Progress Towards a Forward Model of the Complete Acoustic Emission Process

2006 ◽  
Vol 13-14 ◽  
pp. 69-76 ◽  
Author(s):  
Paul D. Wilcox ◽  
C.K. Lee ◽  
Jonathan J. Scholey ◽  
Michael I. Friswell ◽  
M.R. Wisnom ◽  
...  
Keyword(s):  
Acoustic Emission ◽  
Guided Waves ◽  
Deterministic Model ◽  
Numerical Data ◽  
Structural Features ◽  
Guided Wave ◽  
Probability Of Detection ◽  
Modular Architecture ◽  
Element Analysis ◽  
Industrial Sectors

Acoustic emission (AE) techniques have obvious attractions for structural health monitoring (SHM) due to their extreme sensitivity and low sensor density requirement. A factor preventing the adoption of AE monitoring techniques in certain industrial sectors is the lack of a quantitative deterministic model of the AE process. In this paper, the development of a modular AE model is described that can be used to predict the received time-domain waveform at a sensor as a result of an AE event elsewhere in the structure. The model is based around guided waves since this is how AE signals propagate in many structures of interest. Separate modules within the model describe (a) the radiation pattern of guided wave modes at the source, (b) the propagation and attenuation of guided waves through the structure, (c) the interaction of guided waves with structural features and (d) the detection of guided waves with a transducer of finite spatial aperture and frequency response. The model is implemented in the frequency domain with each element formulated as a transfer function. Analytic solutions are used where possible; however, by virtue of its modular architecture it is straightforward to include numerical data obtained either experimentally or through finite element analysis (FEA) at any stage in the model. The paper will also show how the model can used, for example, to produce probability of detection (POD) data for an AE testing configuration.

scholarly journals Fatigue crack detection in pipes with multiple mode nonlinear guided waves

2018 ◽  
Vol 18 (1) ◽  
pp. 180-192 ◽  
Author(s):  
Ruiqi Guan ◽  
Ye Lu ◽  
Kai Wang ◽  
Zhongqing Su
Keyword(s):  
Fatigue Crack ◽  
Crack Detection ◽  
Guided Waves ◽  
Second Harmonic ◽  
Experimental Testing ◽  
Harmonic Wave ◽  
Guided Wave ◽  
Element Analysis ◽  
Fatigue Crack Detection ◽  
Wave Modes

This study elaborates fundamental differences in fatigue crack detection using nonlinear guided waves between plate and pipe structures and provides an effective approach for analysing nonlinearity in pipe structures. For this purpose, guided wave propagation and interaction with microcrack in a pipe structure, which introduced a contact acoustic nonlinearity, was analysed through a finite element analysis in which the material nonlinearity was also included. To validate the simulation results, experimental testing was performed using piezoelectric transducers to generate guided waves in a specimen with a fatigue crack. Both methods revealed that the second harmonic wave generated by the breathing behaviour of the microcrack in a pipe had multiple wave modes, unlike the plate scenario using nonlinear guided waves. Therefore, a proper index which considered all the generated wave modes due to the microcrack was developed to quantify the nonlinearity, facilitating the identification of microscale damage and further assessment of the severity of the damage in pipe structures.

scholarly journals Connection looseness detection of steel grid structures using piezoceramic transducers

2018 ◽  
Vol 14 (2) ◽  
pp. 155014771875923 ◽  
Author(s):  
Shi Yan ◽  
Weiling Liu ◽  
Gangbing Song ◽  
Putian Zhao ◽  
Shuai Zhang
Keyword(s):  
Wave Energy ◽  
Guided Waves ◽  
Evaluation Method ◽  
Guided Wave ◽  
Experimental Results ◽  
Structure Model ◽  
Nonlinear Regularity ◽  
Detection Mechanism ◽  
Element Analysis ◽  
Key Techniques

Connection looseness phenomena of steel grid structures might induce issues of lowering integrity, large deformation, even total collapse of the structures. The goal of this article is to propose an evaluation method for bolt-sphere joint looseness of steel grid structures using piezoceramic guided wave–based method through experiments and numerical simulations. A single bolt-sphere joint looseness experimental model is established and tested, considering grid member connection angles of 0°, 45°, 90°, and 180°, respectively. Then, multiple bolt-sphere joint looseness detection tests by selecting six kinds of cases for a steel grid structure model are performed. Piezoceramic patch arrays bonded on the surface of grid members are used as transducers to generate and receive detection guided waves, and external torques are applied to indirectly simulate the bolt-sphere joint looseness effect. The experimental results show that the bolt-sphere joint looseness impact on the ultrasonic wave energy attenuation has a nonlinear regularity. Based on the regularity, an evaluation method and key techniques for the bolt-sphere joint looseness detection based on guided wave energy are proposed and experimentally validated. To further clarify the bolt-sphere joint looseness detection mechanism, the ABAQUS software is used for a finite element analysis of the single bolt-sphere joint looseness evaluation. The numerical and experimental results match well, verifying the feasibility of the proposed method.

scholarly journals Guided Waves for Damage Detection in Complex Composite Structures: The Influence of Omega Stringer and Different Reference Damage Size

2020 ◽  
Vol 10 (9) ◽  
pp. 3068
Author(s):  
Jochen Moll ◽  
Christian Kexel ◽  
Jens Kathol ◽  
Claus-Peter Fritzen ◽  
Maria Moix-Bonet ◽  
...  
Keyword(s):  
Composite Structures ◽  
Guided Waves ◽  
Fiber Composite ◽  
Composite Plates ◽  
Guided Wave ◽  
Probability Of Detection ◽  
Carbon Fiber Composite ◽  
Technical Validation ◽  
Pod Analysis ◽  
The Impact

The third dataset dedicated to the Open Guided Waves platform aims at carbon fiber composite plates with an additional omega stringer at constant temperature conditions. The two structures used in this work are representative for real aircraft components. Comprehensive measurements were recorded in order to study (I) the impact of the omega stringer on guided wave propagation, and (II) elliptical reference damages of different sizes located at three separate positions on the structure. Measurements were recorded for narrowband excitation (5-cycle toneburst with varying carrier frequencies) and broadband excitation (using chirp waveforms). The paper presents the results of a technical validation including numerical modelling, and enables further research, for example related to probability of detection (POD) analysis.

scholarly journals An Investigation on a Quantitative Tomographic SHM Technique for a Containment Liner Plate in a Nuclear Power Plant with Guided Wave Mode Selection

Sensors ◽  
2019 ◽  
Vol 19 (12) ◽  
pp. 2819 ◽  
Author(s):  
Yonghee Lee ◽  
Younho Cho
Keyword(s):  
Power Plant ◽  
Nuclear Power Plant ◽  
Elastic Wave ◽  
Nuclear Power ◽  
Guided Waves ◽  
Mode Selection ◽  
Wave Mode ◽  
Guided Wave ◽  
Element Analysis ◽  
Wave Tomography

The containment liner plate (CLP) in a nuclear power plant is the most critical part of the structure of a power plant, as it prevents the radioactive contamination of the surrounding area. This paper presents feasibility of structural health monitoring (SHM) and an elastic wave tomography method based on ultrasonic guided waves (GW), for evaluating the integrity of CLP. It aims to check the integrity for a dynamic response to a damaged isotropic structure. The proposed SHM technique relies on sensors and, therefore, it can be placed on the structure permanently and can monitor either passively or actively. For applying this method, a suitable guided wave mode tuning is required to verify wave propagation. A finite element analysis (FEA) is performed to figure out the suitable GW mode for a CLP by considering geometric and material condition. Furthermore, elastic wave tomography technique is modified to evaluate the CLP condition and its visualization. A modified reconstruction algorithm for the probabilistic inspection of damage tomography algorithm is used to quantify corrosion defects in the CLP. The location and shape of the wall-thinning defects are successfully obtained by using elastic GW based SHM. Making full use of verified GW mode to Omni-directional transducer, it can be expected to improve utilization of the SHM based evaluation technique for CLP.

Propagation of Guided Waves in Pressure Vessel and its Application for Damage Detection

2012 ◽  
Author(s):  
Xuewei Sun ◽  
Fucai Li ◽  
Jinfu Wang ◽  
Guang Meng ◽  
Limin Zhou
Keyword(s):  
Structural Health Monitoring ◽  
Health Monitoring ◽  
Pressure Vessel ◽  
Guided Waves ◽  
Pressure Vessels ◽  
Guided Wave ◽  
Special Equipment ◽  
Element Analysis ◽  
Structural Health ◽  
Monitoring Technique

Pressure vessel is a kind of special equipment with explosion and leakage dangerous. Therefore, structural health monitoring (SHM) techniques for pressure vessel should ensure the safe operation of this kind of equipments and is becoming more crucial in petroleum, chemical, and relative industries. Guided wave-based structural health monitoring technique can be an appropriate method for real-time and online non-destructive damage monitoring technique. In recent years, applications of guided wave-based structural health monitoring techniques are mainly limited in simple structures, such as plates and tubes. Relatively few research papers focused on the application of this technique in large and complex structures like pressure vessels. Propagation characteristics of guided waves in pressure vessel are investigated in this study. Dispersion curves calculated by using numerical methods for longitudinal, circumferential, and torsional modes are presented. On the basis of comprehensive analysis of the guided waves dispersion and experimental waveforms, the parameters of the excitation wave are therefore optimized. In order to overcome the difficulties to identify the damage characteristics of signal, the layout scheme of sensor network is designed and optimized in this paper to simplify the waveform. Furthermore, both finite element analysis (FEA) and experiment methods are employed to investigate the propagation of elastic guided waves in a standard pressure vessel.

Acoustic emission propagation characteristics in plate structure with various materials, cracks and coating metal

2016 ◽  
Vol 231 (11) ◽  
pp. 2080-2088
Author(s):  
Kuanfang He ◽  
Zhi Tan ◽  
Yong Cheng ◽  
Xuejun Li
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Acoustic Emission ◽  
Guided Waves ◽  
Propagation Characteristic ◽  
Guided Wave ◽  
Propagation Characteristics ◽  
The Finite Element Method ◽  
Plate Structure ◽  
Element Method

The propagation characteristic of guided waves is important to acoustic emission nondestructive detection for the structural integrity of engineering components. The finite element method is introduced to study the propagation of guided waves in plate structure with different materials, cracks and coating metal. The displacement contours and wave curve at different receiving positions are examined first for the propagation characteristics of guided waves in plate structure with different homogeneous material of steel 45 and GCr15. Next, the interface reflection, refraction and diffraction characteristics of guided waves in plate structure with cracks and steel 45 with coating metal of aluminium 2024 are investigated. Finally, these FE results are compared with the mechanical pencil lead fracture experiment results. The results of this study clearly illustrate the accuracy and reasonableness of the finite element method to predict propagation characteristic of guided wave.

Strategies for guided-wave structural health monitoring

2007 ◽  
Vol 463 (2087) ◽  
pp. 2961-2981 ◽  
Author(s):  
A.J Croxford ◽  
P.D Wilcox ◽  
B.W Drinkwater ◽  
G Konstantinidis
Keyword(s):  
Structural Health Monitoring ◽  
Health Monitoring ◽  
Temperature Compensation ◽  
Guided Waves ◽  
Reference Data ◽  
Reference Signal ◽  
Structural Features ◽  
Guided Wave ◽  
Structural Health ◽  
Signal Suppression

Structural health monitoring (SHM) using guided waves is one of the only ways in which damage anywhere in a structure can be detected using a sparse array of permanently attached sensors. To distinguish damage from structural features, some form of comparison with damage-free reference data is essential, and here subtraction is considered. The detectability of damage is determined by the amplitude of residual signals from structural features remaining after the subtraction of reference data. These are non-zero due to changing environmental conditions such as temperature. In this paper, the amplitude of the residual signals is quantified for different guided-wave SHM strategies. Comparisons are made between two methods of reference signal subtraction and between two candidate sensor configurations. These studies allow estimates to be made of the number of sensors required per unit area to reliably detect a prescribed type of damage. It is shown that the number required is prohibitively high, even in the presence of modest temperature fluctuations, hence some form of temperature compensation is absolutely essential for guided-wave SHM systems to be viable. A potential solution is examined and shown to provide an improvement in signal suppression of approximately 30 dB, which corresponds to two orders of magnitude reduction in the number of sensors required.

A Helmholtz Potential Approach to the Analysis of Guided Wave Generation During Acoustic Emission Events

2017 ◽  
Vol 1 (2) ◽  
Author(s):  
Mohammad Faisal Haider ◽  
Victor Giurgiutiu
Keyword(s):  
Acoustic Emission ◽  
Crack Propagation ◽  
Displacement Field ◽  
Guided Waves ◽  
Guided Wave ◽  
The Body ◽  
Peak Amplitude ◽  
Bulk Wave ◽  
Vector Potentials ◽  
Body Forces

This paper addresses the predictive simulation of acoustic emission (AE) guided waves that appear due to sudden energy release during incremental crack propagation. The Helmholtz decomposition approach is applied to the inhomogeneous elastodynamic Navier–Lame equations for both the displacement field and body forces. For the displacement field, we use the usual decomposition in terms of unknown scalar and vector potentials, Φ and H. For the body forces, we hypothesize that they can also be expressed in terms of excitation scalar and vector potentials, A* and B*. It is shown that these excitation potentials can be traced to the energy released during an incremental crack propagation. Thus, the inhomogeneous Navier–Lame equation has been transformed into a system of inhomogeneous wave equations in terms of known excitation potentials A* and B* and unknown potentials Φ and H. The solution is readily obtained through direct and inverse Fourier transforms and application of the residue theorem. A numerical study of the one-dimensional (1D) AE guided wave propagation in a 6 mm thick 304-stainless steel plate is conducted. A Gaussian pulse is used to model the growth of the excitation potentials during the AE event; as a result, the actual excitation potential follows the error function variation in the time domain. The numerical studies show that the peak amplitude of A0 signal is higher than the peak amplitude of S0 signal, and the peak amplitude of bulk wave is not significant compared to S0 and A0 peak amplitudes. In addition, the effects of the source depth, higher propagating modes, and propagating distance on guided waves are also investigated.

Protein Interaction Domains and Post-Translational Modifications: Structural Features and Drug Discovery Applications

2020 ◽  
Vol 27 (37) ◽  
pp. 6306-6355 ◽  
Author(s):  
Marian Vincenzi ◽  
Flavia Anna Mercurio ◽  
Marilisa Leone
Keyword(s):  
Drug Discovery ◽  
Protein Interaction ◽  
Protein Interactions ◽  
Structural Information ◽  
Protein Complexes ◽  
Structural Features ◽  
Protein Protein Interactions ◽  
Modular Architecture ◽  
Post Translational Modifications ◽  
Interaction Domains

Background:: Many pathways regarding healthy cells and/or linked to diseases onset and progression depend on large assemblies including multi-protein complexes. Protein-protein interactions may occur through a vast array of modules known as protein interaction domains (PIDs). Objective:: This review concerns with PIDs recognizing post-translationally modified peptide sequences and intends to provide the scientific community with state of art knowledge on their 3D structures, binding topologies and potential applications in the drug discovery field. Method:: Several databases, such as the Pfam (Protein family), the SMART (Simple Modular Architecture Research Tool) and the PDB (Protein Data Bank), were searched to look for different domain families and gain structural information on protein complexes in which particular PIDs are involved. Recent literature on PIDs and related drug discovery campaigns was retrieved through Pubmed and analyzed. Results and Conclusion:: PIDs are rather versatile as concerning their binding preferences. Many of them recognize specifically only determined amino acid stretches with post-translational modifications, a few others are able to interact with several post-translationally modified sequences or with unmodified ones. Many PIDs can be linked to different diseases including cancer. The tremendous amount of available structural data led to the structure-based design of several molecules targeting protein-protein interactions mediated by PIDs, including peptides, peptidomimetics and small compounds. More studies are needed to fully role out, among different families, PIDs that can be considered reliable therapeutic targets, however, attacking PIDs rather than catalytic domains of a particular protein may represent a route to obtain selective inhibitors.

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