scholarly journals Optimum Tuning of Passive Tuned Mass Dampers for the Mitigation of Pulse-Like Responses

2018 ◽  
Vol 140 (6) ◽  
Author(s):  
Jonathan Salvi ◽  
Egidio Rizzi ◽  
Emiliano Rustighi ◽  
Neil S. Ferguson
Keyword(s):  
Seismic Isolation ◽  
Passive Control ◽  
Structural Response ◽  
Optimization Procedure ◽  
Control Device ◽  
Average Response ◽  
Tuned Mass Dampers ◽  
Unit Impulse ◽  
Base Displacement ◽  
The Time Domain

Tuned mass dampers (TMDs) are typically introduced and calibrated as natural passive control devices for the vibration mitigation of the steady-state response of primary structures subjected to persistent excitations. Otherwise, this work investigates the optimum tuning of TMDs toward minimizing the transient structural response. Specifically, a single-degree-of-freedom (SDOF) system is considered as a primary structure, with added TMD, subjected to pulse-like excitations. First, the system is analytically analyzed, within the time domain, for unit impulse base displacement, through Laplace transform. Then, the tuning process is numerically explored by an optimization procedure focused on an average response index, to extract the optimum condition toward best TMD calibration. The efficiency of the proposed control device is then assessed and demonstrated through further post-tuning numerical tests, by considering as dynamic loadings: first, a time unit impulse base displacement, coherent with the source description above; second, different pulse-like excitations, to detect the effectiveness of the so-conceived TMD for generic ideal shock actions; third, a set of nonstationary earthquake excitations, to enquire the achievable level of seismic isolation. It is shown that this leads to a consistent passive TMD in such a transient excitation context, apt to mitigate the average response. Additionally, the present tuning forms a necessary optimum background for a possible upgrade to a hybrid TMD, with the potential addition of an active controller to the so-optimized TMD, to achieve even further control performance, once turned on, specifically for abating the peak response, too.

Analytical analysis for the design of nonlinear tuned mass damper

2020 ◽  
Vol 26 (9-10) ◽  
pp. 646-658
Author(s):  
Lu-yu Li ◽  
Tianjiao Zhang
Keyword(s):  
Passive Control ◽  
Design Method ◽  
Tuned Mass Damper ◽  
Control Device ◽  
Control Performance ◽  
Tuned Mass Dampers ◽  
Mass Damper ◽  
Practical Engineering ◽  
Optimum Formula ◽  
Nonlinear Tuned Mass Damper

A tuned mass damper is a passive control device that has been widely used in aerospace, mechanical, and civil engineering as well as many other fields. Tuned mass dampers have been studied and improved over the course of many years. In practical engineering applications, a tuned mass damper inevitably produces some nonlinear characteristics due to the large displacement and the use of the limiting devices, but this nonlinearity is often neglected. The simulation results in this study confirm that neglecting the nonlinearity in the design process can produce adverse effects on the control performance. This paper takes into account the nonlinearity of the tuned mass damper produced in the process of vibration and deduces an optimum formula for the frequency of a tuned mass damper by the complexification averaging method and multiscale method. Based on this formula, a modified design method for the frequency of a tuned mass damper is presented. The numerical results show that the nonlinear tuned mass damper after modification is better than a linear tuned mass damper in terms of control performance.

scholarly journals Optimal design and performance evaluation of tuned mass damper inerter in building structures

2021 ◽  
Author(s):  
Daniel Caicedo Diaz ◽  
Luis Lara-Valencia ◽  
John Blandon
Keyword(s):  
Performance Evaluation ◽  
Case Studies ◽  
Seismic Performance ◽  
Passive Control ◽  
Control Device ◽  
Design Parameters ◽  
Building Structures ◽  
Tuned Mass Dampers ◽  
Seismic Accelerations ◽  
And Performance

This paper concerns the numerical performance evaluation of multi-degree-of-freedom systems equipped with Tuned Mass Dampers-Inerter (TMDIs); a passive control device used for the mitigation of mechanical vibrations induced by dynamic loads. The inerter device is commonly used to increase the apparent mass of classics tuned mass dampers (TMDs), improving its seismic performance. To evaluate the TMDI action, three case studies are employed, determined from three real buildings of Medellin city from low, medium to high rise (30 meters, 97 meters, and 144 meters, respectively). Optimum design parameters are found using a metaheuristic optimization based on the differential evolution method, first, for the minimization of the horizontal peak displacements, and then, for the minimization of the root mean square (RMS) response of displacements. Besides, the case studies are assessed using eight seismic accelerations records representative of the literature. Finally, the seismic performance is evaluated on each case study considering different levels of inertance induced by the inerter device: 5%, 20%, and 50% with respect to the total mass of the building, for which it is observed a better dynamic behavior when TMDIs with lower values of inertance are implemented.

scholarly journals Seismic Isolation System using U-Shaped Steel Damper

2019 ◽  
Vol 8 (4) ◽  
pp. 12336-12339
Keyword(s):  
Seismic Isolation ◽  
Base Isolation ◽  
Structural Response ◽  
Time History ◽  
Earthquake Ground Motion ◽  
Isolation System ◽  
Isolation Technique ◽  
Base Isolation System ◽  
The Time Domain ◽  
External Forces

In the present paper base isolation system is analyzed and its seismic behavior is investigated using U-shaped steel dampers as an isolator by placing it at the bottom of the structure. It is the most popular way of protecting the structure using control techniques for earthquake ground motion. The dampers significantly reduced damage factors such as displacement and drift. To reduce structural response to external forces, which can be accomplished through the use of special protective systems. So to prevent these damages, seismic isolation technique can be used for newly constructed structures. The time history analysis of the time domain on this structure is conducted by using SAP2000 software

scholarly journals Dynamic response of tension leg platform with tuned mass dampers

2013 ◽  
Vol 10 (2) ◽  
pp. 149-156 ◽  
Author(s):  
Srinivasan Chandrasekaran ◽  
Deepak Kumar ◽  
Ranjani Ramanathan
Keyword(s):  
Large Amplitude ◽  
Passive Control ◽  
Control Device ◽  
Tension Leg Platform ◽  
Tuned Mass Dampers ◽  
Response Control ◽  
Wide Range ◽  
Mass Damper ◽  
H2 Optimization ◽  
Large Amplitude Motion

Tension Leg Platform (TLP) is a taut-moored compliant offshore platform that deploys tethers under high initial pretension to counteract the excess buoyancy. TLPs show large amplitude responses under the encountered lateral forces, which challenges the serviceability of the platform in critical sea states. One of the passive control device i.e. Tuned Mass Damper (TMD) is attempted in the present study to control large amplitude motion of TLPs. In the present study, response control of TLP using single and multiple TMDs is compared. Optimized parameters of multiple tuned mass dampers (MTMD) are obtained using H2 optimization algorithm for the maximum control of the motion of the platform. Based on the studies conducted, it is seen that MTMD systems show better response control in comparison to the single TMD. Higher robustness of the MTMD system is also examined to highlight the use of MTMD over a wide range of excitation frequencies in extreme sea states.DOI: http://dx.doi.org/10.3329/jname.v10i2.16184

scholarly journals Convolution-based time-domain simulation for fluidelastic instability in tube arrays

2021 ◽  
Author(s):  
Mingjie Zhang ◽  
Ole Øiseth
Keyword(s):  
Impulse Response ◽  
Response Function ◽  
Time Domain ◽  
Impulse Response Function ◽  
Time Domain Simulation ◽  
Unit Step ◽  
Tube Arrays ◽  
Unit Impulse ◽  
The Time Domain ◽  
Unit Impulse Response

AbstractA convolution-based numerical algorithm is presented for the time-domain analysis of fluidelastic instability in tube arrays, emphasizing in detail some key numerical issues involved in the time-domain simulation. The unit-step and unit-impulse response functions, as two elementary building blocks for the time-domain analysis, are interpreted systematically. An amplitude-dependent unit-step or unit-impulse response function is introduced to capture the main features of the nonlinear fluidelastic (FE) forces. Connections of these elementary functions with conventional frequency-domain unsteady FE force coefficients are discussed to facilitate the identification of model parameters. Due to the lack of a reliable method to directly identify the unit-step or unit-impulse response function, the response function is indirectly identified based on the unsteady FE force coefficients. However, the transient feature captured by the indirectly identified response function may not be consistent with the physical fluid-memory effects. A recursive function is derived for FE force simulation to reduce the computational cost of the convolution operation. Numerical examples of two tube arrays, containing both a single flexible tube and multiple flexible tubes, are provided to validate the fidelity of the time-domain simulation. It is proven that the present time-domain simulation can achieve the same level of accuracy as the frequency-domain simulation based on the unsteady FE force coefficients. The convolution-based time-domain simulation can be used to more accurately evaluate the integrity of tube arrays by considering various nonlinear effects and non-uniform flow conditions. However, the indirectly identified unit-step or unit-impulse response function may fail to capture the underlying discontinuity in the stability curve due to the prespecified expression for fluid-memory effects.

Seismic Control Effect for Nonlinear Benchmark Building Using Passive or Semi-Active Damper

2002 ◽  
Author(s):  
Akira Fukukita ◽  
Tomoo Saito ◽  
Keiji Shiba
Keyword(s):  
Active Control ◽  
Passive Control ◽  
Feedforward Control ◽  
Electrical Power ◽  
Control Device ◽  
Control Effect ◽  
Damping Force ◽  
Active Device ◽  
Seismic Control ◽  
Control Forces

We study the control effect for a 20-story benchmark building and apply passive or semi-active control devices to the building. First, the viscous damping wall is selected as a passive control device which consists of two outer plates and one inner plate, facing each other with a small gap filled with viscous fluid. The damping force depends on the interstory velocity, temperature and the shearing area. Next, the variable oil damper is selected as a semi-active control device which can produce the control forces by little electrical power. We propose a damper model in which the damping coefficient changes according to both the response of the damper and control forces based on an LQG feedback and feedforward control theory. It is demonstrated from the results of a series of simulations that the both passive device and semi-active device can effectively reduce the response of the structure in various earthquake motions.

scholarly journals Structural Reliability Sensitivities under Nonstationary Random Vibrations

2013 ◽  
Vol 2013 ◽  
pp. 1-21 ◽  
Author(s):  
Rita Greco ◽  
Francesco Trentadue
Keyword(s):  
Structural Reliability ◽  
Structural Parameters ◽  
Time Integration ◽  
Structural Response ◽  
Integration Scheme ◽  
Structural Systems ◽  
Frame Building ◽  
Time Integration Scheme ◽  
Noise Input ◽  
The Time Domain

Response sensitivity evaluation is an important element in reliability evaluation and design optimization of structural systems. It has been widely studied under static and dynamic forcing conditions with deterministic input data. In this paper, structural response and reliability sensitivities are determined by means of the time domain covariance analysis in both classically and nonclassically damped linear structural systems. A time integration scheme is proposed for covariance sensitivity. A modulated, filtered, white noise input process is adopted to model the stochastic nonstationary loads. The method allows for the evaluation of sensitivity statistics of different quantities of dynamic response with respect to structural parameters. Finally, numerical examples are presented regarding a multistorey shear frame building.

Use of a Pendulum for Passive Structural Vibrations Control: An Experimental Study

1993 ◽  
Author(s):  
A. Ertas ◽  
O. Cuvalci
Keyword(s):  
Experimental Study ◽  
Dynamic Response ◽  
Passive Control ◽  
Control Device ◽  
Structural Vibrations ◽  
Pendulum System ◽  
Series Of Experiments ◽  
Tip Mass

Abstract The dynamic response of a beam-tip mass-pendulum system subjected to sinusoidal excitations is considered. The conditions under which resonant and nonresonant oscillations occur are investigated and discussed. The main objective of this study was to conduct a series of experiments to investigate the autoparametric interaction between the first two modes of the system. The use of a pendulum as a passive control device was experimentally evaluated.

Passive Control of Structural Vibration in Base-Isolated Shear Structures

1995 ◽  
Author(s):  
R. Hussein
Keyword(s):  
Passive Control ◽  
Structural Response ◽  
Viscous Friction ◽  
Structural Vibration ◽  
Shear Structures ◽  
Oscillating Systems ◽  
Analytic Models

Abstract This paper presents three analytic models for predictions or structural response of oscillating systems with Coulomb and viscous friction. Numeric results were obtained from the models and compared to demonstrate the effects of friction on vibration amplification.

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