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Nondestructive testing

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Full-Text Articles in Engineering

Damage Detection In Reinforced Concrete Member Using Local Time-Frequency Transform Applied To Vibration Measurements, Ning Liu, Thomas Schumacher, Yan Li, Lina Xu, Bo Wang Jan 2023

Damage Detection In Reinforced Concrete Member Using Local Time-Frequency Transform Applied To Vibration Measurements, Ning Liu, Thomas Schumacher, Yan Li, Lina Xu, Bo Wang

Civil and Environmental Engineering Faculty Publications and Presentations

Signal processing and analysis of structural vibration measurements are key components of structural damage detection (SDD) in structural health monitoring (SHM). The goal of signal processing is to extract subtle changes in the measured signals, which can be used to infer changes in structural parameters and damage. Time-frequency analysis is one of the most popular characterization methods for studying non-stationary vibration signals. In this article, the local time-frequency transform (LTFT) is applied and evaluated to calculate the time-domain signals because of its excellent time-frequency energy distribution properties. The LTFT matches the input data by the Fourier basis in an inverse …


Nondestructive Evaluation Of Structural Defects In Concrete Slabs, Ehsanul Kabir Jan 2023

Nondestructive Evaluation Of Structural Defects In Concrete Slabs, Ehsanul Kabir

Electronic Theses and Dissertations

Nondestructive testing (NDT) is a reliable method for determining the structural integrity of new and old construction and understanding the condition of structural defects. It is widely acknowledged that the interpretation of nondestructive evaluation (NDE) has a significant impact on the reliability and consistency of this technology. However, NDT data acquisition remains subjective and heavily dependent on the operator’s knowledge and expertise. As a result, there are still issues to be resolved regarding the imaging and diagnostic procedures for NDT-based concrete inspection. NDT methods such as ground penetrating radar (GPR), and impact-echo (IE), have been extensively used to inspect concrete …


Experimental Study On Nondestructive Testing Of Anchor Cable In Pumped Storage Power Station, Yan Liangping, Zhou Liming, Cui Botao, Wang Bolin, Lu Jiangang Aug 2022

Experimental Study On Nondestructive Testing Of Anchor Cable In Pumped Storage Power Station, Yan Liangping, Zhou Liming, Cui Botao, Wang Bolin, Lu Jiangang

Coal Geology & Exploration

In order to demonstrate the effect of elastic wave reflection method, the nondestructive testing test of anchor cables was carried out at the bank slope of Fukang Pumped Storage Power Station in Xinjiang. On the basis of the basic theory of elastic wave reflection method, the anchor cable sensor is embedded, and the data acquisition, signal excitation position and wave velocity of anchor body in the process of nondestructive testing of anchor cable are systematically studied. The following results are obtained: When the receiving sensor position is fixed and the excitation part is the steel strand where the receiving sensor …


Multi-Sensor Data Collection And Fusion Using Autoencoders In Condition Evaluation Of Concrete Bridge Decks, Sepehr Pashoutani, Jinying Zhu, Chungwook Sim, Kwanghee Won, Brian A. Mazzeo, W Spencer Guthrie Jun 2021

Multi-Sensor Data Collection And Fusion Using Autoencoders In Condition Evaluation Of Concrete Bridge Decks, Sepehr Pashoutani, Jinying Zhu, Chungwook Sim, Kwanghee Won, Brian A. Mazzeo, W Spencer Guthrie

Department of Civil and Environmental Engineering: Faculty Publications

This paper presents a multi-sensor data collection and data fusion procedure for nondestructive evaluation/testing (NDE/NDT) of a concrete bridge deck. Three NDE technologies, vertical electrical impedance (VEI), ground-penetrating radar (GPR), and high-definition imaging (HDI) for surface crack detection, were deployed on the bridge deck. A neural network autoencoder was trained to quantify the relationship between VEI and GPR results using the data collected at common positions. This relationship was then used for fusion of VEI and GPR data to increase the reliability and spatial resolution of the NDE measurements and to generate a data-fused condition map that showed novel characteristics. …


Electrical Capacitance Measurements To Assess European Corn Borer Infestation In Maize, Mavrik D. Thomas Apr 2021

Electrical Capacitance Measurements To Assess European Corn Borer Infestation In Maize, Mavrik D. Thomas

Theses and Dissertations

The European Corn Borer (ECB), Ostrinia nubilalis, is an agricultural pest which bores small holes in the rind of maize stalks and then proceeds to consume the pith. Because most of the damage to the stalk is internal, it is difficult to quantify the damage to an individual stalk without time-consuming, manual examination. This work explored the hypothesis that internal damage could be detected and quantified using non-destructive, electromagnetic measurements. Laboratory experiments and numerical simulation studies predicted changes in capacitance of stalks due to hollow core ECB damage. A guarded probe device to measure electrical impedance from 500 Hz to …


Nondestructive Electromagnetic Characterization Of Uniaxial Sheet Media Using A Two-Flanged Rectangular Waveguide Probe, Neil G. Rogers, Michael J. Havrilla, Milo W. Hyde Iv, Alexander G. Knisely Jun 2020

Nondestructive Electromagnetic Characterization Of Uniaxial Sheet Media Using A Two-Flanged Rectangular Waveguide Probe, Neil G. Rogers, Michael J. Havrilla, Milo W. Hyde Iv, Alexander G. Knisely

Faculty Publications

Excerpt: Recent advancements in fabrication capabilities have renewed interest in the electromagnetic characterization of complex media, as many metamaterials are anisotropic and/or inhomogeneous. Additionally, for composite materials, anisotropy can be introduced by load, strain, misalignment, or damage through the manufacturing process [1], [2]. Methods for obtaining the constitutive parameters for isotropic materials are well understood and widely employed [3]–[8]. Therefore, it is crucial to develop a practical method for the electromagnetic characterization of anisotropic materials.


Multifidelity Modeling By Polynomial Chaos-Based Cokriging To Enable Efficient Model-Based Reliability Analysis Of Ndt Systems, Xiaosong Du, Leifur Leifsson Mar 2020

Multifidelity Modeling By Polynomial Chaos-Based Cokriging To Enable Efficient Model-Based Reliability Analysis Of Ndt Systems, Xiaosong Du, Leifur Leifsson

Mechanical and Aerospace Engineering Faculty Research & Creative Works

This work proposes a novel multifidelity metamodeling approach, the polynomial chaos-based Cokriging (PC-Cokriging). The proposed approach is used for fast uncertainty propagation in a reliability analysis of nondestructive testing systems using model-assisted probability of detection (MAPOD). In particular, PC-Cokriging is a multivariate version of polynomial chaos-based Kriging (PC-Kriging), which aims at combining the advantages of the regression-based polynomial chaos expansions and the interpolation-based Kriging metamodeling methods. Following a similar process as Cokriging, the PC-Cokriging advances PC-Kriging by enabling the incorporation of multifidelity physics information. The proposed PC-Cokriging is demonstrated on two analytical functions and three ultrasonic testing MAPOD cases. The …


Dynamic Testing: An Experimental Approach To Defect Identification In Additive Manufactured Parts, Aimee Allen Jan 2020

Dynamic Testing: An Experimental Approach To Defect Identification In Additive Manufactured Parts, Aimee Allen

Dissertations, Master's Theses and Master's Reports

Today’s additive manufacturing (AM) industry produces specialized parts at low volume or with complex geometries. Traditional testing methods are effective, but costly and time consuming to perform. The AM industry lacks an optimized testing method for identifying internal defects that occur in parts. The evaluation of multiple parts printed on the same build plate for internal defects using various nondestructive (dynamic) testing techniques is presented. From these experiments, perspective was gained on when and how dynamic testing can be used to find defects. Insight gained from these experiments can help the industry in future testing for internal defects.


A Novel Structural Health Monitoring Method For Reinforced Concrete Bridge Decks Using Ultrasonic Guided Waves, Ece Erdogmus, Eric Garcia, Ahmad Shoaib Amiri, Michael Schuller Jan 2020

A Novel Structural Health Monitoring Method For Reinforced Concrete Bridge Decks Using Ultrasonic Guided Waves, Ece Erdogmus, Eric Garcia, Ahmad Shoaib Amiri, Michael Schuller

Durham School of Architectural Engineering and Construction: Faculty Publications

This article presents the latest improvements in a recently developed nondestructive testing (NDT) approach for early detection of various flaws (corrosion, delamination, and concrete cracking) in reinforced concrete (RC) bridge decks. The proposed method involves the use of internal steel reinforcement as a wave guide for transmitting ultrasonic waves through the system and the measurement of leaked energy from the surface of the concrete. This paper builds upon the progress made in the previously published phases of the project and aims to further explore the capabilities and practicality of the proposed NDT method. Specifically, the limits of propagation distance, effect …


Prediction Of The Compressive Strength And Dynamic Modulus Of Fiber Reinforced Concrete By Ultrasonic Pulse Velocity Measurement At Early Ages, Daniel A. Castillo Pereira Jan 2020

Prediction Of The Compressive Strength And Dynamic Modulus Of Fiber Reinforced Concrete By Ultrasonic Pulse Velocity Measurement At Early Ages, Daniel A. Castillo Pereira

Electronic Theses and Dissertations

This research investigates the relationship between early age ultrasonic pulse velocity and the compressive strength and dynamic modulus of steel, polypropylene, nylon, and glass fiber reinforced concrete. Previous studies prove that adding fibers to concrete alters the propagation of ultrasonic pulse velocity waves. Therefore, each type of fiber-reinforced concrete will have a unique relationship between ultrasonic pulse velocity and its compressive strength and dynamic modulus depending on fiber type, fiber volume fraction, water to cement ratio, and test age. To test this hypothesis, an experimental program comprising of one hundred eighty-nine 100 mm x 200 mm fiber reinforced concrete cylinders …


Evaluation Of Low And High Frequency Dynamic Response For Condition Assessment Of Reinforced Concrete Structures, Ali Hafiz Aug 2019

Evaluation Of Low And High Frequency Dynamic Response For Condition Assessment Of Reinforced Concrete Structures, Ali Hafiz

Dissertations and Theses

Concrete is widely used for civil infrastructure structures and they experience deterioration and degradation due to aging, increases in the traffic loads, harsher environmental conditions, use of deicing chemicals, etc. Therefore, evaluating the integrity of reinforced concrete structures has become of increasing interest for infrastructure owners and managers. A number of non-destructive testing (NDT) and structural health monitoring (SHM) methods have been developed in recent decades to aid in evaluating structures and provide input for asset management. One family of these methods uses the dynamic response of a structural member: stress waves (high frequency) and structural vibrations (low frequency). Both …


Physics-Based Signal Processing Methods For Terahertz Non-Destructive Evaluation Of Layered Media, Scott G. Schecklman Jun 2019

Physics-Based Signal Processing Methods For Terahertz Non-Destructive Evaluation Of Layered Media, Scott G. Schecklman

Dissertations and Theses

In recent years Terahertz (THz) time domain spectroscopy has emerged as a promising new technology with potential applications in a variety of fields, including industrial manufacturing, security screening and medical imaging. Pulsed THz systems are uniquely suited for non-destructive evaluation (NDE) of the sub-surface layers of dielectric packaging and coating materials, because they provide high dynamic range over a wide bandwidth in the far infrared portion of the electromagnetic spectrum. Often the dielectric materials of the packaging and/or surface coating layers exhibit relatively low loss and abrupt changes in the refractive index at the layer boundaries can be observed as …


Diagnostic Imaging Of Structural Concrete Using Ground Penetrating Radar And Ultrasonic Array, Sina Mehdinia, Thomas Schumacher, Eric Wan, Xubo Song May 2019

Diagnostic Imaging Of Structural Concrete Using Ground Penetrating Radar And Ultrasonic Array, Sina Mehdinia, Thomas Schumacher, Eric Wan, Xubo Song

Student Research Symposium

Structural concrete is the most widely used construction material in the world. Many structures critical to a society such as bridges, hospitals, and airports are built with concrete. While this material is well understood from a mechanical design point of view, still no accurate quantitative tools exist to assess it for damage and deterioration. This is of particular concern for an urban area like Portland with a mega-thrust earthquake waiting to occur. Non-destructive evaluation tools that can quickly and accurately give a full picture of the integrity of structural concrete elements will be key to help plan effective and safe …


Passively-Coded Embedded Microwave Sensors For Materials Characterization And Structural Health Monitoring (Shm), Katelyn Rose Brinker Jan 2019

Passively-Coded Embedded Microwave Sensors For Materials Characterization And Structural Health Monitoring (Shm), Katelyn Rose Brinker

Masters Theses

"Monitoring and maintaining civil, space, and aerospace infrastructure is an ongoing critical problem facing our nation. As new complex materials and structures, such as multilayer composites and inflatable habitats, become ubiquitous, performing inspection of their structural integrity becomes even more challenging. Thus, novel nondestructive testing (NDT) methods are needed. Chipless RFID is a relatively new technology that has the potential to address these needs. Chipless RFID tags have the advantage of being wireless and passive, meaning that they do not require a power source or an electronic chip. They can also be used in a variety of sensing applications including …


Hardware Architectures For Compact Microwave And Millimeter Wave Cameras, Matthew Jared Horst Jan 2019

Hardware Architectures For Compact Microwave And Millimeter Wave Cameras, Matthew Jared Horst

Doctoral Dissertations

"Millimeter wave SAR imaging has shown promise as an inspection tool for human skin for characterizing burns and skin cancers. However, the current state-of-the-art in microwave camera technology is not yet suited for developing a millimeter wave camera for human skin inspection. Consequently, the objective of this dissertation has been to build the necessary foundation of research to achieve such a millimeter wave camera. First, frequency uncertainty in signals generated by a practical microwave source, which is prone to drift in output frequency, was studied to determine its effect on SAR-generated images. A direct relationship was found between the level …


Fast Uncertainty Propagation Of Ultrasonic Testing Simulations For Mapod And Sensitivity Analysis, Xiaosong Du, Leifur Leifsson, Praveen Gurrala, Jiming Song, Slawomir Koziel Oct 2018

Fast Uncertainty Propagation Of Ultrasonic Testing Simulations For Mapod And Sensitivity Analysis, Xiaosong Du, Leifur Leifsson, Praveen Gurrala, Jiming Song, Slawomir Koziel

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Model-assisted probability of detection (MAPOD) and sensitivity analysis (SA) are widelyused for measuring the reliability of nondestructive testing (NDT) systems., such as ultrasonictesting (UT), and understanding the effects of uncertainty parameters. In this work, a stochastic expansion-based metamodel is used in lieu of the physics-based NDT simulation model for efficient uncertainty propagation while keeping satisfactory accuracy. The proposed stochasticmetamodeling approach is demonstrated for MAPOD and SA on a benchmark case for UT simulations on a fused quartz block with a spherically-void defect. The proposed approach is compared with direct Monte Carlo sampling (MCS), and MCS with Kriging metamodels. The results …


Development Of Active Microwave Thermography For Structural Health Monitoring, Ali Foudazi Jan 2017

Development Of Active Microwave Thermography For Structural Health Monitoring, Ali Foudazi

Doctoral Dissertations

"Active Microwave Thermography (AMT) is an integrated nondestructive testing and evaluation (NDT&E) method that incorporates aspects of microwave NDT and thermography techniques. AMT uses a microwave excitation to generate heat and the surface thermal profile of the material or structure under test is subsequently measured using a thermal camera (or IR camera). Utilizing a microwave heat excitation provides advantages over traditional thermal excitations (heat lamps, etc.) including the potential for non-contact, selective and focused heating. During an AMT inspection, two heating mechanisms are possible, referred to as dielectric and induction heating. Dielectric heating occurs as a result of the interaction …


An Electronic Portable Device Design To Spectroscopically Assess Fruit Quality, Ali̇ Sarikaş, Merve Doğruyol Başar Jan 2017

An Electronic Portable Device Design To Spectroscopically Assess Fruit Quality, Ali̇ Sarikaş, Merve Doğruyol Başar

Turkish Journal of Electrical Engineering and Computer Sciences

As a rapid and nondestructive sensing technique, reflection spectroscopy is useful in monitoring and managing horticultural production; in other words, the ripening of fruits and vegetables can be evaluated using reflection spectroscopy. Based on laboratory data obtained from an ultraviolet/visible/near-infrared (UV/Vis/NIR) spectrophotometer with a diffuse reflectance accessory, we developed a prototype handheld device. The device operates at a range of 400 nm to 1100 nm (blue, green, red, and NIR). LEDs, photodiodes, a microcontroller, digital-to-analog converters, a graphical LCD display, and a keypad were used for instrumentation. With our user-friendly software interface, measurements can be performed and controlled in real …


Nondestructive Testing System Design For Biological Product Based On Vibration Signal Analysis Of Acceleration Sensor, Xiaohao Li, Tao Shen Jan 2017

Nondestructive Testing System Design For Biological Product Based On Vibration Signal Analysis Of Acceleration Sensor, Xiaohao Li, Tao Shen

Department of Mechanical and Materials Engineering: Faculty Publications

In order to reduce the disadvantages of current biological product quality testing methods, taking the quality testing in cocoon trade markets as an example, this paper has proposed a quality nondestructive testing method for biological products based on the analysis of vibration signal from acceleration sensors. According to the wavelet transformation analysis on the random vibration signal acquired from the acceleration sensor, the random vibration signal related to the silkworm chrysalis quality has been analyzed and reconstructed; then the characteristic values such as: mean value, variance, mean square root, waveform index, pulse factor, and so on of the quality signal …


Continuous Long-Term Health Monitoring Using Ultrasonic Wave Propagation, Ece Erdogmus Dec 2016

Continuous Long-Term Health Monitoring Using Ultrasonic Wave Propagation, Ece Erdogmus

Nebraska Department of Transportation: Research Reports

No abstract provided.


Nondestructive Testing And Structural Health Monitoring Based On Adams And Svm Techniques, Gang Jiang, Yi Ming Deng, Ji Tai Niu Oct 2016

Nondestructive Testing And Structural Health Monitoring Based On Adams And Svm Techniques, Gang Jiang, Yi Ming Deng, Ji Tai Niu

The 8th International Conference on Physical and Numerical Simulation of Materials Processing

No abstract provided.


Physics-Based Imaging Methods For Terahertz Nondestructive Evaluation Applications, Gabriel Paul Kniffin May 2016

Physics-Based Imaging Methods For Terahertz Nondestructive Evaluation Applications, Gabriel Paul Kniffin

Dissertations and Theses

Lying between the microwave and far infrared (IR) regions, the "terahertz gap" is a relatively unexplored frequency band in the electromagnetic spectrum that exhibits a unique combination of properties from its neighbors. Like in IR, many materials have characteristic absorption spectra in the terahertz (THz) band, facilitating the spectroscopic "fingerprinting" of compounds such as drugs and explosives. In addition, non-polar dielectric materials such as clothing, paper, and plastic are transparent to THz, just as they are to microwaves and millimeter waves. These factors, combined with sub-millimeter wavelengths and non-ionizing energy levels, makes sensing in the THz band uniquely suited for …


Surface Roughness Of Electron Beam Melting Ti-6al-4v Effect On Ultrasonic Testing, Evan T. Hanks Mar 2016

Surface Roughness Of Electron Beam Melting Ti-6al-4v Effect On Ultrasonic Testing, Evan T. Hanks

Theses and Dissertations

Experimental research was conducted on the effects of surface roughness on ultrasonic non-destructive testing of Electron Beam Melted (EBM) additively manufactured Ti-6Al-4V. Additive Manufacturing (AM) is a developing technology with many potential benefits, but certain challenges posed by its use require further research before AM parts are viable for widespread use in the aviation industry. Possible applications of this new technology include, Aircraft Battle Damage Repair (ABDR), small batch manufacturing to fill supply gaps, and replacement for obsolete parts. The research presented here assesses the effectiveness of ultrasonic inspection in detecting manufactured flaws in EBM manufactured Ti-6Al-4V. EBM products are …


Field Observation Of Installation And Performance Of Repair Materials, Larisa Diana Susinskas Jan 2016

Field Observation Of Installation And Performance Of Repair Materials, Larisa Diana Susinskas

ETD Archive

The state of Ohio is in a region that commonly experiences drastic changes in weather. States with similar climates are susceptible to pavement cracking and failures due to the frequent or extreme freeze-thaw cycles. Freeze-thaw cycles, paired with de-icing chemicals that are frequently placed on roadways during the winter months will most likely lead to pavement cracks and failure. Ohio Department of Transportation (ODOT) routinely repairs and replaces sections of concrete roadways and bridge decks. Therefore, ODOT is seeking durable, cost-effective materials to repair smaller pavement failures.

The purpose of this study is to determine which high performance repair materials …


Test And Evaluation Of Ultrasonic Additive Manufacturing (Uam) For A Large Aircraft Maintenance Shelter (Lams) Baseplate, Daniel H. Gartland Mar 2015

Test And Evaluation Of Ultrasonic Additive Manufacturing (Uam) For A Large Aircraft Maintenance Shelter (Lams) Baseplate, Daniel H. Gartland

Theses and Dissertations

Additive manufacturing is an exciting new manufacturing technology that could have application to Air Force Civil Engineer (CE) operations. This research replicates a Large Area Maintenance Shelter (LAMS) baseplate design for ultrasonic additive manufacturing (UAM). Due to production problems the test section was not built as designed. Instead, a smaller block of material was submitted for evaluation. After the UAM build, ultrasonic inspection was conducted to identify anomalies in the test piece. The results of this proof of concept study indicate that UAM is not yet ready for CE expeditionary applications requiring a high degree of mechanical strength. The machine …


Advanced Approaches For Bridge Deck Assessment Using Ground Penetrating Radar, Aleksey Kamilevich Khamzin Jan 2015

Advanced Approaches For Bridge Deck Assessment Using Ground Penetrating Radar, Aleksey Kamilevich Khamzin

Doctoral Dissertations

"Ground penetrating radar (GPR) data were acquired across four bridge decks with the objective of developing an advanced workflow for GPR operation that would allow the bridge owners to estimate repair quantities for certain bridge decks, based on GPR data. The primary contributions from this research are as follows: 1. It was demonstrated that the conditions of bridge decks can be cost-effectively and efficiently assessed using the GPR tool. 2. The GPR tool's ability to provide rapid and reliable results in comparison with conventional bridge deck condition assessment techniques was established. 3. The qualitative and quantitative relationships between the GPR …


Characterization Of Waviness In Wind Turbine Blades Using Air Coupled Ultrasonics, Sunil Kishore Chakrapani, Vinay Dayal, David K. Hsu, Daniel J. Barnard, Andrew Gross Aug 2014

Characterization Of Waviness In Wind Turbine Blades Using Air Coupled Ultrasonics, Sunil Kishore Chakrapani, Vinay Dayal, David K. Hsu, Daniel J. Barnard, Andrew Gross

Sunil Kishore Chakrapani

Waviness in glass fiber reinforced composite is of great interest in composite research, since it results in the loss of stiffness. Several NDE techniques have been used previously to detect waviness. This work is concerned with waves normal to the plies in a composite. Air‐coupled ultrasonics was used to detect waviness in thick composites used in the manufacturing of wind turbine blades. Composite samples with different wave aspect ratios were studied. Different wavy samples were characterized, and a three step process was developed to make sure the technique is field implementable. This gives us a better understanding of the effect …


Computational Feasibility Study Of Dual Photon/Neutron Imaging Technique, Jessica Hartman, Alexander Barzilov May 2014

Computational Feasibility Study Of Dual Photon/Neutron Imaging Technique, Jessica Hartman, Alexander Barzilov

College of Engineering: Graduate Celebration Programs

  • Non-destructive testing (NDT) is crucial for industrial applications, particularly when imaging of internal components or structures is desired

  • Current NDT imaging techniques, such as x-rays, focus primarily on isolating unique shapes. Rarely are these methods capable of distinguishing materials or material composition

  • Potential application in the car industry for testing and examining the functional durability of products
    − Vehicle engines are composed of a combination of low-z and high-z materials with significant variation in density
    − Being able to determine the location of material during operation eliminates the need to disassemble an engine during study


A Clamped Dual-Ridged Waveguide Measurement System For The Broadband, Nondestructive Characterization Of Sheet Materials, Milo W. Hyde Iv, Michael J. Havrilla Oct 2013

A Clamped Dual-Ridged Waveguide Measurement System For The Broadband, Nondestructive Characterization Of Sheet Materials, Milo W. Hyde Iv, Michael J. Havrilla

Faculty Publications

A novel two-port probe which uses dual-ridged waveguides for the nondestructive, broadband characterization of sheet materials is presented. The new probe is shown to possess approximately 2 to 3 times the bandwidth of traditional coaxial and rectangular/circular waveguide probe systems while maintaining the structural robustness characteristic of rectangular/circular waveguide probe systems. The theoretical development of the probe is presented, namely, by applying Love’s equivalence theorem and enforcing the continuity of transverse fields at the dual-ridged waveguide apertures, a system of coupled magnetic field integral equations is derived. The system of coupled magnetic field integral equations is solved using the method …


Optimization Of Stress Wave-Based Nondestructive Methods In Identifying Deterioration In Concrete Structures, Hoda Azari Jan 2013

Optimization Of Stress Wave-Based Nondestructive Methods In Identifying Deterioration In Concrete Structures, Hoda Azari

Open Access Theses & Dissertations

The transportation infrastructure across the United States is deteriorating and requires periodic inspection to predict the cost of repair and extent of maintenance activities, to remedy structural problems, and to ensure safety and serviceability. The use of nondestructive testing (NDT) methods in detecting and characterizing flaws in the infrastructure has become more common. Among different NDT methods, the stress wave-based methods, including ultrasonic surface waves (USW) and impact echo (IE) methods, are widely used to maintain concrete structures. In this dissertation, a complete literature review of seismic wave theory and wave propagation in plate like structures, and stress wave-based methods …