Identification of System Parameters of Slab Vibrated With Vibrator by Using Wavelet Transform

2005 ◽  
Author(s):  
Naoto Imanishi ◽  
Akira Sone ◽  
Arata Masuda
Keyword(s):  
Wavelet Transform ◽  
Health Monitoring ◽  
Maintenance Management ◽  
Spring Constant ◽  
System Model ◽  
Mass System ◽  
System Parameters ◽  
Noisy Conditions ◽  
Excitation Force ◽  
Spring Constants

In health monitoring of slabs of a road bridge, it is suitable to carry out on the basis of their stiffness, which is evaluated by spring constants of a spring-mass system model of the slab. When the value of the spring constant is known, the rigidity of the slab and the deflection against the predetermined load can be estimated. These can be used as the basic data of maintenance management of them. The authors have been proposing the method to identify the spring constant of the slab by wavelet transform of an excitation force and acceleration responses. In this paper, the method to identify the spring constants of slabs is theoretically investigated under the noisy conditions. The method to find the specific values of constant α in an analyzing wavelet by which the most reliable value of the spring constant is given according to the graphic form showing the relation between identified mass and constant α.

Experimental Study for Identifying Stiffness of Bridge Slab by Using Wavelet Transform

2006 ◽  
Author(s):  
Naoto Imanishi ◽  
Akira Sone ◽  
Arata Masuda
Keyword(s):  
Experimental Study ◽  
Wavelet Transform ◽  
Reinforced Concrete ◽  
Health Monitoring ◽  
Spring Constant ◽  
Acceleration Response ◽  
Graphic Form ◽  
Noisy Conditions ◽  
Excitation Force ◽  
Spring Constants

In health monitoring of bridge slabs, it is suitable to identify the change in their stiffness. The authors have been proposing the method to identify the spring constant of slab by wavelet transform of an excitation force and acceleration response. In previous paper, the method to identify the spring constants of slabs is theoretically investigated under the noisy conditions. The method to find the specific values of constant α in an analyzing wavelet by which the most reliable value of the spring constant is given according to the graphic form showing the relation between identified mass and constant α. In this paper, the effectiveness of the method is proven from the experiment results using the reinforced concrete panel specimen.

Nonlinear Model and Simulation Experiment Research of Vibratory Rollers

2011 ◽  
Vol 121-126 ◽  
pp. 2121-2125
Author(s):  
Yuan Hao ◽  
Zhao Hui Ren ◽  
Feng Wen
Keyword(s):  
Nonlinear Vibration ◽  
Simulation Experiment ◽  
Response Characteristic ◽  
Soil Mass ◽  
System Model ◽  
System Response ◽  
Experiment Research ◽  
System Parameters ◽  
Model And Simulation ◽  
Excitation Force

On the basis of the relation between force and deformation when the plastic deformation of soil mass is studied, nonlinear vibration roller model is built. Based on one type vibratory rollers select the system parameters and calculate the natural frequency. And according to the selected numerical value proceed the numerical simulation with different excitation force frequencies. Meanwhile, obtain and analyze the experimental data according to the vibratory roller experiment. Then the system response characteristic of nonlinear vibration roller is obtained, and the availability of system model is checked. All above provide the valuable theoretical basis for the research of vibrating compacting.

scholarly journals Sensors for Structural Health Monitoring and Condition Monitoring

Sensors ◽  
2021 ◽  
Vol 21 (5) ◽  
pp. 1558
Author(s):  
Francesc Pozo ◽  
Diego A. Tibaduiza ◽  
Yolanda Vidal
Keyword(s):  
Structural Health Monitoring ◽  
Condition Monitoring ◽  
Health Monitoring ◽  
Structural Control ◽  
Engineering Applications ◽  
System Parameters ◽  
Structural Health ◽  
Agricultural Engineering ◽  
Physical Variables

Structural control and health monitoring as condition monitoring are some essential areas that allow for different system parameters to be designed, supervised, controlled, and evaluated during the system’s operation in different processes, such as those used in machinery, structures, and different physical variables in mechanical, chemical, electrical, aeronautical, civil, electronics, mechatronics, and agricultural engineering applications, among others [...]

The Appropriate Lumped Constants of Vibrating Shaft Systems

1943 ◽  
Vol 10 (4) ◽  
pp. A220-A224
Author(s):  
G. Horvay ◽  
J. Ormondroyd
Keyword(s):  
Total Mass ◽  
Spring Constant ◽  
New Method ◽  
Concentrated Mass ◽  
Shaft System ◽  
Spring Constants

Abstract The present paper is a theoretical supplement to the descriptive article, “Static and Dynamic Spring Constants.” It is concerned with the derivation of the constants (1a)Ki=ki+16miω2=ki(1+16ϵi2)(ϵi2=ω2mi/ki)(1b)Mi=μi+12(mleft+mright) of the appropriately lumped shaft system (Section 1), and with an estimate of the range of the new method (Sections 2, 3, 4). Term ki denotes the distributed static spring constant, mi the total mass of the ith (uniform) shaft section of the system; μi is the ith concentrated mass, ω the frequency of vibration.

scholarly journals Comparative Analysis of Polarimetric SAR Calibration Methods

2018 ◽  
Vol 10 (12) ◽  
pp. 2060 ◽  
Author(s):  
Yoon Jung ◽  
Sang-Eun Park
Keyword(s):  
Comparative Analysis ◽  
Calibration Method ◽  
System Model ◽  
Synthetic Aperture ◽  
Polarimetric Sar ◽  
Alos Palsar ◽  
Polarimetric Synthetic Aperture Radar ◽  
System Parameters ◽  
Calibration Methods ◽  
Polarimetric Calibration

In the diverse applications of polarimetric Synthetic Aperture Radar (SAR) systems, it is a crucial to conduct polarimetric calibration, which aims to remove the radar system distortion effects prior to utilizing polarimetric SAR observations. The objective of this study is to evaluate the performance of different polarimetric calibration methods. Two widely used methods, the Van Zyl and Quegan methods, and one recently proposed method, such as the Villa method, have been selected among various calibration methods in literature. The selected methods have basic differences in their assumptions that are applied to the polarimetric system model. In order to evaluate the calibration performances under different system parameters and ground characteristics, comparative analysis of the calibration results were conducted on synthetic polarimetric SAR data and ALOS PALSAR quad-pol mode data. Based on the experimental results, the advantages and limitations of different methods were clarified, and a simple hybrid calibration method is presented to further improve the polarimetric calibration performance.

Structural Health Monitoring Using Synchrosqueezed Wavelet Transform on IASC-ASCE Benchmark Phase I

2020 ◽  
Vol 20 (12) ◽  
pp. 2050138
Author(s):  
Wilson D. Sanchez ◽  
Jose V. de Brito ◽  
Suzana M. Avila
Keyword(s):  
Wavelet Transform ◽  
Dynamic Response ◽  
Phase I ◽  
Damage Detection ◽  
Health Monitoring ◽  
Natural Frequencies ◽  
Detection Methods ◽  
State Of Health ◽  
Civil Structures ◽  
Synchrosqueezed Wavelet Transform

Civil structures suffer deterioration either for years of service, deficiency due to environmental factors or damages caused by factors such as earthquakes, winds, impact loads, and cyclical loads. When a structure ages, it is necessary to know its state of health and make a decision of maintenance or replacement. When a structure such as a bridge or building is subjected to destructive environmental forces, determining its state of health becomes a priority since its recovery is urgently required to function normally. Structural Health Monitoring (SHM) is a technology that aims to prevent the collapse of structures and loss of human life through early diagnosis of the health status of a structure. There are a large number of damage detection methods that can be classified into (1) non-destructive testing methods, (2) dynamic characteristics-based damage detection methods, (3) dynamic response-based, (4) multi-scale damage detection method and (5) damage detection methods with consideration of uncertainties. In this work, it is implemented synchrosqueezed wavelet transform (SWT), which can be classified as a methods based on the dynamic response. To validate the robustness of the method it is identified first, the natural frequencies of the Benchmark Phase I without damage, which consists of a steel structure of 4-story [Formula: see text] bay 3D steel frame structure subjected to ambient vibrations. Subsequently, some damage patterns are validated according to IASC-ASCE SHM Task Group. The results obtained in the identification of natural frequencies are compared with those reported in literature. SWT was efficient, presenting a minimum error of 0.12[Formula: see text] and a maximum of 3.06[Formula: see text] in the identification of natural frequencies about the AISCE-ASCE group model. SWT overcomes some other damage detection methods, which are deficient in the identification of closely spaced frequencies, commonly present in many civil structures due to symmetric geometry or similar physical properties in different directions.

Evaluation of bridge support condition using bridge responses

2018 ◽  
Vol 18 (3) ◽  
pp. 767-777 ◽  
Author(s):  
Young-Soo Park ◽  
Sehoon Kim ◽  
Namgyu Kim ◽  
Jong-Jae Lee
Keyword(s):  
Sensitivity Analysis ◽  
Numerical Analysis ◽  
Field Test ◽  
Laboratory Tests ◽  
Spring Constant ◽  
Scale Model ◽  
Support Condition ◽  
Bridge Responses ◽  
Spring Constants

This article presents a method for evaluating the support condition of bridges. This is done by representing the aging and deteriorated supports as rotation springs with equivalent spring constants. Sensitivity analysis was performed to obtain a relationship between the spring constant and the bridge responses (deflections/slopes). From this relationship, measured bridge responses can be used to estimate the equivalent spring constants through interpolation. Numerical analysis was performed to check whether the method can be used to calculate equivalent spring constants. Then, the method was verified by performing laboratory tests on a scale model bridge and field test on an actual bridge. In both tests, spring constants were estimated using the proposed method and then verified by calculating the displacements and frequencies and comparing them to the measured values.

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