Figure - available from: Shock and Vibration
This content is subject to copyright. Terms and conditions apply.
Root locus of the DVF (a), the first order PPF (b), and the parallel PPF-DVF (c) added through four small tendons.
Source publication
This paper investigates numerically the active tendon control of a cable-stayed bridge in a construction phase. A linear Finite Element model of small scale mock-up of the bridge is first presented. Active damping is added to the structure by using pairs of collocated force actuator-displacement sensors located on each active cable and decentralize...
Similar publications
Rolling-element bearings are widely used in industrial rotating machines, and hence there is a strong need to accurately predict their influence on the response of such systems. However, this can be challenging due to an interaction between the dynamics of the rotor and the bearing nonlinearities, and it becomes difficult to provide a physical expl...
Under the potential outcomes framework, causal effects are defined as
comparisons between the treatment and control potential outcomes. However, the
average causal effect, generally the parameter of interest, is not well defined
for ordinal outcomes. To address this problem, we propose two new causal
parameters, defined as the probabilities that th...
Citations
... To obtain more comparable results, the finite element model is required to divide into a large number of elements [25]. Many researchers presented several deep investigations in the refined research of single cable or cable-beam subsystem, focusing on the sensitivity of parameters, vibration control, or different analysis approaches [26][27][28][29][30][31][32]. Others provided the research in checking the frequency or modes of one single component instead of simulating the real-time displacement response for global resonance [33][34][35][36][37][38]. ...
The investigation aims to propose a refined model to analyze the parametric resonance under multicable systems such as cable-stayed bridges. Considering the interaction between the adjacent beam portions, the shear difference is applied to modify the vibration equations derived from the multi-degree-of-freedom stiffness method. Furthermore, the difference method is adopted to make the equations more accessible for numerical analysis. The comparison results indicate that the refined model exhibits the key character of parametric resonance and also further verified the simulation methods. The consequences show that the cable will resonate at the fundamental frequency under the support excitation. In particular, when resonance occurs, most of the energy in the subsystem is transferred to the cable, resulting in the resonance amplitude of the beam portion being weakened to some certain extent. Moreover, the global resonance will have a sufficient excitation on the local resonance only when the resonance condition is satisfied.
... This has resulted in the evolution of a new type of vibration control method called active control, which uses a set of actuators and sensors connected by feedback or feedforward loops. 20 Active tendon control [21][22][23][24] has high performance on the target mode and also acts indirectly on other modes. Stability is guaranteed only if the sensors are collocated with the actuators. ...
Tower cranes have, in general, low structural damping, leading to challenges with respect to vibrations induced by natural hazards. Crane failures due to wind excitations are very common around the world. In the present research work, a smart tower crane equipped with pairs of collocated sensors and actuators is proposed to mitigate turbulent wind. A three-dimensional finite element model of the crane is created using MATLAB®/Structural Dynamics Toolbox. Modal analysis is performed to calculate natural frequencies and corresponding mode shapes. Dynamic analysis of the crane is carried out under turbulent wind excitation. A decentralized active vibration control method is then used to prevent collapse of the crane. Active damping is added to the tower crane using pairs of force actuators–displacement sensors collocated on selected elements. A robust control strategy based on decentralized direct velocity feedback is implemented. The vibrations of the tower crane in all directions are significantly damped. It is concluded that the proposed smart tower crane model is highly efficient in mitigating the turbulent wind loads.
... Active devices include the active tendon, magnetorheological (MR) damper, and AMD. El Ouni et al. [18,19] numerically and experimentally studied controlling the vertical vibration of girders by using the active tendon force of the cable with a laboratory-scale cable-stayed bridge model. Crusells-Girona and Aparicio [20] proposed an active control algorithm that adjusts the axial force of the cables in a cable-stayed bridge to reduce the girder displacement and stress. ...
An active mass damper (AMD) was developed that uses a linear motor and coil spring to reduce the vertical vibration of a long-period cable-stayed bridge subjected to wind and earthquake loads. A scaled-down bridge model and AMD were fabricated, and the control effect of the AMD was investigated experimentally and analytically. The AMD was controlled via a linear quadratic Gaussian algorithm, which combines a linear quadratic regulator and Kalman filter. The dynamic properties were investigated using a 1/10 scale indoor experimental model, and the results confirmed that the measured and analytical accelerations were consistent. A vibrator was used to simulate the wind-induced vibration, and the experimental and analytical results were consistent. The proposed AMD was confirmed to damp the free vibration and harmonic load and increase the damping ratio of the bridge model from 0.17% to 9.2%. Finally, the control performance of the proposed AMD was numerically investigated with the scaled-down bridge model subjected to the El Centro and Imperial Valley-02 earthquakes. These results were compared with those of a TMD, and they confirmed that the proposed AMD could reduce excessive vertical vibrations of long-period cable-stayed bridges subjected to wind and earthquakes.
... Then, Song et al. [24] studied the dynamic response of a cable-stayed bridge subjected to a moving vehicle load based on the model in Ref. [23]. Except for theoretically modeling, the researches on cablestayed bridges are mainly carried out by experiments [25][26][27]. Experimental analysis plays a fundamental role in the detection of new dynamic phenomena and their mechanism associated with the actual nonlinearities existing in a given system [28]. Wilson et al. [29] conducted full-scale ambient vibration tests to measure the dynamic response of a 542-m (center span of 274 m) cable-stayed bridge. ...
... Although the response ampli-tudes are slightly reduced compared with those shown in Fig. 16c, the large amplitude parametric vibrations of cable A1 are also observed. Therefore, it can be concluded that when the excitation frequency is close to the frequency of global mode of cable-stayed bridge, the primary resonance of the beam and the parametric vibrations of the long cables can be triggered simultaneously, which can lead to the large vibrations of cables and further verifies the previous theoretical results on the parametric vibration of cables [27]. The more attention should be paid to the parametric vibration in the cable-stayed bridge. ...
The nonlinear dynamic behaviors of the cable-stayed bridge are considerably complicated and very interesting. In order to explore the nonlinear behaviors of a cable-stayed bridge, a scaled physical model with Xiangshangang Bridge as the prototype is established and the systematical experiments are carried out. Firstly, the physical parameters, especially initial tension forces, of cables are measured by free vibration test and the data is dealt with FFT and filtering technology. The corresponding modal analysis is conducted and the test results are in good agreement with those obtained by OECS model and MECS model, which shows the experimental effectivity. Then, the free vibrations of cables are analyzed and the 1:1 resonance between different cables is revealed. Thereafter, by applying a single excitation to the beam, the nonlinear resonance of the cable-stayed bridge is studied and the rich nonlinear phenomena are observed, such as the parametric vibration, harmonic resonance, multiple internal resonance, primary resonance and cable–cable coupling vibration. Finally, some interesting conclusions are drawn, for example, the large amplitude vibrations of cables can be induced when the nonlinear resonance conditions are matched under external excitation.
... El Ouni, et al. [15] investigated numerically the active tendon control of a cable-stayed bridge in a construction phase. A linear Finite Element model of small scale mock-up of the bridge was first presented. ...
... Also, k Θi is the torsional stiffness of the i th column of the substructure about its vertical axis passing through the centroid of the section. Also, e sx and e sy are the stiffness eccentricities of the substructure in the X and Y directions with respect to the mass center respectively, and can be expressed as follows: (15) where, (x smi ,y smi ) is the coordinate of the i th column of the substructure with respect to the mass center. And the matrix [K b ] in XY coordinate system can be written as follows: ...
Skewed bridges due to the specific dynamic characteristics have shown vulnerable in recent strong earthquakes. In this study, an active control strategy is employed to optimize the seismic performance of a typical model of such structures. As the control algorithm, the pole placement method has been used of which the key factor is selection of desired poles to achieve desired dynamic responses. A Performance Index (PI) was defined as a function of displacement and rotation of a bridge deck. The desired poles for the algorithm were extracted by optimizing this index. A previously presented and approved simplified model of a skewed bridge with the three degrees of freedom was selected as a typical model and the methodology was applied on this model. The optimization of PI was carried out by a series of time history analysis. Ten far field ground motion records presented in FEMA-P695 were used for this purpose. The PI was calculated for a range of damping ratio and frequency of the system and the desired poles were selected as for the optimum values of PI. The results show that the control of the model using the selected pole by this method could effectively reduce the displacement and rotation of the bridge model.
... The control forces of the proposed decentralized parallel PPF-DVF strategy are [4]: ...
The objective of the present paper is the investigation of the vibration control of a tall
guyed mast under seismic excitation. Active damping is added to the structure by using pairs of
collocated force actuator- displacement sensors located on each active cable and decentralized
parallel PPF-DVF (Positive Position Feedback - Direct Velocity Feedback). The optimal gain of
the compensator is determined using root locus technique. The responses with and without
control are studied. The results showed that the proposed control strategy is adequate for
vibration mitigation of tall guyed masts.
... Allam et al. made researches using random vibration method [9][10][11][12]. Researchers have also explored effective seismic control strategies for cable-stayed bridges [13][14][15][16] and experimental tests have been carried out [17,18]. The methods for obtaining seismic sources play very important roles for investigating safety performance of cablestayed bridges as well, and Dong and Li have conducted primitive work in this area [19][20][21][22][23]. ...
The seismic responses of a long-span cable-stayed bridge under uniform excitation and traveling wave excitation in the longitudinal direction are, respectively, computed. The numerical results show that the bridge's peak seismic responses vary significantly as the apparent wave velocity decreases. Therefore, the traveling wave effect must be considered in the seismic design of long-span bridges. The bridge's peak seismic responses do not vary monotonously with the apparent wave velocity due to the traveling wave resonance. A new traveling wave excitation method that can simplify the multisupport excitation process into a two-support excitation process is developed.
The cable-stayed fastening-hanging cantilever construction method has been widely used in the construction of arch bridges. Hanging cables’ parametric vibration frequently appears during the cantilever construction stage of arch rings. However, there is a lack of research on hanging cables’ parametric vibration as well as its control strategies for inerter dampers. Although Runge-Kutta method can achieve the transient response of cables’ parametric vibration under arbitrarily support excitation, it might not achieve the large-amplitude solution due to inappropriate initial conditions. Therefore, parametric vibration equation of hanging cable with parallel inerter damper was established and solved both by Runge-Kutta method and method of multiple scales(MMS). The steady-state solution of hanging cables calculated by Runge-Kutta method and its dependence on initial conditions were discussed and analyzed. Numerical stability of Runge-Kutta solution was also investigated by analyzing the phase portraits of multiple-scale solution. Besides, the influence of inerter damper on Runge-Kutta solutions’ numerical stability and initial condition dependence was discussed and explained. Finally, a general method to determine initial conditions of Runge-Kutta method was proposed to achieve large-amplitude solution of hanging cables’ parametric vibration under arbitrary support excitation. The results indicate that different initial conditions cause Runge-Kutta’s transient amplitude to develop along different phase trajectories, and finally to converge to different steady-state solutions. The inerter damper changes the critical phase trajectory of cable-inerter system, which shifts the region of reasonable initial conditions. Runge-Kutta steady-state solutions with inerter damper, solved by the initial conditions for no inerter damper case, may be the small-amplitude solutions, which may lead to overestimation of the control effect of inerter dampers. This study provides a general method to determine initial conditions of Runge-Kutta method for cables’ parametric vibration, which provides a reference for future parametric vibration studies.
Skewed bridges due to the specific dynamic characteristics have shown vulnerability in recent strong earthquakes. In this study, an active control strategy is employed to optimize the seismic performance of a typical model of such structures. As the control algorithm, the pole placement method has been used, of which the key factor is selection of desired poles to achieve desired dynamic responses. A performance index (PI) was defined as a function of displacement and rotation of a bridge deck. The desired poles for the algorithm were extracted by optimizing this index. A previously presented and approved simplified model of a skewed bridge with the three degrees of freedom was selected as a typical model, and the methodology was applied on this model. The optimization of PI was carried out by a series of time-history analysis. Ten far-field ground-motion records presented in FEMA-P695 were used for this purpose. The PI was calculated for a range of damping ratio and frequency of the system, and the desired poles were selected for the optimum values of PI. The results show that the control of the model using the selected pole by this method could effectively reduce the displacement and rotation of the bridge model.
