Engineering Commons^™

Study On Corrosion Activity Of Carbon Steel In Concrete Simulated Pore Solution Under Static Tensile And Compressive Stresses, Yujie Zhang

All Theses

Reinforced concrete is a structure material made up of concrete with relatively lower tensile strength containing reinforcements with higher tensile strength and better ductility, which are embedded into fresh concrete to resist tensile stress in certain regions of concrete. Steel reinforced concrete is most widely used around the world in civil engineering structures, water conservancy and highway construction due to its durability strength and reasonable cost.
However, reinforced concrete structures such as bridges and parking lots slabs inevitably experience variable loads and constant degradation from the aggressive environments, such as marine and deicing salts. Therefore, it is imperative to study …

Electrochemical Deposition Of Porous Vox And Mno2 Nanowires On Stainless Steel Mesh For Flexible Supercapacitors, Shulei Chou, Jiazhao Wang, Hua Liu, S Dou

Shulei Chou

Porous vanadium oxide (VO_x) and MnO₂ nanowires were synthesized by an electrochemical deposition method using stainless steel mesh as substrate. The as-prepared porous VO_x and MnO₂ nanowire films were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), and Raman spectroscopy. The cyclic voltammetry (CV) results show that the MnO₂ nanowire film shows specific capacitance of 195, 170, 158, and 91 F g^-1 at scan rates of 5, 10, 20, and 50 mV s^-1, respectively. The porous VO_x film displays specific capacitance of 152, 124, 99, and 76 F g …

Electrochemical Deposition Of Porous Co(Oh)2 Nanoflake Films On Stainless Steel Mesh For Flexible Supercapacitors, Shulei Chou, Jiazhao Wang, Hua-Kun Liu, S. X. Dou

Shulei Chou

Flexible porous Co(OH)2 nanoflake films were prepared by galvanostatic electrodeposition on lightweight and inexpensive stainless steel mesh. The as-prepared porous Co(OH)2 nanoflake films were characterized by X-ray diffraction, thermogravimetric analysis, and scanning electron microscopy. Electrochemical tests including cyclic voltammetry, constant current charge-discharge, and electrochemical impedance spectroscopy were also used to investigate the electrochemical performance. The results show that the highest capacitance is 609.4 F g-1, the specific capacitance decreases by less than 5% as the mass loading of Co(OH)2 increases by more than 340%, and the specific capacitance only decreases by less than 15% when the current densities increase up …

New Coatings For Bridges (Over-Coat Systems), Sudhir Palle, Theodore Hopwood Ii, Bobby W. Meade

Kentucky Transportation Center Research Report

KYTC sought to identify new coatings technologies consistent with overcoating that offer enhancements in terms of ease of application and performance. KYTC contacted paint manufacturers to obtain sample coating systems for characterization by the KYTC Division of Materials and accelerated performance testing by Kentucky Transportation Center (KTC). A total of 14 coating systems from five manufacturers underwent performance testing according to ASTM D5894.

Incorporation Of Life Cycle Models In Determining Optimal Wind Energy Infrastructural Provision, Brendan Cleary, Aidan Duffy, Alan O'Connor

Conference papers

The deployment of wind energy has grown rapidly over the last two decades with an average annual growth rate of more than 26% since 1990. During this period the development and innovation of wind turbines has resulted in continual growth in wind turbine size with output ranges of 10-15MW likely to be deployed by 2020. This increased output has a knock-on effect on the growth of rotor diameters and tower heights. Wind turbine towers are required to become taller, stronger and stiffer in order to carry the increased weight and associated structural loading. Consequently, the dimensions of the tower cross-sections …

The Effects Of Bolt Pretension, In-Plane Eccentricity, And Friction On The Ductility Of Block Shear Connections, Kevin M. Zmetra

Master's Theses

Block shear is a complex failure mechanism in bolted and welded steel components such as gusset plates, webs of coped beams, angles and tees. It presumes a combination of tension rupture and shear yield. Multiple variables affect the block shear capacity and ductility of a connection. This study investigates the effects of bolt pretension, connection eccentricity and friction force transfer through a series of destructive experiments followed by refined finite element simulation. Clamping forces create a complex triaxial stress field compounded by the stress concentration at the bolt holes. In-plane load eccentricity with respect to the centerline of the connection …

Study On The Fracture Toughness Of Friction Stir Welded Api X80, Allan M. Tribe

Theses and Dissertations

High strength low alloy (HSLA) steels have been developed to simultaneously have high yield strength and high fracture toughness. However, in practical applications steel must be welded. Traditional arc welding has proven detrimental to the fracture toughness of HSLA steels. Friction stir welding has recently shown mixed results in welding HSLA steels. The range of welding parameters used in these recent studies however has been very limited. With only a few welding parameters tested, the effect of spindle speed, travel speed, and heat input on the fracture toughness of friction stir welded HSLA steel remains unknown. To understand how the …

Development And Use Of A Simple Test Method To Evaluate Reheat Cracking Sensitivity In The Weld Deposit Region Of A Submerged Arc Weld, Maxwell Calder Trent

Masters Theses

Several fabricators have recently noted the occurrence of reheat cracking in the weld deposits of 2¼[ two and one fourth]Cr‑1Mo‑¼[one fourth]V (22V) during the fabrication of pressure vessels used in the petrochemical industry. Due to increased oversight now required during fabrication of already expensive pressure vessels, studies have commenced worldwide in an effort to identify root causes and formulate mitigating actions to weld reheat cracking issues. The Materials Joining Group (MJG) at the University of Tennessee at Knoxville (UTK) have adapted an existing reheat cracking test originally developed for use with alloys similar to 22V. This original C‑Ring test was …

Efficient Prestressed Concrete-Steel Composite Girder For Medium-Span Bridges, Yaohua Deng

Department of Construction Engineering and Management: Dissertations, Theses, and Student Research

In this dissertation, a new Prestressed Concrete-Steel Composite (PCSC) girder system is introduced. The PCSC girder is composed of a lightweight W-shape steel section with shear studs on its top and bottom flanges to achieve composite action with the pretensioned concrete bottom flange and the cast-in-place concrete deck. The PCSC girder is lightweight, economical, durable and easy to fabricate. To prove its feasibility and potential, this study is to investigate design and fabrication issues associated with the PCSC girder. A service design procedure is proposed using Age-adjusted Elasticity Modulus Method (AEMM) to evaluate the time-dependent stresses and strains in the …

Buckling And Crippling Of Square Steel Thin-Walled Tubes Fabricated With Symmetrically-Overlapping U-Channels And Foam, David Camenish Gelder

Theses and Dissertations

Testing and analysis has been performed on square steel thin-walled tubes fabricated using symmetrically-overlapping U-channels and foam. This research analyzes flange-to-flange attachment, effect of foam in the columns, effect of adhesive stiffness, and influence of steel thickness, as related to the local buckling loads, global buckling loads, and crippling loads. Four 14-foot (4.27 m) foam-filled, thin-walled, galvanized steel columns were manufactured by Novatek, Inc. and tested in axial compression with pinned boundary conditions. For three of the four configurations, the two-piece 4-in. (10.2-cm) square shell surrounded prefabricated polystyrene foam inserts; the fourth column had no foam insert. The column outer …

Characterization Of Raw Milk Fouling On Plate-Type Heat Exchangers Using Different Alloys And Cow Phenotypes, Stephen Ernest Nelson

Master's Theses

ABSTRACT

Characterization Of Raw Milk Fouling On Plate-Type Heat Exchangers Using Different Alloys And Cow PhenotypeS

Stephen Ernest Nelson

Milk and other dairy products are widely used in many households today. Milk is a popular beverage that is seen as a healthy alternative to other synthetic beverages such as soda pop and other sugar based drinks. It became law that milk, and milk products are pasteurized before its release to the general public (FDA 2003). Pasteurization is a thermal process where the intent is to lower the concentration of microorganisms in the milk to render it safe to drink with …

Influence Of Shielding Gas On Fume Formation Rate For Gas Metal Arc Welding (Gmaw) Of Plain Carbon Steel, Kristin R. Carpenter, Brian J. Monaghan, John Norrish

Brian Monaghan

Shielding gas composition is an important parameter for successful gas metal arc welding (GMAW) and has been shown to affect the fume formation rate (FFR). The present paper compares thirteen shielding gases and their impact on FFR in spray transfer. In Ar-based mixtures, increasing CO2 had a greater impact than raising O2 on FFR. When O2 was increased in ternary mixtures, the FFR increased for Ar-5%CO2 but no discernable increase was observed for the Ar-12%CO2 mixtures. Ar-He-CO2 mixtures had the most stable FFR's. The FFR for 100% CO2 was significantly higher due to the change in weld transfer mode to …

The Evaluation Of Tuyere Coke Probing Data At Bluescope Steel Port Kembla Works, Robert J. Nightingale, John Simpson, Brian J. Monaghan, Andrew Blakey, Vincent Daly

Brian Monaghan

Tuyere coke probings have been conducted at Port Kembla over the past decade. This period of operation spans significant change in coking coal preparation as well as the introduction of pulverised coal injection.

Analysis Of Fume Formation Rate And Fume Particle Composition For Gas Metal Arc Welding (Gmaw) Of Plain Carbon Steel Using Different Shielding Gas Compositions, Kristin R. Carpenter, Brian J. Monaghan, John Norrish

Brian Monaghan

The present paper compares thirteen shielding gases and their impact on FFR and fume particle while welding in the spray transfer regime. There was no obvious influence from the shielding gas on particle composition and fume particles were identified as (Fe,Mn)3O4. There was a slight peak shift that indicated that small levels of Mn, as detected by TEM-EDS, substituted for Fe in the Fe3O4 phase. Shielding gas composition is an important parameter for successful gas metal arc welding (GMAW) and has been shown to affect the fume formation rate (FFR). In Ar-based mixtures, increasing CO2 had a greater impact than …

Material Characterization And Computational Simulation Of Steel Foam For Use In Structural Applications, Brooks H. Smith

Masters Theses 1911 - February 2014

Cellular metals made from aluminum, titanium, or other metals are becoming increasingly popular for use in structural components of automobiles, aircraft, and orthopaedic implants. Civil engineering applications remain largely absent, primarily due to poor understanding of the material and its structural properties. However, the material features a high stiffness to weight ratio, excellent energy dissipation, and low thermal conductivity, suggesting that it could become a highly valuable new material in structural engineering. Previous attempts to characterize the mechanical properties of steel foam have focused almost exclusively upon uniaxial compression tests, both in experimental research and in computational simulations. Further, computational …

Effect Of Grain Size On The Hydrogen Diffusion Process In Steel Using Cellular Automaton Approach, Druce P. Dunne, E V. Pereloma, Nima Yazdipour

Faculty of Engineering - Papers (Archive)

The role of microstructure in susceptibility to hydrogen uptake and property degradation is being evaluated using a number of high strength pipeline steels. To do so, a cellular automaton (CA) model has been used to examine the effect of grain size, as a first step in assessing the influence of microstructure. The simulation results of hydrogen diffusion into microstructures with different grain sizes are presented.

Net Section Tension Capacity Of Bolted Connections In Cold-Reduced Steel Sheets, Lip H. Teh, Benoit P. Gilbert

Faculty of Engineering - Papers (Archive)

This paper examines the accuracy of design equations specified in the North American, European and Australasian codes for coldformed steel structures in determining the net section tension capacity of bolted connections in flat steel sheets. It points out that the shear lag factors embedded in the code equations either yield “anomalous” results or become irrelevant when they exceed unity. The “anomaly” was demonstrated through laboratory tests and is explained by using simple calculus. The configurations of specimens tested in the laboratory include single shear- and double-shear connections, with single or double bolts in a line parallel or perpendicular to the …

Inelastic Stability Analysis Of High Strength Rectangular Concrete-Filled Steel Tubular Slender Beam-Columns, Vipulkumar Ishvarbhai Patel, Qing Quan Liang, Muhammad N. S Hadi

Faculty of Engineering - Papers (Archive)

There is relatively little numerical study on the behavior of eccentrically loaded high strength rectangular concrete-filled steel tubular (CFST) slender beam-columns with large depth-to-thickness ratios, which may undergo local and global buckling. This paper presents a multi scale numerical model for simulating the interaction local and global buckling behavior of hlgh strength thin-walled rectangular CFST slender beam-columns under eccentric loading. The effects of progressive local buckling are taken into account in the mesoscale model based on fiber element formulations. Computational algorithms based on the Muller's method are developed to obtain complete load-deflection responses of CFST slender beam-columns at the macroscale …

Tension Capacity Of Staggered Bolted Connections In Cold-Reduced Steel Sheets, Lip H. Teh, Drew D. A Clements

Faculty of Engineering - Papers (Archive)

This paper examines the assumption implicit in Cochrane’s formula that stresses are uniformly distributed across the net section of a staggered bolted connection. The assumption was found to be overoptimistic for connections in steel having low ductility, leading to unconservative estimates for the tension capacity if the in-plane shear lag is not accounted for. The reduction factor of 0.9 specified in the North American specification for cold-formed steel structures partially but not wholly addresses the problems inherent in the code equations. This paper points out that the “simplification” of Cochrane’s original formula into the standard formula used in steel design …

Block Shear Capacity Of Bolted Connections In Cold-Reduced Steel Sheets, Lip H. Teh, Drew D. A Clements

Faculty of Engineering - Papers (Archive)

This paper examines the mechanisms for block shear failures of bolted connections in steel plates postulated in the design equations specified in the North American, European and Australian steel structures codes. It explains that there is only one feasible mechanism for the limit state of conventional block shear failure, that which involves tensile rupture and shear yielding, irrespective of the steel material ductility. It describes the fundamental shortcomings of various code equations for determining the block shear capacity of a bolted connection. Based on the tensile rupture and shear yielding mechanism, an in-plane shear lag factor, and the active shear …

Effect Of Annealing On The Microstructure, Texture And Mechanical Properties Of Severely Deformed Interstitial Free Steel, Sujoy S. Hazra, Azdiar A. Gazder, E V. Pereloma

Faculty of Engineering - Papers (Archive)

Ti-stabilised interstitial free (IF) steel initially subjected to 8 passes, route B_C equal channel angular pressing (ECAP) was further cold rolled (CR) at room temperature to 95% thickness reduction. Both samples were isothermally annealed at 710 °C following which their microstructures and micro-textures were compared via electron back-scattering diffraction (EBSD). The mechanical properties first obtained by shear punch testing (SPT) were later corroborated by uniaxial tensile tests. In the case of the ECAP material, continuous recrystallisation is followed by abnormal growth at prolonged annealing times with minor increases in high angle boundary (HAGB) fraction. On the other hand, the …

A Novel Laboratory Technique For Introducing Inclusion To Liquid Steel, Neslihan Dogan, Brian J. Monaghan, Raymond J. Longbottom, Mark H. Reid, Xenophon C. Tsekouras

Faculty of Engineering - Papers (Archive)

Previous studies in steel cleanness have been hampered by limited control of inclusions’ phase and composition. This limited control is often a result of studying inclusion formation and development using industrial steel melts and the inclusions therein as starting material. This is an extremely complex situation and not always readily amenable to analysis. A new experimental laboratory technique has been developed that allows addition of inclusions of known, size, phase and composition to be added to liquid steel. These inclusions can then be tracked and changes in morphology with time can be assessed for different melt conditions. The technique involves …

Self-Shape Optimisation Application: Optimisation Of Cold-Formed Steel Columns, Benoit P. Gilbert, Timothee J-M Savoyat, Lip H. Teh

Faculty of Engineering - Papers (Archive)

This paper presents the optimisation of cold-formed steel open columns using the recently developed self-shape optimisation method that aims to discover new profile shapes. The strength of the coldformed steel sections is calculated using the Direct Strength Method, and the rules developed in the present work to automatically determine the local and distortional elastic buckling stresses from the Finite Strip and constrained Finite Strip Methods are discussed. The rules are verified against conventional and optimum sections yielded in this research, and found to accurately predict the elastic buckling stresses. The optimisation method is applied to singly-symmetric (mono-symmetric) cold-formed steel columns, …

Modelling Of Temperature-Dependent Growth Kinetics Of Oxide Scale On Hot-Rolled Steel Strip, Xianglong Yu, Zhengyi Jiang, Dongbin Wei, Xiaodong Wang, Quan Yang

Faculty of Engineering - Papers (Archive)

A numerical simulation, developed to predict the temperature distribution and calculate the growth rale of the oxide scale formed on the microalloyed low carbon steel during the laminar cooling of hot strip rolling, was conducted by two-dimensional finite element method. The model takes into account the different thetmoPhYsical properties of the multilayered oxide scales and the film boundary conditions for the water jet impingement zone and the stable film boiling zone through the run-out table. Complied with the parabolic growth of the oxide layers and the distribution of the oxide phase, it is found that the present of wustite (FeO) …

Precipitation Behavior Of Magnetite In Oxide Scale During Cooling Of Microalloyed Low Carbon Steel, Xianglong Yu, Zhengyi Jiang, Daijun Yang, Dongbin Wei, Quan Yang

Faculty of Engineering - Papers (Archive)

Precipitation behavior of magnetite particles in the thermal grown oxide scale during isothermal cooling of microalloyed low carbon steel was studied using scanning electron microscopy (SEM) and thin film X-ray. The oxide scale was generated from Gleeble 3500 Thermal-Mechanical Simulator connected with a humid air generator, to simulate 550 and 450°C isothermal treatments. Several types of magnetite precipitates were observed during different cooling processes with respect to the possible mechanisms of precipitation have been discussed. It is found that magnetite particles is as a result of pro-eutectoid precipitation from oxygen-rich wustite, and also as a product of the partial decomposition …

Microstructure And Mechanical Properties Of If Steel Deformed During Plane Stress Local Torsion, A H. Shamdani, S Khoddam, P F. Thomson, A Dehghan-Manshadi

Faculty of Engineering - Papers (Archive)

Mechanical joints are inherently vulnerable to failure because the presence of the joint hole causes a stress concentration in the vicinity of the hole. The need for improvement of material strength around a fastener hole can be satisfied by severe plastic deformation (SPD) to produce ultrafine grains. The ultrafine grained (UFG) alloys produced by SPD processing possess higher strengths than their coarse-grained counterparts as a result of the reduced grain size. However, in some circumstances such as SPD processing of Al-Zn and Al-Mg alloys the decomposition of supersaturated solid solutions competes with the Hall-Petch effect and leads to a more …

Effect Of The Austenitising Heat Treatment On The Microstructure And Hardness Of Martensitic Stainless Steel Aisi 420, Lilian D. Barlow, Madeleine Du Toit

Faculty of Engineering and Information Sciences - Papers: Part A

The effect of austenitizing on the microstructure and hardness of two martensitic stainless steels was examined with the aim of supplying heat-treatment guidelines to the user that will ensure a martensitic structure with minimal retained austenite, evenly dispersed carbides and a hardness of between 610 and 740 HV (Vickers hardness) after quenching and tempering. The steels examined during the course of this examination conform in composition to medium-carbon AISI 420 martensitic stainless steel, except for the addition of 0.13% vanadium and 0.62% molybdenum to one of the alloys. Steel samples were austenitized at temperatures between 1000 and 1200 C, followed …

Comparing The Formability Of Aisi 304 And Aisi 202 Stainless Steel, Madeleine Du Toit, Herman G. Steyn

Faculty of Engineering and Information Sciences - Papers: Part A

The formability of AISI 202 austenitic stainless steel was compared with that of type AISI 304 stainless steel. Type 202 is a low-nickel austenitic stainless steel alloyed with manganese and nitrogen. In this study, the formability of the two grades was examined using Erichsen cupping tests and room temperature uniaxial tensile tests performed at various angles to the rolling direction. AISI 202 appears to work-harden at a slightly higher rate than AISI 304, even though the austenite in type 202 is more stable than that in 304 with respect to the formation of deformation-induced a¢ martensite. Although both grades are …

Acoustic Emission Monitoring Of Split Formation During Charpy Impact Testing Of High Strength Steel, Andrii Kostryzhev, R B. Punch, Claire L. Davis, Martin Strangwood

Faculty of Engineering and Information Sciences - Papers: Part A

Acoustic emission (AE) monitoring has been used to detect split formation during room temperature low blow Charpy impact testing of high strength thick strip steels. The AE signal analysis identified separate signals originating from hammer impact, plastic deformation (verified using Charpy impact testing on mild steel with no splits) and split initiation/growth. The presence of splits was confirmed by sectioning and fractography, and the splits were brittle in nature. A possible correlation between the AE signal features and fracture mode is presented.

Nonlinear Inelastic Behavior Of Circular Concrete-Filled Steel Tubular Slender Beam-Columns With Preload Effects, Vipulkumar Ishvarbhai Patel, Qing Quan Liang, Muhammad N. Hadi

Faculty of Engineering and Information Sciences - Papers: Part A

This paper presents a numerical model based on fiber element formulations for simulating the nonlinear inelastic behavior of eccentrically loaded circular concrete-filled steel tubular (CFST) slender beam-columns with preload effects. Deflections caused by preloads are included in the global analysis of CFST slender beam-columns as initial geometric imperfections. Computational algorithms based on the Müller's method are developed to obtain load-deflection responses of CFST slender beam-columns including preload effects. The accuracy of the numerical model is examined by comparisons of computer solutions with experimental results. The numerical model is utilized to investigate the effects of preloads on the axial load-deflection curves, …