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1115 full-text articles. Page 8 of 35.

Full-Field Structural Dynamics By Video Motion Manipulations, Yongchao Yang, Charles Farrara, David Mascarenasa 2016 Los Alamos National Laboratory

Full-Field Structural Dynamics By Video Motion Manipulations, Yongchao Yang, Charles Farrara, David Mascarenasa

Review of Progress in Quantitative Nondestructive Evaluation

Structures with complex geometries, material properties, and boundary conditions, exhibit spatially local, temporally transient, dynamic behaviors. High spatial and temporal resolution vibration measurements and modeling are thus required for high-fidelity characterization, analysis, and prediction of the structure’s dynamic phenomena. For example, high spatial resolution mode shapes are needed for accurate vibration-based damage localization. Also, higher order vibration modes typically contain local structural features that are essential for high-fidelity dynamic modeling of the structure. In addition, while it is possible to build a highly- refined mathematical model (e.g., a finite element model) of the structure, it needs to be ...


Raw Data Based Image Processing Algorithm For Fast Detection Of Surface Breaking Cracks Using In-Line Laser Thermography, Sruthi Krishna, Nithin Puthiyaveettil, P. Biju, Krishnan Balasubramaniam 2016 Indian Institute of Technology Madras

Raw Data Based Image Processing Algorithm For Fast Detection Of Surface Breaking Cracks Using In-Line Laser Thermography, Sruthi Krishna, Nithin Puthiyaveettil, P. Biju, Krishnan Balasubramaniam

Review of Progress in Quantitative Nondestructive Evaluation

The aim of this work is to illustrate the contribution of signal processing techniques in the field of Non-Destructive Evaluation. A component’s life evaluation is inevitably related to the presence of flaws in it. The detection and characterization of cracks prior to damage is a technologically and economically significant task and is of very importance when it comes to safety-relevant measures. The Laser Thermography is the most effective and advanced thermography method for Non-Destructive Evaluation. High capability for the detection of surface cracks and for the characterization of the geometry of artificial surface flaws in metallic samples of laser ...


Full Matrix Capture And The Total Focusing Imaging Algorithm Using Laser Induced Ultrasonic Phased Arrays, Theodosia Stratoudaki, Matt Clark, Paul D. Wilcox 2016 University of Bristol

Full Matrix Capture And The Total Focusing Imaging Algorithm Using Laser Induced Ultrasonic Phased Arrays, Theodosia Stratoudaki, Matt Clark, Paul D. Wilcox

Review of Progress in Quantitative Nondestructive Evaluation

Laser ultrasonics is a technique where lasers are used for the generation and detection of ultrasound instead of conventional piezoelectric transducers. The technique is broadband, non-contact, and couplant free, suitable for large stand-off distances, inspection of components of complex geometries and hazardous environments. In this paper, array imaging is presented by obtaining the full matrix of all possible laser generation, laser detection combinations in the array (Full Matrix Capture), at the nondestructive, thermoelastic regime. An advanced imaging technique developed for conventional ultrasonic transducers, the Total Focusing Method (TFM) [2], is adapted for laser ultrasonics and then applied to the captured ...


Compression Of Multi-Frequency Eddy Current Data Using Principal Components Analysis For Pressure Tube To Calandria Tube Gap Measurement, Shaddy Shokralla, Jordan Morelli, Thomas W. Krause 2016 Queen’s University

Compression Of Multi-Frequency Eddy Current Data Using Principal Components Analysis For Pressure Tube To Calandria Tube Gap Measurement, Shaddy Shokralla, Jordan Morelli, Thomas W. Krause

Review of Progress in Quantitative Nondestructive Evaluation

Inspection of components with multi-variable influential parameters may result in a loss of accuracy for the measurement of the target variable. A particular example occurs in the case of a pressure tube (PT) that is contained within a calandria tube (CT) in the fuel channels of CANDU® nuclear reactors. Eddy current (EC) based measurement of gap between PT and CT, as required by nuclear regulators, is affected by variation of PT wall thickness and resistivity, which may confound the accurate gap measurement. In this work principal components analysis (PCA) is examined as a means of simplifying changes in multi-frequency EC ...


Model Benchmarking And Reference Signals For Angled-Beam Shear Wave Ultrasonic Nde Inspections, John C. Aldrin, Deborah Hopkins, Mark Warchol, Lyudmila V. Warchol, David S. Forsyth, Charlie Buynak, Eric A. Lindgren 2016 Computational Tools, Gurnee

Model Benchmarking And Reference Signals For Angled-Beam Shear Wave Ultrasonic Nde Inspections, John C. Aldrin, Deborah Hopkins, Mark Warchol, Lyudmila V. Warchol, David S. Forsyth, Charlie Buynak, Eric A. Lindgren

Review of Progress in Quantitative Nondestructive Evaluation

NDE modeling and simulation are important tools to support the development and validation of enhanced localization and characterization techniques. Previously, important achievements were made by the USAF to address crack detection in aircraft structures using angled-beam shear wave inspection techniques. However, new work on model benchmarking is needed to move beyond detection and achieve reliable crack characterization. To achieve this goal, simulated studies are needed to verify that models can accurately represent all of the key variables with the inspection of multilayer structures with fastener sites and varying crack conditions. Often with model benchmark studies, the accuracy of the model ...


Existing Weld Seam Recognition And Tracking Based On Sub Region Image Processing, Guoan Liang, Shanshan Wang, Chunlei Tu, Xingsong Wang 2016 Special Equipment Safety Supervision Inspection Institute of Jiangsu Province

Existing Weld Seam Recognition And Tracking Based On Sub Region Image Processing, Guoan Liang, Shanshan Wang, Chunlei Tu, Xingsong Wang

Review of Progress in Quantitative Nondestructive Evaluation

This paper proposes a new algorithm of weld seam recognition for existing weld seam tracking based on sub region neural network. The original images need to be reduced by half and transformed to gray image. Then each picture is divided into 96 small pictures. Sub region neural network of three layers is applied to each small picture. The identification of 96 sub pictures is synthetized to complete the weld seam recognition result of each image. Before training, 5000 samples are obtained in total and they are classified into two categories. 4000 sets of them are considered as training data and ...


Application Of Radon Transform To Wavefield Filtering, Reconstruction, And Imaging Of Dispersive Energies In Quantitative Bone Ultrasound, Lawrence H. Le, Mauricio D. Sacchi 2016 University of Alberta

Application Of Radon Transform To Wavefield Filtering, Reconstruction, And Imaging Of Dispersive Energies In Quantitative Bone Ultrasound, Lawrence H. Le, Mauricio D. Sacchi

Review of Progress in Quantitative Nondestructive Evaluation

Multichannel ultrasonic axial-transmission data are multimodal by nature. Multichannel analysis of dispersive ultrasonic energies requires a reliable mapping of the data from the time– distance (t-x) domain to the frequency–wavenumber (f-k) or frequency–phase velocity (f-c) domain. The mapping is usually performed with the classical 2-D Fourier transform (FT) from t- x plane to f-k plane or to f-c plane with a subsequent substitution and interpolation via c=ω/k. The extracted dispersion trajectories of the guided modes lack the resolution in the transformed domain to discriminate wave modes. The resolving power associated with the FT is closely linked ...


Further Development Of Image Processing Algorithms To Improve Detectability Of Defects In Sonic Ir Nde, Omar Obeidat, Qiuye Yu, Xiaoyan Han 2016 Wayne State University

Further Development Of Image Processing Algorithms To Improve Detectability Of Defects In Sonic Ir Nde, Omar Obeidat, Qiuye Yu, Xiaoyan Han

Review of Progress in Quantitative Nondestructive Evaluation

Sonic Infrared Imaging (SIR) technology is a relatively new NDE technique that has received significant acceptance in the NDE community. SIR NDE is a super-fast, wide range NDE method. The technology uses short pulses of ultrasonic excitation together with infrared imaging to detect defects in the structures under inspection. Defects become visible to the IR camera when the temperature in the crack vicinity increases due to various heating mechanisms in the specimen. Defect detection is highly affected by noise levels as well as mode patterns in the image. Mode patterns result from the superposition of sonic waves interfering within the ...


Nonlinear Mixing Algorithm For Rivet Signal Suppression In Ec-Gmr Inspection Of Multilayer Structures, Seyed Safdernejad, Oleksii Karpenko, Chaofeng Ye, Lalita Udpa, Satish Udpa 2016 Michigan State University

Nonlinear Mixing Algorithm For Rivet Signal Suppression In Ec-Gmr Inspection Of Multilayer Structures, Seyed Safdernejad, Oleksii Karpenko, Chaofeng Ye, Lalita Udpa, Satish Udpa

Review of Progress in Quantitative Nondestructive Evaluation

Giant Magneto-Resistive (GMR) sensors have recently emerged as a promising tool for Eddy Current (EC) inspection of multi-layer riveted structures. However, the detection of defects under fasteners remains a challenging problem, since the distortion of the induced magnetic field introduced by subsurface flaws is masked by the strong responses from steel fasteners and structural edges. Multi-frequency EC-GMR measurements can be used to suppress the rivet signal, while retaining defect indications and hence increase the detectability of defects. In this paper, we propose a novel generic filter for processing EC-GMR measurements acquired at a single or multiple excitation frequencies to suppress ...


Evaluation Of High Spatial Resolution Imaging Of Magnetic Stray Fields For Early Damage Detection, Robert Stegemann, Nadja Sonntag, Sandra Cabeza, Viktor Lyamkin, Matthias Pelkner, Giovanni Bruno, Birgit Skrotzki, Marc Kreutzbruck 2016 BAM

Evaluation Of High Spatial Resolution Imaging Of Magnetic Stray Fields For Early Damage Detection, Robert Stegemann, Nadja Sonntag, Sandra Cabeza, Viktor Lyamkin, Matthias Pelkner, Giovanni Bruno, Birgit Skrotzki, Marc Kreutzbruck

Review of Progress in Quantitative Nondestructive Evaluation

Metal magnetic memory (MMM) technique with associated ISO 24497-1:3 [1] is gaining considerable interest in the magnetic NDT community. In contrast to traditional Magnetic Flux Leakage (MFL) testing, the inspection objects are not intentionally magnetized by an external magnetic field [1,2]. Due to the physical coupling between mechanical stress and magnetization of ferromagnetic materials [3], it is assumed that the distribution of the residual MFL correspond to the internal stress of the specimen [2,4], or in the most general sense, to a degradation of the material [1,2].

Usually, MMM measurements are performed by relatively bulky magnetic ...


Detection Of Manufacturing Defects Via Wavefield Image Processing Techniques: An Experimental Study, Peter D. Juarez, Cara A. C. Leckey 2016 NASA Langley Research Center

Detection Of Manufacturing Defects Via Wavefield Image Processing Techniques: An Experimental Study, Peter D. Juarez, Cara A. C. Leckey

Review of Progress in Quantitative Nondestructive Evaluation

Defects that occur during the manufacturing of a composite can have drastic effects on the intended strength or durability of composite structures. These defects include gaps and overlaps in the prepreg tow-tape that can occur during Automated Fiber Placement (AFP) system operations, as well as unintended fiber waviness caused by differential thermal loading during curing cycles. Wavefield imaging offers a non-contact method of detecting various anomalies in composites, and emerging technologies can enable rapid wavefield acquisition. In this work, composite samples were created with intentional and analogous manufacturing defects such as the ones mentioned, and full guided wavefield data was ...


High-Frequency Total-Focusing Method Imaging In Strongly Attenuating Materials With The Decomposition Of The Time Reversal Operator Associated With Orthogonal Coded Excitations, Eduardo Lopez Villaverde, Sébastien Robert, Claire Prada 2016 CEA

High-Frequency Total-Focusing Method Imaging In Strongly Attenuating Materials With The Decomposition Of The Time Reversal Operator Associated With Orthogonal Coded Excitations, Eduardo Lopez Villaverde, Sébastien Robert, Claire Prada

Review of Progress in Quantitative Nondestructive Evaluation

This communication presents a study that aims to improve the ultrasonic array imaging in High Density Polyethylene (HDPE). This material has been used in place of steel alloys in the power, petrochemical and mining industries because of its notable resistance to corrosion. The HDPE is also desirable to be used in nuclear power stations. Compared to metallic welds, the HDPE fusion welds can be considered as homogeneous and isotropic, but the high viscoelastic attenuation of the material makes the weld inspection very difficult. At high frequencies, pulse-echo images present a dramatic electronic noise introduced by the signal acquisition system.

In ...


Novel Wavelet Threshold Denoising Method In Axle Press-Fit Zone Ultrasonic Detection, Chaoyong Peng, Xiaorong Gao, Jianping Peng, Ai Wang 2016 Southwest Jiaotong University

Novel Wavelet Threshold Denoising Method In Axle Press-Fit Zone Ultrasonic Detection, Chaoyong Peng, Xiaorong Gao, Jianping Peng, Ai Wang

Review of Progress in Quantitative Nondestructive Evaluation

Axles are important part of railway locomotives and vehicles. Periodic ultrasonic inspection of axles can effectively detect and monitor axle fatigue cracks. However, in the axle press-fit zone, the complex interface contact condition reduces the signal-noise ratio (SNR). Therefore, the probability of false positives and false negatives increases. In this work, a novel wavelet threshold function is created to remove noise and suppress press-fit interface echoes in axle ultrasonic defect detection. The exponential threshold function proposed by Andria [1] can't get a gradual curve for later optimum searching process; and the novel wavelet threshold function with two variables is ...


Deconvolution Of Ultrasonic Signals In Porous Materials: Estimation Of Acoustic Propagation Parameters Andwave Separation., Nizar Bouhlel, Sébastien Bourguignon 2016 Ecole Centrale de Nantes

Deconvolution Of Ultrasonic Signals In Porous Materials: Estimation Of Acoustic Propagation Parameters Andwave Separation., Nizar Bouhlel, Sébastien Bourguignon

Review of Progress in Quantitative Nondestructive Evaluation

Our study focuses on the development of assessment tools and nondestructive evaluation of porous materials from ultrasonic measurements. These materials are encountered in many industrial applications such as polyurethane foam used for insulation, aluminum foams used in aerospace or cancellous bone for biological applications. Acoustic propagation in these complex heterogeneous materials is governed by the Biot theory [1], involving the propagation of two types of waves: slow and fast wave, whose properties are respectively related to the fluid and solid phases constituting the material. During the propagation, these waves undergo deformations that can be characterized by related propagation models [2 ...


Low Frequency Ultrasonic Array Imaging Using Signal Post-Processing For Concrete Material, Akio Ozawa, Hideki Izumi, Kazuyuki Nakahata, Katsumi Ohira, Kenzo Ogawa 2016 Ehime University

Low Frequency Ultrasonic Array Imaging Using Signal Post-Processing For Concrete Material, Akio Ozawa, Hideki Izumi, Kazuyuki Nakahata, Katsumi Ohira, Kenzo Ogawa

Review of Progress in Quantitative Nondestructive Evaluation

The use of ultrasonic arrays for conducting non-destructive evaluation has been drastically increased in recent years. As one of the array imaging, a post-processing beam-forming technique has been proposed that utilizes a complete set of signals of all combinations of transmission and reception elements. This approach is referred to as full matrix capture (FMC) [1]. In FMC, each array element is sequentially used as an emitter and all other array elements are used as receivers. By changing the emitting element, we obtained a set of flaw signals that was used to form the focal beam. The delay-and-sum beam reconstruction based ...


Electromagnetic Nondestructive Evaluation Of Defects In Ferromagnetic Samples, Weiying Cheng 2016 Japan Power Engineering and Inspection Corporation

Electromagnetic Nondestructive Evaluation Of Defects In Ferromagnetic Samples, Weiying Cheng

Review of Progress in Quantitative Nondestructive Evaluation

There are increasing demands to detect and characterize defects in ferromagnetic materials. In the electromagnetic nondestructive evaluation (ENDE) of cracks in ferromagnetic materials, both the magnetic flux leakage effect and eddy current perturbation coexist and the signals may be a combination of the two effects: signals arise from flux leakage effects when the crack orients transversal to the flux, and signals arise from eddy current perturbation when the crack orients transversal to the eddy currents. The signals due to the two effects are different on signal width, signal phases, and etc. By the way, surface and back-side cracks can be ...


Experimental Characterization Of Sulfate Damage Of Concrete Based On The Harmonic Wave Modulation Technique, Tinyuan Yin, Wanlin Meng, Neda Talebzadeh, Jun Chen 2016 Beihang University

Experimental Characterization Of Sulfate Damage Of Concrete Based On The Harmonic Wave Modulation Technique, Tinyuan Yin, Wanlin Meng, Neda Talebzadeh, Jun Chen

Review of Progress in Quantitative Nondestructive Evaluation

The objective of this paper is to characterize cracking progression of concrete samples subjected to sulfate attack cycles by employment of a nonlinear wave modulation technique. The sidebands in frequency domain (f1±f2) are produced due to the modulation of two ultrasonic waves (high frequency f1 and low frequency f2) and the relative amplitude of sidebands is defined as the nonlinear parameter considered as a caliber for structural damage. Different from previous work where the low frequency signal was generated by the instrumented hammer, the low frequency signal in this research is a harmonic wave produced by an electromagnetic exciter ...


The Use Of Binary Quantisation For The Acquisition Of Low Snr Ultrasonic Signals: A Study Of The Input Dynamic Range, Julio Isla-Garcia, Frederic Cegla 2016 Imperial College London

The Use Of Binary Quantisation For The Acquisition Of Low Snr Ultrasonic Signals: A Study Of The Input Dynamic Range, Julio Isla-Garcia, Frederic Cegla

Review of Progress in Quantitative Nondestructive Evaluation

Several types of transducer, such as electromagnetic acoustic transducers (EMATs), piezoelectric paints or air-coupled transducers, produce weak signals that can be below the noise threshold at the receiver. In such scenarios averaging or pulse-compression is employed to increase the signal-to-noise ratio (SNR). This paper explores quantisation strategies for these weak signals. It is shown that when the SNR is low, binary (one-bit) quantisation can be used without experiencing significant losses compared to analog-to-digital converters (ADCs). Binary quantizers are simple analog comparators, which make the electronics faster, cheaper, more compact and energy efficient than ADCs. This is especially important when arrays ...


Windowing Of Full Wavefield Data In Multiple Domains To Characterize Angle-Beam Shear Wave Scattering, Yu Weng, Jennifer E. Michaels 2016 Georgia Institute of Technology

Windowing Of Full Wavefield Data In Multiple Domains To Characterize Angle-Beam Shear Wave Scattering, Yu Weng, Jennifer E. Michaels

Review of Progress in Quantitative Nondestructive Evaluation

Angle-beam ultrasonic inspection methods are frequently based on shear waves since they are readily generated using conventional longitudinal transducers and a wedge. Full wavefield imaging can be employed to measure such waves on the surface of a plate-like specimen after they have scattered from a feature or defect of interest, and multiple shear wave arrivals, or “skips,” are readily visible due to beam spread [1]. Because of the complexity of the total wavefield, which also includes Rayleigh and longitudinal waves, it is challenging to experimentally quantify scattering from the primary skip of interest. Considered here is a methodology to isolate ...


Data Interpolation Beyond Aliasing, Arno Volker, Paul van Neer 2016 Netherlands Organization for Applied Scientific Research

Data Interpolation Beyond Aliasing, Arno Volker, Paul Van Neer

Review of Progress in Quantitative Nondestructive Evaluation

Proper spatial sampling is critical for many applications. If the sampling criterion is not met, artifacts appear for example in images. Last year an iterative approach was presented using wave field extrapolation to interpolate spatially aliased signals. This main concept behind this approach is that after inverse wave field extrapolation the signal is concentrated in a small region with a high amplitude, while the aliasing artifacts are spread-out through the domain. Inverse wave field extrapolation focusses optimally at one depth, making the performance of the reconstruction depth dependent. Obviously the method can be repeated for several depths. This year we ...


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