scholarly journals A Reduced-Domain Method of Structural Damage Identification: Application to a Spectral Element Beam Model

2003 ◽  
Vol 10 (5-6) ◽  
pp. 313-324 ◽  
Author(s):  
Usik Lee
Keyword(s):  
Structural Damage ◽  
Damage Identification ◽  
Dynamic Stiffness ◽  
Experimental Tests ◽  
Element Model ◽  
Spectral Element ◽  
Beam Specimen ◽  
Identification Algorithm ◽  
Beam Model ◽  
Domain Method

Though there have been many efforts to make the inverse problem of damage identification small by reducing its finite element degrees-of-freedom, there have been few efforts to make it small by reducing its spatial domain of problem. Thus, as the extension of the author's previous work in which the damage identification algorithm was formulated from the dynamic stiffness equation of motion, the present study introduces a spectral element model (SEM)-based reduced-domain method (RDM) of damage identification. In the present RDM, a three-steps process is used to reduce the domain of problem by iteratively searching out and removing damage-free parts of structure in the course of the damage identification analysis. To validate the present RDM, numerically simulated damage identification tests are conducted. The experimental tests for a damaged cantilevered beam specimen show that the present RDM can fairly well locates and quantifies all local damages (i.e., slots) placed along the beam specimen.

scholarly journals Detection of Sparse Damages in Structures

2019 ◽  
Author(s):  
Natalia Sabourova ◽  
Niklas Grip ◽  
Ulf Ohlsson ◽  
Lennart Elfgren ◽  
Yongming Tu ◽  
...  
Keyword(s):  
Structural Damage ◽  
Damage Identification ◽  
Model Updating ◽  
Element Model ◽  
Total Variation Regularization ◽  
Regularization Technique ◽  
Spatial Properties ◽  
Ill Posed ◽  
Pros And Cons ◽  
Kirchhoff Plate Model

<p>Structural damage is often a spatially sparse phenomenon, i.e. it occurs only in a small part of the structure. This property of damage has not been utilized in the field of structural damage identification until quite recently, when the sparsity-based regularization developed in compressed sensing problems found its application in this field.</p><p>In this paper we consider classical sensitivity-based finite element model updating combined with a regularization technique appropriate for the expected type of sparse damage. Traditionally, (I), &#119897;2- norm regularization was used to solve the ill-posed inverse problems, such as damage identification. However, using already well established, (II), &#119897;l-norm regularization or our proposed, (III), &#119897;l-norm total variation regularization and, (IV), general dictionary-based regularization allows us to find damages with special spatial properties quite precisely using much fewer measurement locations than the number of possibly damaged elements of the structure. The validity of the proposed methods is demonstrated using simulations on a Kirchhoff plate model. The pros and cons of these methods are discussed.</p>

Pseudo Strain Energy Density-Based Structural Damage Identification

2009 ◽  
Vol 413-414 ◽  
pp. 71-78
Author(s):  
Xiao Qiang Chen ◽  
Hong Ping Zhu ◽  
Dan Sheng Wang
Keyword(s):  
Energy Density ◽  
Strain Energy Density ◽  
Structural Damage ◽  
Strain Energy ◽  
Damage Identification ◽  
Wavelet Packet ◽  
Damage Index ◽  
Dynamic Strain ◽  
Beam Model ◽  
Measured Strain

In this paper, a new time-domain method for detecting structural local damage has been developed, which is based on the measured strain signals. The “pseudo strain energy density (PSED)” is defined and used to build two major damage indexes, the “average pseudo strain energy density” (APSED) and the “average pseudo strain energy density changing rate” (APSEDR). A probability and mathematical statistics technique is utilized to derive a standardized damage index. Afterwards, these indexes are used to establish the damage identification strategies for beam structures and plate structures respectively. Furthermore, the wavelet packet transform is used to pre-process the measured dynamic strain signals. Then, the effectivity of the new damage identification method is confirmed by numerical simulations. Finally, a laboratory beam model experiment is conducted to verify this method examine the feasibility and applicability of the new method.

scholarly journals Structural Damage Detection Using Energy Flow Models

2008 ◽  
Vol 15 (3-4) ◽  
pp. 217-230 ◽  
Author(s):  
E.R.O. Santos ◽  
V.S. Pereira ◽  
J.R.F. Arruda ◽  
J.M.C. Dos Santos
Keyword(s):  
Damage Detection ◽  
Energy Flow ◽  
Structural Damage ◽  
Spectral Element Method ◽  
Crack Nucleation ◽  
Structural Response ◽  
Experimental Tests ◽  
Spectral Element ◽  
Localized Damping ◽  
Element Method

The presence of a crack in a structure modifies the energy dissipation pattern. As a consequence, damaged structures can present high localized damping. Experimental tests have revealed that crack nucleation and growth increase structural damping which makes this phenomenon useful as a damage locator. This paper examines the energy flow patterns caused by localized damping in rods, beams and plates using the Energy Finite Element Method (EFEM), the Spectral Element Method (SEM) and the Energy Spectral Element Method (ESEM) in order to detect and locate damage. The analyses are performed at high frequencies, where any localized structural change has a strong influence in the structural response. Simulated results for damage detection in rods, beams, and their couplings calculated by each method and using the element loss factor variation to model the damage, are presented and compared. Results for a simple thin plate calculated with EFEM are also discussed.

scholarly journals Structural Damage Identification of Bridges from Passing Test Vehicles

Sensors ◽  
2018 ◽  
Vol 18 (11) ◽  
pp. 4035 ◽  
Author(s):  
Yang Yang ◽  
Yuanhao Zhu ◽  
Li Wang ◽  
Bao Jia ◽  
Ruoyu Jin
Keyword(s):  
Structural Damage ◽  
Damage Identification ◽  
Least Squares Method ◽  
Field Tests ◽  
Bending Stiffness ◽  
Frequency Domain Method ◽  
Residual Vector ◽  
Test Vehicle ◽  
Domain Method ◽  
Structural Damage Identification

This paper presents two approaches for the structural damage identification of a bridge from the dynamic response recorded from a test vehicle during its passage over the bridge. Using the acceleration response recorded by the vibration sensors mounted on a test vehicle during its passage over the bridge, along with the computed displacement response, the bending stiffness of the bridge can be determined using either: (1) the frequency-domain method based on the improved directed stiffness method with the identified frequency and corresponding mode shape, or (2) the time-domain method based on the residual vector of the least squares method with a fourth-order displacement moment. By comparing the bending stiffness values identified from the vehicle-collected data for the bridge under the undamaged and damaged states that are monitored regularly by the test vehicle, the bridge damage location and severity can be identified. Through numerical simulations and field tests, the present approaches are shown to be effective and feasible.

Damage identification using structural modes based on substructure virtual distortion method

2016 ◽  
Vol 20 (2) ◽  
pp. 257-271 ◽  
Author(s):  
Qingxia Zhang ◽  
Łukasz Jankowski
Keyword(s):  
Frequency Response ◽  
Response Function ◽  
Structural Damage ◽  
Frequency Response Function ◽  
Damage Identification ◽  
Element Model ◽  
Frequency Responses ◽  
Computational Work ◽  
Structural Reanalysis ◽  
Identification Approach

A damage identification approach is presented using substructure virtual distortion method which takes the advantage of the fast structural reanalysis technique of virtual distortion method. The formulas of substructure virtual distortion method are deduced in frequency domain, and then the frequency response function of the damaged structure is constructed quickly via the superposition of the frequency response function of the intact structure and the frequency responses caused by the damage-coupling virtual distortions of the substructures. The structural damage extents are identified using the measured modal parameters. Two steps are adopted to increase the efficiency of optimization: the modals of finite element model are estimated quickly from the fast constructed frequency response function during the optimization and the primary distortions of the substructures are extracted by contribution analysis to further reduce the computational work. A six-story frame numerical model and an experiment of a cantilever beam are carried out, respectively, to verify the efficiency and accuracy of the proposed method.

scholarly journals Bridge Damping Extraction Method from Vehicle–Bridge Interaction System Using Double-Beam Model

2021 ◽  
Vol 11 (21) ◽  
pp. 10304
Author(s):  
Fengzong Gong ◽  
Fei Han ◽  
Yingjie Wang ◽  
Ye Xia
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Traffic Flow ◽  
Dynamic Stiffness ◽  
Damping Ratio ◽  
Element Model ◽  
Beam Model ◽  
Modal Shape ◽  
Structural Dynamic ◽  
Double Beam

When vehicles interact with a bridge, a vehicle–bridge interaction (VBI) system is created. The frequency and modal shape of VBI systems have been widely studied, but the damping of VBI systems has not been adequately investigated. In recent years, several incidents of abnormal bridge vibration due to changes in bridge damping have occurred and aroused widespread concern in society. Damping is an important evaluation index of structural dynamic performance. Knowing the damping ratio of a VBI system is useful for analyzing the damping changes while a bridge is in service. This paper presents a method to extract bridge damping values from a VBI system, which can serve as a guide for bridge damping evaluation. First, a double-beam theoretical model was used to simplify the VBI system for cases involving uniform traffic flow. The damping ratio equation for the simplified VBI system was obtained using the extended dynamic stiffness method (EDSM). A double-beam finite element model and a VBI finite element model were established. The damping ratios of the two models were separately calculated and then compared with the simplified VBI model results. The results verified the accuracy of the simplified method. This paper then explains that bridge damping values can be extracted by estimating the equivalent traffic flow parameters and using the damping formula for the simplified VBI system. The bridge damping ratios extracted using this method in an engineering case ranged from 0.75% to 0.78%, which is smaller than the range that was directly identified using monitoring data (0.83–1.19%). The results show that the method can effectively extract bridge damping ratios and improve damping ratio identification.

scholarly journals Structural Damage Identification and Location Using Grammian Matrices

2012 ◽  
Vol 19 (3) ◽  
pp. 287-299 ◽  
Author(s):  
D.D. Bueno ◽  
C.R. Marqui ◽  
V. Lopes Jr. ◽  
M.J. Brennan ◽  
Daniel J. Inman
Keyword(s):  
Structural Damage ◽  
Simple Structure ◽  
Damage Identification ◽  
Dynamic Properties ◽  
State Space Model ◽  
Experimental Tests ◽  
Reduced Order ◽  
Monitoring Applications ◽  
Controllability Grammian ◽  
Order State

In this paper, an approach using observability and controllability grammian matrices is proposed to determine if structural damage has occurred together with an estimate of its location. The theory is outlined and simulations are carried out on a simple structure to demonstrate the method. Experimental tests were also carried out to demonstrate the validity of the approach using real signals. The dynamic properties of the structure are identified using the eigensystem realization algorithm (ERA) and a reduced order state-space model of the system subsequently constructed. Either the observability or controllability grammians can then be used depending on the number of sensors available. It is shown that these are sensitive to both the degree and location of the damage and offer promise for structural health monitoring applications.

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