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Full-Text Articles in Mechanical Engineering

Non Destructive Evaluation Of Containment Walls In Nuclear Power Plants, V. Garnier, C. Payan, Martin Lott, Nari Ranaivamonana, Jp Balayssac, E. Larose, Yuxiang Zhang, J. Saliba, A. Boniface, Z. M. Sbartai, Bogdan Piwakowski, Charles Ciccarone, Hamid Hafid, Jean Marie Henault, Florian Ouvrier Buffet Jan 2016

Non Destructive Evaluation Of Containment Walls In Nuclear Power Plants, V. Garnier, C. Payan, Martin Lott, Nari Ranaivamonana, Jp Balayssac, E. Larose, Yuxiang Zhang, J. Saliba, A. Boniface, Z. M. Sbartai, Bogdan Piwakowski, Charles Ciccarone, Hamid Hafid, Jean Marie Henault, Florian Ouvrier Buffet

Review of Progress in Quantitative Nondestructive Evaluation

Two functions are regularly tested on the containment walls in order to anticipate a possible accident. The first is mechanical to resist at a possible internal over-pressure and the second is to prevent leakage. The reference accident LLOCA (Large Loss of Coolant Accident) is the rupture of a pipe in the primary circuit of a nuclear plant. In this case, the pressure and temperature can reach 5 bar and 180°C in 20 seconds.

The national project ‘Non-destructive testing of the containment structures of nuclear plants’ aims at studying the non-destructive techniques capable to evaluate the concrete properties and its ...


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

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 ...


A New Khz Rate Laser-Ultrasound Scanner For Ply-By-Ply Imaging Of Defects, Pores And Inconsistencies In Composite Structures, Ivan Pelivanov, Łukasz Ambrozinski, Matthew O’Donnell Jan 2016

A New Khz Rate Laser-Ultrasound Scanner For Ply-By-Ply Imaging Of Defects, Pores And Inconsistencies In Composite Structures, Ivan Pelivanov, Łukasz Ambrozinski, Matthew O’Donnell

Review of Progress in Quantitative Nondestructive Evaluation

Among NDT methods, only US and X-ray tomography can precisely locate three- dimensional defects regardless of composite type. X-ray systems, however, are very expensive, time-consuming and cumbersome. In addition, the chamber limits the size of the sample to several centimeters and makes it completely unsuitable for field applications. Conventional US pulse-echo techniques usually require couplants or full sample immersion for optimal energy transfer, which can affect overall scan speed and limit the applications where they can be used. Laser-ultrasound (LU) has many advantages over conventional US. First, laser-generated US transients are ultra-wideband, providing at least 3 times better resolution compared ...


Polarization-Resolved Terahertz Imaging Of Impact Damage In A Hybrid Fiber-Reinforced Composite Laminate, Junliang Dong, Alexandre Locquet, Nico F. Declercq, D. S. Citrin Jan 2016

Polarization-Resolved Terahertz Imaging Of Impact Damage In A Hybrid Fiber-Reinforced Composite Laminate, Junliang Dong, Alexandre Locquet, Nico F. Declercq, D. S. Citrin

Review of Progress in Quantitative Nondestructive Evaluation

Terahertz (THz) imaging is applied to characterize a hybrid fiber-reinforced composite laminate subjected to low-velocity impact in this study. The hybrid fiber-reinforced composite laminate comprises unidirectional glass/epoxy and carbon/epoxy plies with a cross-ply stack pattern, shown in Fig.1. Both impact-induced intra- and inter-laminar damages are successfully detected, and the damage evolution throughout the thickness is also evaluated. The interaction between the THz polarization and carbon-fiber orientation is investigated in detail. Inter-laminar damage at the interface (delamination) and the intra-laminar damage close to the same interface are differentiated via polarization-resolved imaging, as shown in Fig.2. With a ...


Assessing The Integrity Of Spillway Foundations, Chih-Hung Chiang, Keng-Tsang Hsu, Chia-Chi Cheng Jan 2016

Assessing The Integrity Of Spillway Foundations, Chih-Hung Chiang, Keng-Tsang Hsu, Chia-Chi Cheng

Review of Progress in Quantitative Nondestructive Evaluation

The erosion under a spillway can be a long-term issue that threatens the structural integrity of a water reservoir. The spillway under investigation was suspected to be defective after it had been commissioned in 1987 (Figure 1). Potholes and subsurface cavities were confirmed in the safety assessment using various NDT techniques including ground penetrating radar and impact echo. The GPR inspection was able to differentiate the intact region from the cavities under concrete slabs (Figure 2). The impact echo results and associated analyses provided further evidence of inferior condition in the soil under the concrete slabs. The engineering team designed ...


Novel Methods To Measure Surface Wave Velocity By Using Laser-Generated Tone-Burst Surface Wave, Ju-Ho Lee, Jongbeom Kim, Kyung-Young Jhang Jan 2016

Novel Methods To Measure Surface Wave Velocity By Using Laser-Generated Tone-Burst Surface Wave, Ju-Ho Lee, Jongbeom Kim, Kyung-Young Jhang

Review of Progress in Quantitative Nondestructive Evaluation

Ultrasonic wave velocity is a characteristic of material, which is considered as a significant factor of nondestructive testing (NDT) techniques. Generally, bulk wave velocity is measured by Time-of-Flight (TOF) of pulse echo from back wall reflection; however, pulse-echo method cannot be applied to surface acoustic wave in a case that an edge does not exist in a close range. Even when we use through-transmission method, it is quite cumbersome to measure the accurate distance between transmitter and receiver; this problem is more critical when using contact angle transducers.

This study proposes two new signal processing methods to measure laser-generated surface ...


Influence Of Grain Size Distribution On Ultrasonic Scattering, Andrea Arguelles, Joseph A. Turner Jan 2016

Influence Of Grain Size Distribution On Ultrasonic Scattering, Andrea Arguelles, Joseph A. Turner

Review of Progress in Quantitative Nondestructive Evaluation

Elastic wave scattering at grain boundaries in polycrystalline media can be quantified to determine microstructural properties. The amplitude drop observed for coherent wave propagation (attenuation) as well as diffuse-field scattering events (such as the single-scattering response) have been extensively studied. In all cases, the scattering shows a clear dependence on grain size, grain geometric morphology, and material texture (i.e., macroscale anisotropy). Scattering models used to quantify such scattering experiments are often developed under the assumption of a single effective grain diameter implying a very narrow distribution of grain size throughout the sample. However, several microscopy studies suggest that most ...


Blind Sparse Deconvolution Of Regularly Spaced Ultrasonic Echoes For Thickness Measurement, Sébastien Bourguignon, Ewen Carcreff, Chunze Lin, Jiafan Peng Jan 2016

Blind Sparse Deconvolution Of Regularly Spaced Ultrasonic Echoes For Thickness Measurement, Sébastien Bourguignon, Ewen Carcreff, Chunze Lin, Jiafan Peng

Review of Progress in Quantitative Nondestructive Evaluation

We present a method for estimating the thickness of thin materials from ultrasonic data, in the context of coating measurement or thickness estimation of tubes and pipes. When sending an ultrasonic pulse in normal incidence in a homogeneous material, a set of regularly spaced echoes is received. Thickness is then obtained from the estimation of the time delay between echoes. If thin structures are inspected (or if a low frequency transducer is used), then echoes may overlap. Then, visual interpretation is made difficult and standard automatic methods may fail. We propose a blind sparse deconvolution approach to this problem, where ...


Multi-Site Delamination Detection And Quantification In Composites Through Guided Wave Based Global-Local Sensing, Zhenhua Tian, Cara Leckey, Lingyu Yu Jan 2016

Multi-Site Delamination Detection And Quantification In Composites Through Guided Wave Based Global-Local Sensing, Zhenhua Tian, Cara Leckey, Lingyu Yu

Review of Progress in Quantitative Nondestructive Evaluation

Advanced composite materials are contributing to a revolution in aerospace applications. Rapid inspection techniques for detecting and quantifying damage in large composites are critical for ensuring operability and safety of composite structures. Moreover, in the development and manufacturing of next-generation composite materials, rapid inspection techniques are imperative for evaluating and certifying the materials.

This paper presents a guided wave based global-local sensing method for rapid detection and quantification of delamination damage in large composite panels. The global-local approach uses a hybrid system consisting of a piezoelectric transducer (PZT) for generating guided waves and a non-contact scanning laser Doppler vibrometer (SLDV ...


Gas Turbine Coatings Eddy-Current Quantitative And Qualitative Evaluation, Remo Ribichini, Carlo Giolli, Erica Scrinzi Jan 2016

Gas Turbine Coatings Eddy-Current Quantitative And Qualitative Evaluation, Remo Ribichini, Carlo Giolli, Erica Scrinzi

Review of Progress in Quantitative Nondestructive Evaluation

Gas turbine blades (buckets) are among the most critical and expensive components of the engine. Buckets rely on protective coatings in order to withstand the harsh environment in which they operate. The thickness and the microstructure of coatings during the lifespan of a unit are fundamental to evaluate their fitness for service. A frequency scanning Eddy Current instrument can allow the measurement of the thickness and of physical properties of coatings in a Non-Destructive manner. The method employed relies on the acquisition of impedance spectra and on the inversion of the experimental data to derive the coating properties and structure ...


Wave Speed Propagation Measurements On Highly Attenuative Wax At Elevated Temperatures, David G. Moore, Sarah L. Stair, David A. Jack Jan 2016

Wave Speed Propagation Measurements On Highly Attenuative Wax At Elevated Temperatures, David G. Moore, Sarah L. Stair, David A. Jack

Review of Progress in Quantitative Nondestructive Evaluation

Ultrasonic stress wave amplitude and time-of-flight values change drastically as a media is heated. The measurement of relatively small variations in velocity and material attenuation can detect and quantify significant variations within a material microstructure. This paper discusses experimental setups, ultrasonic wave speed tracking methods and signal analysis algorithms that document the changes within highly attenuative wax material as it is either being heated or cooled from 25˚C to 90˚C. The experimental set-up utilizes ultrasonic probes in a pulse-echo and through-transmission configuration. The ultrasonic waveforms are recorded and analyzed during long duration thermal experiments. To complement the ultrasonic ...


Improved Scattering Models For Guided Wave Tomography, P. Huthwaite Jan 2016

Improved Scattering Models For Guided Wave Tomography, P. Huthwaite

Review of Progress in Quantitative Nondestructive Evaluation

Water collecting at pipe supports will accelerate corrosion, reducing the pipe life at a very difficult-to-inspect location. A traditional approach would require the pipe to be emptied, lifted and an ultrasonic thickness gauge be scanned across the surface. Guided wave tomography could potentially address these problems: by sending waves from an array on one side of the support through to a set of receivers on the other side, an image of the thickness can be produced, which is typically achieved by exploiting the dispersive nature of guided waves causing their speed to change depending on the thickness. However, this assumption ...


Ultrasonic Scattering From Ahemispherical Pit Theory And Experimentalmeasurement Precision, Thomas J. Eason, Leonard J. Bond, Mark G. Lozev Jan 2016

Ultrasonic Scattering From Ahemispherical Pit Theory And Experimentalmeasurement Precision, Thomas J. Eason, Leonard J. Bond, Mark G. Lozev

Review of Progress in Quantitative Nondestructive Evaluation

The accuracy and precision of ultrasonic thickness measurement systems are influenced by systematic and environmental factors including the back-wall reflection surface profile. The scattering amplitude from a relatively flat and smooth back-wall surface can be characterized by the acoustic impedance ratio of the two materials at the interface. If the back-wall surface increases in roughness due to internal corrosion, then the arrival time of the incident wave upon the various surface heights will be slightly different, resulting in slight phase changes within the reflected field. In addition, the roughness of the internal surface will result in various impingement anglesrelative to ...


Effect Of Skew Angle On Second Harmonic Guided Wave Measurement In Composite Plates, Hwanjeong Cho, Sungho Choi, Cliff J. Lissenden Jan 2016

Effect Of Skew Angle On Second Harmonic Guided Wave Measurement In Composite Plates, Hwanjeong Cho, Sungho Choi, Cliff J. Lissenden

Review of Progress in Quantitative Nondestructive Evaluation

Waves propagating in anisotropic media are subject to skewing effects due to the media having directional wave speed dependence, which are characterized by slowness curves. Likewise, the generation of second harmonics is sensitive to micro-scale damage that is generally not detectable from linear features of ultrasonic waves. Here, the effect of skew angle on second harmonic guided wave measurement in a transversely isotropic lamina and a quasi-isotropic laminate are studied numerically. The strain energy density function for a nonlinear transversely isotropic material is formulated in terms of the Green-Lagrange strain invariants. The guided wave mode pairs for cumulative second harmonic ...


Thermal Diffusivity Measurements On Certified Standards Using Flash Ir Thermography, Vijay Nalladega, Bryon Knight Jan 2016

Thermal Diffusivity Measurements On Certified Standards Using Flash Ir Thermography, Vijay Nalladega, Bryon Knight

Review of Progress in Quantitative Nondestructive Evaluation

Infrared thermography has been increasingly used as an NDE tool for detection of defects in different types of components. At GE Global Research, the flash IR system is routinely used for inspecting for delaminations, porosity, and coating thickness and integrity. For defects such as delaminations and other larger defects, single-sided imaging, where the heat buildup due to the presence of defects can be visualized is used. However, in some cases, measurement of thermal diffusivity can also be used as an indicator of presence of damage. In this study, we report our findings on the accuracy of the diffusivity measurements using ...


Results Of The 2016 Ut Modeling Benchmark Obtained With Models Implemented In Civa, Gwénaël Toullelan, Raphaële Raillon, Steve Mahaut, Sylvain Chatillon, Sébastien Lonne Jan 2016

Results Of The 2016 Ut Modeling Benchmark Obtained With Models Implemented In Civa, Gwénaël Toullelan, Raphaële Raillon, Steve Mahaut, Sylvain Chatillon, Sébastien Lonne

Review of Progress in Quantitative Nondestructive Evaluation

For several years, the World Federation of NDE Centers, WFNDEC, proposes benchmark studies in which simulated results (in either ultrasonic, X-rays or eddy current NDT configurations) obtained with various models are compared to experiments. This year the proposed UT benchmark concerns inspection configurations with multi-skips echoes. This technique is commonly used to inspect thin specimen and/or in case of limited access inspection. This technique relies on the use of T45° mode in order to avoid mode conversion and to facilitate the interpretation of the echoes. To evaluate the influence of the beam divergence on the detectability after several skips ...


A Non-Collinear Mixing Technique To Measure The Acoustic Nonlinearity Parameter Of Adhesive Bond From Only One Side Of The Sample, Taeho Ju, Jan D. Achenbach, Laurence J. Jacobs, Jianmin Qu Jan 2016

A Non-Collinear Mixing Technique To Measure The Acoustic Nonlinearity Parameter Of Adhesive Bond From Only One Side Of The Sample, Taeho Ju, Jan D. Achenbach, Laurence J. Jacobs, Jianmin Qu

Review of Progress in Quantitative Nondestructive Evaluation

The acoustic nonlinearity parameter (ANLP) of a material is often positively correlated with the damage in the material. Therefore, the ability to nondestructively measure the ANLP may enable the nondestructive characterization of the material’s remaining strength. In this work, we developed a non-collinear mixing technique to measure the ANLP of adhesive bonds. One of the most significant features of the new method is that it requires only one-side access to the adhesive bond being measured, which significantly increases it utility in field measurements. Specifically, the test sample considered in this study consists of two aluminum plates adhesively joined together ...


Non-Contact Inline Monitoring Of Thermoplastic Cfrp Tape Quality Using Air-Coupled Ultrasound, Wolfgang Adebahr, Peter Fey, Marc Kreutzbruck Jan 2016

Non-Contact Inline Monitoring Of Thermoplastic Cfrp Tape Quality Using Air-Coupled Ultrasound, Wolfgang Adebahr, Peter Fey, Marc Kreutzbruck

Review of Progress in Quantitative Nondestructive Evaluation

Besides the aerospace industry, fibre reinforced plastics have also spread towards many further applications such as automotive, civil engineering as well as sports and leisure articles. Their superior strength and stiffness to mass ratio made them the number one material for achieving high performance. Especially continuous fibre reinforced plastics allow for the construction of structures which are custom tailored to their mechanical loads by adjusting the paths of the fibres to the loading direction. The two main constituents of CFRP are carbon fibres and matrix. Two possibilities for matrix material exist: thermosetting and thermoplastic matrix. While thermosetting matrix may yield ...


A Fully Coupled Model For Actuation Of Higher Order Modes Of Lamb Waves, Baiyang Ren, Cliff J. Lissenden Jan 2016

A Fully Coupled Model For Actuation Of Higher Order Modes Of Lamb Waves, Baiyang Ren, Cliff J. Lissenden

Review of Progress in Quantitative Nondestructive Evaluation

Lamb waves have proven to be a valuable tool for structural health monitoring (SHM) of plate-like structures susceptible to degradation. It is well-known that the multi-modal propagation characteristics provide both challenges and opportunities. Piezoelectric transducers are widely used in SHM applications because of their low cost, small profile and strong electromechanical coupling. Properly designing a piezoelectric transducer to excite a particular mode is of great importance to successful SHM practice. The mode tuning capability of piezoelectric transducers has been studied both theoretically and experimentally in the literature for exciting A0 and S0 modes. However, the tuning characteristics of higher order ...


Influence Of Local Mechanical Properties Of High Strength Steel From Large Size Forged Ingot On Ultrasonic Wave Velocities, Frederic Dupont-Marillia, Mohammad Jahazi, Pierre Belanger, Serge Lafreniere Jan 2016

Influence Of Local Mechanical Properties Of High Strength Steel From Large Size Forged Ingot On Ultrasonic Wave Velocities, Frederic Dupont-Marillia, Mohammad Jahazi, Pierre Belanger, Serge Lafreniere

Review of Progress in Quantitative Nondestructive Evaluation

In the metallurgical industry, ultrasonic inspection is routinely used for the detection of defects. For the nondestructive inspection of small high strength steel parts, the material can be considered isotropic. However, when the size of the parts under inspection is large, the isotropic material hypothesis does not necessarily hold. The aim of this study is to investigate the effect of the variation in mechanical properties such as grain size, Young's modulus, Poisson’s ratio, chemical composition on longitudinal and transversal ultrasonic wave velocities. A 2 cm thick slice cut from a 40-ton bainitic steel ingot that was forged and ...


Interaction Of Guided Waves With Delaminations In Composite Plate Structures, Saurabh Gupta, Xudong Yu, Zheng Fan, Prabhu Rajagopal Jan 2016

Interaction Of Guided Waves With Delaminations In Composite Plate Structures, Saurabh Gupta, Xudong Yu, Zheng Fan, Prabhu Rajagopal

Review of Progress in Quantitative Nondestructive Evaluation

This paper addresses a gap in the literature on the 3-dimensional scattering of the fundamental symmetric Lamb mode 𝑆𝑆0 from delimitations in composite plates. We study the scattering of low-frequency 𝑆𝑆0 mode by delamination in a stiffened 4-ply CFRP composite plate with 0/0/0/0 ply orientation. The work is carried out using three dimensional finite element simulation validated by experiments. Far field scattering coefficients for the 𝑆𝑆0 mode are plotted as a function of circumferential position around the delamination. Results show that the delamination size and through thickness location have less influence on 𝑆𝑆0 Lamb wave scattering in ...


Evaluation Of The Depth Of Surface Deterioration For Concrete Structure Using Dispersion Characteristics Of Surface Wave, Chia-Chi Cheng, Ying-Tzu Ke, Keng-Tsang Hsu, Hung-Yu Tao, Chih-Hung Chiang Jan 2016

Evaluation Of The Depth Of Surface Deterioration For Concrete Structure Using Dispersion Characteristics Of Surface Wave, Chia-Chi Cheng, Ying-Tzu Ke, Keng-Tsang Hsu, Hung-Yu Tao, Chih-Hung Chiang

Review of Progress in Quantitative Nondestructive Evaluation

Surface waves generated by an impact are used to assess depth of deterioration for concrete plate. The proposed method uses one receiver positioned away from the impacting source. The spectrogram of the group velocity obtained from the signal recorded from the receiver is calculated by Short-Time Fourier Transform and the reassignment technique [1]. Experiments were conduct on the concrete plate with different thickness of mortar top layer to simulate concrete with serious aggregate segregation and bleeding. In the experiment, the source-receiver distance for concrete plate with different thickness of weak top layer are explored. Figure 1 shows the comparison between ...


Calibration Of Air-Coupled Transducers For Absolute Nonlinear Ultrasonic Measurements, Nicholas Selby, David Torello, Jin-Yeon Kim, Laurence J. Jacobs Jan 2016

Calibration Of Air-Coupled Transducers For Absolute Nonlinear Ultrasonic Measurements, Nicholas Selby, David Torello, Jin-Yeon Kim, Laurence J. Jacobs

Review of Progress in Quantitative Nondestructive Evaluation

We describe a novel calibration technique of air-coupled transducers for nonlinear ultrasonic measurements through homogenous, isotropic media. Our calibration technique combines laser interferometrywith a model-based approach to derive a relationship between received force at the transducer face and the measured output voltage. Conventional nonlinear ultrasonic measurement techniques have relied upon contact receiving transducers that are heavily influenced by contact conditions (e.g. inconsistent coupling) and laser interferometers that are prohibitively expensive and rely on a mirror-finished surface or complicated optics. Air-coupled transducers are significantly less expensive than laser interferometers and are robust relative to surface conditions, but current calibration techniques ...


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

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 ...


Determination Of Absolute Material Nonlinearity In Aluminum And Fused Silica With Air-Coupled Ultrasonic Receivers, David Torello, Nicholas Selby, Jin-Yeon Kim, Jianmin Qu, Laurence J. Jacobs Jan 2016

Determination Of Absolute Material Nonlinearity In Aluminum And Fused Silica With Air-Coupled Ultrasonic Receivers, David Torello, Nicholas Selby, Jin-Yeon Kim, Jianmin Qu, Laurence J. Jacobs

Review of Progress in Quantitative Nondestructive Evaluation

Knowledge of the absolute material nonlinearity parameter, β, of a specimen allows for quantitative evaluation of its current microstructural state, making it a powerful tool in the NDE toolbox. However, the various methods used in the past to measure β each suffer from significant limitations. Piezoelectric contact transducers, while easy to use in many ways, are hindered by the unreliability of the interfacial contact between transducer and specimen surface, which offsets their high sensitivity to nonlinear signals. Laser interferometry provides non-contact detection, but requires carefully prepared specimens or expensive and complicated optics to maximize sensitivity to the nonlinear components of ...


Time Reversal Method For Arch Bridge Cables Inspection Using Longitudinal Guided Waves, Zhang Pengfei, Tang Zhifeng, Lv Fuzai, Yang Keji Jan 2016

Time Reversal Method For Arch Bridge Cables Inspection Using Longitudinal Guided Waves, Zhang Pengfei, Tang Zhifeng, Lv Fuzai, Yang Keji

Review of Progress in Quantitative Nondestructive Evaluation

Arch bridge cables consist of anchor heads, steel wires parallel arranged in an equilateral hexagon and hot-extruding PE sheathing layers outside the wires. The complex structure and contact force between wires aggravates the dispersion and attenuation of guided waves in steel wires. In order to reduce the attenuation of acoustical energy, below 80kHz low-frequency longitudinal guided waves is usually adopted. Low-frequency guided waves attenuate more slowly than high-frequency waves, but the received signal packets are wider and less recognizable. In this paper, the process of the time reversal method[1] is presented and the related parameters are calculated. Over a ...


Damage Detection Using High Order Longitudinal Guided Waves In The Anchorage Zone Of Stayed-Cable, Yongdong Pan, Feng Yang Jan 2016

Damage Detection Using High Order Longitudinal Guided Waves In The Anchorage Zone Of Stayed-Cable, Yongdong Pan, Feng Yang

Review of Progress in Quantitative Nondestructive Evaluation

High order longitudinal guided waves (HOLGW) are studied for the damage detection in the anchorage zone of stayed cable through the theoretical analysis, numerical simulation and experimental validation. First, based on the theory of elastic wave propagation in cylinder, the dispersion curves of longitudinal modes were obtained and calculated analytically and the high-frequency such as 5MHz corresponding to the higher order longitudinal guided wave modes are identified for the damage detection. Then, the ultrasonic guided waves propagating in a steel wire with or without defects were simulated by using the finite element method and the effects of defect depth and ...


Optimal Design Of A Piezoelectric Transducer For Exciting Guided Wave Ultrasound In Rails, Dineo A. Ramatlo, Daniel N. Wilke, Philip W. Loveday Jan 2016

Optimal Design Of A Piezoelectric Transducer For Exciting Guided Wave Ultrasound In Rails, Dineo A. Ramatlo, Daniel N. Wilke, Philip W. Loveday

Review of Progress in Quantitative Nondestructive Evaluation

An existing Ultrasonic Broken Rail Detection System [1] installed in South Africa on a heavy duty railway line is currently being upgraded to include defect detection and location. To accomplish this, an ultrasonic piezoelectric transducer to strongly excite a guided wave mode with energy concentrated in the web (web mode) of a rail is required. A previous study [2] demonstrated that the recently developed SAFE-3D (Semi-Analytical Finite Element – 3 Dimensional) method can effectively predict the guided waves excited by a resonant piezoelectric transducer. In this study, the SAFE-3D model is used in the design optimization of a rail web transducer ...


Acoustic Emission As A Screening Tool For Ceramic Matrix Composites, Greg Ojard, Dan Goberman, John Holowczak Jan 2016

Acoustic Emission As A Screening Tool For Ceramic Matrix Composites, Greg Ojard, Dan Goberman, John Holowczak

Review of Progress in Quantitative Nondestructive Evaluation

Ceramic matrix composites are composite materials with ceramic fibers in a high temperature matrix of ceramic or glass-ceramic. This emerging class of materials is viewed as enabling for efficiency improvements in many energy conversion systems. The key controlling property of ceramic matrix composites is a relatively weak interface between the matrix and the fiber that aids crack deflection and fiber pullout resulting in greatly increased toughness over monolithic ceramics. United Technologies Research Center has been investigating glass-ceramic composite systems as a tool to understand processing effects on material performance related to the performance of the weak interface. Changes in the ...


A Parameterized Delamination Model For Use In Complex Damage Characterization Of Composite Laminatesin Ultrasonic Inspections, Heather Reed, Gerald Harvey, Jeff Dobson, Cara Leckey Jan 2016

A Parameterized Delamination Model For Use In Complex Damage Characterization Of Composite Laminatesin Ultrasonic Inspections, Heather Reed, Gerald Harvey, Jeff Dobson, Cara Leckey

Review of Progress in Quantitative Nondestructive Evaluation

Ultrasonic damage detection and characterization is commonly used in nondestructive evaluation (NDE) of aerospace composite components. However, in real materials and structures, the dispersive waves can result in complicated behavior, particularly in the presence of complex damage scenarios and structural components. Accurate three dimensional finite element models (FEMs), using PZFlex, of guided wave interactions with realistic damage scenarios can be used to study quantitative NDE ultrasonic damage detection techniques numerically, to supplement or replace expensive experimental testing. Novel data analysis techniques such as filter reconstruction imaging methods can be used to create practical comparisons between experimental and simulated data. To ...