Study of multiple-site structural damage detection application using vibration response

2020 ◽  
Vol 64 (1-4) ◽  
pp. 1411-1419
Author(s):  
Bingrong Miao ◽  
Shuwang Yang ◽  
Mingyue Wang ◽  
Chuanying Jiang ◽  
Qiming Peng ◽  
...  
Keyword(s):  
Wavelet Transform ◽  
Structural Damage ◽  
Damage Identification ◽  
Vibration Response ◽  
Modal Parameters ◽  
Small Scale ◽  
Engineering Practice ◽  
Noise Performance ◽  
Displacement Mode ◽  
Rotation Mode

The identification effects of different modal parameters (displacement mode, rotation mode, and curvature mode) of the beam structure on structural damage during crack initiation are studied in this paper. Firstly, the displacement mode, the rotation mode and the curvature mode of the two-span simply supported beam are calculated using the vibration response. Secondly, combining the multi-resolution and singularity analysis characteristics of continuous wavelet transform, the wavelet transform coefficients of three modal parameters are calculated to identify the singularity of structural modal parameters. Thirdly, the recognition effects of each method on structural damage are compared by adding different degrees of random noise to the simulation data. The results show that the damage identification methods based on three different modal parameters can locate small-scale structural damage, but the anti-noise performance of each method is different, the anti-noise performance of the rotation mode is the best, the displacement mode is second and the curvature mode is poor. Finally, the experimental data is used to verify the recognition effect of each damage identification method based on different modal parameters on the actual structural damage. The experimental results show that the damage recognition effect of the rotation mode parameters is better, while the displacement mode and the curvature mode parameters are similar, but the curvature mode method is more likely to be interfered at the smaller damage. These analysis results provide a reference for the selection of different damage identification parameters according to the environment and response characteristics in engineering practice.

scholarly journals Structural Damage Identification Based on Integrated Utilization of Inverse Finite Element Method and Pseudo-Excitation Approach

Sensors ◽  
2021 ◽  
Vol 21 (2) ◽  
pp. 606
Author(s):  
Tengteng Li ◽  
Maosen Cao ◽  
Jianle Li ◽  
Lei Yang ◽  
Hao Xu ◽  
...  
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Structural Damage ◽  
Damage Identification ◽  
Displacement Measurement ◽  
Engineering Practice ◽  
Position Measurement ◽  
Inverse Finite Element Method ◽  
Pseudo Excitation ◽  
Element Method

The attempt to integrate the applications of conventional structural deformation reconstruction strategies and vibration-based damage identification methods is made in this study, where, more specifically, the inverse finite element method (iFEM) and pseudo-excitation approach (PE) are combined for the first time, to give rise to a novel structural health monitoring (SHM) framework showing various advantages, particularly in aspects of enhanced adaptability and robustness. As the key component of the method, the inverse finite element method (iFEM) enables precise reconstruction of vibration displacements based on measured dynamic strains, which, as compared to displacement measurement, is much more adaptable to existing on-board SHM systems in engineering practice. The PE, on the other hand, is applied subsequently, relying on the reconstructed displacements for the identification of structural damage. Delamination zones in a carbon fibre reinforced plastic (CFRP) laminate are identified using the developed method. As demonstrated by the damage detection results, the iFEM-PE method possesses apparently improved accuracy and significantly enhanced noise immunity compared to the original PE approach depending on displacement measurement. Extensive parametric study is conducted to discuss the influence of a variety of factors on the effectiveness and accuracy of damage identification, including the influence of damage size and position, measurement density, sensor layout, vibration frequency and noise level. It is found that different factors are highly correlated and thus should be considered comprehensively to achieve optimal detection results. The application of the iFEM-PE method is extended to better adapt to the structural operational state, where multiple groups of vibration responses within a wide frequency band are used. Hybrid data fusion is applied to process the damage index (DI) constructed based on the multiple responses, leading to detection results capable of indicating delamination positions precisely.

Damage Analysis of the Bridge Structure Based on the Modal Parameters

2011 ◽  
Vol 255-260 ◽  
pp. 1034-1038 ◽  
Author(s):  
Ke Ding
Keyword(s):  
Structural Damage ◽  
Vibration Mode ◽  
Modal Parameters ◽  
Damage Factor ◽  
Displacement Mode ◽  
Before And After ◽  
Bridge Structures ◽  
Modal Curvature ◽  
Bridge Damage

Reduction of intensity or rigidity and losses of quality of the bridge structures can induce the changes of modal parameters of the structure. It is possible to analyze and detect the damage of bridge based on comparing the changes of modal parameters of the structure before and after damaging. Natural frequency, displacement mode and modal curvature are the important parameters in dynamic Analysis. In this paper, their adaptive capacities to bridge damage assessment are discussed. And the damage factor is used to determine the damage location. Model experiments show that the damage factor not only reflects the position of bridge damage, and the damage factor of some vibration mode also indicates the length of damage element. At the equilibrium position of the vibration mode, it is difficult to determine structural damage using the damage factor.

Research on Structural Damage Diagnosis Based on Strain Modal

2013 ◽  
Vol 438-439 ◽  
pp. 739-742
Author(s):  
Yi Na Zhang ◽  
Lei Cao
Keyword(s):  
Damage Detection ◽  
Cantilever Beam ◽  
Theoretical Basis ◽  
Structural Damage ◽  
Damage Identification ◽  
Damage Diagnosis ◽  
Strain Mode ◽  
Engineering Structure ◽  
Displacement Mode ◽  
Analysis Theory

The damage diagnosis theory and method of engineering structure is one of the hot issues concerned by the engineering circles at present. Based on the strain modal analysis theory, it expounds the connection among displacement mode, strain mode and curvature mode, with a heavy rubber as the material to make a cantilever beam, and establishing the different damage conditions of the cantilever beam, studying about dynamic structural damage identification under the incentive, which provides the theoretical basis and technical support for the research on damage detection of large engineering structure.

scholarly journals Operational modal analysis using lifted continuously scanning laser Doppler vibrometer measurements and its application to baseline-free structural damage identification

2019 ◽  
Vol 25 (7) ◽  
pp. 1341-1364 ◽  
Author(s):  
Y.F. Xu ◽  
Da-Ming Chen ◽  
W.D. Zhu
Keyword(s):  
Structural Damage ◽  
Damage Identification ◽  
Laser Doppler Vibrometer ◽  
Laser Doppler ◽  
Scanning Laser ◽  
Mode Shapes ◽  
Modal Parameters ◽  
Experimental Investigations ◽  
Scanning Laser Doppler Vibrometer ◽  
White Noise Excitation

A continuously scanning laser Doppler vibrometer (CSLDV) system is capable of efficient and spatially dense vibration measurements by sweeping its laser spot along a scan path assigned on a structure. This paper proposes a new operational modal analysis (OMA) method based on a data processing method for CSLDV measurements of a structure, called the lifting method, under white-noise excitation and applies a baseline-free method to identify structural damage using estimated mode shapes from the OMA method. The lifting method enables transformation of raw CSLDV measurements into measurements at individual virtual measurement points, as if the latter were made by use of an ordinary scanning laser Doppler vibrometer in a step-wise manner. It is shown that a correlation function with nonnegative time delays between lifted CSLDV measurements at two virtual measurement points on a structure under white-noise excitation and its power spectrum contain modal parameters of the structure, that is, natural frequencies, modal damping ratios, and mode shapes. The modal parameters can be estimated by using a standard OMA algorithm. A major advantage of the proposed OMA method is that curvature mode shapes associated with mode shapes estimated by the method can reflect local anomaly caused by small-sized structural damage, while those estimated by other existing OMA methods that use CSLDV measurements cannot. Numerical and experimental investigations are conducted to study the OMA method and baseline-free structural damage identification method. In the experimental investigation, effects of the scan frequency of a CSLDV system on the two methods were studied. It is shown in both the numerical and experimental investigations that modal parameters can be accurately estimated by the OMA method and structural damage can be successfully identified in neighborhoods with consistently high values of curvature damage indices.

scholarly journals Changes in the Dynamic Characteristics of a Small-Scale Gymnasium Model Due to Simulated Earthquake Damage

2021 ◽  
Vol 16 (7) ◽  
pp. 1074-1085
Author(s):  
Jun Fujiwara ◽  
Akiko Kishida ◽  
Takashi Aoki ◽  
Ryuta Enokida ◽  
Koichi Kajiwara ◽  
...  
Keyword(s):  
Structural Damage ◽  
Natural Frequencies ◽  
Mode Shapes ◽  
Modal Parameters ◽  
Small Scale ◽  
Building Structures ◽  
Shake Table Tests ◽  
Large Span ◽  
Similarity Rule ◽  
Measured Response

In this study, the authors used shake-table tests to assess the modal parameters of a small-scale gymnasium model with simulated damage, the feasibility of estimating the damage to large-span building structures was studied. In Japan, large-span structures, such as gymnasiums, are expected to be used as evacuation shelters when a natural disaster occurs. As the shelter itself may be damaged in case of an earthquake, it is critical to determine whether damage has occurred, where it occurred, and how serious it is, before the shelter is used. The small-scale gymnasium was designed based on the similarity rule. Observed earthquake ground motions scaled to aftershock levels were applied to the model. The natural frequencies and mode shapes were obtained from the measured response accelerations. To study the influence of structural damage on the modal parameters, a gymnasium model with simulated damage was also tested. The results indicate that the modal parameters, e.g., natural frequencies and mode shapes, can be obtained from the response accelerations, and the damage patterns can be estimated from the changes in these modal parameters.

scholarly journals Damage Identification of Ancient Timber Structure Based on Autocorrelation Function

2021 ◽  
Vol 2021 ◽  
pp. 1-12
Author(s):  
Yanfang Hou ◽  
Weibing Hu ◽  
Xin Wang ◽  
Tingting Hou ◽  
Congli Sun
Keyword(s):  
Autocorrelation Function ◽  
Structural Damage ◽  
Damage Identification ◽  
Good Condition ◽  
Vibration Response ◽  
Value Change ◽  
Change Rate ◽  
Damage Location ◽  
Degree Of Damage ◽  
Peak Value

A damage location method for the autocorrelation peak value change rate based on the vibration response of a random vibration structure is established. To calculate the autocorrelation function of the vibration response of each measurement point, we transformed the maximum values into an autocorrelation peak vector. Under a good condition, the autocorrelation peak vector has a fixed shape; hence, it can be used as a basis for structural damage identification. The two adjacent measurement points with the largest change corresponding to the two nodes of the damage unit and the damage location are determined to calculate the change rate of the autocorrelation peak values between damaged and intact structures. When the degree of damage is 5%, the autocorrelation peak value change rate of the acceleration response on the two nodes of the damage unit is significantly greater than that of the other points, which can accurately determine the damage location, indicating that the damage location index constructed has good damage sensitivity. The damage location index can determine a single damage, as well as a double damage. The antinoise capability of the damage location index gradually improves with an increase in the degree of damage. At 45% degree of damage and signal-to-noise ratio (SNR) of 0 dB, the damage location index can still accurately determine the damage location, which has good antinoise interference capability. The Xi’an Bell Tower is used as a case study, and the feasibility of this method is verified, which provides a new method for the study of damage location of ancient timber structures.

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