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The effect of soil-structure interaction (SSI) cannot be neglected in semi-active vibration control of structures located on soft soil. To investigate the mitigating effect of magnetorheological (MR) damper on the semi-active control of structures considering the SSI, shaking table tests were conducted to evaluate the performance of the MR damper-based semi-active control system for structures on soft soil. In addition to a novel fuzzy control method based on online learning deep neural network (OL-DFNN), various control strategies, including passive OFF, passive ON, ON–OFF and deep neural network fuzzy control (DFNN) were systematically evaluated. The test results showed that the OL-DFNN control method exhibited superior adaptability to varying ground motion and structural dynamic characteristics compared to the other control methods. In particular, the OL-DFNN controller effectively mitigated the peak displacement and root mean square displacement, outperforming the passive OFF, passive ON, ON–OFF and DFNN control strategies. The test results highlight the effectiveness of the OL-DFNN control method in addressing the challenges posed by dynamic and time-varying characteristics in structural vibration control systems considering SSI.

Sedimentation immunity is one of the key features of magnetorheological (MR) dampers, which means the lifetime-long service without degradation under the sedimentation of MR fluid. In this paper, an active-dispersing mechanism is established with twin-tube configuration toward the sedimentation immunity, by adding a circulation channel powered by rotating blades between the tubes when the MR damper is not in operation. Finite element (FE) method is employed to reveal the re-dispersion process once the MR fluid settled to a specific degree, and the benefits of circulating channel and twin-tube sedimentation-immunity system for the MR fluid are discovered by the simulation. Ultimately, a self-adaptive system could be built to ensure the MR fluid in the damper keeping in a relative uniform and thus the sedimentation immunity is fulfilled.

Intelligent and adaptive control systems are naturally suitable to deal with dynamic uncertain systems with non-smooth nonlinearities; they constitute an important advantage over conventional control approaches. This control technology can be used to design powerful and robust controllers for complex vibration engineering problems such as vibration control of civil structures. Fuzzy logic based controllers are simple and robust systems that are rapidly becoming a viable alternative for classical controllers. Furthermore, new control devices such as magnetorheological (MR) dampers have been widely studied for structural control applications. In this paper, we design a semi-active fuzzy controller for MR dampers using an adaptive neuro-fuzzy inference system (ANFIS). The objective is to verify the effectiveness of a neuro-fuzzy controller in reducing the response of a building structure equipped with a MR damper operating in passive and semi-active control modes. The uncontrolled and controlled responses are compared to assess the performance of the fuzzy logic based controller.

Structures designed against earthquake loads based on using control systems may experience explosions during their lifetime. In this paper, the performance of a hybrid control system composed of a low-damping base isolation and a supplemental magneto-rheological (MR) damper under external explosion has been studied. Base isolation system has the ability of decreasing the maximum structural response under blast loadings by shifting the period of the structure. In addition, MR damper improves the base isolation system performance by controlling the base drift of the structure. Hence, in this paper, the capability of a hybrid base isolation system equipped with an MR damper at the base has been evaluated in reducing the maximum structural response and base drift under external blast loadings. To determine the voltage of the semi-active MR damper, the H₂/Linear Quadratic Gaussian (LQG) and clipped-optimal control algorithms have been applied. For numerical simulations, a 10-storey shear frame subjected to blast loadings applied on different floors has been considered and the performance of the hybrid isolation system and MR damper has been studied. The results have proven the effectiveness of the hybrid control system in controlling the maximum response and base drift of the isolated structure against spherical external explosion. Furthermore, comparing the performance of the hybrid passive and semi-active base isolation systems indicates that the semi-active hybrid base isolation system is more effective in reducing the root-mean-square (RMS) value of the base drift. Similarly, it has been found that the semi-active hybrid base isolation system also performs better than the high-damping base isolation system.

In this paper, the semi-active suspension in railway vehicles based on the controlled magnetorheological (MR) fluid dampers is examined, and compared with the semi-active low and semi-active high suspension systems to enhance the running safety and ride quality for a high-speed rail vehicle. Predictive model controllers are used as system controllers to determine the desired damping forces for front and rear bogie frame with force track-ability. A 28 degree of freedom (DoF) mathematical model of the rail vehicle is formulated using nonlinear vehicle suspension and nonlinear heuristic creep model. The MR model of Ali and Ramaswamy is formulated to characterize the behavior of the MR damper. The simulation result is validated using the experimental results. Four different suspension strategies are proposed with MR damper, i.e. passive, semi-active low, semi-active high and semi-active smart controller based on predictive model controller. A comparison indicates that the semi-active controller gives the optimum for comfort vibration actuation and improves the ride quality and it has little influence on derailment quotients, offload factors, as a result, it will not endanger the running safety of rail vehicle.

In this paper, a smart structure is developed by integrating a semi-active control strategy with an online synchronization-based damage detection method. In this algorithm, the structural damages are identified in real-time with the synchronization-based method using displacement and velocity measurements of the structure. Then, a fuzzy logic controller is applied for determination of the control forces according to the occurrence of damages. A five-story linear shear building equipped with magneto-rheological (MR) dampers is studied numerically to verify the performance and efficiency of the proposed integrated method for both damage detection and vibration suppression. One damage scenario and four earthquake records are used for such purpose. Results demonstrate that the proposed algorithm has the capability of identifying structural damages satisfactorily while exerting suitable control forces to compensate for the damages occurrence and mitigating the dynamic responses of the structure. Furthermore, it is shown that in comparison with the long-established method of only vibration control, the total energy consumption is significantly reduced, an issue of concern in optimal control of structures.

Smart base isolation composed of a low-damping base isolation and a supplemental magneto-rheological (MR) damper is one of the most effective semi-active control systems to protect the structures against earthquake. In this study, optimal placement of sensors is determined by using a mixed-integer genetic algorithm for best possible performance. The results show significant effect of sensor configuration on the control system performance, revealing that the sensor configuration should be taken as an important factor in design process of smart base isolation. Besides, although optimal determination of sensor placement improves the control system performance, a high number of sensors is needed to measure structure responses. A method using the least number of sensors is proposed in order to reduce the control cost. The results show the effectiveness of this method in achieving near-optimal response and reducing the control cost.

In recent years, significant advances in vibration control of structures have been achieved due greatly to the emergent technologies based on smart materials, such as mangnetorheological (MR) fluids. This paper develops a computational algorithm for the modeling and identification of the MR dampers by using wavelet systems to handle the nonlinear terms. By taking into account the Haar wavelets, the properties of integral operational matrix and of product operational matrix are introduced and utilized to find an algebraic representation form instead of the differential equations of the dynamical system. It is shown that MR damper parameters can be estimated easily by considering only the algebraic equations obtained.

The goal of this research is to study the effect of cable vibration through a number of control cases of a cable-stayed bridge. In order to consider the complicated dynamic behaviour of the full-scale bridge, a three-dimensional numerical model of the MATLAB-based analysis tool has been developed by the complete simulation of the Gi-Lu bridge. The dynamic characteristics of cables in the cable-stayed bridge are verified between the field experiment and the result from numerical simulation using geometrically nonlinear beam elements in MATLAB program. Three types of control devices are selected to reduce the response of the bridge deck which includes: actuators, viscous-elastic dampers with large capacity, and base isolations. Moreover, two types of control devices, MR dampers and viscous dampers, are installed either between the deck and cables and/or between two neighbouring cables for controlling the cable vibration. A modified bi-viscous model combined with convergent rules is used to describe the behaviour of MR dampers. Finally, through evaluation criteria the control effectiveness on the cable-stayed bridge using different control strategies is examined.

The paper investigates the effectiveness of a smart base-isolation system for seismic response mitigation of extra-large liquified natural gas (LNG) storage tanks. The mathematical model of the base-isolated LNG tank with smart dampers, the magneto-rheological (MR) dampers, is presented. The governing equations of motion of the smart system are derived and solved by the classical transition matrix method in the time domain. The linear quadratic regulator (LQR) control scheme is employed to command MR dampers. The LNG tank system is analyzed under six artificial accelerograms, compatible with operational basis earthquake (OBE) and safe shutdown earthquake (SSE) response spectrum, generated using a method of a random set of phase angles with amplitudes obtained from power spectral density function. A time-delay compensation procedure based on the Taylor series expansion is applied to reduce the deterioration of control performance due to time delay. To investigate the effectiveness of smart base-isolation, the responses are compared with the fixed-base tank, base-isolated tank, and tank with passive MR damper. The results show that the smart base-isolation is effective in reducing the seismic response of extra-large LNG tanks, especially the displacement at the isolation level without much altering other responses. The passive MR damper is also found effective and showed fail-safe behavior even under the failure of the control algorithm. Moreover, the application of time-delay compensation using the Taylor series increased the performance and overall efficiency of the LNG tank system.

This paper investigates the performance of skyhook control designed for use with a magnetorheological damper through MATLAB simulation. The fuzzy logic simulation was observed for increased performance over conventional passive damper systems, and for behaviour in keeping with the skyhook control theory. Once it was established that the controller was accurately simulating skyhook control, the overall performance and system response was analysed. It was found that the semi-active system improved the response of the vehicle sprung mass at the expense of unsprung mass control, proving that greater occupant comfort can be achieved via semi-active suspension control.