Structural Materials Commons^™

Post-Failure Capacity Of Built-Up Steel Members, Matthew H. Hebdon

Purdue Road School

Mechanically fastened built-up steel members have long been known to possess internal member redundancy and, as a result, multiple load paths which can be exploited to increase their functional life. Internal redundancy provides the ability to resist total member failure in the event of a fracture of an individual component. However, there is little experimental data in the literature regarding post-fracture capacity in terms of strength and subsequent fatigue life. The experimental study currently underway will provide needed information on parameters that affect the ability of built- up members to arrest a fracture as well as the available remaining fatigue …

Mechanical And Transport Properties Of Alkali-Activated Natural Pozzolans As Sustainable Binders, Brittany Radke

Calvert Undergraduate Research Awards

OPC production accounts for 5 to 7% of the global carbon dioxide (CO₂) emissions, contributing to global warming. The desire to reduce CO₂ emissions and produce more durable concrete has given impetus to search for new binders. It is suggested that alkali-activated natural pozzolans have the potential for use as a sustainable replacement for OPC in concrete.

The current study presented herein evaluated fresh, mechanical, and transport properties of alkali-activated natural pozzolan mortars containing various concentrations of sodium hydroxide solutions as an alkaline activator. To this aim, alkali-activated natural pozzolan mortars were made with concentrations of sodium …

Development Of Cementitious Materials For Adhesion Type Applications Comprising Calcium Sulfoaluminate (Csa) Cement And Latex Polymer, Joshua V. Brien

Theses and Dissertations--Civil Engineering

The objective of this research was to develop high performing polymer modified calcium sulfoaluminate (CSA) cement materials for use in applications requiring superior adhesion characteristics. Little information is available describing interactions of CSA cement containing minor phase tri-calcium aluminate (C₃A) with commonly used admixtures. Given the scarcity of information, a basic approach for developing cementitious materials was followed. The basic approach consisted of four tasks: cement design, admixture design, polymer design and testing developed materials. The iterative, time consuming process is necessary for understanding the influence of specific constituent components on overall system behavior. Results from the cement …

Shape Memory Behavior Of Single And Polycrystalline Nickel Rich Nickel Titanium Alloys, Irfan Kaya

Theses and Dissertations--Mechanical and Aerospace Engineering

NiTi is the most commonly used shape memory alloy (SMA) and has been widely used for bio-medical, electrical and mechanical applications. Nickel rich NiTi shape memory alloys are coming into prominence due to their distinct superelasticity and shape memory properties as compared to near equi-atomic NiTi shape memory alloys. Besides, their lower density and higher work output than steels makes these alloys an excellent candidate for aerospace and automotive industry. Shape memory properties and phase transformation behavior of high Ni-rich Ni₅₄Ti₄₆ (at.%) polycrystals and Ni-rich Ni₅₁Ti₄₉ (at.%) single-crystals are determined. Their properties are sensitive …

Precipitation, Orientation And Composition Effects On The Shape Memory Properties Of High Strength Nitihfpd Alloys, Emre Acar

Theses and Dissertations--Mechanical and Aerospace Engineering

NiTiHf high temperature shape memory alloys are attractive due to their high operating temperatures (>100 ^oC) and acceptable transformation strain compared to NiTi. However, NiTiHf has limitations due to their lack of ductility and low strength, resulting in poor shape memory properties. In this study, Pd has been added to NiTiHf alloys in an attempt to improve their shape memory behavior. A combined approach of quaternary alloying and precipitation strengthening was used.

The characterization of a Ni_45.3Ti_29.7Hf₂₀Pd₅ (at. %) polycrystalline alloy was performed in compression after selected aging treatments. Transmission electron …

Analysis Of The Influence Of Organic Corrosion Inhibitors On Corrosion Of Reinforcement In Concrete Bridge Structure Under Simulated Field Service Environment, Liang Shi, J. Ye, C. C. Chen, Y. Wu, J. Z. Liu

International Conference on Durability of Concrete Structures

For concrete bridge projects in marine environments, attention must be paid to the reinforcement corrosion problems caused by chloride intrusion. As kinds of functional admixtures, which can reduce the reinforcement corrosion rate, corrosion inhibitors are becoming very popular in China in new bridge projects. Corrosion inhibitors cover both inorganic and organic inhibitors. Nitrite is representative of inorganic corrosion inhibitors, but its carcinogenicity has hindered its further development. Organic corrosion inhibitors such as small-molecule-based alcohol amine series are becoming the focus of attention. To guide the scientific applications of organic corrosion inhibitors, China is carrying out broad applications technology research. But …

Freeze Thaw Durability Of Internally Cured Concrete Made Using Superabsorbent Polymers, Wesley A. Jones, W. Jason Weiss

International Conference on Durability of Concrete Structures

The use of superabsorbent polymers (SAPs) to produce internally cured concrete has been shown to be effective in reducing the potential for restrained shrinkage cracking of high performance concrete mixtures. However, not much is known regarding the freeze–thaw durability of concrete mixtures that incorporate SAPs for internal curing (IC). When SAP particles desorb (or partially desorb) the “water” (pore fluid) they contain for the purposes of IC, some believe that the void space created by these particles can provide enough empty voids to accommodate the additional volume caused by water expansion upon freezing. This paper investigates the freeze–thaw durability of …

Influence Of Organic Inhibitor On Corrosion Resistance Of Steel In Simulated Concrete Pore Solution, Jingshun S. Cai, C. C. Chen, J. Z. Liu, J. P. Liu

International Conference on Durability of Concrete Structures

Organic corrosion inhibitor is one of lower cost technologies that limit the deterioration of concrete structures. The influence of a newly prepared organic corrosion inhibitor on the corrosion behavior of carbon steel in simulated concrete pore solution was investigated by polarization curves, electrochemical impedance spectroscopy, and so on. The effect of organic corrosion inhibitors on concrete working performance was also studied. The results show that the corrosion rate decreases with the concentration of inhibitor increase; when the content of inhibitor up to 1.5% versus water, the oxide film was completely passive. Organic corrosion inhibitor had no effect on work performance.

Co2 Sequestration In Cement-Based Materials During Mixing Process Using Carbonated Water And Gaseous Co2, Jacek Kwasny, P. A. Muhammed Basheer, Mark I. Russell, William Doherty, Kieran Owens, Neil Ward

International Conference on Durability of Concrete Structures

This paper presents selected findings from a recently completed research project, aimed at the investigation of CO₂ sequestration in cement-based materials during the early stages of hydration when the cement paste is being mixed. Portland cement pastes were carbonated during the mixing process, using both carbonated water and gaseous CO₂, and their properties were compared to the control non-carbonated mix. All mixes were prepared in a purpose-designed chamber that permitted carbonated water and gaseous CO₂ to be mixed with the cementbased materials during the mixing process, without losses of CO₂ to the external environment. Temperature …

The Effect Of Surface Corrosion Damage On The Fatigue Life Of Extruded Aluminum Alloy 6061-T6, Matthew Weber

UNF Graduate Theses and Dissertations

Aluminum alloy 6061-T6 is a common engineering material used in aerospace, automotive, structural applications. Despite its wide use, little has been published about the effects of damage from surface corrosion on its fatigue life. An investigation was performed where 6061-T6 extrusions were exposed to a 3.5% NaCl solution at pH 2 for 2 days and 24 days. The length of time and pH were chosen in order to create distinct surface flaws. The effect of these flaws on the fatigue life was then investigated and analyzed using scanning electron microscopy (SEM) and Weibull statistics. It was determined that samples corroded …

Mode I Fracture Toughness Of Eight-Harness-Satin Carbon Cloth Weaves For Co-Cured And Post-Bonded Laminates, Josh E. Smith

Master's Theses

Mode I interlaminar fracture of 3k 8-Harness-Satin Carbon cloth, with identical fill and weft yarns, pre-impregnated with Newport 307 resin was investigated through the DCB test (ASTM D5528). Crack propagations along both the fill and weft yarns were considered for both post-bonded (co-bonded) and co-cured laminates. A patent-pending delamination insertion method was compared to the standard Teflon film option to assess its applicability to mode I fracture testing. The Modified Beam Theory, Compliance Calibration method, and Modified Compliance Calibration method were used for comparative purposes for these investigations and to evaluate the validity of the proposed Equivalent Stiffness (EQS) method. …

Next Generation Crystal Viewing Tool, Zach Schaffter, Gerhard Klimeck

The Summer Undergraduate Research Fellowship (SURF) Symposium

The science and engineering community is limited when it comes to crystal viewing software tools. Each tool lacks in a different area such as customization of structures or visual output. Crystal Viewer 2.0 was created to have all of these features in one program. This one tool simulates virtually any crystal structure with any possible material. The vtkvis widget offers users advanced visual options not seen in any other crystal viewing software. In addition, the powerful engine behind Crystal Viewer 2.0, nanoelectronic modeling 5 or (NEMO5), performs intensive atomic calculations depending on user input. A graphical user interface, or GUI, …

Compression Testing And Failure Modes Of Steel-Concrete Composite (Sc) Structures For Nuclear Containment, Patrick Michael Wanamaker, Amit H. Varma

The Summer Undergraduate Research Fellowship (SURF) Symposium

Although being able to provide much cleaner power than burning coal and other fossil fuels, nuclear power plants are still a tough sell to the general public due to their history of being spontaneously dangerous. The containment structures surrounding these nuclear plants, however, can play a huge role in reducing the risks associated with them. Relatively new designs for these containment assemblies, known as SC (steel-concrete composite) structures, aim to increase the strength and durability of the containment facilities while keeping costs down. By varying the spacing between shear studs, the ratio of concrete to steel, and the ratio of …

Validation Of Long-Fiber Thermoplastic Composite Models, Christian A. Vuong, Megan Kinney, Michael Sangid

The Summer Undergraduate Research Fellowship (SURF) Symposium

With increased pressure to reduce energy consumption, long-fiber reinforced thermoplastic composites (LFTs) are of interest to aerospace and automotive industries due to their light weight in combination with other desirable mechanical properties and ease of manufacturing to replace common materials such as aluminum and magnesium. However, the performance of LFTs is highly dependent on microstructural variables such as fiber length and orientation, which are heavily influenced by the manufacturing process. Accurately predicting these factors would allow for more rapid advances in LFTs by reducing the experiments needed for certification and decreasing expenses. While models that serve this purpose exist, the …

Effect Of Zinc Galvanization On The Microstructure And Fracture Behavior Of Low And Medium Carbon Structural Steels, Ignatius C. Okafor, Ronald J. O'Malley, Kaushal R. Prayakarao, Heshmat A. Aglan

Materials Science and Engineering Faculty Research & Creative Works

Microstructure and fracture behavior of ASTM 572 Grade 65 steels used for wind tower applications have been studied. Steels of two carbon level chemistries designed for this grade were used in the study. Fracture toughness of the steels was studied using 3-point bend test on samples coated with zinc and not coated with zinc. Lower carbon steel showed higher resistance to fracture than medium carbon steel after zinc galvanization. SEM study suggests that zinc and zinc bath additives that migrated to crack tips are responsible for the loss in ductility. The phenomenon of Liquid Metal Embrittlement (LME) is suggested to …

Structural Reliability Analysis Of Corroded Steel Girder Bridge, Mohammed Shaalan Al Badran

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

The natural aging, environmental impact, and appropriate design are certainly playing a serious role in safety of the bridges function. The functional safety of bridge constitutes a prime element of the transportation system serving commuters, passengers and freight. According to Federal Highway Administration, the steel bridges share represents a large amount of the United States’ bridges. In last century, the collapse of both the Silver Bridge at Point Pleasant, West Virginia over the Ohio River on December 15, 1967 and over the Mianus River Bridge in Connecticut on June 28, 1983 showed that steel corrosion has been the leading reason …

Engineering Performance Of A New Siloxane-Based Corrosion Inhibitor, Niall Holmes, R. O'Brien, P. A. M. Basheer

Articles

This paper presents an evaluation of a new non-toxic corrosion inhibitor on selected engineering properties of concrete mixes with different cementitious materials following a corrosion and durability study on concrete samples. Corrosion inhibitors consist of powders or solutions which are added to concrete when mixed to prevent or delay corrosion of steel by their reaction with ferrous ions to form a stable and passive ferric oxide film on the steel surface. The new inhibitor functions slightly differently and its corrosion inhibition effect is due to the formation of a siloxane coating on the steel surface. Therefore, the performance of the …

High-Speed Imaging Of A Bulk Metallic Glass During Uniaxial Compression, Wendelin Wright, Rachel R. Byer, Xiaojun Gu

Faculty Journal Articles

High-speed imaging directly correlates the propagation of a particular shear band with mechanical measurements during uniaxial compression of a bulk metallic glass. Imaging shows shear occurs simultaneously over the entire shear plane, and load data, synced and time-stamped to the same clock as the camera, reveal that shear sliding is coincident with the load drop of each serration. Digital image correlation agrees with these results. These data demonstrate that shear band sliding occurs with velocities on the order of millimeters per second. Fracture occurs much more rapidly than the shear banding events, thereby readily leading to melting on fracture surfaces.

Materials Education And Research In Art And Design: A New Role For Libraries (Survey Stats), Mark Pompelia

Materials Education and Research in Art and Design: A New Role for Libraries

No abstract provided.

Materials Education And Research In Art And Design: A New Role For Libraries (Program Sheet), Mark Pompelia

Materials Education and Research in Art and Design: A New Role for Libraries

No abstract provided.