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... The system's ability to provide a bigger damping force as the structural reaction grew was previously seen as its cleverness. Its benefits include its simple design and assembly as well as the absence of any external energy source during excitation [11]. ...
... SEMI-ACTIVE PENDULUM TMD SYSTEM USING A MAGNETO-RHEOLOGICAL DAMPER[11]. ...
The system and artificial intelligence are still important modern technologies. A structure can modify its behavior under dynamic stresses by using active controls. The term "intelligent" or "smart" structures refers to these self-modifying structures. The structural engineering discipline may experience a revolution thanks to smart structure technologies. Particularly for huge structures, It is anticipated to have major effects. Effects with regard to the avoidance of fatalities and damage to the structure and its contents, particularly with regard to huge buildings that have thousands of elements. An efficient control algorithm to establish the magnitude of the actual forces to be applied to the construction is one of the most critical components in the successful use of smart active control technology. An overview of the primary active control approaches for the reduction of vibration in intelligent mechanical and civil structures that are subject to external dynamic loads is provided in this study. Different control algorithms' benefits and drawbacks are examined. Finally, recent advances in the study of control algorithms are highlighted, including the use of multiparadigm strategies, decentralized control, deep learning techniques applied to neural networks design of controls for sustainability, and a merging of the domains of vibration control and structural health monitoring.
... These systems may be classified into passive, semi-active, and active categories. In the passive systems, ranging from base isolation [2] and viscoelastic dampers [3] to various forms of vibration absorbers, including tuned mass dampers (TMDs) [4], tuned liquid column dampers (TLCDs) [5], pendulum tuned mass dampers (PTMDs) [6,7], and so forth, it is aimed to attenuate the transmitted vibrations to the structure through built-in auxiliary equipment like base isolation, friction, and viscoelastic dampers or attached subsystems. ...
High power demand of active structural control systems in tall buildings and incapability of energy storage system (ESS) in supplying the demanded power results in a power shortage which, in turn, can adversely affect their performance. Energy regeneration in active structural control systems may contribute to efficient energy management and sustainable power supply in these systems. This paper explores various aspects of energy regeneration of active pendulum system (APS) in tall buildings. A regenerative hybrid passive-active pendulum system (HPAPS) is proposed to control the wind-induced vibrations in a benchmark tall building. The vibration control system includes an APS that incorporates a fuzzy logic controller (FLC) to calculate the stabilizing torque. The regeneration system comprises an energy management system (EMS), DC-DC convertor, AC boost rectifier, ESS, and their corresponding controllers which have been carefully modeled and included in the simulations. Furthermore, the system is implemented in a laboratory-scale structure, and extensive shake table tests are carried out to examine the system's performance in the presence of seismic disturbances. The findings of this research are as follows: the proposed APS can well reduce the transmitted vibrations to the structure; the top story’s displacements and accelerations are reduced by 47 and 50 percent respectively in the benchmark model, implying the effectiveness of the active structural control system in enhancing simultaneous structural safety and inhabitants’ comfort. Moreover, the energy regeneration scheme can restore 34 percent of the APS’s power. Experimental results also verify the simulation results where a considerable drop in both the top story’s displacement and acceleration is reported for the test structure under seismic load. Furthermore, 44 percent of the active pendulum power is restored in the battery of the laboratory-scale APS.
... To mitigate the vibrations of offshore platforms, the abovementioned studies considered TMD systems in which the mass is located on a set of rails and moves in one or two directions (translational TMD systems). However, the inherent performance limitations of TMDs led to the development of various TMD topologies (Lourenco, 2011). Some of the limitations are related to: the robustness of changes in the structural stiffness; the spatial limitations within the structure (Setareh et al., 2004); the cost and lifespan of the TMD system; the existence of a set of rails or roller bearings (expensive and susceptible to wear over the lifespan of the TMD system); and unidirectional or bidirectional performance of TMD systems. ...
... In Fig. 1, θ refers to the pendulum angular displacement (rad), The values of these parameters can affect the dynamic response of the structure, and so the design of a tuned-mass damper generally is an optimization issue (Lourenco, 2011). The optimization can be calculated by finding the optimal values of ξ d , m, and β when the objective function is σ which indicates the performance of the damper. ...
... The schematic and free body diagram of a PTMD model mounted to the structure is illustrated in Fig. 2. In this figure, k, b, M, F(t)and x(t) respectively refer to structure stiffness constant (N/m), structure viscous damping coefficient (Ns/m), structure mass (kg), structure excitation force (N), and structure horizontal displacement (m). The resultant model contains the dynamics of the structure and PTMD models separately and coupling dynamics between the two models (Lourenco, 2011). ...
We investigate effects of pendulum tuned mass damper (PTMD) configuration as well as structural excitation frequency by ocean waves on the dynamic response of a jacket platform. To do this, an offshore jacket platform equipped with a PTMD with different values of frequency ratio (β), damping ratio (ξd) and mass ratio (m‾) is numerically simulated in ANSYS software under the action of irregular waves with different values of structural excitation frequency ratio (α). The results of the numerical simulations are validated against the experimental and numerical data available in the literature. The validations were in complete agreement with the benchmarking data. The results suggest that with a constant β, an increase in ξd of about 20 times reduces the standard deviation of the deck displacements (σ) tblf about 7.41%. Further, with an increase in β, σ increases when β>1 and decreases when β≤1. Regarding the pendulum mass ratio, an increase in m‾ of about 14 times results in a 12.91% reduction in σ within the range of ξd≤0.15. Out of the latter range (i.e. for ξd>0.15), σ is not significantly affected by m‾. Considering σ as the fitness function, the most optimal configuration for the PTMD system is achieved for α=1.2, β=1 and ξd=0.2.
... 30,20,22,[31][32][33] The Pendulum Tuned Mass Damper (PTMD) is an alternative for TMD where the passive device is a pendulum. 24,27,[34][35][36][37][38][39] Gerges and Vickery used a PTMD to reduce the structure RMS displacement. 40 The 3D PTMD to control tower vibration of FOWT 24,41,42 is responsible by increasing the damage life of wind tower more than 50% (to short-term fatigue damage, up to 90%) and mooring lines. ...
Offshore wind turbines (OWTs) are complex systems that may experience excessive vibrations due to winds, waves, rotor torque, or seismic loads during the operation. Tuned mass dampers (TMDs) have been a widely used vibration passive control device in structures, including wind turbines. The TMD works as a damper that transfers the kinetic energy from the main structure to a secondary mass usually attached to the hub. The spectral element method (SEM) is suitable for analyzing dynamic structural problemss with accuracy and low computational cost. This paper presents a monopile wind turbine fitted with a pendulum-TMD (PTMD) modeled by spectral elements. An optimum pendulum design is performed through the genetic algorithm technique. The wind turbine selected is a National Renewable Energy Lab (NREL) monopile 5MW baseline wind turbine fitted with a PTMD, subjected to winds and waves simulated as random spectra in the analysis. Numerical results show the efficiency of the proposed spectral model and the optimum PTMD design for the OWT under random excitation.
... In these studies, the effect of the finite element method was compared with the operational and experimental modal analysis method. With all this knowledge, this new study has been carried [26], [27], [28], [29], [30], [31], [32] about pendulum tuned mass damper (PTMD). ...
Earthquake engineers have taken many precautions in their building designs to protect and minimize destructive effects. In this way, many new design and reinforcement methods have been developed against seismic loads. The use of a pendulum tuned mass damper (PTMD) is one of the developed methods. One of the most important negative aspects of the use of PTMD is the increase in the structural period. Therefore, in this study, the effects of PTMD on periods and mode shapes in symmetrically reinforced concrete water tank model were investigated. For this, two models with and without PTMD were created by the finite element method and modal parameters were compared. As a result of the data obtained, it has been observed that the water tank model makes more balanced displacements, as can be understood from the mode shapes, without increasing the period of the water tank to a dangerous level. It is known that PTMD reduces the seismic effect by acting in the opposite direction to the seismic effect on the structure. Pendulum tuned mass damper can be used in reinforced concrete water tanks, provided that it does not increase period too much.
... In contrast, the optimal passive TMD becomes off-tuned when damage occurs. Lourenco [17] described the design, construction, implementation, and performance of a prototype adaptive PTMD. The experimental studies' results demonstrate the importance of optimizing the PTMD frequency and damping ratio to reduce structural vibrations. ...
Different types of tuned mass dampers (TMD) have been applied to reduce wind and seismic induces vibrations in buildings. We analyze a pendulum tuned mass damper (PTMD) to reduce vibrations of structures that exhibit elastoplastic behavior subjected to ground motion excitation. Using a simple dynamic model of the primary structure with and without the PTMD and a random process description of the ground acceleration, the performance improvement of the structure is assessed using statistical linearization. The Liapunov equation is used to estimate the mean-square response in the stationary condition of the random process and optimize PTMD parameters. The optimum values of the PTMD frequency and damping ratio are defined as PTMD design values for a specific maximum seismic intensity design criterion. The results show that: (1) The values of the PTMD effectiveness criterion and the optimal design values of the frequency ratio are higher when the damping ratio of the primary structure decreases. (2) The performance of the optimized PTMD is higher when the structure exhibits a linear hysteresis loop (low seismic intensity). (3) The optimized PTMD controls the development of structural plasticity reducing vulnerability. (4) There is a strong dependence of the optimum PTMD parameters on the dynamic soil properties of the building foundation. (5) The PTMD performance improves as its mass increases. The optimum frequency ratio decreases, and the damping ratio increases as the mass of the pendulum increases. The PTMD designed and optimized with the proposed methodology reduces vibrations, controls the development of plasticity, and protects the primary structure, particularly in low and medium-intensity earthquakes.
... Ω stands for the excitation frequency by waves (rad/s), g is the gravitational acceleration (9.81 m/s 2 ) , and K is the lateral stiffness of the structure (N/m). Detailed information on the PTMD systems can be found in Lourenco (2011). ...
... The values of these parameters can affect the dynamic response of the structure, and so the design of a tuned-mass damper generally is an optimization issue (Lourenco, 2011). The optimization can be calculated by finding the optimal values for the PTMD damping coefficient (ξ d ), the mass ratio (m), and the tuned frequency ratio (β) when the objective function is the standard deviation of the deck displacements (σ) which indicates the performance of the damper. ...
We implemented Particle Swarm Optimization (PSO) to determine the most optimal properties of the brace-viscous damper system (BVDS), pendulum tuned mass damper (PTMD), and combined BVDS-PTMD system in mitigation of dynamic response of a jacket platform. To do this, a scaled prototype of an offshore jacket is numerically simulated in ANSYS subjected to ocean waves. Concerning BVDS, at each story, the variables being optimized are (1) BVDS configuration such as chevron, toggle, diagonal; (2) damping coefficient, and (3) brace area. The properties of PTMD being optimized are the damping ratio (ξ_d), frequency ratio (β), structural excitation frequency ratio (α), and mass ratio (m ̅). To do the optimization, the results of ANSYS are exploited to calculate the PSO cost function (standard deviation of deck displacements (σ_sd)). Regarding the deck displacement and base shear force, the optimization results proved that the optimal BVDS-PTMD combined system outperforms the optimal BVDS and the optimal BVDS performance is better than that of the PTMD system. Both in the optimal BVDS and integrated BVDS-PTMD, the chevron configuration for the top floor and toggle configuration for the first to third floors are evaluated as the optimum arrangement by the optimization algorithm.
... Lourenco [18] theoretically and experimentally analyzed the performance of an active TMD pendulum type, attached to two-story shear building subjected to wide-band spectra. The optimization of the TMD parameters was performed in real time by the algorithm, updating the frequency, damping and mass ratios. ...
Purpose: An experimental–numerical study of an inverted pendulum system to control a reduced model of a main system is developed in this work.
Method: Initially, a dynamic system model with one degree of freedom (1DoF) translational in the horizontal direction is analyzed. To this system is coupled a passive control device in the geometry of a tuned mass damper inverted pendulum (TMD-IP). Different TMD-IP configurations are analyzed. The theoretical formulation adopted for free and forced vibration analysis is presented. Subsequently, an experimental bench composed of a reduced model with 1DoF, an TMD-IP and a dynamic exciter is designed and constructed. The data acquisition is performed via video techniques. A sensitivity analysis is performed, as well as an optimization, with the intention of finding the optimal parameters for the TMD-IP.
Results: Experimental and numerical analyses are performed on free vibration as well as forced vibration. Comparison of the results obtained showed a good agreement.
Conclusions: The TMD-IP showed to be a good solution reducing the main system horizontal vibrations.
... Pendulum Tuned Mass Dampers (PTMDs) are substituted with a translational spring and damper system with a pendulum, it comprises of a mass sustained by a cable which pivots about a point. They are often designed as a simple pendulum [7]. Even slight angular oscillations make the PTMD act similar to a translational. ...
... Among the possible geometric configurations used for TMD we have the simple pendulum [12][13][14][15][16][17][18][19][20]. Alternatively, Ahn et al. [21] proposed a TMD type as inverted pendulum (TMD-IP). ...
