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In this paper, a real-time hybrid shaking table testing method (RHSTTM) is experimentally implemented for evaluating the performance of a tuned liquid damper (TLD) controlling a seismically excited building structure. The RHSTTM does not require a physical building structural model in performing the experiment of a TLD–structure interaction system...
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... identified and measured structural accelerations in the time domain match very well as shown in Fig. 8. The identified structural damping and stiffness coefficients slightly vary according to input earthquake waves, as shown in Table 1. The averaged damping and stiffness coefficients are 13.4 N s/m and 10,222 N/m, respectively, which correspond to 0.5% of damping ratio and 1.23 Hz of structural natural frequency. ...Similar publications
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Citations
... In order to verify the damping performance of the TLD on the steel platform system, a shaking table test study was carried out for the super-tall monolithic jacking steel platform moulding system. Due to the size and load carrying capacity of the shaking table, the structure and TLD need to be scaled down and the substructure selected for testing [8][9][10][11]. To this end, this paper proposes an isolated substructure test method that isolates the steel platform and TLD from the overall structure and inputs the common ...
To meet the engineering demand for vibration control of a super-tall integral jacking platform moulding system, a tuned liquid damper (TLD) is used for the tuned control device of the construction steel platform. An experimental method for isolating the substructure is proposed, and the effectiveness of the TLD for vibration damping control of the steel platform is verified by shaking table tests. The test results show that the dynamic response of the construction steel platform and the main body of the structure under earthquake can be suppressed simultaneously by controlling the mass ratio of TLD to the construction platform within 5%, and the displacement damping effect is good.
... TLDs have been used as vibration suppression dampers for rotating wind turbine blades in [37] and for controlling the lateral tower vibrations of multimegawatt wind turbines in [38]. Furthermore, the TLD was employed for seismic mitigation in [39] where real-time hybrid shaking table was used to study the dynamic response mitigation of building structure attached with TLD. ...
Dynamical and structural systems are susceptible to sudden excitations and loadings such as wind gusts, blasts, earthquakes, and others which may cause destructive vibration amplitudes and lead to catastrophic impact on human lives and economy. Therefore, various vibration absorbers of linear and nonlinear coupling dynamics have been widely studied in plenty of publications where some have been applied in real-world practical applications. Firstly, the tuned-mass-damper (TMD), the first well-known linear vibration absorber that has been well-studied in the literature and applied with various structural and dynamical systems, is discussed. The linear vibration absorbers such as TMDs are widely used in real-life small- and large-scale structures due to their robust performance in vibration suppression of the low natural frequency structural modes. However, the TMD performs efficiently at narrowband frequency range where its performance is deteriorated by any changes in the frequency content in the structure and the TMD itself. Therefore, the targeted-energy-transfer mechanism which is found to be achieved by nonlinear energy sinks (NESs) has ignited the interest in passive nonlinear vibration suppression. Unlike TMDs, the NESs are dynamical vibration absorbers that achieve vibration suppression for wide range of frequency-energy levels. Given the very rapid growth in this field and the extensive research studies supporting the robustness of the NESs, this paper presents the different types of NESs and their applications with main emphasis on the rotary-based and impact-based NESs since they are of high impact in the literature due to their strong nonlinear dynamical behavior and robust targeted energy transfer.
... This fundamental approach is for example applied in the compensation of the dynamic behavior of vibrating tables for seismic investigations. 31 Due to the high influence of the modeling quality, numerous combined control strategies have been developed, especially for EHST. Combinations of the FIMC with internal model control (IMC), modeling error compensation (MEC), or an online adaptive inverse control (AIC) perform better in terms of modeling errors or system uncertainties. ...
This paper presents a method for replicating transient signals induced in a passenger car by single-obstacle crossings. These replicated signals should be used in a ride comfort simulator. By using feedforward-inverse-model-control with direct identification of the inverse transfer function, time-consuming iterations of conventional time waveform replication methods are eliminated. The quality of the system identification for approximating the inverse transfer function is significantly increased by decomposing the frequency band and the complexity is considerably reduced. The use of nonlinear block-oriented models significantly decreases the replication errors in frequency bands with high nonlinearity influence.
... In 1987, the first application of TLD in an engineering project for wind vibration control of a ground structure was established in Japan. Thus far, TLD has been widely researched and applied [24][25][26] due to its advantages, such as cost savings, easy installation, versatility (as it can be used as water storage device at the same time), etc. ...
In order to make full use of the advantages of PD (particle damper) and TLD (tuned liquid damper) technologies, a new kind of damping system combining these two already-existing dampers is proposed and was named as PDAL (tuned particle damper with additional liquid). A shaking table test of a steel frame structure with a PDAL system is conducted here for the purpose of vibration control analysis. The results of the test demonstrate well the reliability and effectiveness of the PDAL system under various seismic waves. Seismic responses (mainly acceleration value) are investigated thoroughly for parameter analysis based on the experimental data, and some suggestions are proposed for future designs, including the necessity for parameter optimization and awareness of the dynamic characteristic changes that might occur in actual structures if attached with a PDAL system. This paper constitutes a preliminary study for the PDAL system, and it can serve as a baseline and conceptual reference for future investigations.
... The actuator based RTHS is developed for structural component testing, such as damper [4], base isolator [5]. The shaking table based RTHS focus on the dynamic response of the whole structure, such as the structure with tuned mass damper [6], tuned liquid damper [7], and soil-structure interaction system [8,9]. ...
Stability prediction is a key step to implement a real-time hybrid simulation (RTHS) testing successfully. There are two kinds of stability prediction methods based on continuous and discrete transfer function. In the family of continuous transfer function based methods, the numerical and physical substructures are seen as continuous systems together with loading system. In discrete family, all subsystems in RTHS are regarded as discrete systems. Actually, in a real RTHS, the numerical substructure is discrete; the physical substructure is continuous. Meanwhile, the signal coordination is needed to balance the sampling interval between numerical solution and physical loading, which is ignored in the reported methods. In order to predict the stability of RTHS system more accurately, this work develops a discrete-continuous stability analysis method through the concept of gain margin, which can consider the performance of numerical substructure, physical substructure, loading system and signal coordination comprehensively. And the accuracy of the method is verified by SIMULINK simulation and experimental testing. Based on shaking table and actuator RTHS systems, the performance of continuous and discrete methods is compared with the proposed method analytically. The results show that the discrete method and continuous method have slight influence on the stability prediction with a small integration step (e.g 1 ms). However, with the increase of integration step, compared with the discrete-continuous method, the discrete method and continuous method may overestimate or underestimate the stability of a real RTHS system.
... Igarashi et al. [26] proposed a hybrid loading test method using a shake table and a hydraulic actuator to evaluate the real-time dynamic responses of structural systems under a strong seismic excitation; in this method, digital filters, namely, finite impulse response (FIR), are employed to compensate for the delays. Lee [27,28] proposed an STST with an inverse transfer function of the shaking table to accurately reproduce the interface accelerations and implemented it on a structure with a tuned liquid damper (TLD). A full-scale STST was proposed with a rubber-and-mass system that amplifies the table motion to reproduce large floor responses of high-rise buildings [29]. ...
To improve the experimental accuracy and stability of shaking table substructure testing (STST), an explicit central difference method (CDM) and a three-variable control method (TVCM) with velocity positive feedback (VPF) are proposed in this study. First, the explicit CDM is presented for obtaining an improved control accuracy of the boundary conditions between the numerical and experimental substructures of STST. Compared with the traditional CDM, the proposed method can provide explicit control targets for displacement, velocity, and acceleration. Furthermore, a TVCM-VPF is proposed to improve the control stability and accuracy for loading the explicit control targets of displacement, velocity, and acceleration. The effectiveness of the proposed methods is validated by experiments on a three-story frame structure with a tuned liquid damper loaded on an old shaking table originally designed with the traditional displacement control mode. The experimental results show that the proposed explicit CDM works well, and the response rate and control accuracy of the shaking table are significantly improved with the contribution of the TVCM-VPF compared with those of the traditional proportional integral derivative (PID) controller. This indicates the advantage of the proposed TVCM-VPF over the traditional PID for STST. A comparison between the traditional shaking table test and STST shows that when the latter is based on the TVCM-VPF, it exhibits an excellent performance in terms of the stability and accuracy of displacement and an acceptable performance in terms of the acceleration accuracy.
... To further explore the suppressing mechanism of TLD for coupled TLD-SSP system with external excitations, several experimental and numerical investigations have been carried out [21][22][23]. In addition, a realtime hybrid testing method has been developed to evaluate the acceleration of the model under dynamically excited motions [24]. An experimental study which considered dynamic loads of different directions was performed on a prototype structure, and the results for different damping ratios and vibration amplitudes of different excitation modes were presented [25]. ...
A liquid storage container installed on the top of a fixed offshore platform is used as a tuned liquid damper (TLD) to suppress structural vibration through sloshing motion and viscous energy dissipation. To further optimize TLD capability on suppressing vibration and accurately predict nonlinear coupled processes between TLD and offshore platform, a two-way coupling numerical model was developed to investigate the nonlinear vibration of TLD and elastic supporting structural platform (SSP). Meanwhile, laboratory experiments of TLD interaction with the SSP were also conducted on a six-degree-of-freedom motion simulator to validate the developed model. The bottom plate of the SSP was fixed to the motion simulator and subjected to sinusoidal excitation in the horizontal direction. The natural frequency of bare SSP was obtained firstly by shaking table tests at a wide range of external excitation frequencies and finite element modal analysis. The developed numerical model was validated by using the present experimental data in terms of both the roof plate displacements of the SSP and the free surface elevation and waveforms in TLD. Effects of TLD in suppressing the nonlinear vibration of the elastic SSP were further investigated numerically by varying the mass and frequency ratio of TLD to the SSP. Wavelet transform was used to analyze the nonlinear interaction and energy distribution characteristics of the sloshing wave in TLD. It was shown that the peak displacement response of the roof plate had been significantly reduced, and at the same time a frequency shift occurred after TLD installed on the SSP. In addition, the sudden excitation breaks the balance of energy absorption and production in fluids, resulting in larger wave height. Finally, a mass ratio of 2% and a frequency ratio of 1 were found to be optimal by considering the frequency shift and energy dissipation.
... Rather than full-scale testing, the behavior of the complete structure is commonly inferred from test results obtained from experiments on a scaled model of the entire structure or testing of a critical component of the structure (Lee et al. 2007). One approach to characterizing a system's dynamic response is pseudo-dynamic testing (PsD), in which only a vital element of the entire structure (typically a complex, difficult to model component) is tested physically while the remainder of the structure is modeled numerically (Takanashi 1980, Takanasi 1975, Mahin 1989. ...
Controlled laboratory vibration testing has been the preferred method to experimentally quantify a system's governing dynamic response. However, dynamic testing of full-scale commercial structures in service environments can be an expensive and challenging endeavor to perform due to structural size and complexities. Hybrid substructuring is a method that involves performing tests on components of interest coupled with a numerical model simulating behavior of the primary system. The physical test and the numerical model are combined to represent the dynamic response of the complete system. Hybrid substructuring could also be implemented in the opposite fashion: the primary system as the physical substructure and a component of interest as the numerical substructure. Such an approach enables predictions of the dynamic response of a critical component when it cannot be directly measured during a system test. Within the numerical model uncertainties in the coupling of substructures can be accounted for through probabilistic model parameters. Using this approach, the effects of uncertainties in the component of interest and its interface to the primary system, such as those due to jointed connections, are captured. This paper aims to quantify a system's uncertainties by incorporating a suite of experimental data with inverse analysis to determine distributions of uncertain parameters, thus allowing a hybrid substructuring scheme to make statistically bounded predictions. The approach is demonstrated through an analysis of the bolted joints uncertainties in the Box and Removable Component test structure. INTRODUCTION Determining the complete dynamic response of large-scale engineering systems is critical for assessing performance of complex systems in their real-world operating environments. However, performing full-scale testing is difficult due to size, weight, and cost. Accurate testing and qualification of a full system, as well as each of its components, becomes increasingly difficult with system complexity. Test scenarios meant to replicate real-world conditions are rarely ideal. Examples of common challenges in testing include (1) inability to instrument a component directly (2) variability in jointed connections coupling the component to its system (3) laboratory test configurations unable to represent complexity of true service environment. New methods to increase reliability, reduce uncertainty, and limit over testing are of great interest to the structural dynamics community. Herein, we seek to alleviate such physical constraints to the greatest extent possible by representing critical components as a numerical substructure coupled to a physical substructure of the larger system.
... employed RTHT to investigate the performance of magnetic resonance dampers in controlling different structures. The performance of the tuned liquid damper for single-degree-of-freedom and multiple-degree-of-freedom structures has been investigated comprehensively through RTHT (Lee et al., 2007;Wang et al., 2016). Test results have been used to calibrate numerical models (Malekghasemi et al., 2015). ...
... employed RTHT to investigate the performance of magnetic resonance dampers in controlling different structures. The performance of the tuned liquid damper for single-degree-of-freedom and multiple-degree-of-freedom structures has been investigated comprehensively through RTHT (Lee et al., 2007;Wang et al., 2016). Test results have been used to calibrate numerical models (Malekghasemi et al., 2015). ...
