Ultrasonic damage imaging of structural components with bulk and guided waves using match coefficients

2017 ◽  
Author(s):  
S. Sternini ◽  
A. Quattrocchi ◽  
R. Montanini ◽  
F. Lanza di Scalea
Keyword(s):  
Guided Waves ◽  
Structural Components ◽  
Damage Imaging ◽  
Ultrasonic Damage

Defect Localization for Pressure Vessel Based on Circumferential Guided Waves: An Experimental Study

2018 ◽  
Author(s):  
Shuangmiao Zhai ◽  
Chaofeng Chen ◽  
Gangyi Hu ◽  
Shaoping Zhou
Keyword(s):  
Pressure Vessel ◽  
Guided Waves ◽  
Pressure Vessels ◽  
Guided Wave ◽  
Normal Operation ◽  
Propagation Characteristics ◽  
Dense Array ◽  
Imaging Algorithm ◽  
Sparse Array ◽  
Damage Imaging

Pressure vessels are normally employed under extreme environments with high temperature and high pressure. Inevitably, the defects like crack and corrosion that easily occur in the equipment and can significantly influence the normal operation. Guided wave-based method is a cost-effective means to measure the utility of pressure vessel. In this paper, finite element (FE) simulation is used to explore the propagation characteristics of circumferential guided waves in pressure vessel. Based on the propagation characteristics, the experiments with different configurations of piezoelectric transducers (PETs), which contain a sparse array and a dense array, have been conducted on pressure vessel respectively. Different imaging methods, including discrete ellipse imaging algorithm and probability damage imaging algorithm have been applied to locate the defect based on the configurations above. Furthermore, a multi-channel ultrasonic guided wave detection system has been set up for pressure vessel inspection. The experimental results show that the sparse array with the discrete ellipse imaging algorithm can locate the defect effectively. The imaging results based on probability damage imaging algorithm show that the dense array presents the better localization result.

Damage Imaging of Pipes in Nuclear Power Plants Using Torsional Guided Wave Modes

2013 ◽  
Vol 577-578 ◽  
pp. 661-664
Author(s):  
Zhao Xiang Wei ◽  
Hong Xu ◽  
Hong Yuan Li
Keyword(s):  
Power Plant ◽  
Nuclear Power Plant ◽  
Nuclear Power ◽  
Power Plants ◽  
Guided Waves ◽  
Axial Position ◽  
Imaging Method ◽  
Long Distance ◽  
Torsional Mode ◽  
Damage Imaging

Ultrasonic guided waves can propagate a long distance in pipeline with little attenuation. This means the damage in nuclear power plant can be detected from a remote single position. In the paper, the propagation of the guided waves are analyzed for the nuclear power plant pipes, and the axisymmetric torsional mode T(0,1) is chosen as the detection mode. An imaging method based on the synthetic focusing algorithm is used to obtain the damage information. The method is then verified by the finite element model. Results illustrate that the damage can be detected and located accurately by the damage imaging method. Not only the axial position, but also the circumferential position can be located simultaneously.

Damage imaging in skin-stringer composite aircraft panel by ultrasonic-guided waves using deep learning with convolutional neural network

2021 ◽  
pp. 147592172110239
Author(s):  
Ranting Cui ◽  
Guillermo Azuara ◽  
Francesco Lanza di Scalea ◽  
Eduardo Barrera
Keyword(s):  
Neural Network ◽  
Deep Learning ◽  
Convolutional Neural Network ◽  
Structural Damage ◽  
Guided Waves ◽  
Complex Structure ◽  
Guided Wave ◽  
Training Data ◽  
Composite Panel ◽  
Damage Imaging

The detection and localization of structural damage in a stiffened skin-to-stringer composite panel typical of modern aircraft construction can be addressed by ultrasonic-guided wave transducer arrays. However, the geometrical and material complexities of this part make it quite difficult to utilize physics-based concepts of wave scattering. A data-driven deep learning (DL) approach based on the convolutional neural network (CNN) is used instead for this application. The DL technique automatically selects the most sensitive wave features based on the learned training data. In addition, the generalization abilities of the network allow for detection of damage that can be different from the training scenarios. This article describes a specific 1D-CNN algorithm that has been designed for this application, and it demonstrates its ability to image damage in key regions of the stiffened composite test panel, particularly the skin region, the stringer’s flange region, and the stringer’s cap region. Covering the stringer’s regions from guided wave transducers located solely on the skin is a particularly attractive feature of the proposed SHM approach for this kind of complex structure.

Robust Localization and Classification of Barely Visible Indentations in Composite Structures by Fusion of Ultrasonic Damage Indices

2019 ◽  
Vol 2 (3) ◽  
Author(s):  
Mohammad Ali Fakih ◽  
Samir Mustapha ◽  
Ali Abdul-Aziz
Keyword(s):  
Composite Structures ◽  
Guided Waves ◽  
Composite Sandwich ◽  
Wave Measurements ◽  
Damage Indices ◽  
Intact Condition ◽  
Ultrasonic Damage ◽  
Detection And Localization ◽  
Indentation Damage

This study aims to detect, localize, and assess the severity of barely visible indentation damage in a composite sandwich structure using ultrasonic guided waves. A quasistatic loading was gradually applied on a specimen of carbon fiber reinforced epoxy resulting in dents on the surface. Lamb-wave measurements, from a sensor network mounted on the panel's surface, were taken for the intact condition and three damage cases (0.2, 0.5, and 2.7-mm dents). Three approaches were adopted to define the damage indices (DIs) toward anomaly detection, namely, amplitude variation, symbolic dynamics, and root mean square deviation. Data fusion was performed between measurements from multiple excitation frequencies for single and multiple DIs, where the anomaly combination between all the frequencies and the DIs was called a total anomaly. An imaging algorithm was implemented for damage localization in conjunction with single and combined DIs. It was shown that combining the effects of different frequencies and/or different DIs increases the robustness and consistency of the damage detection and localization process. Moreover, a distance-based classification technique was applied using features from single DIs and the combined anomaly measure. Accuracies higher than 91% were attained for the majority of the cases tested.

Development of Lamb Waves-Based SHM Systems

2012 ◽  
Vol 518 ◽  
pp. 87-94 ◽  
Author(s):  
Lukasz Ambrozinski ◽  
Tadeusz Stepinski ◽  
Tadeusz Uhl ◽  
Janusz Ochonski ◽  
Andrzej Klepka
Keyword(s):  
Composite Structures ◽  
Guided Waves ◽  
Lamb Waves ◽  
Safety Standards ◽  
Promising Tool ◽  
Self Focusing ◽  
Half Wavelength ◽  
Damage Imaging ◽  
Synthetic Aperture Focusing ◽  
Design And Manufacture

Guided waves (GW) based methods are a promising tool for structural health monitoring (SHM) of plate-like metallic and composite structures in which high safety standards are required. In this paper we present research with the aim to design and manufacture a prototype of Lamb waves (LW) SHM system. Two approaches can be applied for SHM of plate-like structures. One of them can be based on a sparse array and damage imaging involving incoherent summation of signals envelope. The second approach involves phased arrays with transducers spaced at a distance lower than half wavelength of the excited Lamb-mode. The influence of an arrays parameters on beamforming of Lamb waves is discussed in the case of linear array. It appears that an unequivocal localization of damage on a plate requires a 2D arrays topology; therefore a star-shaped active array was designed and manufactured for the developed SHM system. Two signal processing approaches were applied for that array, the standard one, based on the delay and sum (DAS) synthetic aperture focusing scheme, and the second one, using a self-focusing technique to obtain the separate images for each scatterer existing in the plate.

Guided Waves in a Plate With a Delamination-Like Discontinuity

2016 ◽  
Author(s):  
Christoph Schaal ◽  
Ajit Mal
Keyword(s):  
Cross Sections ◽  
Composite Structures ◽  
Guided Waves ◽  
Lamb Waves ◽  
Near Field ◽  
Experimental Methods ◽  
Structural Components ◽  
Inspection Systems ◽  
Frame Work ◽  
Theoretical Results

In this paper, some of the useful properties of guided Lamb waves are investigated, using analytical, numerical and experimental methods, in an effort to provide the knowledge base required for the development of viable nondestructive evaluation (NDE) systems for composite structures. An analytical frame-work that considers propagating, nonpropagating and evanescent Lamb waves to analyze the scattering of an incident ultrasonic Lamb wave at delaminations and disbonds is presented. In addition to the delamination problem, the interaction of Lamb waves with a step discontinuity, which can be found at common stiffeners, is investigated using a similar analytical approach. A near-field solution is obtained, and power flows through the cross-sections of the plate are evaluated. The agreement between experimental, numerical and theoretical results is shown to be excellent in certain frequency ranges, providing guidance for the design of reliable and effective inspection systems for modern aeronautical and aerospace structural components.

scholarly journals A match coefficient approach for damage imaging in structural components by ultrasonic synthetic aperture focus

2017 ◽  
Vol 199 ◽  
pp. 1544-1549 ◽  
Author(s):  
S. Sternini ◽  
A. Quattrocchi ◽  
R. Montanini ◽  
A. Pau ◽  
F. Lanza di Scalea
Keyword(s):  
Synthetic Aperture ◽  
Structural Components ◽  
Damage Imaging
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