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Civil and Environmental Engineering

Structural health monitoring

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Full-Text Articles in Engineering

Performance Of 3d Printed Columns Using Self-Sensing Cementitious Composites, Cynthia D. Atkinson, Farhad Aslani Apr 2023

Performance Of 3d Printed Columns Using Self-Sensing Cementitious Composites, Cynthia D. Atkinson, Farhad Aslani

Research outputs 2022 to 2026

Self-sensing cementitious composites can be used as an economical method of structural health monitoring. This is achieved by using the piezoresistivity effect to assist in the detection of defects and enabling repairs to be conducted early which can therefore avoid structural failures. This study uses an established self-sensing cementitious composite mix to 3D print column to examine its structural performance and sensing capabilities in components of large-scale concrete structures. An extrusion-based 3D printer was used to print hollow square column segments. These segments were then joined and filled with steel rebar reinforcement and cast concrete. Another column was created using …


Speckle Development And Application In Uav-Based Digital Image Correlation For Transportation Infrastructure Monitoring And Assessment, Taylor Wyatt Apr 2023

Speckle Development And Application In Uav-Based Digital Image Correlation For Transportation Infrastructure Monitoring And Assessment, Taylor Wyatt

Theses and Dissertations

A critical aspect of civil infrastructure is structural health monitoring, of which digital image correlation (DIC) has been proven to be an effective and appropriate method. There is sufficient literature on the use of stationary DIC, but an unexplored aspect is DIC-equipped unmanned aircraft systems. It has been verified in University of South Carolina labs but has not been proved in a field environment. One of the challenges of field implementation is large scale speckle application. This work focusses on identifying and addressing challenges in bringing UAV-DIC technology from the lab to the field. This includes the development of optimized …


Investigation Of Electrically Isolated Capacitive Sensing Skins On Concrete To Reduce Structure/Sensor Capacitive Coupling, Emmanuel Ogunniyi, Alexander Vareen, Austin Downey, Simon Laflamme, Jian Li, Caroline Bennett, William Collins, Hongki Jo, Alexander Henderson, Paul Ziehl Feb 2023

Investigation Of Electrically Isolated Capacitive Sensing Skins On Concrete To Reduce Structure/Sensor Capacitive Coupling, Emmanuel Ogunniyi, Alexander Vareen, Austin Downey, Simon Laflamme, Jian Li, Caroline Bennett, William Collins, Hongki Jo, Alexander Henderson, Paul Ziehl

Faculty Publications

Damage to bridges can result in partial or complete structural failures, with fatal consequences. Cracks develop in concrete infrastructure from fatigue loading, vibrations, corrosion, or unforeseen structural displacement. Effective long-term monitoring of civil infrastructure can reduce the risk of structural failures and potentially reduce the cost and frequency of inspections. However, deploying structural health monitoring technologies for crack detection on bridges is expensive, especially long-term, due to the density of sensors required to detect, localize, and quantify cracks. Previous research on soft elastomeric capacitors (SECs) has shown their viability for low-cost monitoring of cracks in transportation infrastructure. However, when deployed …


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 …


Artificial Intelligence In Civil Infrastructure Health Monitoring—Historical Perspectives, Current Trends, And Future Visions, Tarutal Ghosh Mondal, Genda Chen Sep 2022

Artificial Intelligence In Civil Infrastructure Health Monitoring—Historical Perspectives, Current Trends, And Future Visions, Tarutal Ghosh Mondal, Genda Chen

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

Over the past 2 decades, the use of artificial intelligence (AI) has exponentially increased toward complete automation of structural inspection and assessment tasks. This trend will continue to rise in image processing as unmanned aerial systems (UAS) and the internet of things (IoT) markets are expected to expand at a compound annual growth rate of 57.5% and 26%, respectively, from 2021 to 2028. This paper aims to catalog the milestone development work, summarize the current research trends, and envision a few future research directions in the innovative application of AI in civil infrastructure health monitoring. A blow-by-blow account of the …


Hybrid Structural Health Monitoring Using Data-Driven Modal Analysis And Model-Based Bayesian Inference., Jice Zeng Dec 2021

Hybrid Structural Health Monitoring Using Data-Driven Modal Analysis And Model-Based Bayesian Inference., Jice Zeng

Electronic Theses and Dissertations

Civil infrastructures that are valuable assets for the public and owners must be adequately and periodically maintained to guarantee safety, continuous service, and avoid economic losses. Vibration-based structural health monitoring (VBSHM) has been a significant tool to assess the structural performance of civil infrastructures over the last decades. Challenges in VBSHM exist in two aspects: operational modal analysis (OMA) and Finite element model updating (FEMU). The former aims to extract natural frequency, damping ratio, and mode shapes using vibrational data under normal operation; the latter focuses on minimizing the discrepancies between measurements and model prediction. The main impediments to real-world …


A Systematic Review Of Convolutional Neural Network-Based Structural Condition Assessment Techniques, Sandeep Sony, Kyle Dunphy, Ayan Sadhu, Miriam A M Capretz Jan 2021

A Systematic Review Of Convolutional Neural Network-Based Structural Condition Assessment Techniques, Sandeep Sony, Kyle Dunphy, Ayan Sadhu, Miriam A M Capretz

Electrical and Computer Engineering Publications

With recent advances in non-contact sensing technology such as cameras, unmanned aerial and ground vehicles, the structural health monitoring (SHM) community has witnessed a prominent growth in deep learning-based condition assessment techniques of structural systems. These deep learning methods rely primarily on convolutional neural networks (CNNs). The CNN networks are trained using a large number of datasets for various types of damage and anomaly detection and post-disaster reconnaissance. The trained networks are then utilized to analyze newer data to detect the type and severity of the damage, enhancing the capabilities of non-contact sensors in developing autonomous SHM systems. In recent …


Robustness And Accuracy Bounds Of Model-Based Structural Health Monitoring, Nestor Ramon Polanco Jan 2021

Robustness And Accuracy Bounds Of Model-Based Structural Health Monitoring, Nestor Ramon Polanco

Graduate College Dissertations and Theses

The strength and stiffness of structures degrade with time due to a combination of external forces and environmental conditions. A vehicular bridge, an offshore platform, a ship hull, or a wind turbine are examples of structures that for decades must endure cumulative degradation of their mechanical properties due to cyclic loading. Fatigue-induced damage typically starts at the exterior surface of the component unless microscopic or macroscopic imperfections are present in the material's structure. Structural Health Monitoring (SHM) provides a scientific non-destructive framework to estimate the structure's current state and remaining service life. In many model-based structural health monitoring applications, the …


Development Of A Self-Powered Weigh-In-Motion System, Athanassios Papagiannakis, Athanassios Papagiannakis, Samer Dessouky, Sara Ahmed, Reza Khalili, Gopal Vishwakarma Dec 2020

Development Of A Self-Powered Weigh-In-Motion System, Athanassios Papagiannakis, Athanassios Papagiannakis, Samer Dessouky, Sara Ahmed, Reza Khalili, Gopal Vishwakarma

Data

This report describes the development of a novel weigh-in-motion (WIM) system that utilizes piezoelectric elements for sensing load and powering an ultra-low power microcontroller unit (MCU) that serves as its data acquisition system. A system of 4 piezoelectric (PZT) stacks serves as the energy harvester, while load sensing is done via a set of 4 PZT elements connected in parallel. Two alternative MCUs were considered, with various data handling capabilities and power consumption requirements. These MCUs have very short “wake-up” times allowing vehicle sensing without the need for inductive loops commonly used in conventional WIM systems. Special electric circuits were …


Development Of A Self-Powered Weigh-In-Motion System, Athanassios Papagiannakis, Sarah Ahmed, Samer Dessouky, Reza Khalili, Gopal Vishwakarma Dec 2020

Development Of A Self-Powered Weigh-In-Motion System, Athanassios Papagiannakis, Sarah Ahmed, Samer Dessouky, Reza Khalili, Gopal Vishwakarma

Publications

This report describes the development of a novel weigh-in-motion (WIM) system that utilizes piezoelectric elements for sensing load and powering an ultra-low power microcontroller unit (MCU) that serves as its data acquisition system. A system of 4 piezoelectric (PZT) stacks serves as the energy harvester, while load sensing is done via a set of 4 PZT elements connected in parallel. Two alternative MCUs were considered, with various data handling capabilities and power consumption requirements. These MCUs have very short “wake-up” times allowing vehicle sensing without the need for inductive loops commonly used in conventional WIM systems. Special electric circuits were …


Lessons Learned From Six Different Structural Health Monitoring Systems On Highway Bridges, Abheetha Peiris, Charlie Sun, Issam E. Harik Sep 2020

Lessons Learned From Six Different Structural Health Monitoring Systems On Highway Bridges, Abheetha Peiris, Charlie Sun, Issam E. Harik

Kentucky Transportation Center Faculty and Researcher Publications

Structural health monitoring has been utilized in numerous ways to investigate the performance and integrity of highway bridges. This paper highlights the use of six structural health monitoring systems, which were deployed to monitor distinct behaviors on six bridges in Kentucky. The structural health monitoring systems are as follows: (1) Over-height truck impact detection and monitoring on the I-64 over US 60 bridge, (2) Barge impact detection and monitoring on northbound US 41 over the Ohio River, (3) effectiveness of carbon fiber-reinforced polymer retrofit evaluation based on prestressed concrete I-girder crack movement on the I-65 elevated expressway in Louisville, (4) …


Material Evaluation And Structural Monitoring Of Early-Age Masonry Structures, Kyle Dunphy Aug 2020

Material Evaluation And Structural Monitoring Of Early-Age Masonry Structures, Kyle Dunphy

Electronic Thesis and Dissertation Repository

During the initial construction period, “early-age” masonry walls are susceptible to lateral loads induced by wind or earthquake, which may result in damages or catastrophic failures. To mitigate such consequences at construction sites, temporary bracings are adopted to provide lateral support to masonry walls until they are matured enough to serve as the inherent lateral system of the structure. However, current temporary bracing guidelines provide oversimplified design due to the lack of available information on the material properties of early-age masonry. Moreover, there are no existing techniques for monitoring masonry walls to detect cracks due to construction activities. …


Data-Driven And Model-Based Methods With Physics-Guided Machine Learning For Damage Identification, Zhiming Zhang Jun 2020

Data-Driven And Model-Based Methods With Physics-Guided Machine Learning For Damage Identification, Zhiming Zhang

LSU Doctoral Dissertations

Structural health monitoring (SHM) has been widely used for structural damage diagnosis and prognosis of a wide range of civil, mechanical, and aerospace structures. SHM methods are generally divided into two categories: (1) model-based methods; (2) data-driven methods. Compared with data-driven SHM, model-based methods provide an updated physics-based numerical model that can be used for damage prognosis when long-term data is available. However, the performance of model-based methods is susceptible to modeling error in establishing the numerical model, which is usually unavoidable due to model simplification and omission. The major challenge of data-driven SHM methods lies in data insufficiency, e.g., …


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 …


Post-Fire Damage Geospatial Assessment Via Point Clouds Of A Highway Bridge Structure, Yijun Liao, M Ebrahim Mohammadi, Richard L. Wood, Christine E. Wittich Jan 2019

Post-Fire Damage Geospatial Assessment Via Point Clouds Of A Highway Bridge Structure, Yijun Liao, M Ebrahim Mohammadi, Richard L. Wood, Christine E. Wittich

Department of Civil and Environmental Engineering: Faculty Publications

This paper discusses the quantitative post-fire damage assessment of a steel girder bridge via point clouds. In this case study, the point cloud was collected using light detection and ranging (lidar) for a detailed geometric and shape analysis. The out-of-plane deformation was analyzed to locate and quantify buckling across the length of the steel girders.


Sdnet2018: An Annotated Image Dataset For Non-Contact Concrete Crack Detection Using Deep Convolutional Neural Networks, Sattar Dorafshan, Robert J. Thomas, Marc Maguire Nov 2018

Sdnet2018: An Annotated Image Dataset For Non-Contact Concrete Crack Detection Using Deep Convolutional Neural Networks, Sattar Dorafshan, Robert J. Thomas, Marc Maguire

Civil and Environmental Engineering Faculty Publications

SDNET2018 is an annotated image dataset for training, validation, and benchmarking of artificial intelligence based crack detection algorithms for concrete. SDNET2018 contains over 56,000 images of cracked and non-cracked concrete bridge decks, walls, and pavements. The dataset includes cracks as narrow as 0.06 mm and as wide as 25 mm. The dataset also includes images with a variety of obstructions, including shadows, surface roughness, scaling, edges, holes, and background debris. SDNET2018 will be useful for the continued development of concrete crack detection algorithms based on deep convolutional neural networks (DCNNs), which are a subject of continued research in the field …


Comparison Of Deep Convolutional Neural Networks And Edge Detectors For Image-Based Crack Detection In Concrete, Sattar Dorafshan, Robert J. Thomas, Marc Maguire Aug 2018

Comparison Of Deep Convolutional Neural Networks And Edge Detectors For Image-Based Crack Detection In Concrete, Sattar Dorafshan, Robert J. Thomas, Marc Maguire

Civil and Environmental Engineering Faculty Publications

This paper compares the performance of common edge detectors and deep convolutional neural networks (DCNN) for image-based crack detection in concrete structures. A dataset of 19 high definition images (3420 sub-images, 319 with cracks and 3101 without) of concrete is analyzed using six common edge detection schemes (Roberts, Prewitt, Sobel, Laplacian of Gaussian, Butterworth, and Gaussian) and using the AlexNet DCNN architecture in fully trained, transfer learning, and classifier modes. The relative performance of each crack detection method is compared here for the first time on a single dataset. Edge detection methods accurately detected 53–79% of cracked pixels, but they …


Structural Cyber-Physical Systems: A Confluence Of Structural Health Monitoring And Control Technologies, Rosana E. Martínez-Castro, Shinae Jang Jan 2018

Structural Cyber-Physical Systems: A Confluence Of Structural Health Monitoring And Control Technologies, Rosana E. Martínez-Castro, Shinae Jang

CEE Articles

Many bridges in the nation’s transportation infrastructure network have been found to be structurally deficient. In face of a natural or man-made disaster, this poses a serious threat to the execution of emergency respondent logistics, as the failure of such structures could disconnect communities from the necessary provisions and services that must remain accessible after a disaster. To predict such an eventuality, dependable information on structural status for decision-making can be obtained from structural health monitoring (SHM) systems. However, the avoidance of such a situation is preferred. Structural control systems offer an option to improve structural response during extreme loading …


Cross-Correlation-Based Structural System Identification Using Unmanned Aerial Vehicles., Hyungchul Yoon, Vedhus Hoskere, Jong-Woong Park, Billie F. Spencer Sep 2017

Cross-Correlation-Based Structural System Identification Using Unmanned Aerial Vehicles., Hyungchul Yoon, Vedhus Hoskere, Jong-Woong Park, Billie F. Spencer

Michigan Tech Publications

Computer vision techniques have been employed to characterize dynamic properties of structures, as well as to capture structural motion for system identification purposes. All of these methods leverage image-processing techniques using a stationary camera. This requirement makes finding an effective location for camera installation difficult, because civil infrastructure (i.e., bridges, buildings, etc.) are often difficult to access, being constructed over rivers, roads, or other obstacles. This paper seeks to use video from Unmanned Aerial Vehicles (UAVs) to address this problem. As opposed to the traditional way of using stationary cameras, the use of UAVs brings the issue of the camera …


Large-Scale Flexible Membrane For Automatic Strain Monitoring Of Transportation Infrastructure, Simon Laflamme, Venkata D. Kolipara, Hussam S. Saleem, Randall L. Geiger Jun 2017

Large-Scale Flexible Membrane For Automatic Strain Monitoring Of Transportation Infrastructure, Simon Laflamme, Venkata D. Kolipara, Hussam S. Saleem, Randall L. Geiger

Randall Geiger

Structural Health Monitoring (SHM) of transportation infrastructures is a complex task, typically conducted by visual inspection due to the technical and economical constrains of existing health monitoring technologies. It results that health monitoring is highly dependent on scheduling and on the judgment of the inspectors, which can be costly and ineffective. Thus, it is fundamental to automate the SHM process to allow timely inspection, maintenance, and management of transportation infrastructure. The authors propose a flexible membrane that can be deployed over large surfaces, at low cost, for automatic and continuous monitoring of strains. The membrane, termed sensing skin, is constituted …


Development Of A Wireless Mems Multifunction Sensor System And Field Demonstration Of Embedded Sensors For Monitoring Concrete Pavements, Halil Ceylan, Liang Dong, Shuo Yang, Yueyi Jiao, Sunghwan Kim, Kasthurirangan Gopalakrishnan, Peter Taylor, Seval Yavas Jun 2017

Development Of A Wireless Mems Multifunction Sensor System And Field Demonstration Of Embedded Sensors For Monitoring Concrete Pavements, Halil Ceylan, Liang Dong, Shuo Yang, Yueyi Jiao, Sunghwan Kim, Kasthurirangan Gopalakrishnan, Peter Taylor, Seval Yavas

Liang Dong

Pavements tend to deteriorate with time under repeated traffic and/or environmental loading. By detecting pavement distresses and damage early enough, it is possible for transportation agencies to develop more effective pavement maintenance and rehabilitation programs and thereby achieve significant cost and time savings. The structural health monitoring (SHM) concept can be considered as a systematic method for assessing the structural state of pavement infrastructure systems and documenting their condition. Over the past several years, this process has traditionally been accomplished through the use of wired sensors embedded in bridge and highway pavement. However, the use of wired sensors has limitations …


Integration Of A Prototype Wireless Communication System With Micro-Electromechanical Temperature And Humidity Sensor For Concrete Pavement Health Monitoring, Shuo Yang, Keyan Shen, Halil Ceylan, Sunghwan Kim, Daji Qiao, Kasthurirangan Gopalakrishnan Jun 2017

Integration Of A Prototype Wireless Communication System With Micro-Electromechanical Temperature And Humidity Sensor For Concrete Pavement Health Monitoring, Shuo Yang, Keyan Shen, Halil Ceylan, Sunghwan Kim, Daji Qiao, Kasthurirangan Gopalakrishnan

Daji Qiao

In recent years, structural health monitoring and management (SHMM) has become a popular approach and is considered essential for achieving well-performing, long-lasting, sustainable transportation infrastructure systems. Key requirements in ideal SHMM of road infrastructure include long-term, continuous, and real-time monitoring of pavement response and performance under various pavement geometry-materials-loading configurations and environmental conditions. With advancements in wireless technologies, integration of wireless communications into sensing device is considered an alternate and superior solution to existing time- and labor-intensive wired sensing systems in meeting the requirements of an ideal SHMM. This study explored the development and integration of a wireless communications sub-system …


Non-Contact Based Structural Damage Assessment Using Stochastic Subspace Identification And Finite Element Model Updating., Li Yang May 2017

Non-Contact Based Structural Damage Assessment Using Stochastic Subspace Identification And Finite Element Model Updating., Li Yang

Electronic Theses and Dissertations

This research proposed and verified an innovative method to identify and locate structural damage using only the response of operational vibration, that is the displacement acquired by a non-contact optical method. The most efficient and economical way to detect damage within the structure is to monitor its structural health while in operation. However, the uncertainties and the randomness of ambient vibrations due to the operation and environments cause a challenge in conducting the operational analysis. Current technology limits the ability to collect data on the properties of the structure without the interruption of operation. Frequencies and mode shapes have been …


Application Of Wavelet Transform In Structural Health Monitoring, Yashodhya Swarna Sri Dhanapala Liyana Kankanamge Dec 2016

Application Of Wavelet Transform In Structural Health Monitoring, Yashodhya Swarna Sri Dhanapala Liyana Kankanamge

Masters Theses

Structural Health Monitoring (SHM) is a process of implementing a damage detection strategy in structures to evaluate the condition of existing structures to ensure the safety of users in the future. The changes in the material, geometric and/or structural properties affect structural responses, which can be captured and analyzed for condition assessment. Various vibration-based damage detection algorithms have been developed in the past decades. Among them, the Continuous Wavelet Transform (CWT) gained popularity as an efficient method of signal processing to build a framework to identify model properties and detect damage in structures. In this study, the application of wavelet …


Bridge Rating Based On In-Situ Weigh-In-Motion And Health Monitoring Data, Dana Feng Jan 2016

Bridge Rating Based On In-Situ Weigh-In-Motion And Health Monitoring Data, Dana Feng

LSU Doctoral Dissertations

Parallel to the bridge design methodology changes from the Allowable Stress Design to the Load Factor Design, and then to the reliability based Load and Resistance Factor Design (LRFD), bridge load rating method has also been evolving. Applying the reliability theory to the bridge load rating is more complex than applying to the LRFD since any conservatism can have a significant effect on the assessment of bridge capacity, particularly in load posting and bridge replacement. Although the current Load and Resistant Factor Rating (LRFR) method applying the concept of reliability analyses, it uses very limited site-specific data due to practical …


Rfid Tags For Detecting Concrete Degradation In Bridge Decks, Tyler J. Lesthaeghe, Samuel Frishman, Stephen D. Holland, Terry J. Wipf Jun 2015

Rfid Tags For Detecting Concrete Degradation In Bridge Decks, Tyler J. Lesthaeghe, Samuel Frishman, Stephen D. Holland, Terry J. Wipf

Tyler J Lesthaeghe

Steel reinforcing bar (rebar) corrosion due to chlorine ingress is the primary degradation mechanism for bridge decks. In areas where rock salt is used as a de-icing agent, salt water seeps into the concrete through cracks, causing corrosion of the rebar and potentially leading to catastrophic failure if not repaired. This project explores the use of radio frequency identification (RFID) tags as low-cost corrosion sensors. RFID tags, when embedded in concrete, will fail due to corrosion in the same manner as rebar after prolonged exposure to salt water. In addition, the presence of salt water interferes with the ability to …


Structural Health Monitoring Of Bridges Using Wireless Sensor Networks, Seyed Behrad Ghazi Sharyatpanahi May 2015

Structural Health Monitoring Of Bridges Using Wireless Sensor Networks, Seyed Behrad Ghazi Sharyatpanahi

Theses

Structural Health Monitoring, damage detection and localization of bridges using Wireless Sensor Networks (WSN) are studied in this thesis. The continuous monitoring of bridges to detect damage is a very useful tools for preventing unnecessary costly and emergent maintenance. The optimal design aims to maximize the lifetime of the system, the accuracy of the sensed data, and the system reliability, and to minimize the system cost and complexity

Finite Element Analysis (FEA) is carried out using LUSAS Bridge Plus software to determine sensor locations and measurement types and effectively minimize the number of sensors, data for transmission, and volume of …


Damage Detection Methodologies For Structural Health Monitoring Of Thin-Walled Pressure Vessels, Arturo Modesto Jan 2015

Damage Detection Methodologies For Structural Health Monitoring Of Thin-Walled Pressure Vessels, Arturo Modesto

Electronic Theses and Dissertations

There is a need in exploring structural health monitoring technologies for the composite structures particularly aged Composite Overwrapped Pressure Vessels (COPVs) for the current and future implementation of COPVs for space missions. In this study, the research was conducted in collaboration with NASA Kennedy Space Center and also NASA Marshall Space and Flight Center engineers. COPVs have been used to store inert gases like helium (for propulsion) and nitrogen (for life support) under varying degrees of pressure onboard the orbiter since the beginning of the Space Shuttle Program. After the Columbia accident, the COPVs were re-examined and different studies (e.g. …


Bayesian Filtering In Nonlinear Structural Systems With Application To Structural Health Monitoring, Kalil Erazo Jan 2015

Bayesian Filtering In Nonlinear Structural Systems With Application To Structural Health Monitoring, Kalil Erazo

Graduate College Dissertations and Theses

During strong earthquakes structural systems exhibit nonlinear behavior due to low-cycle fatigue, cracking, yielding and/or fracture of constituent elements. After a seismic event it is essential to assess the state of damage of structures and determine if they can safely resist aftershocks or future strong motions. The current practice in post-earthquake damage assessment relies mainly on visual inspections and local testing. These approaches are limited to the ability of inspectors to reach all potentially damaged locations, and are typically intended to detect damage near the outer surfaces of the structure leaving the possibility of hidden undetected damage. Some structures in …


Structural Health Monitoring Using Novel Sensing Technologies And Data Analysis Methods, Seyedmasoud Malekzadeh Jan 2014

Structural Health Monitoring Using Novel Sensing Technologies And Data Analysis Methods, Seyedmasoud Malekzadeh

Electronic Theses and Dissertations

The main objective of this research is to explore, investigate and develop the new data analysis techniques along with novel sensing technologies for structural health monitoring applications. The study has three main parts. First, a systematic comparative evaluation of some of the most common and promising methods is carried out along with a combined method proposed in this study for mitigating drawbacks of some of the techniques. Secondly, nonparametric methods are evaluated on a real life movable bridge. Finally, a hybrid approach for non-parametric and parametric method is proposed and demonstrated for more in depth understanding of the structural performance. …