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Full-Text Articles in Engineering

Self-Assembly Of Exfoliated Graphene Flakes As Anticorrosive Coatings For Additive Manufactured Steels, Kaleb Hood, Wen Qian, Yi Xia, Savannah Krupa, Annie Dao, Sarah Ahmed, Samuel Olson, Nam Nguyen, Joseph A. Turner, Jun Jiao May 2023

Self-Assembly Of Exfoliated Graphene Flakes As Anticorrosive Coatings For Additive Manufactured Steels, Kaleb Hood, Wen Qian, Yi Xia, Savannah Krupa, Annie Dao, Sarah Ahmed, Samuel Olson, Nam Nguyen, Joseph A. Turner, Jun Jiao

Department of Mechanical and Materials Engineering: Faculty Publications

This study demonstrates the feasibility of using liquid exfoliation of expandable graphite into multilayer exfoliated graphene flakes (EGFs) to form a self-assembled thin film on an air–water interface. The film can coat the surface of additive manufactured (AM) steel substrates to enhance surface properties, specifically AM 316 stainless-steel (AM316), AM 8620 steel (AM8620), and samples of the same alloys made by conventional manufacturing (CM) processes. Liquid exfoliation offers a high yield route for an EGF coating that can cover up to 95% of the sample surface with a single application. The thin, flexible EGFs can coat a rough AM metal …


Novel Peridynamic Models For Material Degradation And Mass Transport, Jiangming Zhao Nov 2021

Novel Peridynamic Models For Material Degradation And Mass Transport, Jiangming Zhao

Department of Mechanical and Materials Engineering: Dissertations, Theses, and Student Research

Fracture and corrosion are two major causes of structure failure. They can interact with each other, leading to faster material degradation. They are also under the influence of environmental conditions. The corrosion rate highly depends on the transportation rate of involving substances, while the fracture can be accelerated significantly due to fluid flow. These complex mechanisms involved in structure failure have troubled classical models for decades. The peridynamic (PD) theory introduced in 2000 has shown great potential in modeling such problems. In this work, we develop novel PD models for fracture, corrosion, mass transport, and viscous flow, which are building …


A Comparison Between Ultrasonic Guidedwave Leakage And Half-Cell Potential Methods In Detection Of Corrosion In Reinforced Concrete Decks, Ahmad Shoaib Amiri, Ece Erdogmus, Dana Richter-Egger Jun 2021

A Comparison Between Ultrasonic Guidedwave Leakage And Half-Cell Potential Methods In Detection Of Corrosion In Reinforced Concrete Decks, Ahmad Shoaib Amiri, Ece Erdogmus, Dana Richter-Egger

Durham School of Architectural Engineering and Construction: Faculty Publications

This article presents the advantages and limitations of a recently developed Ultrasonic Guided Wave Leakage (UGWL) method in comparison to the well-known Half-Cell Potential (HCP) method in their ability to detect corrosion in reinforced concrete (RC) bridge decks. This research also establishes a correlation between UGWL data and chloride content in concrete RC slabs. Concrete slabs submerged in a 10% NaCl solution were monitored using both methods over a period of six months. The chloride content from the three cores (0.84, 0.55, and 0.18%) extracted from the slab after the 6-month long process all exceeded the chloride threshold values suggested …


Novel And Fast Peridynamic Models For Material Degradation And Failure, Siavash Jafarzadeh Jun 2021

Novel And Fast Peridynamic Models For Material Degradation And Failure, Siavash Jafarzadeh

Department of Mechanical and Materials Engineering: Dissertations, Theses, and Student Research

Fracture is one of the main mechanisms of structural failure. Corroded surfaces with chemically-induced damage are, notably, potential sites for crack initiation and propagation in metals, which can lead to catastrophic failure of structures. Despite some progress in simulating fracture and damage using classical models, realistic prediction of complex damage progression and failure has been out of reach for many decades. Peridynamics (PD), a nonlocal theory introduced in 2000, opened up new avenues in modeling material degradation and failure. Existing numerical methods used to discretize PD equations, however, are quite expensive as the PD nonlocal interactions make them unaffordable for …


Prototype System For Implementing The Ultrasonic Guided Wave Method On The Field, Ece Erdogmus, Eric Garcia, Michael Schuller, Ahmad Shoaib Amiri Jun 2020

Prototype System For Implementing The Ultrasonic Guided Wave Method On The Field, Ece Erdogmus, Eric Garcia, Michael Schuller, Ahmad Shoaib Amiri

Nebraska Department of Transportation: Research Reports

This report presents the latest improvements in a recently developed nondestructive testing (NDT) technique for early detection of various flaws such as corrosion, delamination, and concrete cracking in reinforced concrete (RC) bridge decks. The method, named Ultrasonic Guided Wave Leakage (UGWL) method by the developing authors, involves use of internal steel reinforcement (rebar) as a wave guide for transmitting ultrasonic waves through the system and the measurement of leaked energy at the surface of the concrete. This report builds upon the progress made in the previously published phases of the project (M029 and M066), and aims to further explore the …


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 …


Performance Assessment Of Deteriorated And Retrofitted Steel Hp Piles, Steven T. Stauffer May 2016

Performance Assessment Of Deteriorated And Retrofitted Steel Hp Piles, Steven T. Stauffer

Department of Civil and Environmental Engineering: Dissertations, Theses, and Student Research

Deterioration of aging bridges can be attributed to an assortment of mechanisms throughout the structure, with remediation policies also varying. This study focused on assessing the validity of the Nebraska Department of Roads’ (NDOR) reinforced concrete encasement retrofit for corroded steel HP piles. Experiments were designed and conducted to test the capacity of the NDOR retrofit and evaluate failure limit states. Two pile locations were considered: abutment and pile bent. For each location there was a non-deteriorated, deteriorated, and retrofitted case. These cases represented the pile at key stages during its life. NDOR’s concrete encasement retrofit provided the required stability …


Nondestructive Method To Detect Corrosion Of Steel Elements In Concrete, Saeed Javidi Niroumand, Aaron Jon Yakel, Atorod Azizinamini, Marcelo Dasilva Apr 2009

Nondestructive Method To Detect Corrosion Of Steel Elements In Concrete, Saeed Javidi Niroumand, Aaron Jon Yakel, Atorod Azizinamini, Marcelo Dasilva

Nebraska Department of Transportation: Research Reports

No abstract provided.


Corrosion And Dissolution Protection Of A Conductive Silver/Polymer Composite, Ravi F. Saraf Jan 2001

Corrosion And Dissolution Protection Of A Conductive Silver/Polymer Composite, Ravi F. Saraf

Department of Chemical and Biomolecular Engineering: Patents

A conductive composite is described containing silver particles and a polymer which covers each silver particle and wherein a heterocyclic organic compound containing nitrogen such as benzotriazole (BTA) is present to reduce Ag dissolution and ion mobility by forming a water insoluble complex with the Ag ion. The invention overcomes the problem of silver dissolution or corrosion a conductive composite as a result of normal high Ag ion mobility in the presence of moisture and an electric field