Integration of identification and vibration control of time-varying structures subject to unknown seismic ground excitation

2020 ◽  
Vol 26 (15-16) ◽  
pp. 1330-1344 ◽  
Author(s):  
Ying Lei ◽  
Jubin Lu ◽  
Jinshan Huang
Keyword(s):  
Vibration Control ◽  
Real Time ◽  
Dynamic Responses ◽  
Structural Vibration ◽  
Earthquake Ground Motion ◽  
Time Varying ◽  
Earthquake Excitation ◽  
Structural Dynamic ◽  
Invariant Structure ◽  
Unknown Inputs

The synthesis of structural health monitoring and vibration control is important in order to provide facilities for constructing smart structures. In recent years, some techniques have been developed to integrate structural identification and optimal vibration control. However, it is still challenging to integrate the identification and vibration control of time-varying structures subject to unknown earthquake excitation. The main difficulties are that structural dynamic responses collected by a simple harmonic motion system are absolute responses under unknown earthquake ground motion while previous identification approaches for unknown external excitation are not applicable for this situation and the need of an efficient algorithm to accurately track the various scenarios of time-varying structures with inexpensive computation to ensure the real-time performance requested by structural vibration control. In this paper, a novel algorithm is presented, in which structural time-varying parameters are treated as ‘virtual unknown inputs’ to the underlying time-invariant structure, a generalized Kalman filter with unknown inputs is proposed for joint identification of joint structural state, unknown earthquake excitation and ‘virtual unknown inputs’ with only partially measured structural absolute responses, and the identification results are integrated in real-time with the instantaneous optimal control scheme to reach the goal of optimal semi-active control provided by magneto-rheological dampers. Some numerical examples of integrated identification and vibration control of various time-varying structures subject to unknown earthquake excitation are used to demonstrate the performances of the proposed algorithm.

scholarly journals Data-Driven Adaptive Iterative Learning Method for Active Vibration Control Based on Imprecise Probability

Symmetry ◽  
2019 ◽  
Vol 11 (6) ◽  
pp. 746 ◽  
Author(s):  
Liang Bai ◽  
Yun-Wen Feng ◽  
Ning Li ◽  
Xiao-Feng Xue ◽  
Yong Cao
Keyword(s):  
Iterative Learning ◽  
Dynamic Responses ◽  
Data Driven ◽  
Structural Vibration ◽  
Time Varying ◽  
Imprecise Probability ◽  
Source Information ◽  
Structural Dynamic ◽  
Model Free ◽  
P Type

A data-driven adaptive iterative learning (IL) method is proposed for the active control of structural vibration. Considering the repeatability of structural dynamic responses in the vibration process, the time-varying proportional-type iterative learning (P-type IL) method was applied for the design of feedback controllers. The model-free adaptive (MFA) control, a data-driven method, was used to self-tune the time-varying learning gains of the P-type IL method for improving the control precision of the system and the learning speed of the controllers. By using multi-source information, the state of the controlled system was detected and identified. The square root values of feedback gains can be considered as characteristic parameters and the theory of imprecise probability was investigated as a tool for designing the stopping criteria. The motion equation was driven from dynamic finite element (FE) formulation of piezoelectric material, and then was linearized and transformed properly to design the MFA controller. The proposed method was numerically and experimentally tested for a piezoelectric cantilever plate. The results demonstrate that the proposed method performs excellent in vibration suppression and the controllers had fast learning speeds.

scholarly journals Identification of Sudden Stiffness Change in the Acceleration Response of a Nonlinear Hysteretic Structure

2020 ◽  
Vol 2020 ◽  
pp. 1-20
Author(s):  
Sheng-Lan Ma ◽  
Shao-Fei Jiang ◽  
Chen Wu ◽  
Si-Yao Wu
Keyword(s):  
Structural Model ◽  
Dynamic Responses ◽  
Physical Parameters ◽  
Discrete Wavelet ◽  
Time Varying ◽  
Ground Acceleration ◽  
Structural Dynamic ◽  
Filter Tuning ◽  
Structural Responses ◽  
Extent Of Damage

The integration of discrete wavelet transform and independent component analysis (DWT-ICA) method can directly identify time-varying changes in linear structures. However, better metrics of structural seismic damage and future performance after an event are related to structural permanent and total plastic deformations. This study proposes a two-stage technique based on DWT-FastICA and improved multiparticle swarm coevolution optimization (IMPSCO) using a baseline nonlinear Bouc–Wen structural model to directly identify changes in stiffness caused by damage as well as plastic or permanent deflections. In the first stage, the measured structural dynamic responses are preprocessed firstly by DWT, and then the Fast ICA is used to extract the feature components that contain the damage information for the purpose of initially locating damage. In the second stage, the structural responses are divided at the identified damage instant into segments that are used to identify the time-varying physical parameters by using the IMPSCO, and the location and extent of damage can accordingly be identified accurately. The efficiency of the proposed method in identifying stiffness changes is assessed under different ground motions using a suite of two different ground acceleration records. Meanwhile, the effect of noise level and damage extent on the proposed method is also analyzed. The results show that in a realistic scenario with fixed filter tuning parameters, the proposed approach identifies stiffness changes within 1.25% of true stiffness within 8.96 s; therefore, it can work in real time. Parameters are identified within 14% of the actual as-modeled value using noisy simulation-derived structural responses. This indicates that, in accordance with different demands, the proposed method can not only locate and quantify damage within a short time with a high precision but also has excellent noise tolerance, robustness, and practicality.

scholarly journals Operational Modal Identification of Time-Varying Structures via a Vector Multistage Recursive Approach in Hybrid Time and Frequency Domain

2015 ◽  
Vol 2015 ◽  
pp. 1-13 ◽  
Author(s):  
Si-Da Zhou ◽  
Li Liu ◽  
Wu Yang ◽  
Zhi-Sai Ma
Keyword(s):  
Parameter Estimation ◽  
Frequency Domain ◽  
Real Time ◽  
Time Estimation ◽  
Recursive Estimation ◽  
Modal Parameters ◽  
Time Varying ◽  
Modal Parameter ◽  
Structural Dynamic ◽  
Modal Parameter Estimation

Real-time estimation of modal parameters of time-varying structures can conduct an obvious contribution to some specific applications in structural dynamic area, such as health monitoring, damage detection, and vibration control; the recursive algorithm of modal parameter estimation supplies one of fundamentals for acquiring modal parameters in real-time. This paper presents a vector multistage recursive method of modal parameter estimation for time-varying structures in hybrid time and frequency domain, including stages of recursive estimation of time-dependent power spectra, frozen-time modal parameter estimation, recursive modal validation, and continuous-time estimation of modal parameters. An experimental example validates the proposed method finally.

scholarly journals Vibration Control of Tower Structure with Multiple Cardan Gyroscopes

2017 ◽  
Vol 2017 ◽  
pp. 1-11 ◽  
Author(s):  
Haoxiang He ◽  
Xin Xie ◽  
Wentao Wang
Keyword(s):  
Degrees Of Freedom ◽  
Dynamic Control ◽  
Dynamic Responses ◽  
Structural Vibration ◽  
Structural Dynamic ◽  
Torsion Effect ◽  
Tower Structure ◽  
Rotational Degrees Of Freedom ◽  
Earthquake Action ◽  
Control Equation

Tower structure is sensitive to hurricane and earthquake, and it is easy to generate large deflection and dynamic response. The multiple cardan gyroscope has two rotational degrees of freedom, which can generate strong moments to constrain the two horizontal orthogonal deflections if the rotor operates in high speeds, so the structural dynamic responses can be decreased. Hence, the method of dynamic control of the tower structure under wind load and earthquake action is proposed by using the multiple cardan gyroscopes as the dampers. The dynamic mechanism and the fixed axis principle of the multiple cardan gyroscope are introduced, and the dynamic equation of the gyroscope is established. The damping mechanism of the gyroscope is also described. For the tower structure equipped with the multiple cardan gyroscope dampers, the multidimensional control equation considering torsion effect is established, and the equivalent state space equation is presented. Taking a TV Tower with a number of gyroscope dampers as an analysis example, the structural dynamic responses and damping performance under fluctuating wind loads and earthquake action is studied. The results show that the multiple cardan gyroscope dampers with suitable parameters can effectively decrease the structural vibration in horizontal directions and torsional direction.

Mitigation of Wind-Induced Vibration of a 600m High Skyscraper

2019 ◽  
Vol 19 (02) ◽  
pp. 1950015 ◽  
Author(s):  
J. W. Zhang ◽  
Q. S. Li
Keyword(s):  
Vibration Control ◽  
Tall Buildings ◽  
Tall Building ◽  
Dynamic Responses ◽  
Structural Vibrations ◽  
Structural Dynamic ◽  
High Rise ◽  
Structural Responses ◽  
Detailed Assessment ◽  
Wind Induced Vibration

The serviceability of super-tall buildings depends primarily on the wind-induced structural responses, especially accelerations. To mitigate the discomforting structural vibrations, pendulum-type tuned mass damper (TMD) systems are commonly employed in high-rise buildings. However, for a super-tall building with a considerably low fundamental natural frequency, the suspension length of a pendulum-suspended TMD (PTMD) becomes too long to be feasible as it would occupy substantial building space. For the sake of saving valuable space in a super-tall building, a multistage PTMD system is recommended for vibration control. This paper presents a detailed assessment study on the performance of a multistage PTMD system designed for a 600 m high skyscraper located in a typhoon-prone region in China. Wind tunnel tests are first conducted to determine the wind loads on the building for estimation of structural dynamic responses for the scenarios with and without installation of the multistage PTMD system. Optimal design of the multistage PTMD system is then carried out through examining the mitigation efficiency of the PTMD system for a variety of mass and damping ratios. To restrict the strokes of mass dampers in the PTMD system, two-section damping strategy is proposed. The assessment results demonstrate that the multistage PTMD system with two-section damping can function efficiently to suppress the excessive vibrations of the skyscraper, while occupying a minimal space in vertical and horizontal directions. This paper aims to provide an effective and economic design strategy for vibration control of super-tall buildings under wind excitations.

Dynamic Responses of the Powerhouse Structure of Hydropower Stations due to Hydraulic Excitation

2011 ◽  
Vol 105-107 ◽  
pp. 233-237
Author(s):  
Jing Chen ◽  
Zhen Yue Ma ◽  
Yun Liang Zhang
Keyword(s):  
Dynamic Responses ◽  
Structural Vibration ◽  
Structural Dynamic ◽  
Operation Process ◽  
Water Head ◽  
Different Types ◽  
Spiral Case ◽  
Exciting Vibration ◽  
Frequency Behavior ◽  
Hydropower Stations

As the capacity and water head of large hydropower projects become higher and higher, the flow-induced structural vibration of powerhouse becomes a very important problem for the design and operation process. Especially as the water head and the running speed are much higher for the pump-turbine than the general turbine, the hydraulic exciting vibration is very remarkable. In this paper the simulation results of free-vibration characteristics of powerhouse structure for different types were concluded and the frequency behavior of the pressure fluctuation in spiral case and draft tube were discussed. The structural dynamic responses under hydraulic exciting were presented including the dynamic responses of displacement, velocity, acceleration and stresses. Based on the vibration criterion of the powerhouse structure, the vibration evaluation was made.

Earthquake Response and Design of Energy Dissipation for a 22 Story Apartment Building

2013 ◽  
Vol 639-640 ◽  
pp. 836-840
Author(s):  
C.C. Lv ◽  
W.F. He ◽  
Yan Guo ◽  
W.G. Liu
Keyword(s):  
Mild Steel ◽  
Vibration Control ◽  
Dynamic Responses ◽  
Earthquake Response ◽  
Apartment Building ◽  
Viscous Dampers ◽  
Structural Dynamic ◽  
Control Plan ◽  
Viscoelastic Dampers ◽  
Control Schemes

Vibration control of a 22 story RC frame-shear wall apartment building with large aspect ratio was studied in this paper. Three vibration control plan with mild steel dampers, viscous dampers and viscoelastic dampers were proposed to control structural dynamic responses under earthquake. The dynamic responses of the structure with the proposed control schemes under earthquake excitations were investigated and their vibration control effects were compared. The numerical analysis results show that structural dynamic responses under earthquake excitations can be decreased effectively using the proposed plan. The earthquake response with viscous dampers was smaller than that with mild steel dampers and viscoelastic dampers. The shear force, drift and the acceleration of the structure with viscous dampers were 20%-40% less than the structure without any dampers for the slender structure.

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