Progressive Damage Detection/Diagnosis on Composite Using Electromechanical Impedance Spectroscopy

2011 ◽  
Author(s):  
Lingyu Yu ◽  
Matthieu Gresil ◽  
Patrick Pollock ◽  
Michael Sutton
Keyword(s):  
Impedance Spectroscopy ◽  
Structural Damage ◽  
Structural Changes ◽  
Dynamic Responses ◽  
Bonding Layer ◽  
Structural Dynamic ◽  
Electromechanical Impedance ◽  
Damage Progression ◽  
Electromechanical Transduction ◽  
Piezoelectric Wafer

Electromechanical impedance approach infers the structural dynamic characteristics at relatively high frequencies by using self-sensing piezoelectric wafer elements. Structural damage can be detected by comparing structural dynamic responses of damaged and undamaged structures. This paper presents an ongoing effort using piezoelectric wafer sensors to measure structural electromechanical impedance response under tensile loading and quantitatively correlate the measurements with damage progression. The purpose is not only to develop a better understanding of the damage progression in composite materials, but also to establish a relationship between electromechanical impedance measurements with local material damage progression. Multi-physics finite element codes are used to simulate the electromechanical resonance of a free piezoelectric wafer sensor to better understand the effect of electromechanical transduction. The effects on impedance measurement from bonding layer degradation and PWAS degradation are also studied. Our study confirms that the EMI changes are related to very small amount material or structural changes, indicating that electromechanical impedance spectroscopy offers a potential for detection of the progression of small damage at the material level.

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.

Finite Element Modeling and Effect of Electrical/Mechanical Parameters on Electromechanical Impedance Damage Detection

2009 ◽  
Author(s):  
Daniel J. Kitts ◽  
Andrei N. Zagrai
Keyword(s):  
Finite Element ◽  
Structural Damage ◽  
Active Material ◽  
Piezoelectric Element ◽  
Adhesive Bond ◽  
Structural Element ◽  
Structural Dynamic ◽  
Electromechanical Impedance ◽  
Sensor Structure ◽  
Host Structure

Electromechanical Impedance (EMI) is a popular SHM technique, which has found applications in many fields of engineering: mechanical, aerospace, civil and others. Active elements of the technique are piezoelectric wafer active sensors bonded or embedded into a structural element. EMI detection of structural damage is achieved by comparing high frequency structural dynamic signatures reflected in the electromechanical impedance measured at the sensor terminals. Over a past decade, substantial efforts have been devoted to analytical and numerical modeling of various aspects of EMI method. The majority of prior studies focused on fundamental understanding of the sensor transduction mechanism and sensor-structure interaction. Although basic principles of the EMI method are now well understood, modeling of practical structural diagnostic scenarios remains challenging. This contribution expands current modeling efforts in the EMI SHM by considering issues related to energy dissipation in piezoelectric sensor and host structure, as well as its effect on detectability of structural damage. Piezoelectric element and a host structure were modeled using Comsol® Multiphysics finite element package. The finite element implementation allowed for considering contributions of active material, adhesive bond and structural damage. These contributions were studied parametrically for various model settings including mechanical and electrical losses. The study shows that sensor position may directly control damage manifestation in EMI signature; effect of adhesive bond thickness is comparable in magnitude to the effect of bond stiffness; influence of piezoelectric mechanical losses on the impedance signature is different for damaged and undamaged cases.

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 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.

Diagnosis and validation of damaged piezoelectric sensor in electromechanical impedance technique

2016 ◽  
Vol 28 (7) ◽  
pp. 837-850 ◽  
Author(s):  
Demi Ai ◽  
Hui Luo ◽  
Hongping Zhu
Keyword(s):  
Structural Health Monitoring ◽  
Health Monitoring ◽  
Structural Damage ◽  
Piezoelectric Sensor ◽  
Bonding Layer ◽  
The Real ◽  
Electromechanical Impedance ◽  
Structural Health ◽  
Validity Assessment ◽  
Impedance Technique

Piezoelectric sensor diagnosis and validity assessment as a prior component of structural health monitoring system are necessary in the practical application of electromechanical impedance technique. This article proposed an innovative sensor self-diagnosis process based on extracting the characterization of the real admittance (inverse of impedance) signature within a high-frequency range, which covered both diagnosis on damaged sensor after its installation and discrimination of sensor and structural damages during structural health monitoring process. Theoretical analysis was derived from the impedance model of piezoelectric-bonding layer-structure dynamic interaction system. Experimental investigations on piezoelectric sensor-bonded steel beam involved with structural damages of mass addition and notch damage were conducted to verify the process. It was found that the real admittance was reliable and critical in sensor diagnosis, and sensor faults of debonding, scratch, and breakage can be identified and differentiated from structural damage. Validity assessment of the diagnosed damaged sensor was addressed through resonant frequency shift method. The results showed that the validity of damaged sensor for structural health monitoring was inordinately depreciated by sensor damage. This article is expected to be useful for structural health monitoring application especially when damaged piezoelectric sensors existed.

Experimental Research on Structural Damage Alarming of Benchmark Structure Based on Empirical Mode Decomposition

2011 ◽  
Vol 243-249 ◽  
pp. 61-66
Author(s):  
Li Lin Cao ◽  
Ai Qun Li ◽  
Yang Deng
Keyword(s):  
Empirical Mode Decomposition ◽  
Structural Damage ◽  
Structural Response ◽  
Dynamic Responses ◽  
Test Model ◽  
Intrinsic Mode Functions ◽  
Structural Dynamic ◽  
Mode Decomposition ◽  
Structural Dynamic Characteristics ◽  
Damage Alarming

A structural damage alarming method is proposed using empirical mode decomposition. The basic idea of this method is that with respect to the intact model and damaged models, the energy redistribution of the intrinsic mode functions decomposed from the structural response can represent the variation of the structural dynamic characteristics caused by the structural damage. By taking the Benchmark test model as the research object, the structural dynamic responses from the hammer-impact tests are collected then the damage alarming parameters and the damage alarming indices are evaluated. The experimental results reveal that the structural damage alarming indices based on empirical mode decomposition is able to effectively detect the structural initial damage with preferable damage alarming capacity.

Evaluation of single-electron movies of glutamine synthetase molecules

1983 ◽  
Vol 41 ◽  
pp. 280-281
Author(s):  
W. Kunath ◽  
E. Zeitler ◽  
M. Kessel
Keyword(s):  
Electron Microscope ◽  
Glutamine Synthetase ◽  
Electron Irradiation ◽  
Structural Damage ◽  
Structural Changes ◽  
Single Electron ◽  
Continuous Series ◽  
Digital Recording ◽  
Recording Device ◽  
Low Exposure

The features of digital recording of a continuous series (movie) of singleelectron TV frames are reported. The technique is used to investigate structural changes in negatively stained glutamine synthetase molecules (GS) during electron irradiation and, as an ultimate goal, to look for the molecules' “undamaged” structure, say, after a 1 e/Å2 dose.The TV frame of fig. la shows an image of 5 glutamine synthetase molecules exposed to 1/150 e/Å2. Every single electron is recorded as a unit signal in a 256 ×256 field. The extremely low exposure of a single TV frame as dictated by the single-electron recording device including the electron microscope requires accumulation of 150 TV frames into one frame (fig. lb) thus achieving a reasonable compromise between the conflicting aspects of exposure time per frame of 3 sec. vs. object drift of less than 1 Å, and exposure per frame of 1 e/Å2 vs. rate of structural damage.

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