Application of Frequency Ratio in Structural Damage Detection

2014 ◽  
Vol 578-579 ◽  
pp. 1153-1156
Author(s):  
Hong Biao Liu ◽  
Qiang Zhang
Keyword(s):  
Damage Detection ◽  
Frequency Ratio ◽  
Structural Damage ◽  
Model Tests ◽  
Steel Frame ◽  
Frame Structure ◽  
Diagnostic Parameter ◽  
Structural Damage Detection ◽  
Cable Structure ◽  
Steel Frame Structure

In order to verify the feasibility and validity of frequency ratio as diagnostic parameter in structural damage detection proposed in the Musical Tone Law Method (MTLM), steel pipes and three-story steel frame structure model tests are carried out. According to the experiment results, it is clear that the diagnostic parameter is effective for symmetrical structure in structural damage detection, such as cable structure, framed structure, and so on. Model tests prove that the frequency ratio is effective in detecting the 3mm width crack damage of steel pipe. In the damage detection test of three-story steel frame structure, the parameter also successfully diagnosed the damage caused by bolts loosening at the node of model.

scholarly journals Structural Damage Identification Based on the Minimum System Realization and Sensitivity Analysis

2014 ◽  
Vol 2014 ◽  
pp. 1-12
Author(s):  
W. R. Li ◽  
Y. F. Du ◽  
S. Y. Tang ◽  
L. J. Zhao
Keyword(s):  
Sensitivity Analysis ◽  
Damage Detection ◽  
Structural Damage ◽  
Damage Identification ◽  
Structural Information ◽  
Structural Response ◽  
Frame Structure ◽  
Structural Damage Detection ◽  
System Realization ◽  
Minimum System

On the basis of the thought that the minimum system realization plays the role as a coagulator of structural information and contains abundant information on the structure, this paper proposes a new method, which combines minimum system realization and sensitivity analysis, for structural damage detection. The structural damage detection procedure consists of three steps: (1) identifying the minimum system realization matrixes A, B, and R using the structural response data; (2) defining the mode vector, which is based on minimum system realization matrix, by introducing the concept of the measurement; (3) identifying the location and severity of the damage step by step by continuously rotating the mode vector. The proposed method was verified through a five-floor frame model. As demonstrated by numerical simulation, the proposed method based on the combination of the minimum realization system and sensitivity analysis is effective for the damage detection of frame structure. This method not only can detect the damage and quantify the damage severity, but also is not sensitive to the noise.

A Structural Damage Alarm Index Based on the Statistical Probability of Abnormal Frequency Offset

2012 ◽  
Vol 226-228 ◽  
pp. 1214-1217
Author(s):  
Yan Sheng Song ◽  
Zong Guang Sun ◽  
Li Ye Sun
Keyword(s):  
Frequency Domain ◽  
Structural Damage ◽  
Frequency Offset ◽  
Steel Frame ◽  
Frame Structure ◽  
Test Cases ◽  
Statistical Probability ◽  
Damage Alarming ◽  
Steel Frame Structure

Based on the statistical probability of abnormal frequency offset, this paper puts forward a new structural damage alarm index. Demonstrating the feasibility of corresponding structural damage alarming method, this article introduces the index to analize a steel frame structure in frequency domain. The results show the abnormal index defined in sense of statistics indicates the abnormity of corresponding test cases clearly.

scholarly journals Modal Strain Energy-Based Structural Damage Detection Using Convolutional Neural Networks

2019 ◽  
Vol 9 (16) ◽  
pp. 3376 ◽  
Author(s):  
Shuai Teng ◽  
Gongfa Chen ◽  
Gen Liu ◽  
Jianbin Lv ◽  
Fangsen Cui
Keyword(s):  
Neural Network ◽  
Neural Networks ◽  
Damage Detection ◽  
Structural Damage ◽  
Strain Energy ◽  
Frame Structure ◽  
Modal Parameters ◽  
Structural Damage Detection ◽  
Simulation Data ◽  
Modal Strain Energy

In this paper, a convolutional neural network (CNN) was used to extract the damage features of a steel frame structure. As structural damage could induce changes of the modal parameters of the structure, the convolution operation was used to extract the features of modal parameters, and a classification algorithm was used to judge the damage state of the structure. The finite element method was applied to analyze the free vibration of the steel frame and obtain the first-order modal strain energy for various damage scenarios, which was used as the CNN training sample. Then vibration experiments were carried out, and modal parameters were obtained from the modal analysis of the vibration signals. The experimental data were inputted into the CNN to verify its damage detection capability. The result showed that the CNN was effective in detecting the intact structure, single damage, and multi damages with an accuracy of 100%. For comparison, the same samples were also applied to the traditional back propagation (BP) neural network, which failed to detect the intact structure and multiple-damage cases. It was found that: (1) The proposed CNN could be trained from finite element simulation data and used in real frame structure damage detection, and it performed better in structural damage detection than BP neural networks; (2) the measured data of a real structure could be supplemented by numerical simulation data, and satisfactory results have been demonstrated.

A DE-Based Algorithm for Structural Damage Detection

2014 ◽  
Vol 919-921 ◽  
pp. 303-307 ◽  
Author(s):  
Yong Ming Fu ◽  
Ling Yu
Keyword(s):  
Damage Detection ◽  
Objective Function ◽  
Structural Damage ◽  
Model Updating ◽  
Heuristic Method ◽  
Identification Accuracy ◽  
Frame Structure ◽  
Mode Shapes ◽  
Fe Model ◽  
Structural Damage Detection

The development of a methodology for the accurate and reliable assessment of structural damages, as one crucial step in the structural health monitoring (SHM) field, is very important to ensure the safety, integrity and stability of structures. An improved adaptive differential evolution (IADE) algorithm is proposed for structural damage detection (SDD) based on DE algorithm and FE model-updating techniques. An objective function is defined as minimizing the discrepancies between the experimental and analytical modal parameters (namely, natural frequencies and mode shapes). It is set as a nonlinear least-squares problem with bound constraints. Unlike the commonly used line-search methods, the IADE approach, a heuristic method for the direct search of the optimal point of the given objective function, is employed to make the optimization process more robust and reliable. Some numerical simulations for single and multiple damage cases of a 25-bar space truss frame structure have been conducted for evaluation on the reliability and robustness of the proposed method. The illustrated results show that the IADE algorithm is very effective for SDD. It can not only locate the structural damages but also quantify the severity of damages. Regardless of slight damage or multiple damages, the identification accuracy is very high and noise immunity is better, which shows that the IADE algorithm is feasible and effective for SDD.

Experimental Research and Finite Element Analysis on Behavior of Steel Frame with Semi-Rigid Connections

2010 ◽  
Vol 168-170 ◽  
pp. 553-558
Author(s):  
Feng Xia Li ◽  
Bu Xin
Keyword(s):  
Architectural Design ◽  
Plastic Hinge ◽  
Steel Frames ◽  
Seismic Energy ◽  
Internal Force ◽  
Steel Frame ◽  
Frame Structure ◽  
Element Analysis ◽  
Rigid Deformation ◽  
Steel Frame Structure

Most steel beam-column connections actually show semi-rigid deformation behavior that can contribute substantially to overall displacements of the structure and to the distribution of member forces. Steel frame structure with semi-rigid connections are becoming more and more popular due to their many advantages such as the better satisfaction with the flexible architectural design, low inclusive cost and environmental protect as well. So it is very necessary that studying the behavior of those steel frame under cyclic reversal loading. On the basics of connections experiments the experiment research on the lateral resistance system of steel frame structure has been completed. Two one-second scale, one-bay, two-story steel frames with semi-rigid connections under cyclic reversal loading. The seismic behavior of the steel frames with semi-rigid connections, including the failure pattern, occurrence order of plastic hinge, hysteretic property and energy dissipation, etc, was investigated in this paper. Some conclusions were obtained that by employing top-mounted and two web angles connections, the higher distortion occurred in the frames, and the internal force distributing of beams and columns was changed, and the ductility and the absorbs seismic energy capability of steel frames can be improved effectively.

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