Structural Seismic Damage Detection Using Fractal Dimension of Time-Frequency Feature

2013 ◽  
Vol 558 ◽  
pp. 554-560 ◽  
Author(s):  
Dong Wang Tao ◽  
Dong Yu Zhang ◽  
Hui Li
Keyword(s):  
Fractal Dimension ◽  
Structural Damage ◽  
Nonlinear Behavior ◽  
Fractal Dimensions ◽  
Seismic Damage ◽  
Shaking Table ◽  
Dynamic Responses ◽  
Structural Dynamic ◽  
Time Frequency ◽  
Frequency Feature

In this paper, a data-driven approach to localizing structural damage subjected to ground motion is proposed by using the fractal dimension of the time-frequency features of structural dynamic responses. The time-frequency feature is defined as the real part of wavelet coefficient and the fractal dimension adopts the box-counting method. It is shown that the proposed fractal dimensions at each story of linear system are identical, while the fractal dimension at the stories with nonlinearity is different from those at the stories with linearity. Therefore, the nonlinear behavior of structural damage caused by strong ground motions can be detected and localized through comparing the fractal dimensions of structural responses at different stories. Shaking table test on a uniform 16-story 3-bay steel frame with added friction dampers modelling interstory nonlinear behavior was conducted. The experiment results validate the effectiveness of the proposed method to localize single and multi seismic damage of structures.

DAMAGE DETECTION OF RC SLABS USING NONLINEAR VIBRATION FEATURES

2009 ◽  
Vol 09 (04) ◽  
pp. 687-709 ◽  
Author(s):  
XINQUN ZHU ◽  
HONG HAO
Keyword(s):  
Reinforced Concrete ◽  
Nonlinear Vibration ◽  
Structural Damage ◽  
Concrete Structures ◽  
Dynamic Responses ◽  
Mode Shapes ◽  
Reinforced Concrete Structures ◽  
Vibration Frequencies ◽  
Skeleton Curve ◽  
Time Frequency

Studied herein are the signatures of nonlinear vibration characteristics of damaged reinforced concrete structures using the wavelet transform (WT). A two-span RC slab built in 2003 was tested to failure in the laboratory. Vibration measurements were carried out at various stages of structural damage. The vibration frequencies, mode shapes, and damping ratios at each loading stage were extracted and analyzed. It is found that the vibration frequencies are not sensitive to small damages, but are good indicators when damage is severe. The dynamic responses are also analyzed in the time–frequency domain by WT and the skeleton curve is constructed to describe the nonlinear characteristics in the reinforced concrete structures. The results show that the skeleton curves are good indicators of damage in the reinforced concrete structures because they are more sensitive to small damages than vibration frequencies.

Seismic Structural Damage Detection Based on Time Frequency Response Function

2011 ◽  
Vol 219-220 ◽  
pp. 243-249
Author(s):  
Bai Sheng Wang ◽  
Lie Sun ◽  
Zhi Wei Chang
Keyword(s):  
Frequency Response ◽  
Response Function ◽  
Structural Damage ◽  
Frequency Response Function ◽  
Dynamic Properties ◽  
Response Analysis ◽  
Central Frequency ◽  
Structural Dynamic ◽  
Time Frequency ◽  
Marginal Spectrum

Considering that Hilbert-Huang Transformation (HHT) can be used to analyze instantaneous frequency in structural dynamic analysis, this paper proposes the concept of HHT marginal spectrum based time frequency response function. It also defines “central frequency”, which is used to reflect the change of structural dynamic properties during earthquakes, and discloses time-varying development of seismic structural damage. Using a three-story shear frame model, which is subjected to the El Centro seismic wave, the HHT time frequency response analysis of its acceleration response has been made, results show that the adoption of central frequency can successfully indicate the damage inception instant and its development.

Structural damage detection using transmissibility together with hierarchical clustering analysis and similarity measure

2016 ◽  
Vol 16 (6) ◽  
pp. 711-731 ◽  
Author(s):  
Yun-Lai Zhou ◽  
Nuno M.M. Maia ◽  
Rui P.C. Sampaio ◽  
Magd Abdel Wahab
Keyword(s):  
Damage Detection ◽  
Hierarchical Clustering ◽  
Similarity Measure ◽  
Clustering Analysis ◽  
Structural Damage ◽  
Real Life ◽  
Dynamic Responses ◽  
Hierarchical Clustering Analysis ◽  
Structural Damage Detection ◽  
Structural Dynamic

Maintenance and repairing in actual engineering for long-term used structures, such as pipelines and bridges, make structural damage detection indispensable, as an unanticipated damage may give rise to a disaster, leading to huge economic loss. A new approach for detecting structural damage using transmissibility together with hierarchical clustering and similarity analysis is proposed in this study. Transmissibility is derived from the structural dynamic responses characterizing the structural state. First, for damage detection analysis, hierarchical clustering analysis is adopted to discriminate the damaged scenarios from an unsupervised perspective, taking transmissibility as feature for discriminating damaged patterns from undamaged ones. This is unlike directly predicting the structural damage from the indicators manifestation, as sometimes this can be vague due to the small difference between damaged scenarios and the intact baseline. For comparison reasons, cosine similarity measure and distance measure are also adopted to draw out sensitive indicators, and correspondingly, these indicators will manifest in recognizing damaged patterns from the intact baseline. Finally, for verification purposes, simulated results on a 10-floor structure and experimental tests on a free-free beam are undertaken to check the suitability of the raised approach. The results of both studies are indicative of a good performance in detecting damage that might suggest potential application in actual engineering real life.

Vibration-Based Damage Detection of Composite Wingbox Structures Using Improved Hilbert-Huang Transform

2006 ◽  
Vol 324-325 ◽  
pp. 539-542 ◽  
Author(s):  
Huan Guo Chen ◽  
Yun Ju Yan ◽  
Jie Sheng Jiang
Keyword(s):  
Structural Damage ◽  
Wavelet Packet ◽  
Dynamic Responses ◽  
Structural Dynamic ◽  
Hilbert Huang Transform ◽  
Mode Function ◽  
Index Vector ◽  
Selection For ◽  
Instantaneous Energy ◽  
Composite Wing

A vibration-based approach to detect crack damage in a cantilever composite wingbox is studied using the improved Hilbert-Huang Transform (HHT). The improved HHT is composed of HHT with Wavelet Packet Transform (WPT) and a simple but effective method for intrinsic mode function (IMF) selection. For different damage status, in order to obtain structural dynamic responses, which imply plentiful damage information, the composite wing boxes were excited by a contrived square wave signal. Then, the dynamic responses of intact wingbox and damaged wingbox are disposed using improved HHT. Finally, a feature index vector of structural damage, i.e. the ariation quantity of instantaneous energy, is constructed. The obtained results show that the proposed damage feature index vector is more sensitive to small damage than those in traditional signal processing.

Investigation the Behavior of a Four-Storey Steel Frame Using Viscous Damper

2015 ◽  
Vol 735 ◽  
pp. 149-153 ◽  
Author(s):  
Meisam Gordan ◽  
Ahmad Haddadiasl ◽  
Abdul Kadir Marsono ◽  
Masine Md Tap
Keyword(s):  
Structural Damage ◽  
Experimental Tests ◽  
Steel Frame ◽  
Shaking Table ◽  
Dynamic Responses ◽  
Viscous Damper ◽  
Sea Waves ◽  
Damping Characteristics ◽  
Tall Structures ◽  
Structural Responses

Vibration is a serious concern for tall structures during a natural disaster such as earthquake, wind storms, sea waves and hurricanes. The risk of occurrence of structural damage can be decreased by using a controlled vibration system to increase the damping characteristics of a structure. Damping is defined as the ability of the structure to dissipate a portion of the energy released during a dynamic loading event. The aims of this study are (1) to investigate a 4-storey 2D steel frame retrofit with viscous damper to reduce its vibration and (2) to demonstrate the performance of such a damper when fitted to a structure by analysis and tests the model. Therefore, a series of shaking table tests of the 4-storey 2D steel frame with and without viscous damper (VD) was carried out to evaluate the performance of the structure. The results of the experimental tests illustrate that viscous dampers decrease the structural responses of slender frame without changing their behavior on the shaking table. In other words, the displacement of the structure is reduced, however, there is no any transition of flexible to stiff structure related to its dynamic responses.

Damage Diagnosis of a Structure in Time-Frequency Domain

2015 ◽  
Vol 764-765 ◽  
pp. 1051-1057
Author(s):  
Wei Chih Su ◽  
Chiung Shiann Huang ◽  
Liane Jye Chen
Keyword(s):  
Life Cycle ◽  
Damping Ratio ◽  
Dynamic Responses ◽  
Short Time Fourier Transform ◽  
Structural Dynamic ◽  
Damage Diagnosis ◽  
Time Frequency ◽  
Input Model ◽  
Short Time ◽  
Vector Approach

This work proposes a simple and efficient approach to locating the storeys whose stiffness change in the life cycle of a structure. The storeys that may be damaged are determined by comparing the unitary stiffness matrix in different stages in the life cycle of a building. An appropriate ARX (autoregressive with exogenous input) model of structure in established from the structural dynamic responses in terms of acceleration or velocity. The parameters in an ARX model are identified through the short time Fourier transform, and the natural frequency and damping ratio of structure are estimated directly through these identified parameters. The effectiveness of the proposed procedure is verified using the numerically simulated earthquake acceleration responses of a six-storey structure that is damaged at one or two storeys. The proposed scheme is compared to the DLV approach (flexibility-based damage locating vector approach) in identifying damage storeys.

Damage Detection of Steel Beam Using Frequency Response Function Measurement Data and Fractal Dimension

2015 ◽  
Vol 137 (3) ◽  
Author(s):  
Eun-Taik Lee ◽  
Hee-Chang Eun
Keyword(s):  
Fractal Dimension ◽  
Frequency Response ◽  
Response Function ◽  
Frequency Response Function ◽  
Measurement Data ◽  
Fractal Dimensions ◽  
Dynamic Responses ◽  
Steel Beam ◽  
Health State ◽  
Measured Frequency Response

Fractal-dimension-based signal processing has been extensively applied to various fields for nondestructive testing. The dynamic response signal can be utilized as an analytical tool to evaluate the structural health state without baseline data. The fractal features of the dynamic responses with fractal dimensions (FDs) were investigated using the Higuchi, Katz, and Sevcik methods. The waveform FD proposed by these methods was extracted from the measured frequency response function (FRF) data in the frequency domain. Damage was observed within this region, which resulted in an abrupt change in the curvature of the FD. The effectiveness of the methods was investigated via the results of a steel beam test and a numerical experiment to detect damage.

scholarly journals Investigation of Dynamic Responses and Vibration Serviceability of Temporary Grandstands by a 3 DOF Interaction Model due to Swaying Motion

2022 ◽  
Vol 2022 ◽  
pp. 1-32
Author(s):  
Jian Yuan ◽  
Suhui Yu ◽  
Cong Liu ◽  
Chengqiang Gao ◽  
Wei Wang ◽  
...  
Keyword(s):  
Damping Ratio ◽  
Force Plate ◽  
Interaction Model ◽  
Reference Value ◽  
Experimental Results ◽  
Shaking Table ◽  
Dynamic Responses ◽  
Random Waves ◽  
Lateral Direction ◽  
Structural Dynamic

Excessive vibration of temporary grandstand by the crowd has lateral rhythmic motions, which attracted increasing attention in the recent years. This paper focuses on experiments where a temporary grandstand occupied by 20 participants is oscillated by a shaking table with a series of random waves and the crowd-induced rhythmic swaying motions at lateral direction, respectively. The dynamic forces that were induced by participants who have swayed at 0.5–1.8 Hz are recorded by a tri-axial human biomechanics force plate. A new relationship between the annoyance rate and structural acceleration at logarithmic coordinate is investigated and proposed, and the swaying load model is given. Based on these experimental results, a simplified three-degree-of-freedom lumped dynamic model of the joint human–structure system is reinterpreted. Afterwards, combined with a feasible range of crowd/structural dynamic parameters, a series of interaction models are analyzed, the vibration dose value (VDV) of the structure is obtained and discussed, and the notable parameters for interaction model are predicted. The experimental results show that the lateral serviceability limit is 1.29 m/s1.75 and the upper boundary is 2.32 m/s1.75. The dynamic response of model indicated that the VDV of structure will be decreased with increasing the mass of static crowd and damping ratio of the dynamic crowd. The max response of the model is α ≤ 0.6, f2 = 1.8 Hz or α > 0.6, f2 = 1.5 Hz or f1 = 2.5–3.5 Hz. It may be used as a reference value in vibration safety and serviceability assessment of TDGs, to estimate realistically the vibration response on the occasions when the crowds are swaying.

Damage Detection in Initially Nonlinear Structures Based on Variational Mode Decomposition

2020 ◽  
Vol 20 (10) ◽  
pp. 2042009
Author(s):  
Yu Xin ◽  
Jun Li ◽  
Hong Hao
Keyword(s):  
Damage Detection ◽  
Structural Damage ◽  
Dynamic Responses ◽  
Modal Parameters ◽  
Nonlinear Structures ◽  
Variational Mode Decomposition ◽  
Structural Dynamic ◽  
Numerical Studies ◽  
Mode Decomposition ◽  
Frequency Domain Methods

Nonlinear characteristics in the dynamic behaviors of civil structures degrade the performance of damage detection of the linear theory based traditional time- and frequency-domain methods. To overcome this challenge, this paper proposes a damage detection approach for nonlinear structures based on Variational Mode Decomposition (VMD). In this approach, the measured dynamic responses from nonlinear structures under earthquake excitations are adaptively decomposed into a finite number of monocomponents by using VMD. Each decomposed mono-component represents an amplitude modulated and frequency modulated (AMFM) signal with a limited frequency bandwidth. Hilbert transform is then employed to identify the instantaneous modal parameters of the decomposed monomodes, including instantaneous frequencies and mode shapes. Based on the identified modal parameters from the decomposed structural dynamic responses, two damage indices are defined to identify the location and severity of structural damage, respectively. To validate the effectiveness and accuracy of the proposed approach, a nonlinear seven-storey shear building model with four different damage cases under earthquake excitations is used in the numerical studies. In experimental verifications, data from shake table tests on a 12-storey scaled reinforced concrete frame structure with different earthquake excitations are analyzed with the proposed approach. The results in both numerical studies and experimental validations demonstrate that the proposed approach can be successfully applied for nonlinear structural damage identification.

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