scholarly journals An Exact Approach for Structural Damage Assessment

2013 ◽  
Vol 2013 ◽  
pp. 1-7 ◽  
Author(s):  
Q. W. Yang
Keyword(s):  
Damage Assessment ◽  
Structural Damage ◽  
Damage Identification ◽  
Structural Stiffness ◽  
Static Displacement ◽  
Exact Approach ◽  
Flexibility Matrix ◽  
Before And After ◽  
The Matrix ◽  
Exact Relationship

An exact approach is proposed for damage identification in statically determinate structures. The contribution of this study is twofold. Firstly, a rigorous disassembly formulation of structural global flexibility matrix is presented based on the matrix spectral decomposition, which can provide an exact relationship between the modifications of structural stiffness parameters and the associated flexibility matrix. Secondly, the static minimum-rank flexibility change is derived to obtain the exact flexibility change before and after damage. The proposed method is economical in computation and is simple to implement. For the statically determinate structures, the proposed method can exactly compute the elemental perturbed stiffness parameter only using a few of incomplete static displacement data. The efficiency of the proposed method is demonstrated by two statically determinate structures.

Structural Damage Assessment Using Output-Only Measurement: Localization and Quantification

2013 ◽  
Author(s):  
Chin-Hsiung Loh ◽  
Min-Hsuan Tseng ◽  
Shu-Hsien Chao
Keyword(s):  
Damage Detection ◽  
Damage Assessment ◽  
Structural Damage ◽  
Damage Identification ◽  
Model Updating ◽  
Null Space ◽  
Singular Spectrum Analysis ◽  
Damage Index ◽  
Computation Efficiency ◽  
Output Only

One of the important issues to conduct the damage detection of a structure using vibration-based damage detection (VBDD) is not only to detect the damage but also to locate and quantify the damage. In this paper a systematic way of damage assessment, including identification of damage location and damage quantification, is proposed by using output-only measurement. Four level of damage identification algorithms are proposed. First, to identify the damage occurrence, null-space and subspace damage index are used. The eigenvalue difference ratio is also discussed for detecting the damage. Second, to locate the damage, the change of mode shape slope ratio and the prediction error from response using singular spectrum analysis are used. Finally, to quantify the damage the RSSI-COV algorithm is used to identify the change of dynamic characteristics together with the model updating technique, the loss of stiffness can be identified. Experimental data collected from the bridge foundation scouring in hydraulic lab was used to demonstrate the applicability of the proposed methods. The computation efficiency of each method is also discussed so as to accommodate the online damage detection.

Structural Multi-Damage Identification Based on Modal Strain Energy Equivalence Index Method

2014 ◽  
Vol 14 (07) ◽  
pp. 1450028 ◽  
Author(s):  
Hui Yong Guo ◽  
Zheng Liang Li
Keyword(s):  
Energy Dissipation ◽  
Structural Damage ◽  
Strain Energy ◽  
Damage Identification ◽  
Index Method ◽  
Modal Strain Energy ◽  
Energy Equivalence ◽  
Before And After ◽  
Accurate Expression ◽  
Equivalence Theory

In order to solve structural multi-damage identification problems, a damage detection method based on modal strain energy equivalence index (MSEEI) is presented. First, an accurate expression of modal strain energy (MSE) before and after damage occurs is given. Then, according to the energy equivalence theory that the change in MSE caused by the damage should be equivalent to the energy dissipation caused by the same damage, an energy equivalence equation is deduced. Finally, four roots of the energy equivalence equation are found and a MSEEI is obtained from the four roots. Simulation results demonstrate that the proposed MSEEI method can identify structural damage locations and extent with good accuracy. Identification precision of the proposed method is clearly better than that of the modal strain energy dissipation ratio index (MSEDRI) method.

Performance Comparison among Vibration Based Indicators in Damage Identification of Structures

2014 ◽  
Vol 592-594 ◽  
pp. 2081-2085 ◽  
Author(s):  
Bharadwaj Nanda ◽  
Aditi Majumdar ◽  
Damodar Maity ◽  
Dipak K. Maiti
Keyword(s):  
Inverse Problem ◽  
Damage Assessment ◽  
Natural Frequencies ◽  
Damage Identification ◽  
Performance Comparison ◽  
Vibration Data ◽  
Flexibility Matrix ◽  
Damage Indicator ◽  
Damage Indicators ◽  
Shape Data

A simple and robust methodology is presented to identify damages in a structure using changes in vibration data. A comparison is made among damage indicators such as natural frequencies, mode shape data, curvature damage factors and flexibility matrices to study their efficacy in damage assessment. Continuous ant colony optimization (ACOR) technique is used to solve the inverse problem related to damage identification. The outcome of the simulated results demonstrates that the flexibility matrix as a damage indicator provides better damage identification.

A Coupled Sensitivity Method for Structural Damage Detection

2013 ◽  
Vol 681 ◽  
pp. 271-275
Author(s):  
Jing Li ◽  
Pei Jun Wei
Keyword(s):  
Damage Detection ◽  
Mode Shape ◽  
Structural Damage ◽  
Damage Identification ◽  
Perturbation Approach ◽  
Structural Damage Detection ◽  
Beam Structure ◽  
Flexibility Matrix ◽  
Eigenvalue Sensitivity ◽  
Sensitivity Method

Based on the vibration information, a mixed sensitivity method is presented to identify structural damage by combining the eigenvalue sensitivity with the generalized flexibility sensitivity. The sensitivity of structural generalized flexibility matrix is firstly derived by using the first frequency and the corresponding mode shape only and then the eigenvalue sensitivity together with the generalized flexibility sensitivity are combined to calculate the elemental damage parameters. The presented mixed perturbation approach is demonstrated by a numerical example concerning a simple supported beam structure. It has been shown that the proposed procedure is simple to implement and may be useful for structural damage identification.

Damage Identification Research of Cantilever Truss Based on the Principle of Strain Mode

2012 ◽  
Vol 226-228 ◽  
pp. 1432-1435
Author(s):  
Jun Hai Zhang ◽  
Nai Juan Du ◽  
Yue Guo Shen
Keyword(s):  
Structural Damage ◽  
Damage Identification ◽  
Damage Location ◽  
Strain Change ◽  
Before And After ◽  
Force Element ◽  
Damage Extent ◽  
Simulation Results ◽  
Modal Change ◽  
Identification Research

This paper presents a method converting the modal distance of the node into elemental strain based on the special characteristic of two-force element .The strain change before and after damage is applied to the damage identification. The change rule of the relative strain for the same location of the truss occur the various damage extent and the various location of the truss occur the same damage extent, respectively, is obtained according to the strain modal simulation using APDL language. The simulation results show that the strain modal change ratio is sensitive to the cantilever truss damage detection. The damage location and damage extent will be identified. It is an effective nodestructive test way to identify the cantilever truss structural damage.

Detection Indicator of Structural Nondestructive Damage Based on Flexibility Curvature Difference Rate

2015 ◽  
Vol 744-746 ◽  
pp. 46-52 ◽  
Author(s):  
Chang Sheng Xiang ◽  
Yu Zhou ◽  
Sheng Kui Di ◽  
Li Xian Wang ◽  
Jian Shu Cheng
Keyword(s):  
Structural Damage ◽  
Damage Identification ◽  
Continuous Beam ◽  
Change Rate ◽  
Modal Frequency ◽  
Numerical Examples ◽  
Modal Flexibility ◽  
Structural Damage Identification ◽  
Before And After ◽  
Better Than

Applied to the structural damage identification, Modal Flexibility is better than the Modal Frequency and Modal Displacement, the indicators of Flexibility Curvature are effective and sensitive. This paper proposes a new detection indicator which is Flexibility Curvature Difference Rate (FCDR) that by using the change rate of diagonal elements of flexibility curvature difference when before and after damage. The numerical examples of a simple beam, a continuous beam and a frame with the damage conditions of the different positions and different degrees are used to verify FCDR. The result shows that FCDR can well identify the numerical examples damages, and sensitively diagnose the damage near the supports of beam and the nodes of framework.

Crack Damage Identification of Reinforced Concrete Simply Supported Beam Based on BP Neural Network

2012 ◽  
Vol 468-471 ◽  
pp. 738-741
Author(s):  
Xiao Ming Yang ◽  
Fu Li
Keyword(s):  
Neural Network ◽  
Reinforced Concrete ◽  
Bp Neural Network ◽  
Structural Damage ◽  
Damage Identification ◽  
Simply Supported Beam ◽  
Simply Supported ◽  
Before And After ◽  
Trained Neural Network ◽  
Application Prospects

Considering the good forecasting capability of BP neural network, a new crack damage identification method for reinforced concrete simply supported beam is proposed in this paper. After simulating the crack damage of a reinforced concrete simply supported beam, the natural frequency of the beam is chosen as the input parameters of the BP neural network. The data before and after damage of the simply supported beam are put into the trained neural network to judge the structural damage. The results demonstrate that the approach has a better application prospects in structural damage identification.

Structural Damage Identification Based on Acceleration Response Vibration Transmissibility

2012 ◽  
Vol 236-237 ◽  
pp. 640-645
Author(s):  
Yan Song Diao ◽  
Qi Liang Zhang ◽  
Dong Mei Meng
Keyword(s):  
Neural Network ◽  
Bp Neural Network ◽  
Structural Damage ◽  
Damage Identification ◽  
Back Propagation ◽  
Principal Component ◽  
Network Stability ◽  
Before And After ◽  
Vibration Transmissibility ◽  
Damage Characteristic

When the frequency response function (FRF) and Back-propagation (BP) neural network are used to identify the structural damage, problems such as the excitation information can not be got easily, the network is difficult to converge and the network stability is poor as the oversize input vectors. So, in this paper, two node acceleration responses of the structure under the white noise are directly used to construct the vibration transmissibility, and principal component analysis (PCA) is pursued to the amplitude of the vibration transmissibility for dimensionality reduction. The combinations of principal component variation before and after damage are used as the damage characteristic vectors, and which are input into the BP neural network for damage identification, the influences of the different degrees of noise during the damage identification are considered simultaneously. The results of numerical simulation and model experiment of offshore platform show that the method can identify the different degrees of structural damage.

Structural Damage Detection Using Static Test Data

2014 ◽  
Vol 501-504 ◽  
pp. 852-855
Author(s):  
Cui Hong Li ◽  
Qiu Wei Yang
Keyword(s):  
Damage Detection ◽  
Measurement Errors ◽  
Structural Damage ◽  
Damage Identification ◽  
Singular Values ◽  
Beam Structure ◽  
Static Displacement ◽  
Simply Supported Beam ◽  
Static Test ◽  
Simply Supported

This paper presents a static-based method for damage identification in the simply supported beam structure using the incomplete measured static displacement parameters. The presented method makes use of the singular value decomposition of structural static displacement change, which is obtained by the static test of structure. It has been shown that structural damage can be detected by the number of the non-zero singular values of the static displacement change. The significant advantage of the proposed method is that it is economical in computation and is simple to implement. A simply supported beam structure is analyzed as a numerical example to verify the present method. Results show that the proposed method performs well even if the measurement errors inevitably make the damage assessment more difficult. It has been shown that the presented static-based methodology may be a promising tool to be used by research groups working on experimental damage detection.

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