scholarly journals Model-Free Method for Damage Localization of Grid Structure

2019 ◽  
Vol 9 (16) ◽  
pp. 3252 ◽  
Author(s):  
Qiuwei Yang ◽  
Chaojun Wang ◽  
Na Li ◽  
Shuai Luo ◽  
Wei Wang
Keyword(s):  
Structural Damage ◽  
Damage Identification ◽  
Dynamic Test ◽  
Length Change ◽  
Rate Of Change ◽  
Damage Localization ◽  
Grid Structure ◽  
Model Free ◽  
Space Grid ◽  
Before And After

A model-free damage identification method for grid structures based on displacement difference is proposed. The inherent relationship between the displacement difference and the position of structural damage was deduced in detail by the Sherman–Morrison–Woodbury formula, and the basic principle of damage localization of the grid structure was obtained. That is, except for the tensile and compressive deformations of the damaged elements, the deformations of other elements were small, and only rigid body displacements occurred before and after the structural damage. According to this rule, a method for identifying the position of the damage was proposed for the space grid structure by using the rate of change of length for each element. Taking a space grid structure with a large number of elements as an example, the elastic modulus reduction method was used to simulate the damage to the elements, and the static and dynamic test parameters were simulated respectively to obtain the difference in displacement before and after the structural damage. The rate of change of length of each element was calculated based on the obtained displacement difference, and data noise was added to the simulation. The results indicated that the element with the larger length change rate in the structure was the most likely to be damaged, and the damaged element can be accurately evaluated even in the presence of noise in data.

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.

Research on Structural Damage Localization by Improved Curvature Method

2011 ◽  
Vol 255-260 ◽  
pp. 439-443
Author(s):  
Jun Chang ◽  
Yu Meng Wu
Keyword(s):  
Structural Damage ◽  
Damage Identification ◽  
Health Condition ◽  
Steel Beam ◽  
Damage Localization ◽  
Local Damage ◽  
Improved Method ◽  
Damage Location ◽  
Simple Support ◽  
Ideal Method

Damage identification is one of the main contents of structural health condition assessment. Curvature mode is an ideal method to identify structural damage location, with advantages of easy to be operated and sensitive to local damage, while the frequency is easy to test with high precision. An improved structural damage identification method is presented, which combines curvature and frequency. Finally, the improved method presented herein is verified by a simple support steel beam tested in laboratory. The results show that the improved method can effectively identify structural damage location.

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.

Experimental investigation of damage identification in beam structures based on the strain statistical moment

2016 ◽  
Vol 20 (5) ◽  
pp. 747-758 ◽  
Author(s):  
Dansheng Wang ◽  
Zhen Chen ◽  
Wei Xiang ◽  
Hongping Zhu
Keyword(s):  
Damage Detection ◽  
Structural Damage ◽  
Damage Identification ◽  
Gaussian White Noise ◽  
Statistical Moment ◽  
Least Square ◽  
Detection Technique ◽  
Before And After ◽  
Beam Type ◽  
Strain Responses

A new two-step damage detection technique based on the fourth strain statistical moment was recently proposed by the authors, and its sensitivity to local structural damage has been numerically demonstrated for beam-type structures. In this article, the proposed method is extended to an experimental beam to assess its feasibility and practicality. A simply supported steel beam was manufactured and subjected to Gaussian white-noise excitation before and after damage. The strain responses of each measurement point were recorded based on which fourth strain statistical moments were calculated. The proposed two-step technique was implemented to locate the damaged elements of the experimental beam, for which the damage sizes were identified based on the least-square updating algorithm. The experimental results show that the proposed fourth strain statistical moment index and the two-step damage detection technique are effective and feasible for beam-type structures.

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