Materials Science and Engineering Commons^™

Metamodels Of Residual Stress Buildup For Machining Process Modeling, Stuart B. Mccrorie, Michael Sangid

The Summer Undergraduate Research Fellowship (SURF) Symposium

In the process of machining materials, stresses, called residual stresses, accumulate in the workpiece being machined that remain after the process is completed. These residual stresses can affect the properties of the material or cause part distortion, and it is important that they be calculated to prevent complications from arising due to the residual stresses. However, these calculations can be incredibly computationally intensive, and thus other methods are needed to predict the residual stresses in materials for quick decision-making during machining. By using metamodels - a method of representing data where few data points exist - we can achieve an …

Large Scale Monolithic Solar Panel Simulation - A Study On Partial Shading Degradation, Suhas V. Baddela, Xingshu Sun, Muhammad A. Alam

The Summer Undergraduate Research Fellowship (SURF) Symposium

Shadow-induced degradation is a major concern for both power output and long-term reliability in solar cells. Apart from the obvious fact that shading reduces the amount of solar irradiance available to solar panels, it may lead to formation of hot spots, where solar cells are forced to reverse breakdown with localized heating, and potentially, permanent damage. To get a better understanding of shadow-induced degradation, we develop an electro-thermal coupled simulator that can self-consistently solve the electrical and thermal distributions of solar panel under arbitrary shading conditions. The simulation framework consists of two part: a) compact models that can describe the …

Mechanical Investigation Of Phase-Transforming Cellular And Origami Materials, John M. Cleveland, David Restrepo, Yunlan Zhang, Pablo Zavattieri, Nilesh Mankame

The Summer Undergraduate Research Fellowship (SURF) Symposium

Cellular materials, such as honeycombs and metallic foams, have attracted much attention due to their exceptional ability to absorb and diffuse mechanical energy. These materials have a wide range of applications, such as improving vehicle crash safety and helmet impact resistance. However, many of these materials are rendered unusable after one application. Phase-transforming cellular materials (PXCMs) utilize a reversible bistable mechanism to facilitate energy absorption from one-dimensional impacts and loads. These mechanisms have the added benefit over other cell structures of reusability. In this study, various PXCM designs are discussed and examined to determine their energy absorption capabilities.

Three different …

High Strain Rate Experiments Of Energetic Material Binder, Roberto Rangel Mendoza, Michael Harr, Weinong Chen

The Summer Undergraduate Research Fellowship (SURF) Symposium

Energetic materials, in particular HMX, is widely used in many applications as polymer bonded explosives (PBX) and rocket propellant. However, when damaged, HMX is known to be an unstable substance which renders it a hazardous material and in some cases unreliable. Finding critical mechanical conditions at high rates that render various forms of energetic materials as unreliable would be vital to understand the effects that vibrations and compression forces have on energetic materials. A better understanding would enable the ability to develop improvements in the manufacturing of PBX and rocker propellant. The method utilized to evaluate the mechanical properties of …

Characterization Of Suspension Polymerized Polyacrylamide And Poly(Sodium Acrylate-Acrylamide) Copolymer And Their Size Influence On The Properties Of Concrete, Cole R. Davis, Kendra A. Erk, Stacey L. Kelly

The Summer Undergraduate Research Fellowship (SURF) Symposium

Shrinkage leading to cracking and mechanical instability is a major problem for concrete due to the loss of water during the curing process. However, through the addition of Superabsorbent Polymer (SAP) hydrogels, shrinkage can be prevented, increasing the strength of concrete. Characterization of suspension polymerized polyacrylamide (PAM) poly(sodium acrylate-polyacrylamide) (PANa-PAM) copolymer microsphere sizes, morphology and swelling behavior was conducted before adding them to concrete. Size was determined using microscopy paired with ImageJ analysis. Coulter Counter size characterization was also used to determine the particle size distribution. Swelling behavior was determined using the tea bag method as well as size analysis …

Characterization Of Superabsorbent Polymers In Aluminum Solutions, Nicholas D. Macke, Matthew J. Krafcik, Kendra A. Erk

The Summer Undergraduate Research Fellowship (SURF) Symposium

Over the past few decades, super absorbent polymers (SAPs) have been the topic of research projects all around the world due to their incredible ability to absorb water. They have applications in everything from disposable diapers to high performance concrete. In concrete, aqueous cations permeate the polymer network, reducing swelling and altering properties. One of these ions, aluminum, alters SAP properties by creating a stiff outer shell and greatly reducing absorbency, but these effects have not been well characterized. One method of characterizing the effects of aluminum on SAP hydrogels was performing gravimetric swelling tests to determine equilibrium water capacity …

Experimental Study Of Breakage Of Particles Under Compression, Haoze Zhou, Niranjan Parab, Weinong W. Chen

The Summer Undergraduate Research Fellowship (SURF) Symposium

Granular materials are used widely and can be seen in natural and industrial applications such as sand bags or pharmaceutical pills. During their manufacturing, processing, transport and use, granular materials are subjected to various kinds of loadings. If the amplitude of the loading is above the strength threshold, particles constituting granular materials may fracture. It is very important to understand the failure of particles under these loading conditions to prevent or control their failure during all stages of their manufacturing and use. Better characterization of the fracture behavior of particles composed of different materials and sizes will allow more precise …

Dna Bound Avicel Network: The Beginnings Of A Self-Healing Material, Emily R. Coleman, Michael R. Ladisch, Eduardo Ximenes, Marissa Karp, Kathleen Howell, Seockmo Ku, Nathan Mosier, Iman Beheshti Tabar

The Summer Undergraduate Research Fellowship (SURF) Symposium

Self-healing materials could potentially provide many improvements to engineering projects, including reduced maintenance and cost, and increased lifespan. It is desired to create a self-healing material proof of concept, which can then be altered for eventual application to the surfaces of small satellites with the goal of increasing material lifetimes. The intrinsic properties and abilities of DNA base pairing will be studied as a first test of proof of concept. The exploratory research reported in this short communication utilizes oxidation of small (50µm) particles of Avicel using TEMPO, followed by activation of Avicel particles via an EDC (1-Ethyl-3-(3-dimethylaminopropyl) carbodiimide hydrochloride) …

Dislocation Engineering In Novel Nanowire Structures, Christopher Y. Chow, Samuel T. Reeve, Alejandro Strachan

The Summer Undergraduate Research Fellowship (SURF) Symposium

Leveraging defects is a cornerstone of materials science, and has become increasingly important from bulk to nanostructured materials. We use molecular dynamics simulations to explore the limits of defect engineering by harnessing individual dislocations in nanoscale metallic specimens and utilizing their intrinsic behavior for application in mechanical dampening. We study arrow-shaped, single crystal copper nanowires designed to trap and control the dynamics of dislocations under uniaxial loading. We characterize how nanowire cross-section and stacking-fault energy of the material affects the ability to trap partial or full dislocations. Cyclic loading simulations show that the periodic motion of the dislocations leads to …

Modeling Fluid Interactions With The Rigid Mush In Alloy Solidification, Alexander J. Plotkowski

Open Access Dissertations

Macrosegregation is a casting defect characterized by long range composition differences on the length scale of the ingot. These variations in local composition can lead to the development of unwanted phases that are detrimental to mechanical properties. Unlike microsegregation, in which compositions vary over the length scale of the dendrite arms, macrosegregation cannot be removed by subsequent heat treatment, and so it is critical to understand its development during solidification processing. Due to the complex nature of the governing physical phenomena, many researchers have turned to numerical simulations for these predictions, but properly modeling alloy solidification presents a variety of …

Modeling Picking On Pharmaceutical Tablets, Shrikant Swaminathan

Open Access Dissertations

Tablets are the most popular solid dosage form in the pharmaceutical industry because they are cheap to manufacture, chemically and mechanically stable and easy to transport and fairly easy to control dosage. Pharmaceutical tableting operations have been around for decades however the process is still not well understood. One of the common problems faced during the production of pharmaceutical tablets by powder compaction is sticking of powder to the punch face, This is known as 'sticking'. A more specialized case of sticking is picking when the powder is pulled away form the compact in the vicinity of debossed features. In …

Nanoparticle-Based Electrochemical Sensors For The Detection Of Lactate And Hydrogen Peroxide, Aytekin Uzunoglu

Open Access Dissertations

In the present study, electrochemical sensors for the detection of lactate and hydrogen peroxide were constructed by exploiting the physicochemical properties of metal ad metal oxide nanoparticles. This study can be divided into two main sections. While chapter 2, 3, and 4 report on the construction of electrochemical lactate biosensors using CeO2 and CeO2-based mixed metal oxide nanoparticles, chapter 5 and 6 show the development of electrochemical hydrogen peroxide sensors by the decoration of the electrode surface with palladium-based nanoparticles. First generation oxidase enzyme-based sensors suffer from oxygen dependency which results in errors in the response current of the sensors …

Development Of A Novel Polymer-Garnet Solid State Composite Electrolyte Incorporating Li-La-Zr-Bi-O And Polyethylene Oxide, Muhammed Ramazan Oduncu

Open Access Theses

Current lithium ion batteries are comprised of organic liquid electrolytes - a mixture of lithium salts and binary solvents such as ethylene carbonate (EC) and dimethyl carbonate (DMC). The main drawbacks of this liquid mixture related to safety are flammability of the organic solvents and chemical instability with the electrode materials. To date, various ceramic and polymer materials have been considered which overcome safety issues. However, a common problem of these solid state materials is that they are not able to provide high ionic conductivity at ambient temperatures. Garnet-type cubic Li7La 3Zr2O12 ceramic material has attracted much interest because of …

Solution Based Processing Of Garnet Type Oxides For Optimized Lithium-Ion Transport, Derek K. W. Schwanz

Open Access Theses

Current lithium based portable electrochemical storage devices are limited by the inherent instability and volatility of conventional electrolytes materials. Ceramic materials show much promise for use in advanced lithium based battery systems due to their inhibition of dendritic growth and high thermal and chemical stability. The main drawback of solid materials is their low ionic conductivity, relying on lattice hopping to transport ions between electrodes during cycling. Garnet type oxides, specifically of the base compositions Li7La3Zr2O12 and Li5L a3Bi2O12 have been synthesized through Pechini method solution based processing by the dissolution of reagent salts into nitric acid and creation of …

Polymerizable Lipids For Controlled Functionalization Of Layered Materials, Kortney Kaye Rupp

Open Access Theses

Self-assembled monolayers (SAM’s) offer a straightforward approach to tailoring the interfacial properties of metals, metal oxides and semiconductors. Noncovalent functionalization of single-layer graphene offers the possibility to finely tune surface chemistry for future applications in electronics. Polymerization of photochemically reactive molecules in a lying-down phase has been used to increase the strength of intermolecular interactions between long alkanes and HOPG substrates. Long-chain fatty acid derivatives with internal diyne groups yield a conjugated ene-yne polymer upon UV irradiation. Diyne lipids with phosphocholine (diyne PC) and phosphoethanolamine (diyne PE) groups offer a charged form of the head group that is robust towards …

Additive Manufacturing Of Carbon Fiber-Reinforced Thermoplastic Composites, Nicholas M. Denardo

Open Access Theses

Additive manufacturing, or 3D printing, encompasses manufacturing processes that construct a geometry by depositing or solidifying material only where it is needed in the absence of a mold. The ability to manufacture complex geometries on demand directly from a digital file, as well as the decreasing equipment costs due to increased competition in the market, have resulted in the AM industry experiencing rapid growth in the past decade. Many companies have emerged with novel technologies well suited to improve products and/or save costs in various industries.

Until recently, the applications of polymer additive manufacturing have been mainly limited to prototyping. …

Modeling Transport Phenomena And Uncertainty Quantification In Solidification Processes, Kyle S. Fezi

Open Access Dissertations

Direct chill (DC) casting is the primary processing route for wrought aluminum alloys. This semicontinuous process consists of primary cooling as the metal is pulled through a water cooled mold followed by secondary cooling with a water jet spray and free falling water. To gain insight into this complex solidification process, a fully transient model of DC casting was developed to predict the transport phenomena of aluminum alloys for various conditions. This model is capable of solving mixture mass, momentum, energy, and species conservation equations during multicomponent solidification. Various DC casting process parameters were examined for their effect on transport …

Fabrication And Characterization Of Cellulose Nanocrystal Enhanced Sustainable Polymer Nanocomposites Through Surface Chemistry And Processing, Shane X. Peng

Open Access Dissertations

Cellulose nanocrystals (CNCs) belong to a class of cellulose based nanomaterials that are extracted from renewable and sustainable sources and have excellent mechanical and thermal properties. While applications for CNCs have been expanding, one of the challenges of utilizing CNCs is to overcome their low dispersibility in hydrophobic polymers. In the present work, several approaches are utilized to improve the interfacial compatibility and overall performance of CNC/epoxy and CNC/polyamide nanocomposite.

For a two-part epoxy system, a novel approach was taken to disperse CNC in epoxy matrix by pre-formulating CNC into the hardeners. Three types of hardeners were evaluated for their …

Progress Of Carbonation In Chloride Contaminated Concretes, Yaocheng Wang, P. A.M. Basheer, S. Nanukuttan, Y. Bai

International Conference on Durability of Concrete Structures

Concretes used in marine environment are generally under the cyclic effect of CO₂ and chloride ions (Cl^-). To date, the influence of carbonation on ingress of chloride ions in concretes has been widely studied; in comparison, study on the influence of Cl^- on the progress of carbonation is limited. During the study, concretes were exposed to independent and combined mechanisms of carbonation and chloride ingress regimes. Profiles of apparent pH and chloride concentration were used to indicate the progress of carbonation and ingress of Cl^- in concretes. From the apparent pH profile, a carbonation front …

Carbon Fiber As Anode Material For Cathodic Prevention In Cementitious Materials, Emma Qingnan Zhang, Luping Tang, Thomas Zack

International Conference on Durability of Concrete Structures

Cathodic prevention (CPre) technique is a promising method and has been used for the past two decades to prevent steel from corrosion in concrete structures. However, wide application of this technique has been restricted due to high costs of anode materials. In order to lower the cost and further improve this technique, carbon fiber composite anode has been introduced as an alternative anode material with affordable price and other outstanding properties. This paper presents the study of using carbon fiber mesh as anode material for long-term cathodic prevention system and the effect of accelerated current on macro- and microstructure of …

Corrosion Of Steel In Concrete And Its Prevention In Aggressive Chloride-Bearing Environments, Luca Bertolini, Maddalena Carsana, Matteo Gastaldi, Federica Lollini, Elena Redaelli

International Conference on Durability of Concrete Structures

This keynote paper deals with the durability of reinforced concrete (RC) structures exposed to aggressive environments characterized by high concentration of chloride ions, namely, marine environments or the use of de-icing salts. The mechanism of chloride-induced corrosion of steel in concrete is introduced, and its influence on the service life of RC structures is analyzed. Factors affecting the time to corrosion initiation are described with regard to both concrete properties and environmental exposure conditions. Design approaches available for achieving durability targets associated with the design service life are analyzed, focusing on studies carried out by the authors in recent years …

Energy Transfer And Localization In Molecular Crystals, Mitchell A. Wood

Open Access Dissertations

With the aim of developing new technologies for the detection and defeat of energetic materials, this collection of work was focused on using simulations to characterize materials at extremes of temperature, pressure and radiation. Each branch of the work here is collected by which material response is potentially used as the detectable signal.

Where the chemical response is of interest, this work will explore the possibility of non-statistical chemical reactions in condensed-phase energetic materials via reactive molecular dynamics (MD) simulations. We characterize the response of three unique high energy density molecular crystals to different means of energy input: electric fields …

Assessing The Performance Of A Soy Methyl Ester -Polystyrene Topical Treatment To Extend The Service Life Of Concrete Structures, D'Shawn G. Thomas

Open Access Theses

Experimental results show that soy methyl ester (SME), a derivative of soy bean oil, along with the incorporation of polystyrene (PS) is a non-toxic, biodegradable and renewable material that can be used effectively as a topical concrete surface treatment. While, concrete sealants and topical surface treatments can be used to extend to durability of concrete structures, it is difficult to predict the durability of concrete structures sealed with a sealant or topical surface treatment. This is due to a lack of necessary model inputs that can be used to address the durability of concrete structures treated with these materials. In …

Techniques And Technologies For Decontaminating Chemically Contaminated Premise Plumbing Infrastructure, Karen S. Casteloes

Open Access Theses

Recent large-scale drinking water chemical contamination incidents in Canada and the U.S. have affected more than 1,000,000 people. In all cases premise plumbing has become contaminated and disparate plumbing decontamination approaches have been applied. Premise plumbing components include the service line and piping within the building as well as various appurtenances (i.e., tanks, valves, fixtures). The overall research goal was to identify techniques and technologies that can be used for premise plumbing decontamination. To achieve this goal two separate studies were conducted and are presented as two independent thesis chapters.

The study described in Chapter 1 was designed to understand …

Fabrication And Drying Of Cnc-Based Microcapsules With Pdms/Antimicrobial Oil Cores Via The Microcapillary Device, Yunze Dai

Open Access Theses

Cellulose nanocrystals (CNC) which are the crystalline regions of elementary microfibrils found in cellulose are becoming a promising biocompatible nanoscale building block. We report on the generation, evolution, and drying of CNC capsules with oil cores, obtained from double emulsion drops. Microcapillary devices were used to generate the double emulsion drops with outer diameters ranging from 75 to 225 µm, and shell thicknesses ranging from 5 to 60 µm. 10 wt% aqueous CNC suspensions without and with the addition of PEGDA, a UV-crosslinkable binder, were used as the shell material while 10 cSt PDMS oil was used in the core. …

Nanoscale Phonon Thermal Conductivity Via Molecular Dynamics, Jonathan M. Dunn

Open Access Theses

Molecular dynamics (MD) simulations provide a useful and simple means of calculating the nanoscale thermal properties of materials, which requires special analysis since the thermal properties of materials change when their dimensions reach the nanoscale. In this research, MD is used to investigate the nanoscale phonon thermal transport of materials that are attracting much interest in the areas of materials science and nuclear physics. In order to evaluate two distinct methods of calculating the thermal conductivity of materials using MD, the simulation methods are first applied to Si. Once an understanding of each simulation method is established, they are then …

Effect Of Humidity On The Creep Response Of Cellulose Nanocrystals Films, Marianne C. Valone

Open Access Theses

Cellulose nanocrystals (CNCs) are a derivative of cellulose, the Earth’s most abundant source of a sustainable polymer. There are many applications for CNCs such as batteries, antimicrobial films, flexible displays and drug delivery. This research is focused on CNCs films and the mechanical properties once humidity was introduced.

The creation of self-aligned CNCs films was utilized to perform dynamic mechanical analysis (DMA) testing. The Forest Products Lab (FPL) in Madison, Wisconsin provided the CNCs used. Both 3.5 wt.% and 9.1 wt.% films were made and tested. A DMA method was created to test the creep response of the CNCs films …

The Impact Of Damage Accumulation On The Kinetics Of Network Strength Recovery For A Physical Polymer Gel Subjected To Shear Deformation, Travis Thornell, Krithika Subramaniam, Kendra Erk

School of Materials Engineering Faculty Publications

Shear rheophysical experiments were used to quantify the kinetics of strength recovery of model thermoreversible polymer gels that were fractured and ultimately sheared to different total magnitudes of strain (700 and 4000%) before resting for set periods of time. Relationships between the amount of strength recovered and the normalized ratio of resting times to characteristic relaxation times were developed. It was found that gels displayed fully healed networks within timescales that were 2-3 orders of magnitude greater than the gel’s characteristic relaxation time. Gels deformed to 700% applied strain either healed slower at lower gel concentrations as compared to experiments …

Characterization Of Superabsorbent Poly(Sodium-Acrylate Acrylamide) Hydrogels And Infuence Of Chemical Structure On Internally Cured Mortar, Matthew J. Krafcik, Kendra Erk

School of Materials Engineering Faculty Publications

Internal curing of mortar through superabsorbent polymer hydrogels is explored as a solution to self-desiccation. Four different hydrogels of poly(sodium-acrylate acry- lamide) are synthesized and the impact of chemical composition on mortar is assessed with relative humidity and autogenous shrinkage testing. The hydrogels are characterized with swelling tests in different salt solutions and compression tests. Chemical composition af- fected both swelling kinetics and gel network size. Mortar containing these hydrogels had increased relative humidity and markedly reduced autogenous shrinkage. Additionally, the chemical structure of the hydrogels was found to signifcantly impact the mortar’s shrink- age. Hydrogels that quickly released most …

Analytical And Experimental Investigation Of Microstructural Alterations In Bearing Steel In Rolling Contact Fatigue, Sina Mobasher Moghaddam

Open Access Dissertations

Rolling Contact Fatigue (RCF) is one the most common failure modes in bearings. RCF is usually associated with particular microstructural alterations. Such alterations (i.e. white etching cracks, butterflies, etc.) which lead to RCF failure are known to be among the most concerning matters to bearing industry.

In the current work, an analytical as well as experimental approaches are used to investigate “butterfly wing” formation, crack initiation and propagation from inclusions. A new damage evolution equation coupled with a FE model is employed to account for the effect of mean stresses and alternating stresses simultaneously to investigate butterfly formation. The proposed …