scholarly journals Modal Parameters Estimation of Building Structures from Vibration Test Data Using Observability Measurement

2015 ◽  
Vol 2015 ◽  
pp. 1-13
Author(s):  
Jae-Seung Hwang ◽  
Hongjin Kim ◽  
Bong-Ho Cho
Keyword(s):  
Experimental Data ◽  
State Space ◽  
Shaking Table Test ◽  
State Space Model ◽  
Parameters Estimation ◽  
Shaking Table ◽  
Mode Shapes ◽  
Vibration Test ◽  
Space Model ◽  
Participation Factor

The load distribution to each mode of a structure under seismic loading depends on the modal participation factors and mode shapes and thus the exact estimation of modal participation factors and mode shapes is essential to analyze the seismic response of a structure. In this study, an identification procedure for modal participation factors and mode shapes from a vibration test is proposed. The modal participation factors and mode shapes are obtained from the relationship between observability matrices realized from the system identification. Using the observability matrices, it is possible to transform an arbitrarily identified state space model obtained from the experimental data into a state space model which is defined in a domain with physical meaning. Then, the modal participation factor can be estimated based on the transformation matrix between two state space models. The numerical simulation is performed to evaluate the proposed procedure, and the results show that the modal participation factor and mode shapes are estimated from the structural responses accurately. The procedure is also applied to the experimental data obtained from the shaking table test of a three-story shear building model.

scholarly journals Identifying the stiffness parameters of a structure using a subspace approach and the Gram–Schmidt process in a wavelet domain

2017 ◽  
Vol 9 (7) ◽  
pp. 168781401770764 ◽  
Author(s):  
Wei-Chih Su ◽  
Chiung-Shiann Huang ◽  
Ho-Cheng Lien ◽  
Quang-Tuyen Le
Keyword(s):  
Stiffness Matrix ◽  
Natural Frequencies ◽  
Shaking Table Test ◽  
State Space Model ◽  
Measured Data ◽  
Shaking Table ◽  
Mode Shapes ◽  
Modal Parameters ◽  
Wavelet Domain ◽  
Space Model

This article presents a procedure to improve the accuracy of calculated stiffness matrix of a structure based on the identified modal parameters from its measured responses. First, a continuous wavelet transform is applied to the measured responses of a structure, and the state–space model can be reconstructed by the wavelet coefficients of acceleration that can be obtained from the measured noisy responses. The modal parameters are identified using the subspace approach. Second, the identified mode shapes are corrected via Gram–Schmidt process. Finally, the identified natural frequencies and the corrected mode shapes in previous steps are utilized to build the stiffness matrix of structure. The accuracy of the proposed approach is numerically confirmed, and the noise effects on the ability to precisely identify the stiffness matrix are also investigated. The measured data of two eight-story steel frames in a shaking table test are analyzed to demonstrate the applicability of the procedure to real structures.

Analysis of a Hydrofoil Craft with a Suspension System

2020 ◽  
Author(s):  
Michel Touw ◽  
Jacob Lotz ◽  
Ido Akkerman
Keyword(s):  
Experimental Data ◽  
Control System ◽  
State Space ◽  
State Space Model ◽  
Suspension System ◽  
Future Research ◽  
Passive System ◽  
Height Control ◽  
Space Model ◽  
Front Wing

In this paper we investigate the efficacy of augmenting, or replacing, an active height control system for a submerged hydrofoil with a passive system based on springs and dampers. A state-space model for submerged hydrofoils is formulated and extended to allow for a suspension at the front wing, aft wing or both wings. The model is partially verified by obtaining results in the fixed-wing limit and comparing these with experimental data from the MARIN Foiling Future Demonstrator. In the current study we limit ourselves to translational springs, only allowing suspension motion in the heave direction. This results in unfavorable behavior: either the motions increased or the system becomes unstable. It is therefore recommended for future research to try rotational springs.

scholarly journals Parameters Estimation of Interharmonic Based on State Space Model

2014 ◽  
Vol 2014 ◽  
pp. 1-5
Author(s):  
Yuan Shiji ◽  
Pei Bin ◽  
Liu Zhihua ◽  
Huang Wenjing ◽  
Sun Mingfeng
Keyword(s):  
State Space ◽  
Gaussian Noise ◽  
State Space Model ◽  
Hankel Matrix ◽  
Parameters Estimation ◽  
White Gaussian Noise ◽  
Joint Estimation ◽  
Superior Performance ◽  
Space Model ◽  
Simulation Results

The special Hankel matrix is structured from interharmonic sampling, which is described by state space model. A method of parameters estimation based on state space model is proposed, which can achieve interharmonics frequency, amplitude and, phase of the joint estimation. The simulation results show that the method can effectively restrain white Gaussian noise, with superior performance.

Optimal Control Deconvolution for Velocity Meter Signals

1988 ◽  
Vol 110 (1) ◽  
pp. 17-23
Author(s):  
P. M. Clarkson ◽  
J. K. Hammond
Keyword(s):  
Experimental Data ◽  
Optimal Control ◽  
State Space ◽  
State Space Model ◽  
The State ◽  
Measurement Noise ◽  
Deconvolution Method ◽  
System Parameters ◽  
Space Model ◽  
Inaccurate Estimation

A method of deconvolution has been developed which uses the techniques of optimal control. The application of the technique to velocity meter signals is presented. It is shown that provided a state-space model of the transducer dynamics can be obtained the method can provide effective deconvolution even when the data are corrupted by measurement noise. As well as the deconvolution method and the control of the measurement noise the formation of the state-space model and the effects of inaccurate estimation of system parameters are considered. Results are presented using both simulated and experimental data.

Shaking table control via real-time inversion of hydraulic servoactuator linear state-space model

2021 ◽  
pp. 095965182110072
Author(s):  
José Ramírez-Senent ◽  
Jaime H García-Palacios ◽  
Iván M Díaz
Keyword(s):  
State Space ◽  
Real Time ◽  
Feedback Linearization ◽  
Control Method ◽  
State Space Model ◽  
Shaking Table ◽  
Time Inversion ◽  
Space Model ◽  
Control Command ◽  
Linear State

In this work, a Model-Based Control method for a single horizontal degree of freedom shaking table is presented. The proposed approach relies on the real-time inversion of a previously identified linear state-space model of the hydraulic servoactuator which drives the table. The inputs to the model are the control command and the force exerted on servoactuator rod. The latter contains all the relevant information related to the external actions acting on the servoactuator, thus making control system performance independent from the specimen with which the table is loaded and enabling it to cope with specimen non-linear behavior and eventual external forces exerted on it. A parallel proportional integral derivative controller, which accounts for non-modeled dynamics and a feedback linearization scheme, aimed at minimizing servovalve flow non-linearity, complement the previous architecture. The effectiveness of the method has been assessed numerically. According to the simulation results, the performance of the proposed technique appears quite promising; however, several factors must be carefully considered to achieve successful actual implementation.

Study on Flange Bolted-Joints Structure Based on State Space Model

2011 ◽  
Vol 101-102 ◽  
pp. 1151-1155
Author(s):  
Mei Zi Tian ◽  
Deng Feng Zhao ◽  
Guo Ying Zeng ◽  
Hang Rui Yan
Keyword(s):  
State Space ◽  
Simulation Analysis ◽  
State Space Model ◽  
State Equation ◽  
The State ◽  
Bolted Joints ◽  
Vibration Test ◽  
Test Results ◽  
Bolted Connection ◽  
Space Model

Based on the vibration mechanics theory and system’s state equation, the state-space model of the flange bolted-joints structure is established. According to the dynamic characteristics of bolted connection, the parameters of the state-space model, such as rigidity and damping, can be identified. The accuracy of simulation model is validated, by comparing the simulation analysis results with the vibration test results, and an efficient method of recognition or fault diagnosis of bolted joints in vibratory environment is proposed.

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