Electromechanical Impedance Method for Damage Detection of Typical Joint on Jacket Platform

2018 ◽  
Author(s):  
Boying Zhang ◽  
Hamad Hameed ◽  
Yuxin Xu ◽  
Chonglin Zhang ◽  
Yong Bai
Keyword(s):  
Health Monitoring ◽  
Mechanical Impedance ◽  
Theoretical Background ◽  
Impedance Method ◽  
Laboratory Measurements ◽  
Direct Evaluation ◽  
Jacket Platform ◽  
Health Monitoring System ◽  
Electromechanical Impedance ◽  
Experimental Works

Health monitoring of welded structural joints is a very important factor of the engineering community. Electro-mechanical impedance (EMI) technique allows the direct evaluation of structural dynamics by evaluating its E/M impedance or admittance signatures. This paper first gives a brief introduction of the theoretical background on the described method. Then, the described EMI technique is applied to recognize the presence of damage by executing experimental works where the damage in the form of crack is simulated with an impedance analyzer at various distances. Four typical welded metallic joints on a jacket platform successfully produced submillimeter cracks under cyclic loading and root mean square deviation (RMSD) is used to evaluate the degree of crack damage. Finally, an outcome of laboratory measurements performed with developed structural health monitoring system based on the electromechanical impedance phenomenon is presented.

scholarly journals Temperature Effects on Electromechanical Response of Deposited Piezoelectric Sensors Used in Structural Health Monitoring of Aerospace Structures

Sensors ◽  
2019 ◽  
Vol 19 (12) ◽  
pp. 2805 ◽  
Author(s):  
Hamidreza Hoshyarmanesh ◽  
Mojtaba Ghodsi ◽  
Minjae Kim ◽  
Hyung Hee Cho ◽  
Hyung-Ho Park
Keyword(s):  
Structural Health Monitoring ◽  
Health Monitoring ◽  
Mechanical Impedance ◽  
Peak Shift ◽  
Aluminum Plate ◽  
Distinct Advantage ◽  
Compressor Blades ◽  
Turbine Engine ◽  
Electromechanical Impedance ◽  
Structural Health

Turbomachine components used in aerospace and power plant applications preferably require continuous structural health monitoring at various temperatures. The structural health of pristine and damaged superalloy compressor blades of a gas turbine engine was monitored using real electro-mechanical impedance of deposited thick film piezoelectric transducers at 20 and 200 °C. IVIUM impedance analyzer was implemented in laboratory conditions for damage detection in superalloy blades, while a custom-architected frequency-domain transceiver circuit was used for semi-field circumstances. Recorded electromechanical impedance signals at 20 and 200 °C acquired from two piezoelectric wafer active sensors bonded to an aluminum plate, near and far from the damage, were initially utilized for accuracy and reliability verification of the transceiver at temperatures >20 °C. Damage formation in both the aluminum plate and blades showed a peak shift in the swept frequency along with an increase in the amplitude and number of impedance peaks. The thermal energy at 200 °C, on the other hand, enforces a further subsequent peak shift in the impedance signal to pristine and damaged parts such that the anti-resonance frequency keeps reducing as the temperature increases. The results obtained from the impedance signals of both piezoelectric wafers and piezo-films, revealed that increasing the temperature somewhat decreased the real impedance amplitude and the number of anti-resonance peaks, which is due to an increase in permittivity and capacitance of piezo-sensors. A trend is also presented for artificial intelligence training purposes to distinguish the effect of the temperature versus damage formation in sample turbine compressor blades. Implementation of such a monitoring system provides a distinct advantage to enhance the safety and functionality of critical aerospace components working at high temperatures subjected to crack, wear, hot-corrosion and erosion.

An open database for benchmarking guided waves structural health monitoring algorithms on a composite full-scale outer wing demonstrator

2019 ◽  
Vol 19 (5) ◽  
pp. 1524-1541 ◽  
Author(s):  
Alessandro Marzani ◽  
Nicola Testoni ◽  
Luca De Marchi ◽  
Marco Messina ◽  
Ernesto Monaco ◽  
...  
Keyword(s):  
Structural Health Monitoring ◽  
Damage Detection ◽  
Monitoring System ◽  
Health Monitoring ◽  
Guided Wave ◽  
Full Scale ◽  
Composite Panel ◽  
Health Monitoring System ◽  
Electromechanical Impedance ◽  
Structural Health

This article reports on the creation of an open database of piezo-actuated and piezo-received guided wave signals propagating in a composite panel of a full-scale aeronautical structure. The composite panel closes the bottom part of a wingbox that, along with the leading edge, the trailing edge, and the wingtip, forms an outer wing demonstrator approximately 4.5 m long and from 1.2 to 2.3 m wide. To create the database, a structural health monitoring system, composed of a software/hardware central unit capable of controlling a network of 160 piezoelectric transducers secondarily bonded on the composite panel, has been realized. The structural health monitoring system has been designed to (1) perform electromechanical impedance measurement at each transducer, in order to check for their reliability and bonding strength, and (2) to operate an active guided wave screening for damage detection in the composite panel. Electromechanical impedance and guided wave measurements were performed at four different testing stages: before loading, before fatigue, before impacts, and after impacts. The database, freely available at http://shm.ing.unibo.it/ , can thus be used to benchmarking, on real-scale structural data, guided wave algorithms for loading, fatigue, as well as damage detection, characterization, and sizing. As an example, in this work, a delay and sum algorithm is applied on the post-impact data to illustrate how the database can be exploited.

Nonlinear Modeling of Cracked Beams for Impedance Based Structural Health Monitoring

2017 ◽  
Author(s):  
Naserodin Sepehry ◽  
Firooz Bakhtiari-Nejad ◽  
Mahnaz Shamshirsaz ◽  
Weidong Zhu
Keyword(s):  
Structural Health Monitoring ◽  
Linear System ◽  
Frequency Response ◽  
Frequency Domain ◽  
Health Monitoring ◽  
Impedance Method ◽  
Breathing Crack ◽  
Electromechanical Impedance ◽  
Structural Health ◽  
System Equations

One of the main objectives of the structural health monitoring by piezoelectric wafer active sensor (PWAS) using electromechanical impedance method is continuously damage detection applications. In present work impedance method of beam structure is considered and the effect of early crack using breathing crack modeling is studied. In order to model the effect of a crack in beam, the beam is connected with a rotational spring in crack location. The Rayleigh–Ritz method is used to generate ordinary differential equation of cracked beam. Firstly, only open crack is considered that this is leads to linear system equation. In linear system, time domain system equations are converted to frequency domain, and then impedance of PWAS in frequency domain is calculated. Secondly, the breathing crack is modeled to be fully open or fully closed. This phenomenon leads to the nonlinear system equations. These nonlinear equations are solved using pseudo-arc length continuation scheme and collocation method for any harmonic voltage applied to actuator. Then impedance of PWAS is calculated. Two methods are used to detect early crack using breathing crack modeling on PWAS impedance. At the first, frequency response of breathing crack in the frequency range with its sub-harmonics is calculated. Second, only frequency response of one harmonic is computed with its super-harmonics. Finally, the detection method of linear is compared with nonlinear model.

Electromechanical Impedance Modeling for Structural Health Monitoring

2012 ◽  
Author(s):  
Liuxian Zhao ◽  
Lingyu Yu ◽  
Mattieu Gresil ◽  
Michael Sutton ◽  
Siming Guo
Keyword(s):  
Structural Health Monitoring ◽  
Health Monitoring ◽  
Electrical Impedance ◽  
Piezoelectric Materials ◽  
Fiber Composite ◽  
Mechanical Impedance ◽  
Experimental Result ◽  
Electromechanical Impedance ◽  
Structural Health ◽  
Aluminum Beam

Electromechanical impedance (EMI) method is an effective and powerful technique in structural health monitoring (SHM) which couples the mechanical impedance of host structure with the electrical impedance measured at the piezoelectric wafer active sensor (PWAS) transducer terminals. Due to the electromechanical coupling in piezoelectric materials, changes in structural mechanical impedance are reflected in the electrical impedance measured at the PWAS. Therefore, the structural mechanical resonances are reflected in a virtually identical spectrum of peaks and valleys in the real part of the measured EMI. Multi-physics based finite element method (MP-FEM) has been widely used for the analysis of piezoelectric materials and structures. It uses finite elements taking both electrical and mechanical DOF’s into consideration, which allows good differentiation of complicated structural geometries and damaged areas. In this paper, MP-FEM was then used to simulate PWAS EMI for the goal of SHM. EMI of free PWAS was first simulated and compared with experimental result. Then the constrained PWAS was studied. EMI of both metallic and glass fiber composite materials were simulated. The first case is the constrained PWAS on aluminum beam with various dimensions. The second case studies the sensitivity range of the EMI approach for damage detection on aluminum beam using a set of specimens with cracks at different locations. In the third case, structural damping effects were also studied in this paper.. Our results have also shown that the imaginary part of the impedance and admittance can be used for sensor self-diagnosis.

Truss Structure Health Monitoring Based on Electromechanical Impedance Method

2013 ◽  
Vol 330 ◽  
pp. 357-363
Author(s):  
Cun Fu He ◽  
Xiao Ming Cai ◽  
Shen Yang ◽  
Zeng Hua Liu ◽  
Bin Wu
Keyword(s):  
Neural Network ◽  
Health Monitoring ◽  
Truss Structure ◽  
Truss Structures ◽  
Impedance Method ◽  
Nonparametric Model ◽  
Impedance Spectra ◽  
Frequency Range ◽  
Electromechanical Impedance ◽  
Piezoelectric Elements

Truss structure is widely used in civil engineering applications for its advantages of easy transportation, convenient assembly and uniform loading. However, it is difficult to achieve real-time health monitoring because of connection diversity and complexity of truss structures. As a novel structural health monitoring technique, electro-mechanical impedance method could monitor the health state of one structure by measuring the spectra of impedance or admittance of the piezoelectric elements, which are bonded on the surface of this structure. This approach has the advantages of nonparametric model analysis, easy sensor installation and high local sensitivity, especially in sensitive frequency range. The damage information, which is tested and recorded by using electromechanical impedance method, could convert into intuitive results through neural network because of its good ability for nonlinear mapping. In this paper, a three-layer assembly truss structure was chosen as experimental object, piezoelectric elements were bonded on structure joints to measure structural impedance spectra, the change of these structural impedance spectra was tested and recorded under high frequency excitations when different truss bars were loosed, and then, one back-propagation (BP) neural network was built and trained by this damage information, which were treated as input samples. These results show that the sensitivity of impedance method is not the same to different frequency range and trained neural network could quickly identify loosen truss bars.

Electro-Mechanical Impedance Measurements as a Possible SHM Method for Sandwich Debonding Detection

2017 ◽  
Vol 742 ◽  
pp. 763-777 ◽  
Author(s):  
Christoph Kralovec ◽  
Martin Schagerl
Keyword(s):  
Present Article ◽  
Health Monitoring ◽  
Sandwich Panel ◽  
Mechanical Impedance ◽  
Impedance Method ◽  
Constant Thickness ◽  
Fem Model ◽  
Impedance Measurements ◽  
Coupled Field ◽  
Debonding Detection

The present article addresses the evaluation of the electro-mechanical (E/M) impedance method as a Structure Health Monitoring (SHM) method to detect and classify damage, more specific, the debonding of a face layer.In the study the considered structure is simplified as a circular sandwich panel of constant thickness, consisting of isotropic face layers and a honeycomb core.The debonding is assumed to be circular and situated at the center of the panel, only variable in its radius.The article starts with a brief introduction to the basic idea of SHM and the fundamentals of the E/M impedance method.Further, the idealized setting is investigated by two sets of experiments whose results are analyzed by typically used damage metrics and by considering both analytical and numerical models.A coupled-field FEM model is developed and compared to the experimental results.Furthermore, an analytical model is derived to evaluate the experimental and numerical results.All results are presented and discussed extensively on pursuing the objective to detect and classify the size of a debonding.Finally, it is shown how a model based approach can predict the presence but also the size of a debonding in the considered sandwich panels based on the E/M impedance measurements.

A review of structural health monitoring of bonded structures using electromechanical impedance spectroscopy

2021 ◽  
pp. 147592172199341
Author(s):  
A Francisco G Tenreiro ◽  
António M Lopes ◽  
Lucas FM da Silva
Keyword(s):  
Structural Health Monitoring ◽  
Impedance Spectroscopy ◽  
Health Monitoring ◽  
Mechanical Impedance ◽  
Local Area ◽  
Electric Response ◽  
Adhesively Bonded ◽  
Adhesively Bonded Joints ◽  
Electromechanical Impedance ◽  
Structural Health

The article presents a literature review of electromechanical impedance spectroscopy for structural health monitoring, with emphasis in adhesively bonded joints. The concept behind electromechanical impedance spectroscopy is to use variable high-frequency structural vibrations with piezoelectric elements to monitor the local area of a structure for changes in mechanical impedance that may indicate imminent damage. Various mathematical models that correlate the structural impedance with the electric response of the piezoelectric sensors are presented. Several algorithms and metrics are introduced to detect, localize, and characterize damage when using electromechanical impedance spectroscopy. Applications of electromechanical impedance spectroscopy to study adhesive joints are described. Research and development of alternative hardware for electromechanical impedance spectroscopy is presented. The article ends by presenting future prospects and research of electromechanical impedance spectroscopy–based structural health monitoring, and, while advances have been made in algorithms for damage detection, localization, and characterization, this technology is not mature enough for real-world applications.

Multi-Vehicle Load Identification Using Existing Bridge Health Monitoring System

2019 ◽  
Author(s):  
Limu Chen ◽  
Xudong Jian ◽  
Ye Xia ◽  
Limin Sun
Keyword(s):  
Computer Vision ◽  
Monitoring System ◽  
Health Monitoring ◽  
Safety Evaluation ◽  
Field Tests ◽  
Theoretical Background ◽  
Traffic Load ◽  
Systematic Analysis ◽  
Health Monitoring System ◽  
Vehicle Load

<p>Collecting the information of traffic load, especially heavy trucks, is crucial for bridge statistical analysis, safety evaluation, as well as maintenance strategies. This paper presents a traffic sensing methodology that combines a deep learning based computer vision technique with the influence line theory. Theoretical background and derivations are introduced from both aspects of structural analysis and computer vision techniques. In addition, to evaluate the effectiveness and accuracy of the proposed traffic sensing method through field tests, a systematic analysis is performed on a continuous box-girder bridge. The obtained results show that the proposed method can automatically identify the vehicle load and speed with promising efficiency and accuracy, and most importantly cost-effectiveness. All these features make the proposed methodology a desirable bridge weigh-in-motion system, especially for bridges already equipped with structural health monitoring system.</p>

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