Tuned Liquid Column Ball Damper Research Articles

Effect of Tuned Spring on Vibration Control Performance of Modified Liquid Column Ball Damper

This paper reports the theoretical findings of the new modified type of tuned liquid column ball damper (TLCBD), called a tuned liquid column ball spring damper (TLCBSD). In this new modified form, the ball inside the horizontal section of the damper is attached to the spring. Furthermore, two types of this modified version are proposed, known as a tuned liquid column ball spring sliding damper (TLCBSSD) and a tuned liquid column ball spring rolling damper (TLCBSRD). In the former, the rotational motion of the ball attached to the spring is restricted, whereas in the latter, the ball attached to the spring can translate as well as rotate. Mathematical models and optimum design parameters are formulated for both types. The performance of these new modified damper versions is assessed numerically and subjected to harmonic, seismic, and impulse loadings. The results show that the performance of the newly proposed dampers is relatively better than traditional TLCBDs in harmonic and seismic excitations. The peak response reduction soon after the impact load becomes zero is comparatively better in TLCBSDs over TLCBDs. Overall, the newly proposed passive vibration control devices performed excellently in structure response reduction over TLCBDs.

Material optimization of tuned liquid column ball damper (TLCBD) for the vibration control of multi-storey structure using various liquid and ball densities

In this study, a modified form of tuned liquid column damper (TLCD) for multi-degree of freedom (MDOF) structure is presented, which is termed as tuned liquid column ball damper (TLCBD). TLCBD is a passive vibration control device used for the reduction of response induced from earthquake or wind loads. Instead of orifice, a spherical ball is used in the TLCBD for increase in the damping effect by resisting the water motion. TLCBD is placed on the top storey of a 4-storey steel frame, and its effect on vibration response is investigated experimentally. For performance optimization, a combination of varying densities of ball and liquid are used in the TLCBD. The optimal performance of TLCBD is studied under different excitations including harmonic and seismic loadings, through a series of shake table tests. Root mean square (RMS) acceleration is calculated against each loading and for each storey, for all combinations of balls and liquids. In order to better understand the response, percentage reduction of RMS acceleration is also determined, for all combinations. The results confirm that the response reduction for TLCBD controlled structure with liquid and ball having high densities is significantly better as compared to other combinations of liquids and ball having low densities. Moreover, the response reduction for TLCBD is more effective in the seismic excitations as compared to harmonic excitations.

Comparative Performance Study of Tuned Liquid Column Ball Damper for Excessive Liquid Displacement on Response Reduction of Structure

The tuned liquid column damper (TLCD) having a uniform cross-sectional tube of U-shaped, occupied with liquid is used as a vibrational response mitigation device. The tuned liquid column ball damper (TLCBD) is a modified TLCD, where, an immovable orifice, positioned at the middle part of the horizontal portion, is replaced by a metal ball. Different studies on the unconstrained optimization performance of TLCBD subjected to the stochastic earthquake have been performed where limitations on the maximum amplitude of liquid present in the vertical portion of the tube were not imposed. In the case of the high magnitude of earthquake and space constraint, the excessive liquid movement might get generated in the vertical portion of the tube which can create challenging circumstances. This can be taken care of by restricting the liquid movement up to a certain limit. The present investigation considers the optimum performance of the structure with TLCBD for mitigating the vibrational response with limited liquid movement in the vertical portion of the tube. A numerical study has been carried out to demonstrate the difference between constrained and unconstrained optimization of structure-TLCBD system. Numerical results show the influence of constraining cases on optimum parameters and performance behavior of the structure-TLCBD system.

Application of tuned liquid column ball damper (TLCBD) for improved vibration control performance of multi-storey structure.

Tuned liquid column ball damper (TLCBD) is a passive control device used for controlling the building vibrations induced from wind or earthquakes. TLCBD is a modified form of conventional tuned liquid column damper (TLCD). This paper studies the effect of TLCBD on the four-storey steel frame structure. The performance of the TLCBD is also compared with conventional TLCD. The analytical model of both TLCD and TLCBD is presented here. The effectiveness of these analytical models is examined experimentally by series of shaking table tests under different excitation levels including harmonic loadings and seismic excitations. In TLCBD, the vibration is reduced significantly as compared to TLCD by using steel ball as a moving orifice. The difference in diameter of steel ball and tube, containing the liquid column, acts as an orifice which moves with the movement of the ball. This moving orifice phenomenon enhanced the vibration reduction effect by resisting the water motion in the TLCBD. Root mean square (RMS) and peak values of acceleration were calculated for each loading and each storey of uncontrolled and controlled structures. Comparison of the time histories of controlled and uncontrolled structures for different loadings is also reported. Results indicate that the TLCBD is more effective in the earthquake scenarios as compared to the harmonic excitations. The TLCBD controls the vibration of the primary structure significantly in vibration reduction.

Structural control of a fixed offshore structure using a new developed tuned liquid column ball gas damper (TLCBGD)

Structural control of a system can be achieved by employing different control methods. The effectiveness of a control technique straightly depends on the performance of the control device. Among control devices, the tuned liquid column gas damper (TLCGD) has shown high vibration control capabilities. In this study, a newly developed damping system as a tuned liquid column ball gas damper (TLCBGD) system is introduced. The developed system is a combined version of a tuned liquid column ball damper (TLCBD) and a TLCGD system. The new damper is utilized on an offshore jacket platform and its qualification is studied under both regular and irregular wave incidences. The efficiency of the TLCBGD system is investigated numerically by implementing ball-tube ratio and gas pressure parameters. The effects of the ball-tube ratios and the gas pressure values on the vibration suppression capacity of the system are assessed through a parametric study. In comparison to a passive TLCGD system, the results revealed that the utilizing a TLCBGD system in the jacket platform improves the structural vibration suppression capability.

Moving orifice circular liquid column damper for controlling torsionally coupled vibration

The effectiveness of the Tuned Liquid Column Damper (TLCD) has been established in controlling the vibration of structures from wind or earthquakes. The present study demonstrates the effectiveness of the Circular Liquid Column Ball Damper (CLCBD), in conjunction with the Tuned Liquid Column Ball Damper (TLCBD) in controlling torsionally coupled vibration of building subjected to wind excitations. Unlike TLCDs, these devices are equipped with moving orifice, implemented via steel balls, placed at the middle of the liquid tube. The set of equations of motion of the combined structure–damper system are derived using the Lagrange’s approach. The optimal performance is ensured through selection of optimal parameters by minimization the stochastic responses, obtained from random vibration analysis. This is in order to adequately take care of the stochastic excitations. The optimal performances are further verified in respect to the time history responses under simulated wind excitations. Parametric studies are conducted to assess the performance robustness. The proposed TLCBD–CLCBD system offers enhanced control efficiency and significant reduction of the displacement of liquid column than the TLCD. Experimental investigation using Shake table test facility also corroborate with the findings from the analysis.

Tuned liquid column ball damper for seismic vibration control

Summary Tuned liquid column damper (TLCD) is a passive control device for vibration control of structures. Recently, the tuned liquid column ball damper (TLCBD) has been introduced for performance enhancement over the original TLCD. In this paper, the efficiency of the TLCBD is assessed under random earthquake events. The response of a single-degree-of-freedom system with TLCBD is evaluated by stochastic analysis and compared with the TLCD. The study reveals significantly improved performance of TLCBD over TLCD in terms of reducing response of the structure as well as the liquid column. The performance largely hinges on the optimum tuning ratio and the ball-to-tube diameter ratio values, which are proposed herein. The parametric studies establish the performance robustness of the TLCBD under loading and parametric variations. Furthermore, the accuracy of the optimal stochastic responses is verified through deterministic response analysis under recorded seismic motions. Copyright © 2015 John Wiley & Sons, Ltd.

Vibration mitigation of structures subjected to random wave forces by liquid column dampers

The effective performance of two passive vibration mitigating devices namely tuned liquid column damper (TLCD) and tuned liquid column ball damper (TLCBD) are studied for control of wave induced vibration. The stochastic dynamic analysis of structure with and without damper is first presented in frequency domain for parametric study on the performance of both the dampers to control wave induced vibration response. The optimum performance of TLCD and TLCBD systems is further investigated to study the effectiveness of a particular damper system over the other. In order to obtain optimal damper parameters to yield the best possible TLCD and TLCBD performance under a given condition, optimization is performed by minimizing the root mean square displacement of the structure. Numerical study is taken up to explore the effectiveness of both the TLCD and TLCBD. Though there is a wide gap between structural frequency and frequency of wave load, the performances of both the dampers are found to be potential for wave vibration mitigation. The optimum performance study in general shows that TLCBD perform better than TLCD. The performances of both the damper system are further verified in time domain under random wave load.

Recent Advances on Vibration Control of Structures Under Dynamic Loading

In this paper, a review of recent journal articles on passive, active, semi-active, and hybrid vibration control of structures subjected to dynamic loading is presented. Passive systems reviewed include tuned mass damper (TMD), tuned liquid column damper (TLCD), tuned liquid column ball damper (TLCBD), circular TLCD (CTLCD), and pendulum TLCD (PTLCD). Active control systems include active tuned mass dampers (ATMD) and piezoelectric actuators. Semi-active systems include magnetorheological (MR) damper, negative stiffness devices (NSD), magneto-rheological damper TMD (MR-TMD), variable stiffness semi-active TMD (VS-STMD), variable damper STMD (VD-STMD), and recentering variable friction device (RVFD). Hybrid systems include active base isolation system and semi-active MR dampers with nonlinear base isolators. The current frontier of research is semi-active control of structures as well hybridization of various control systems. The problem is complex requiring integration of several different hardware and software technologies with structural design such as smart materials, adaptive dampers, actuators, sensors, and control and signal processing algorithms. This complexity also makes it an exciting area of research and development.

Modified liquid column damper for vibration control of structures

A modified version of the traditional tuned liquid column damper (TLCD) absorber is proposed as a passive vibration control device for structures vibrating at low frequencies. This new version, denoted as tuned liquid column ball damper (TLCBD), is equipped with a coated steel ball, in place of the orifice in TLCD, immersed inside the horizontal column of the damper. The current study examines the performance of TLCBD for a harmonic excitation which is a simplified model for the vortex shedding forces on structures in the cross wind direction. A parametric study to investigate the effect of the ball size and absorber mass on the suppression capacity is carried out. The absorber damping characteristics is identified experimentally using a single point laser vibrometer system and the measured damping factor is used in the mathematical model. Intensive numerical simulations were conduced and the results are compared with the traditional TLCD with optimum parameters. The results revealed an improvement of the vibration suppression capability of the proposed version that exceeds around 66% reduction.