword(s):  
Dynamic Models ◽  
Damping Ratio ◽  
Equations Of Motion ◽  
Elastic Base ◽  
Design Parameters ◽  
Primary System ◽  
Vibration Absorbers ◽  
Equivalent Damping ◽  
System Equations ◽  
Different Levels

Abstract This paper presents the effect of foundation flexibility on the optimum design of vibration absorbers. Flexibility of the base is incorporated into the absorber system equations of motion through an equivalent damping ratio and stiffness value in the direction of motion at the connection point. The optimum values of the uncoupled natural frequency and damping ratio of the absorber are determined over a range of excitation frequencies and the primary system damping ratio. The design parameters are computed and compared for the rigid, static, and dynamic models of the base as well as different levels of base flexibility.

Influence of Material Damping on In-Plane Modal Parameters for Rotating Disks

2012 ◽  
Author(s):  
Hamid R. Hamidzadeh ◽  
Ehsan Sarfaraz
Keyword(s):  
Elastic Moduli ◽  
Damping Ratio ◽  
Equations Of Motion ◽  
Elastic Stability ◽  
Rotating Disks ◽  
Governing Equations ◽  
Annular Disk ◽  
Stress Theory ◽  
Hysteretic Damping ◽  
Circumferential Wave

The linear in-plane free vibration of a thin, homogeneous, viscoelastic, rotating annular disk is investigated. In the development of an analytical solution, two dimensional elastodynamic theory is employed and the viscoelastic material for the medium is allowed by assuming complex elastic moduli. The general governing equations of motion are derived by implementing plane stress theory. Natural frequencies are computed for several modes at specific radius ratios with fixed-free boundary conditions and modal loss factors for different damping ratios are determined. The computed results were compared to previously established results. It was observed that the effects of rotational speed and hysteretic damping ratio on natural frequency and elastic stability of the rotating disks were related to the mode of vibration and type of circumferential wave occurring.

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