Study on Parameters for Identification of Wavelet Packet Energy Spectrum for Structural Damage Alarming

2010 ◽  
Vol 163-167 ◽  
pp. 2693-2698 ◽  
Author(s):  
Peng Sun ◽  
Ai Qun Li ◽  
You Liang Ding ◽  
Yang Deng
Keyword(s):  
Experimental Data ◽  
Energy Spectrum ◽  
Structural Damage ◽  
Online Monitoring ◽  
Wavelet Packet ◽  
Suspension Bridge ◽  
Frame Structure ◽  
Daubechies Wavelet ◽  
Damage Alarming ◽  
Steel Frame Structure

The damage alarming analysis based on wavelet packet energy spectrum is performed with regard to the experimental data of Benchmark steel frame structure and online monitoring data of Runyang Suspension Bridge, on the basis of which the damage alarming effects using various wavelet functions are investigated in detail. Results reveal that the Daubechies wavelet functions and Coiflets wavelet functions are applicable to structural damage alarming.

Application of Wavelet Packet Analysis in Damage Alarming for Steel-Frame Structure

2012 ◽  
Vol 204-208 ◽  
pp. 2883-2886
Author(s):  
Ning Zhang ◽  
Zhuo Bin Wei ◽  
Zi Wang ◽  
Sen Wu
Keyword(s):  
Energy Spectrum ◽  
Response Function ◽  
Damage Identification ◽  
Wavelet Packet ◽  
Impulse Response Function ◽  
Steel Frame ◽  
Frame Structure ◽  
Wavelet Packet Analysis ◽  
Damage Alarming ◽  
Steel Frame Structure

The method of damage alarming based on wavelet packet analysis which applied on steel-frame structure is researched. Firstly, the method of damage identification based on wavelet packet analysis is introduced. Secondly, in view of the dependability of the method on the excitation, virtual impulse response function is brought in to enhance robustness of the method to the excitation. Lastly, through the steel-frame structure experimentation of damage alarming, the two damage modes of the structure are identified by the method based on wavelet packet energy spectrum. The experimentation results show that the effect of damage alarming to the steel-frame structure is completely obvious by wavelet packet analysis. Accordingly, this method has much application value for engineering.

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.

Damage alarming analysis for ancient wood structures based on wavelet packet energy spectrum

2014 ◽  
Vol 10 (4) ◽  
pp. 593-610 ◽  
Author(s):  
Xin Wang ◽  
Wei Bing Hu ◽  
Zhao Bo Meng
Keyword(s):  
Energy Spectrum ◽  
White Noise ◽  
Wavelet Packet ◽  
Energy Ratio ◽  
Noise Robustness ◽  
Wood Structures ◽  
Content Type ◽  
Bell Tower ◽  
Ancient Wood ◽  
Damage Alarming

Purpose – The purpose of this paper is to establish the damage alarming indexes for ancient wood structures and study the damage sensitivity and noise robustness of these indexes under random excitation. Design/methodology/approach – Xi’an Bell Tower is taken as a case in this paper to simulate the damage of ancient wood structures through finite element (FE) simulation and determine the satisfactory damage alarming indexes with wavelet packet energy spectrum. Findings – The results of this paper show that: 1) the damage alarming indexes can effectively identify the damage of ancient wood structures, each index with a different damage sensitivity; 2) the energy ratio deviation is greater than the energy ratio variance and is close to the maximum variation of energy ratio; 3) the energy ratio deviation has a better alarming effect than the energy ratio variance during the initial period of the damage. With the accumulation of the damage, the energy ratio variance outperforms the energy ratio deviation; 4) the sensitivity of the energy ratio deviation and variance varies from positions, changing from the highest to lowest at the mortise-and-tenon joints, the beam mid-span and the plinth; 5) if signal to noise ratio (SNR) is 40db or larger, the indexes can accurately identify the damage of ancient wood structures. As SNR increases, the indexes will have an increasingly higher sensitivity and certain ability to resist noise. Research limitations/implications – The FE model is simpiy, it does not completely reflect Xi’an Bell Tower. Practical implications – It will provide a theoretical basis for the damage alarming of Xi’an Bell Tower. Social implications – It makes structural health monitoring through structural vibration response under ambient excitation a new research field in damage detection as well as a positive way of ancient architecture protection. Originality/value – This paper studies the damage alarming effect on ancient wood structures from different wavelet functions and wavelet packet decomposition levels. To study the effect under white noise environment, this paper adds Gaussian white noise with a SNR of 10, 20, 30, 40 and 50 db to the acceleration response signal of intact structure and damaged structure.

Variability of WPT-Based Dynamic Identification of a Suspension Bridge under Changing Temperature, Wind and Traffic Conditions

2011 ◽  
Vol 291-294 ◽  
pp. 1644-1650
Author(s):  
Ri Chang Lin ◽  
You Liang Ding ◽  
Ai Qun Li ◽  
Yang Deng
Keyword(s):  
Structural Damage ◽  
Environmental Variability ◽  
Wavelet Packet ◽  
Suspension Bridge ◽  
Dynamic Responses ◽  
Effect Of Temperature ◽  
Identification Algorithm ◽  
Dynamic Identification ◽  
Correlation Models ◽  
Seasonal Correlation

This paper addresses the quantification of environmental variability of wavelet packet energy spectrum (WPES) extracted from the ambient dynamic responses of a suspension bridge using wavelet packet transform (WPT). The daily averaged WPES using multi-sample averaging technique are first obtained to eliminate the inherent randomness arising from the identification algorithm. Then the effect of temperature on the measured WPES is quantified using the seasonal correlation models. The traffic-induced and wind-induced variability are further quantitatively evaluated by establishing the traffic-WPES and wind-WPES correlation models. The analysis results reveal that temperature and inherent randomness are the critical sources causing WPES variability, and the WPES variability caused by wind speed and traffic loadings is negligible compared with temperature and inherent randomness. Considering seasonal correlation models of temperature-WPES can effectively eliminate the temperature effect and inherent randomness, it is suitable for structural damage warning of long-span bridges if future seasonal correlation models deviate from these normal models.

Study on Performance Evaluation of MEMS Sensors and Data Integration Methods for Expected Use to Determine Damage Degrees of Existing Structures

2017 ◽  
Vol 12 (5) ◽  
pp. 858-867 ◽  
Author(s):  
Tomohiro Sasaki ◽  
◽  
Koichi Kajiwara ◽  
Takuzo Yamashita ◽  
Takuya Toyoshi
Keyword(s):  
Performance Evaluation ◽  
Structural Damage ◽  
Large Scale ◽  
Earth Science ◽  
Frame Structure ◽  
Micro Electro Mechanical Systems ◽  
Strong Earthquakes ◽  
Existing Structures ◽  
Earthquake Simulator ◽  
Steel Frame Structure

The shake table test of small-scaled steel frame structure was conducted using large-scale earthquake simulator at the National Research Institute for Earth Science and Disaster Resilience (NIED) in Tsukuba, Ibaragi. This paper presents the performance evaluation of Micro Electro Mechanical Systems (MEMS) type accelerometers, which are recently being used in various fields, comparing with the conventional servo type accelerometers. In addition, this paper discussed the integration method of the measured acceleration into displacements, which is suitable for structural damage evaluation due to strong earthquakes.

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.

Optimal Sensor Placement Algorithm for Structural Damage Identification

2020 ◽  
Vol 14 (1) ◽  
pp. 69-81
Author(s):  
C.H. Li ◽  
Q.W. Yang
Keyword(s):  
Structural Damage ◽  
Damage Identification ◽  
Sensor Placement ◽  
Optimization Procedure ◽  
Frame Structure ◽  
Truss Structures ◽  
Optimal Sensor Placement ◽  
Structural Damage Identification ◽  
Placement Algorithm ◽  
Sensor Locations

Background: Structural damage identification is a very important subject in the field of civil, mechanical and aerospace engineering according to recent patents. Optimal sensor placement is one of the key problems to be solved in structural damage identification. Methods: This paper presents a simple and convenient algorithm for optimizing sensor locations for structural damage identification. Unlike other algorithms found in the published papers, the optimization procedure of sensor placement is divided into two stages. The first stage is to determine the key parts in the whole structure by their contribution to the global flexibility perturbation. The second stage is to place sensors on the nodes associated with those key parts for monitoring possible damage more efficiently. With the sensor locations determined by the proposed optimization process, structural damage can be readily identified by using the incomplete modes yielded from these optimized sensor measurements. In addition, an Improved Ridge Estimate (IRE) technique is proposed in this study to effectively resist the data errors due to modal truncation and measurement noise. Two truss structures and a frame structure are used as examples to demonstrate the feasibility and efficiency of the presented algorithm. Results: From the numerical results, structural damages can be successfully detected by the proposed method using the partial modes yielded by the optimal measurement with 5% noise level. Conclusion: It has been shown that the proposed method is simple to implement and effective for structural damage identification.

Analysis on the Seismic Behavior of Extended End-Plate Connections of Steel Frame Structure

2012 ◽  
Vol 193-194 ◽  
pp. 1405-1413 ◽  
Author(s):  
Zhu Ling Yan ◽  
Bao Long Cui ◽  
Ke Zhang
Keyword(s):  
Finite Element ◽  
Cyclic Loading ◽  
Seismic Performance ◽  
Seismic Behavior ◽  
Frame Structure ◽  
End Plate ◽  
Rigid Connection ◽  
Extended End Plate ◽  
Plate Connections ◽  
Steel Frame Structure

This paper conducts analysis on beam-column extended end-plate semi-rigid connection joint concerning monotonic loading and cyclic loading of finite element through ANSYS program, mainly discussed the influence of parameters such as the form of end plate stiffening rib on anti-seismic performance of joint.

scholarly journals Analysis of the robustness of a steel frame structure with composite floors subject to multiple fire scenarios

2021 ◽  
pp. 136943322199249
Author(s):  
Riza Suwondo ◽  
Lee Cunningham ◽  
Martin Gillie ◽  
Colin Bailey
Keyword(s):  
Progressive Collapse ◽  
Three Dimensional ◽  
Steel Structure ◽  
Frame Structure ◽  
Worst Case ◽  
Collapse Resistance ◽  
Fire Scenarios ◽  
Element Approach ◽  
The One ◽  
Steel Frame Structure

This study presents robustness analyses of a three-dimensional multi-storey composite steel structure under the action of multiple fire scenarios. The main objective of the work is to improve current understanding of the collapse resistance of this type of building under different fire situations. A finite element approach was adopted with the model being firstly validated against previous studies available in the literature. The modelling approach was then used to investigate the collapse resistance of the structure for the various fire scenarios examined. Different sizes of fire compartment are considered in this study, starting from one bay, three bays and lastly the whole ground floor as the fire compartment. The investigation allows a fundamental understanding of load redistribution paths and member interactions when local failure occurs. It is concluded that the robustness of the focussed building in a fire is considerably affected by the size of fire compartments as well as fire location. The subject building can resist progressive collapse when the fire occurs only in the one-bay compartment. On the other hand, total collapse occurs when fire is located in the edge three-bay case. This shows that more than one fire scenario needs to be taken into consideration to ensure that a structure of this type can survive from collapse in the worst-case situation.

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