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

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.

2021 ◽  
pp. 147592172199847
Author(s):  
William Soo Lon Wah ◽  
Yining Xia

Damage detection methods developed in the literature are affected by the presence of outlier measurements. These measurements can prevent small levels of damage to be detected. Therefore, a method to eliminate the effects of outlier measurements is proposed in this article. The method uses the difference in fits to examine how deleting an observation affects the predicted value of a model. This allows the observations that have a large influence on the model created, to be identified. These observations are the outlier measurements and they are eliminated from the database before the application of damage detection methods. Eliminating the outliers before the application of damage detection methods allows the normal procedures to detect damage, to be implemented. A multiple-regression-based damage detection method, which uses the natural frequencies as both the independent and dependent variables, is also developed in this article. A beam structure model and an experimental wooden bridge structure are analysed using the multiple-regression-based damage detection method with and without the application of the method proposed to eliminate the effects of outliers. The results obtained demonstrate that smaller levels of damage can be detected when the effects of outlier measurements are eliminated using the method proposed in this article.


2017 ◽  
Vol 17 (4) ◽  
pp. 850-868 ◽  
Author(s):  
William Soo Lon Wah ◽  
Yung-Tsang Chen ◽  
Gethin Wyn Roberts ◽  
Ahmed Elamin

Analyzing changes in vibration properties (e.g. natural frequencies) of structures as a result of damage has been heavily used by researchers for damage detection of civil structures. These changes, however, are not only caused by damage of the structural components, but they are also affected by the varying environmental conditions the structures are faced with, such as the temperature change, which limits the use of most damage detection methods presented in the literature that did not account for these effects. In this article, a damage detection method capable of distinguishing between the effects of damage and of the changing environmental conditions affecting damage sensitivity features is proposed. This method eliminates the need to form the baseline of the undamaged structure using damage sensitivity features obtained from a wide range of environmental conditions, as conventionally has been done, and utilizes features from two extreme and opposite environmental conditions as baselines. To allow near real-time monitoring, subsequent measurements are added one at a time to the baseline to create new data sets. Principal component analysis is then introduced for processing each data set so that patterns can be extracted and damage can be distinguished from environmental effects. The proposed method is tested using a two-dimensional truss structure and validated using measurements from the Z24 Bridge which was monitored for nearly a year, with damage scenarios applied to it near the end of the monitoring period. The results demonstrate the robustness of the proposed method for damage detection under changing environmental conditions. The method also works despite the nonlinear effects produced by environmental conditions on damage sensitivity features. Moreover, since each measurement is allowed to be analyzed one at a time, near real-time monitoring is possible. Damage progression can also be given from the method which makes it advantageous for damage evolution monitoring.


2008 ◽  
Vol 08 (03) ◽  
pp. 367-387 ◽  
Author(s):  
B. ZHU ◽  
A. Y. T. LEUNG ◽  
C. K. WONG ◽  
W. Z. LU

Presented herein is an experiment that aims to investigate the applicability of the wavelet transform to damage detection of a beam–spring structure. By burning out the string that is connected to the cantilever beam, high-frequency oscillations are excited in the beam–spring system, and there results an abrupt change or impulse in the discrete-wavelet-transformed signal. In this way, the discrete wavelet transform can be used to recognize the damage at the moment it occurs. In the second stage of damage detection, the shift of frequencies and damping ratios is identified by the continuous wavelet transform so as to ensure that the abrupt change or impulse in the signal from the discrete wavelet transform is a result of the damage and not the noise. For the random forced vibration, the random decrement technique is used on the original signal to obtain the free decaying responses, and then the continuous wavelet transform is applied to identify the system parameters. Some developed p version elements are used for the parametric studies on the first stage of health monitoring and to find the damage location. The results show that the two-stage method is successful in damage detection. Since the method is simple and computationally efficient, it is a good candidate for on-line health monitoring and damage detection of structures.


2018 ◽  
Vol 148 ◽  
pp. 14004
Author(s):  
Vikas Arora

Stiffness-based structural health monitoring methods are widely used for detecting the damage in a structure. These stiffness-based structural health monitoring methods uses change in natural frequencies and modeshapes for damage detection. These methods are based on identifying the change in stiffness of the healthy and damage structure to predict the damage in the structure. These stiffness-based methods are not efficient for detecting a small damage in a structure as there is a negligible change in natural frequencies and modeshapes due to a small damage in a structure, however the damping characteristics of the structure are highly sensitive to the damage in a structure. In this paper, new damping-based damage detection procedure has been proposed. In the proposed procedure, the changes in damping matrix of the structure has been used to detect the damage in the structure. The proposed procedure is able (or can) to detect both the location of the damage and the extend of the damage in the structure. The proposed procedure of damping-based damage detection is a 2-step procedure. In the first step, damping matrices of both the healthy and damage structure are identified and in the second step, the identified damping matrices are used for damage detection. Numerical and experimental case studies are presented to demonstrate the effectiveness of the proposed procedure. The results have shown that the proposed damping-based damage detection procedure can be used for detecting damage in a structure with confidence.


2009 ◽  
Vol 79-82 ◽  
pp. 1519-1522
Author(s):  
Wei Bing Hu ◽  
Qiang Deng

In this paper, using piezoelectric patches bounded or embedded in composite material structures as actuators and sensors, the system for exciting the structure and sensing its dynamic response can be established. Extracting damage information from the response and monitoring the perturbations of structural dynamics can be implemented using wavelet analysis. This will conduce to the capture of the accurate time of damage occurrence. The method developed in this paper can help to build the system of online damage detection and health monitoring of composite material structures when they cannot be directly observed or measured.


2018 ◽  
Vol 4 (2) ◽  
pp. 305 ◽  
Author(s):  
D. Hamidian ◽  
J. Salajegheh ◽  
E. Salajegheh

This paper presents a technique for irregular plate and regular dam damage detection based on combination of wavelet with adoptive neuro fuzzy inference system (ANFIS). Many damage detection methods need response of structures (such as the displacements, stresses or mode shapes) before and after damage, but this method only requires response of structures after damage, otherwise many damage detection methods study regular plate but this method also studies irregular plate. First, the structure (irregular plate or regular dam) is modelled by using ANSYS software, the model is analysed and structure’s responses with damage are obtained by finite element approach. Second, the responses at the finite element points with regular distances are obtained by using ANFIS. The damage zone is represented as the elements with reduced elasticity modules. Then these responses of structures are analysed with 2D wavelet transform. It is shown that matrix detail coefficients of 2D wavelet transform can specified the damage zone of plates and regular dams by perturbation in the damaged area.


2012 ◽  
Vol 80 (1) ◽  
Author(s):  
Akash Dixit ◽  
Sathya Hanagud

A new physical parameter is presented and it is applied to damage detection to address the two main challenges in the field of vibration-based structural health monitoring: the sensitivity of detection and the requirement of data of the baseline state. The parameter is also shown to be not affected by noise in the detection ambience. Assuming the damaged structure to be a linear system, its response can be expressed as the summation of the responses due to the undamaged and the damaged part. If the part of the response due to the damage is isolated, it forms what can be regarded as the damage signature. In this paper, the occurrence of damage signature is investigated when the damaged structure is excited at one of its natural frequencies, and it is called partial-mode contribution. The existence of damage signature as partial-mode contribution is first verified using an analytical derivation. Thereupon, its existence is ascertained using finite element models and by doing experiments. The limits of size of the damage that can be determined using the method are also investigated.


2016 ◽  
Vol 16 (04) ◽  
pp. 1640025 ◽  
Author(s):  
Wensong Zhou ◽  
Shunlong Li ◽  
Hui Li

A full-scale bridge benchmark problem was issued by the Center of Structural Monitoring and Control at the Harbin Institute of Technology. The data used in this problem were collected by an in situ structural health monitoring system implemented into a full-scale cable-stayed bridge before and after the bridge was damaged, which is very rare in structural health monitoring field. This benchmark problem will help to verify and/or make comparison of the condition assessment and the damage detection methods, which are usually validated by numerical simulation and/or laboratory testing of small-scale structures with assumed deterioration models and artificial damage. With respect to damage detection of girder, one of the benchmark problems, using the monitored and field testing acceleration data, this paper describes a damage detection method, based on a residual generated from a subspace-based covariance-driven identification method, to detect the damage, and give relative quantitative damage indexes. This method was applied on both two parts of the given benchmark problem, and then detailed discussions and results on this problem are reported in this paper.


Author(s):  
Matthew T. Bement ◽  
Thomas R. Bewley

This paper presents a method for designing excitations for the purpose of enhancing the detectability of damage. The field of structural health monitoring (SHM) seeks to assess the integrity of structures for the primary purpose of moving from time-based maintenance to a more cost effective condition-based maintenance strategy. Consequently, most approaches to SHM are nondestructive in nature. One common nondestructive approach is known as vibration-based SHM. In this approach, a structure is instrumented with an array of sensors at various locations. The structure is then excited and its dynamic response recorded. This response is then interrogated to extract features that are correlated with damage. A survey of the SHM literature [1], [2], reveals that a great deal of attention has been paid to the data interrogation portion of the SHM process, with almost no attention paid to the excitation design. This focus is quite understandable in many applications where only ambient excitation is available, such as most civil engineering applications. However there are many applications where the excitation is selectable (e.g., most wave propogation approaches to SHM), and, indeed, where proper excitation selection is essential. As a simple example, consider a beam or column with a crack that is nominally closed due to a preload. If the provided excitation is not sufficient to open and close the crack, the detectability of the crack in the measured output will be severely limited.


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