A damage identification method for a thin plate structure based on PVDF sensors and strain mode

2019 ◽  
Vol 233 (14) ◽  
pp. 4881-4895
Author(s):  
Hongyu Cui ◽  
Weiqiang Peng ◽  
Xin Xu ◽  
Ming Hong
Keyword(s):  
Thin Plate ◽  
Structural Damage ◽  
Polyvinylidene Fluoride ◽  
Damage Identification ◽  
Damage Index ◽  
Modal Identification ◽  
Identification Methods ◽  
Plate Structure ◽  
Fluoride Sensor ◽  
Structural Strain

Damage identification methods for engineering structures based on vibration parameters have the advantages of easy detection and high precision; however, structural strain information is more sensitive to structural damage than displacement information. Traditional resistance strain sensors have low accuracy and poor stability when measuring structural strains. Therefore, this paper uses a highly sensitive polyvinylidene fluoride dynamic strain sensor to identify structural damage in a thin plate. The polyvinylidene fluoride sensor is used to obtain structural strain response information, and structural modal parameters are identified using operational modal identification methods based on the natural excitation technique and the eigensystem realization algorithm. This paper uses a damage index based on mode shape and flexibility. A new damage index based on the LU decomposition of the flexibility matrix is used to identify the damage of the thin plate structure. The effectiveness of the modal identification methods and the new damage index is validated via an elastic thin plate experiment. The results show that the modal identification method and the new damage index proposed in this paper can identify damage in a thin plate structure. Sensor comparison experiments also show that compared with a resistance strain sensor, the polyvinylidene fluoride sensor has higher damage sensitivity, better damage recognition and the ability to recognize farther from the sensor.

Structural Damage Assessment Using Output-Only Measurement: Localization and Quantification

2013 ◽  
Author(s):  
Chin-Hsiung Loh ◽  
Min-Hsuan Tseng ◽  
Shu-Hsien Chao
Keyword(s):  
Damage Detection ◽  
Damage Assessment ◽  
Structural Damage ◽  
Damage Identification ◽  
Model Updating ◽  
Null Space ◽  
Singular Spectrum Analysis ◽  
Damage Index ◽  
Computation Efficiency ◽  
Output Only

One of the important issues to conduct the damage detection of a structure using vibration-based damage detection (VBDD) is not only to detect the damage but also to locate and quantify the damage. In this paper a systematic way of damage assessment, including identification of damage location and damage quantification, is proposed by using output-only measurement. Four level of damage identification algorithms are proposed. First, to identify the damage occurrence, null-space and subspace damage index are used. The eigenvalue difference ratio is also discussed for detecting the damage. Second, to locate the damage, the change of mode shape slope ratio and the prediction error from response using singular spectrum analysis are used. Finally, to quantify the damage the RSSI-COV algorithm is used to identify the change of dynamic characteristics together with the model updating technique, the loss of stiffness can be identified. Experimental data collected from the bridge foundation scouring in hydraulic lab was used to demonstrate the applicability of the proposed methods. The computation efficiency of each method is also discussed so as to accommodate the online damage detection.

Non-model-based damage identification of plates using measured mode shapes

2016 ◽  
Vol 16 (1) ◽  
pp. 3-23 ◽  
Author(s):  
Yongfeng Xu ◽  
Weidong Zhu
Keyword(s):  
Structural Damage ◽  
Damage Identification ◽  
Damage Index ◽  
Thickness Reduction ◽  
Aluminum Plate ◽  
Mode Shapes ◽  
Identification Method ◽  
Model Based

Mode shapes (MSs) have been extensively used to detect structural damage. This paper presents a new non-model-based damage identification method that uses measured MSs to identify damage in plates. A MS damage index (MSDI) is proposed to identify damage near regions with consistently high values of MSDIs associated with MSs of different modes. A MS of a pseudo-undamaged plate can be constructed for damage identification using a polynomial of a properly determined order that fits the corresponding MS of a damaged plate, if the associated undamaged plate is geometrically smooth and made of materials that have no stiffness and mass discontinuities. It is shown that comparing a MS of a damaged plate with that of a pseudo-undamaged plate is better for damage identification than with that of an undamaged plate. Effectiveness and robustness of the proposed method for identifying damage of different positions and areas are numerically investigated using different MSs; effects of crucial factors that determine effectiveness of the proposed method are also numerically investigated. Damage in the form of a machined thickness reduction area was introduced to an aluminum plate; it was successfully identified by the proposed method using measured MSs of the damaged plate.

Pseudo Strain Energy Density-Based Structural Damage Identification

2009 ◽  
Vol 413-414 ◽  
pp. 71-78
Author(s):  
Xiao Qiang Chen ◽  
Hong Ping Zhu ◽  
Dan Sheng Wang
Keyword(s):  
Energy Density ◽  
Strain Energy Density ◽  
Structural Damage ◽  
Strain Energy ◽  
Damage Identification ◽  
Wavelet Packet ◽  
Damage Index ◽  
Dynamic Strain ◽  
Beam Model ◽  
Measured Strain

In this paper, a new time-domain method for detecting structural local damage has been developed, which is based on the measured strain signals. The “pseudo strain energy density (PSED)” is defined and used to build two major damage indexes, the “average pseudo strain energy density” (APSED) and the “average pseudo strain energy density changing rate” (APSEDR). A probability and mathematical statistics technique is utilized to derive a standardized damage index. Afterwards, these indexes are used to establish the damage identification strategies for beam structures and plate structures respectively. Furthermore, the wavelet packet transform is used to pre-process the measured dynamic strain signals. Then, the effectivity of the new damage identification method is confirmed by numerical simulations. Finally, a laboratory beam model experiment is conducted to verify this method examine the feasibility and applicability of the new method.

Study on Damage Location of Spatial Structures Based on Wavelet Analysis of Model Strain Energy

2013 ◽  
Vol 639-640 ◽  
pp. 1033-1037
Author(s):  
Yong Mei Li ◽  
Bing Zhou ◽  
Guo Fu Sun ◽  
Bo Yan Yang
Keyword(s):  
Wavelet Analysis ◽  
Damage Detection ◽  
Structural Damage ◽  
Strain Energy ◽  
Damage Identification ◽  
Damage Index ◽  
Structural Damage Detection ◽  
Modal Strain Energy ◽  
Wavelet Method ◽  
Long Span

The research to identify and locate the damage to the engineering structure mainly aimed at some simple structure forms before, such as beam and framework. Damage shows changes of local characteristics of the signal, while wavelet analysis can reflect local damage traits of the signal in time domain and frequency domain. For confirming the validity and applicability of structural damage identification methods, wavelet analysis is used to spatial structural damage detection. The wavelet analysis technique provides new ideas and methods of spatial steel structural damage detection. Based on the theory of wavelet singularity detection，with the injury signal of modal strain energy as structural damage index，the mixing of the modal strain energy and wavelet method to identify and locate the damage to the spatial structure is considered. The multiplicity of the bars and nodes can be taken into account, and take the destructive and nondestructive modal strain energy of Kiewitt-type reticulated shell with 40m span as an example of numerical simulation，the original damage signal and the damage signal after wavelet transformation is compared. The location of the declining stiffness identified by the maximum of wavelet coefficients，analyzed as signal by db1 wavelet，and calculate the graph relation between coefficients of the wavelets and the damage to the structure by discrete or continuous wavelet transform, and also check the accuracy degree of this method with every damage case. Finally，the conclusion is drawn that the modal strain energy and wavelet method to identify and locate the damage to the long span reticulated shell is practical, effective and accurate, that the present method as a reliable and practical way can be adopted to detect the single and several locations of damage in structures.

Progresses and Perspectives of Damage Identification in Bridge Structure

2013 ◽  
Vol 405-408 ◽  
pp. 1632-1636
Author(s):  
Xiang Nan Wu ◽  
Xiao Guang Wang
Keyword(s):  
Health Monitoring ◽  
Structural Damage ◽  
Damage Identification ◽  
Bridge Engineering ◽  
Load Testing ◽  
Identification Methods ◽  
Identification Method ◽  
Manual Inspection ◽  
Structural Damage Identification ◽  
Statistical Identification

Structural damage identification is the core of Structural health monitoring system. The paper points out existing damage identification methods and analysis the application status and disadvantages of various methods. The research hotspots are summarized on considering the statistical identification method under uncertainty and the environmental impact of damage identification methods. Aiming at the characters of bridge engineering, the paper points out that a four-in-one multi-system damage identification method is the develop direction for bridge structural damage identification, which is established based on construction, load testing, health monitoring and manual inspection.

An automated damage identification technique based on vibration and wave propagation data

2006 ◽  
Vol 365 (1851) ◽  
pp. 479-491 ◽  
Author(s):  
Ajit Mal ◽  
Sauvik Banerjee ◽  
Fabrizio Ricci
Keyword(s):  
Wave Propagation ◽  
Dynamic Response ◽  
Structural Damage ◽  
Damage Identification ◽  
Damage Index ◽  
Composite Plates ◽  
Ambient Conditions ◽  
Current State ◽  
Potential Applications ◽  
Identification Technique

This paper is concerned with the detection and characterization of hidden defects in advanced structures before they grow to a critical size. A novel method is developed using a combination of vibration and wave propagation data to determine the location and degree of damage in structural components requiring minimal operator intervention. The structural component is to be instrumented with an array of actuators and sensors to excite and record its dynamic response. A damage index, calculated from the measured dynamic response of the structure in a reference state (baseline) and the current state, is introduced as a determinant of structural damage. The index is a relative measure comparing the two states of the structure under the same ambient conditions. The indices are used to identify damages in the forms of delaminations and holes in composite plates for different arrangements of the source and the receivers. The potential applications of the approach in developing health monitoring systems in defects-critical structures are discussed.

scholarly journals Structural Damage Identification Based on Principal Curvatures of Mode Shape

2020 ◽  
Vol 25 (4) ◽  
pp. 566-576
Author(s):  
Rahim Gorgin ◽  
Ziping Wang
Keyword(s):  
Mode Shape ◽  
Structural Damage ◽  
Damage Identification ◽  
Mode Shapes ◽  
Principal Curvatures ◽  
Element Analysis ◽  
Identification Methods ◽  
Maximum Curvature ◽  
Curvature Variation ◽  
Identification And Characterization

This paper presents a procedure for damage identification and characterization on plates, based on the principal curvatures of their first mode shape. Each mode shape represents the displacement of the structure at its corresponding natural frequency. Since, variations in the geometry due to cracks or material property degradation, make changes in the mode shapes of the structure, such changes can be used for damage identification methods. The presented procedure only requires the first mode shape of the intact and damaged structure. It is shown that the principal curvatures of the surface defined by the first mode shape of the structure, are sensitive to damage and the maximum principal curvature can be used to highlight damages on the structure. The performance of the developed method is firstly evaluated using finite element analysis. To this aim, the procedure is applied to highlight both single and multi-damages in different locations of the plate with different boundary conditions. It is shown that the location of the maximum curvature variation coincides well with the location of damages and the amount of the maximum curvature change can be used as a parameter to describe damage severity. The accuracy of the proposed method is also experimentally verified by test on an aluminum plate and it is demonstrated that the proposed method remains effective even in experimental condition when only a limited number of measurements are available.

scholarly journals A New Structural Damage Identification Method Based on Wavelet Packet Energy Entropy of Impulse Response

2015 ◽  
Vol 9 (1) ◽  
pp. 570-576 ◽  
Author(s):  
Can He ◽  
Jianchun Xing ◽  
Juelong Li ◽  
Wei Qian ◽  
Xun Zhang
Keyword(s):  
Impulse Response ◽  
Structural Damage ◽  
Damage Identification ◽  
Wavelet Packet ◽  
Damage Index ◽  
Great Influence ◽  
Identification Method ◽  
Wavelet Energy ◽  
Energy Entropy ◽  
Structural Damage Identification

Excitation makes a great influence on the wavelet energy distribution of the response signal, this deficiency leads that the traditional structural damage identification method based on wavelet energy has a low precision. In order to solve this problem, a new structural damage identification method based on wavelet packet energy entropy (WPEE) of impulse response is presented in this paper. Firstly, natural excitation technique (NExT) is adopted to extract structural impulse response. Then, WPEE of the impulse response is computed, and the change rate of WPEE is used to construct the structural damage index. An experiment of damage identification on a pile structure is provided to verify the effectiveness of the proposed method. Experiment results show that this method can accurately identify the single damage and multi-damage.

scholarly journals Novel TQWT Algorithm for Structural Damage Identification

2019 ◽  
Vol 8 (4) ◽  
pp. 5136-5146
Keyword(s):  
Input Signal ◽  
Structural Damage ◽  
Damage Identification ◽  
Damage Index ◽  
Identification Problem ◽  
Oscillatory Behavior ◽  
Mode Shapes ◽  
Q Factor ◽  
Stiffness Loss ◽  
Beam Damage

In this paper tunable Q-factor wavelet transform is implemented into damage identification. Fixed – Fixed beam damage identification problem is demonstrated. Translation and Rotational mode shapes are used as an input signal, the TQWT algorithm depends Q-factor and asymptotic redundancy, when it matches with the oscillatory behavior of the input signal it is tuned. This method decomposes a signal into a high-Q-factor and low-Q-factor component, and it can be used to differentiate the damaged and undamaged mode shapes of the beam structure. TQWT coefficient is used as damage index to locate and quantify the damage. Proposed method evaluated experimentally and results shows TQWT algorithm has a potential to detect even a small damage (10% stiffness loss) present in the structure.

A pseudo-modal structural damage index based on orthogonal empirical mode decomposition

2019 ◽  
Vol 233 (23-24) ◽  
pp. 7545-7564 ◽  
Author(s):  
Egidio Lofrano ◽  
Francesco Romeo ◽  
Achille Paolone
Keyword(s):  
Empirical Mode Decomposition ◽  
Structural Damage ◽  
Degrees Of Freedom ◽  
Damage Identification ◽  
Damage Index ◽  
Experimental Tests ◽  
Intrinsic Mode Functions ◽  
Mode Decomposition ◽  
Identification Technique ◽  
Output Only

A structural damage identification technique hinged on the combination of orthogonal empirical mode decomposition and modal analysis is proposed. The output-only technique is based on the comparison between pre- and post-damage free structural vibrations signals. The latter are either kinematic (displacements, velocities or accelerations) or deformation measures (strains or curvatures). The response data are decomposed by means of the orthogonal empirical mode decomposition to derive a finite set of orthogonal intrinsic mode functions; the latter are used as a multi-frequency and data-driven basis to build pseudo-modal shapes. A new damage index, the so-called pseudo-mode index, is introduced to compare the response obtained for the two states of the structural system and detect potential damages. The performance of the devised index in detecting a localised damage is shown through numerical and experimental tests on two structural models, namely a 4-degrees-of-freedom system and a two-hinged parabolic arch.

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