Engineering Commons^™

Characterization Of Microstructural And Mechanical Properties Of 17-4 Ph Stainless Steel By Cold Rolled And Machining Vs. Dmls Additive Manufacturing, Pablo Moreno-Garibaldi, Melvyn Alvarez-Vera, Juan Alfonso Beltrán-Fernández, Rafael Carrera-Espinoza, Héctor Manuel Hdz-García, J. C. Díaz-Guillen, Rita Muñoz-Arroyo, Javier A. Ortega, Paul Molenda

Mechanical Engineering Faculty Publications and Presentations

The 17-4 PH stainless steel is widely used in the aerospace, petrochemical, chemical, food, and general metallurgical industries. The present study was conducted to analyze the mechanical properties of two types of 17-4 PH stainless steel—commercial cold-rolled and direct metal laser sintering (DMLS) manufactured. This study employed linear and nonlinear tensile FEM simulations, combined with various materials characterization techniques such as tensile testing and nanoindentation. Moreover, microstructural analysis was performed using metallographic techniques, optical microscopy, scanning electron microscopy (SEM) with energy dispersive spectroscopy (EDS), and X-ray diffraction (XRD). The results on the microstructure for 17-4 PH DMLS stainless steel reveal …

Analytical And Experimental Investigation Of Interphase And Dispersion Effects On The Mechanical Stiffness Of Cellulose Nanocomposites, Will Goldberg

McKelvey School of Engineering Theses & Dissertations

The effect of dispersion and interphase properties on the elastic behavior of cellulose nanocomposites was investigated using a number of composite models, experimental data and a thorough literature review. Cellulose nanocomposites consisting of soy protein isolate (SPI) and cellulose nanocrystals (CNC) or polydopamine coated cellulose nanocrystals (PD-CNC) were prepared via solution casting method and tested for mechanical stiffness. These outcomes were compared to standard composite models as well as novel methods adapted from the literature that incorporate data regarding dispersion quality and interphase properties. The literature review verified that both dispersion and interphase properties are highly dependent on interfacial chemistry …

Transient Analysis Of Diffusion-Induced Deformation In A Viscoelastic Electrode, Yaohong Suo, Fuqian Yang

Chemical and Materials Engineering Faculty Publications

In this study, we analyze the transient diffuse-induced-deformation of an electrode consisting of the conducting polymer polypyrrole (PPY) by using the theories of linear viscoelasticity and diffusion-induced stress. We consider two constitutive relationships with dependence of viscosity on strain rate: Kelvin-Voigt model and three-parameter solid model. A numerical method is used to solve the problem of one-dimensional, transient diffusion-induced-deformation under potentiostatic operation. The numerical results reveal that the maximum displacement occurs at the free surface and the maximum stress occurs at the fixed end. The inertia term causes the stress to increase at the onset of lithiation. The stress decreases …

Frequency Response And Recovery Of Muscles And Effects Of Wrapping The Lower Leg On Surface Velocity Measurements, Cameron David Smallwood

Theses and Dissertations

This thesis is comprised of two studies. The objective of the first study was to find the frequency response and stiffness of the biceps brachii muscle group during recovery from exercise induced damage and to determine whether these data could be used to track muscle recovery by correlating changes in the frequency response with changes in muscle stiffness. Stiffness moduli were collected using Shear Wave Elastography (SWE) which were then applied to a proportional first mode frequency analysis. Data were collected for the muscle stiffness and frequency response for fifteen subjects (25.6 +- 4.5). By comparing the proportion of the …

Exploring The Role Of Nanoparticles In Enhancing Mechanical Properties Of Hydrogel Nanocomposites, Josergio Zaragoza, Scott Fukuoka, Marcus Kraus, James Thomin, Prashanth Asuri

Bioengineering

Over the past few decades, research studies have established that the mechanical properties of hydrogels can be largely impacted by the addition of nanoparticles. However, the exact mechanisms behind such enhancements are not yet fully understood. To further explore the role of nanoparticles on the enhanced mechanical properties of hydrogel nanocomposites, we used chemically crosslinked polyacrylamide hydrogels incorporating silica nanoparticles as the model system. Rheological measurements indicate that nanoparticle-mediated increases in hydrogel elastic modulus can exceed the maximum modulus that can be obtained through purely chemical crosslinking. Moreover, the data reveal that nanoparticle, monomer, and chemical crosslinker concentrations can all …

Evaluation Of Elastic Modulus Of Fiber-Reinforced Concrete, Nakin Suksawang, Salam Wtaife, Ahmed Alsabbagh

Mechanical and Civil Engineering Faculty Publications

This paper determines the effect of discrete fibers on the elastic modulus of concrete and cement composites. Five types of discrete fibers consisting of steel, polypropylene, macro-polyolefin, polyvinyl alcohol (PVA), and basalt fibers were investigated. Results show that discrete fibers had little effect on elastic modulus for fiber-reinforced concrete (FRC) with coarse-to-fine aggregate ratio (C/S) greater than 1. However, for FRC with C/S smaller than 1 and fiber-reinforced cement composites (FRCCs), discrete fibers reduced the elastic modulus. Accordingly, a new elastic modulus equation is proposed to better estimate the elastic modulus of FRC with a maximum fiber volume fraction of …

Thermomechanical Properties Of Novel Lanthanum Zirconate Based Thermal Barrier Coatings - An Integrated Experimental And Modeling Study, Xingye Guo

Open Access Dissertations

Thermal barrier coatings (TBCs) are refractory materials deposited on gas turbine components, which provide thermal protection for metallic components at operating conditions. The current state-of-art TBC material is yttria-stabilized zirconia (YSZ), whose service temperature is limited to 1200 celsius, due to sintering and phase transition at higher temperatures. In comparison, lanthanum zirconate (La2Zr2O7, LZ) has become a promising candidate material for TBCs due to its lower thermal conductivity and higher phase stability compared to YSZ.

The primary objective of this thesis is to design a novel robust LZ-based TBC system suitable for applications beyond 1200 celsius. Due to LZ’s low …

Silk As A Biomaterial Paste For Biomimetic Composite, Sang Hyun Park

McKelvey School of Engineering Theses & Dissertations

Silk is a highly promising biomaterial with unique bio-physicochemical properties, such as excellent mechanical and optical properties, biocompatibility and programmable biodegradability. Among many different types, silk from domesticated silkworm, bombyx mori has received wide attention owing to its availability in virtually unlimited quantities and ease of extraction. In this study, we investigated silkworm silk as a protein glue to realize nacre-like composites. We have employed spin assisted layer-by-layer technique to fabricate ultrathin free-standing biocomposite films. Two different composites have been studied: (i) graphene oxide (GO)/silk and (ii) chitin/silk. From our prior work, it is known that the adsorption of amphiphilic …

Numerical Simulation Of Deep Excavation In Gravel Layers, Chien-Yi Wu, Shuh-Gi Chern

Journal of Marine Science and Technology

This study analyzed gravel excavation cases in the Xindian District of Taiwan. Instead of the parameters typically employed in deep excavation analysis we used the deformations of diaphragm walls in a back analysis to achieve recommendations regarding the ideal range of the soil elastic modulus Es in the analysis parameters of numerical simulations for the Xindian District stratum or similar strata. We used Plaxis 2D software to analyze the gravel layer. The results indicated that, when the fifth layer of gravel was set to N = 100 and the range of the soil elastic modulus Es was set between 7.84N …

Micromechanical Modeling For Material Design Of Durable Infrastructural Materials: The Influence Of Aggregate And Matrix Modification On Elastic Behavior Of Mortars, Sumanta Das, Amit Maroli, Narayanan Neithalath

International Conference on Durability of Concrete Structures

This paper reports the fundamental difference in microstress distributions in traditional hardened cement paste with quartz inclusions and a cement paste with lightweight aggregate (LWA) inclusions using microstructurebased numerical simulation involving finite element method with periodic boundary conditions. Variation of relative stress distributions under varying component material properties and varying microstructural features in both the systems is elucidated for a comprehensive understanding. The presented microstructure-based numerical technique accurately captures the stress concentrations inside microheterogeneous systems, which is otherwise not detectible using analytical homogenization schemes. Numerical simulations reveal that strengthening and stiffening of matrix and interfacial transition zone (ITZ) with silica …

Probing Micro- And Nano-Scale Elastic Modulus Variation In Organic-Rich Shale—A Naturally Occurring Composite, Corinne Packard, Taylor Wilkinson, Saeed Zargari, Manika Prasard

Composites at Lake Louise (CALL 2015)

Organic-rich shales are heterogeneous, naturally occurring composites that act as source rocks for oil and gas, which can be extracted through the process of hydraulic fracturing. Shales are composed of clays, minerals, and evolving organic matter and developed through long periods of sedimentation and compression. An elastic modulus mapping technique based on spatially continuous dynamic nanoindentation is applied to map microscale variations in a fine-grained, organic-rich shale consisting of inorganic minerals with an inter-

penetrating network of microscale pores filled with organic matter. A sample of Bakken shale from the Williston Basin was chosen for analysis, in which the organic …

Cure Kinetics And Interfacial Phenomena In Polymer Matrix Composites, John Kieffer, Michael Aldridge, Katherine Sebeck, Eleanor Coyle

Composites at Lake Louise (CALL 2015)

Polymer matrix composites with textile reinforcement are used in a wide range of aerospace and industrial applications. Continuum mechanical predictions of the composite behaviors have been inaccurate, possibly because of the lack of information with regard to polymer materials properties, especially near the interfaces with the reinforcing fibers. Concurrent micro-Brillouin and Raman light scattering provides sufficiently high spatial resolution to probe the mechanical properties and chemical composition of the interphase regions of the matrix, without interfering with the thermo-mechanical equilibrium of the material. Using this technique, we mapped the elastic properties of epoxy resin in between and within the fiber …

Effects Of Nanosecond Pulse Electric Fields On Cellular Elasticity, Diganta Dutta, Anthony Asmar, Michael W. Stacey

Bioelectrics Publications

We investigated the effects of a single 60 nanosecond pulsed electric field (nsPEF) of low (15 kV/cm) and high (60 kV/cm) field strengths on cellular morphology and membrane elasticity in Jurkat cells using fluorescent microscopy and atomic force microscopy (AFM). We performed force displacement measurements on cells using AFM and calculated the Young's modulus for membrane elasticity. Differential effects were observed depending upon pulsing conditions. We found that a single nsPEF of low field strength did not induce any apparent cytoskeletal breakdown and had minor morphological changes. Interestingly, force measurements and calculation of Young's modulus showed a significant decrease in …

The Influence Of Mixture Variables For The Alkali-Activated Slag Concrete On The Properties Of Concrete, Chi-Che Hung, Jiang-Jhy Chang

Journal of Marine Science and Technology

In this study, the influence of three mixture variables named Sand/Aggregate ratio, Liquid/Binder ratio and Paste/Aggregate ratio on the concrete properties were studied. The properties of fresh concrete including the slump, air content and unit weight were examined. In addition, the mechanical properties such as the compressive strength, elastic modulus and splitting tensile strength were studied. Results showed that the alkaliactivated slag concrete has superior strength. The 28-day compressive strength can reach 80% of the 90-day compressive strength. In addition, the influence of the Liquid/Binder ratio on the 28-day compressive strength is not as apparent as the water/cement ratio is …

Mechanical Properties Of Human Amniotic Fluid Stem Cells Using Nanoindentation, Ashkan Aryaei, Ambalangodage Jayasuriya

Faculty Publications

The aim of this study was to obtain nanomechanical properties of living cells focusing on human amniotic fluid stem (hAFS) cell using nanoindentation techniques. We modified the conventional method of atomic force microscopy (AFM) in aqueous environment for cell imaging and indentation to avoid inherent difficulties. Moreover, we determined the elastic modulus of murine osteoblast (OB6) cells and hAFS cells at the nucleus and cytoskeleton using force–displacement curves and Hertz theory. Since OB6 cell line has been widely used, it was selected to validate and compare the obtained results with the previous research studies. As a result, we were able …

Bone Properties By Nanoindentation In Mild And Severe Osteogenesis Imperfecta, Carolyne Albert, John Jameson, Jeffrey M. Toth, Peter Smith, Gerald F. Harris

Biomedical Engineering Faculty Research and Publications

Background

Osteogenesis imperfecta is a heterogeneous genetic disorder characterized by bone fragility. Previous research suggests that impaired collagen network and abnormal mineralization affect bone tissue properties, however, little data is yet available to describe bone material properties in individuals with this disorder. Bone material properties have not been characterized in individuals with the most common form of osteogenesis imperfecta, type I.

Methods

Bone tissue elastic modulus and hardness were measured by nanoindentation in eleven osteotomy specimens that were harvested from children with osteogenesis imperfecta during routine surgeries. These properties were compared between osteogenesis imperfecta types I (mild, n = …

Environmental Effects On Mechanical And Thermal Behaviors Of Zinc Oxide Nanobelts And Dispersion Of Carbon Nanostructures, Yingchao Yang

Theses and Dissertations

One-dimensional (1-D) nanostructures, such as nanowires, nanobelts, and nanotubes of different materials, have significant applications as nanoscale interconnects and active/functional components of electronic and optoelectronic devices, sensors, actuators, nanoelectromechanical systems (NEMS), and energy generation/conversion systems. The thermal and mechanical stabilities of those nanodevices and nanoenabled energy systems are of both theoretical and practical interests. Thermodynamic properties of nanomaterials are different from those of bulk materials. As the size of a solid particle reduces to the nanometer scale, the surface-to-volume ratio increases and the melting temperature may remarkably decrease. The functionality and/or reliability of those nanodevices and nanoenabled energy systems are …

Mechanical Properties Of Recycled Aggregate Concrete With Deformed Steel Re-Bar, Yongjae Kim, Jongsung Sim, Cheolwoo Park

Journal of Marine Science and Technology

This study investigates fundamental properties of the recycled aggregate which was produced through recent hi-technique of recycling. In addition, the mechanical properties of the concrete that was made by the recycled aggregate were compared to the concrete made of natural aggregate. The primary objective of this study was to characterize the concrete-rebar bonding properties of the recycled aggregate concrete. The recycled aggregate concrete showed about 18% decreased bond strength as compared to the natural aggregate concrete. The current prediction equation of bond strength suggested by the design specification does not consider this decreased bond strength by the use of the …

Synthesis, Structural, Optical And Mechanical Characterization Of Srb2O4 Nanorods, Rui Li, Lihong Bao, Xiaodong Li

Faculty Publications

Single crystalline strontium borate (SrB₂O₄) nanorods were synthesized for the first time via a facile sol–gel route at low temperature. The SrB₂O₄ nanorods have a good crystalline nature with the growth direction along the [511] orientation and they are transparent from the ultraviolet to the visible regimes. Nanoscale three-point bending tests were performed directly on individual nanorods to probe their mechanical properties using an atomic force microscope. The elastic modulus of SrB₂O₄ nanorods was measured to be 158.2 ± 2.8 GPa, exhibiting a significant increase compared with other borate nanostructures …

Measuring The Nanoindentation Properties Of Alendronate-Time Treated Canine Cortical, Folorunso Ashaolu

Master's Theses

This study examines the nanoindentation (energy inclusive) properties of 0.2 mg/kg alendronate treated ribs at one and three years against a vehicle treated control in a fresh-frozen, non-cold-mounted, condition. This was to verify if the tissue-level properties for 0.2 ALN treated beagles would increase because of an increased level of mineralization despite a microdamage increase.

A total of twelve (12) skeletally mature (1–2 years old) female beagle dogs were treated daily for three years and one year with oral doses of vehicle (VEH, 1 mL/kg saline) or alendronate (ALN, 0.2 Merck, Rahway, NJ). The 0.2 mg dose corresponds, on a …

Low Cycle Fatigue Behavior Of Concrete With Recycled Concrete Aggregates, Paul Mark Gordon

Master's Theses

A comparison of concrete containing recycled concrete coarse aggregates and natural coarse aggregates subjected to high strain, low cycle compressive fatigue is presented. Using a strain based feedback control loop, concrete cylinders are compressed at 15µε/s to a specified strain then unloaded to zero stress for 10 cycles. After cycling, all samples are loaded to a strain of 0.008. Direct concrete material variables are the water to cement (w/c) ratio, taken as 0.60, 0.45, and 0.39, and percent coarse recycled concrete aggregate content, varied from zero to 100 percent. The primary testing variable is the specified unloading strain. Unloading strains …

Polydimethylsiloxane Mechanical Properties Measured By Macroscopic Compression And Nanoindentation Techniques, Zhixin Wang

USF Tampa Graduate Theses and Dissertations

In this thesis, the relationship between the elastic modulus of PDMS and the base/agent ratio (the amount of crosslinking) is studied. Reliable macroscopic compression test instrument was developed. Preload method was applied for the nanoindentation flat punch test to develop full contact.

In chapter 2, an easy instrument setup for macroscopic compression test is described. A series of PDMS samples with different base/agent ratios were tested using the macroscopic compression method. The relationship between PDMS elastic modulus and its base/agent ratio was established.

In chapter 3, PDMS nanoindentation DMA tests provide stable data with different test control models. The storage …

Ultrasound Elasticity Measurements As A Predictor For Arteriovenous Fistula Maturation, Anna Sorace

All ETDs from UAB

This research thesis examines the applicability of using ultrasound imaging to quantify arterial elasticity and assess potential of arteriovenous fistula maturation in chronic kidney disease (CKD) patients. Tissue-specific abnormalities have proven useful for identifying disease states within oncology, cardiovascular and musculoskeletal system. Using ultrasound-based imaging to evaluate arterial elasticity is a noninvasive and novel technique. It has the potential to contribute further insight into chronic kidney disease fistula failure and become a noninvasive prognostic indicator. Reliable vascular access is critical for delivery of adequate hemodialysis treatment to CKD patients and to maintain long-term connections for dialysis. An arteriovenous fistula is …

Nanoindentation Of Annealed And As-Sputtered Thin Films Of Nickel Titanium Shape Memory Alloys, Matthew Tyson Lewis

Master's Theses

The bottom-up processing techniques used for making Microelectromechanical systems (MEMS) devices can produce material properties different from bulk processing. The material properties must be evaluated with the process parameters used and for changes in the process parameters. The mechanical properties are needed to design MEMS devices. A material of interest for MEMS devices is nickel titanium (NiTi) shape memory alloy (SMA) because of the high work output (~107 J/m3). This thesis will focus on the fabrication of thin film NiTi by DC magnetron sputtering deposition and testing mechanical properties of the fabricated films by nanoindentation. Thin film NiTi SMA was …

Mechanical And Chemical Characterization Of Biological Composite Structures, Bonnie Zimmerman

All Theses

A better understanding of the bioresponse of naturally occurring systems will help
to optimize the engineering of synthetic biomaterials. The aim of this thesis was to
characterize the mechanical and chemical behavior of two distinct biological composite
systems, human teeth and wool fibers. These mechanical and chemical properties were
also studied as a function of natural structure and environmental conditions.
Human teeth are composite systems consisting primarily of hydroxylapatite and
protein. This project investigated how the use of clinical dental treatments and
procedures, such as whitening and etching, affects mechanical properties. Analysis of
nanoindentation with the Oliver-Pharr model provided elastic …

Tobacco Mosaic Virus Templated Synthesis Of One Dimensional Inorganic-Polymer Hybrid Fibres, Jianhua Rong, Fiona Oberbeck, Xinnan Wang, Xiaodong Li, Jerry Oxsher, Zhongwei Niu, Qian Wang

Faculty Publications

Inorganic–polymer hybrid nanofibres were prepared by using a rod-like tobacco mosaic virus (TMV) as a template. With tetraethylorthosilicate (TEOS) as a precursor, long silica-coated TMVfibres were formed via a head-to-tail assembly, which showed a substantial increase of the elastic modulus. Furthermore, homogenous titania–TMV hybrid fibres could be prepared using polyaniline-coated TMV fibres as a template, which were used to form a composite film that was able to sense liquefied petroleum gases.

Modeling The Effective Elastic Modulus Of Rc Beams Exposed To Fire, Jui-Hsiang Hsu, Cherng-Shing Lin, Chang-Bin Huang

Journal of Marine Science and Technology

This work combines thermal and structural analyses to study the effect of fire on the elastic modulus of reinforced concrete beams. The thermal analysis uses the finite difference method to model the temperature distribution of a reinforced concrete beam maintained at high temperature. The structural analysis, using the lumped method, is utilized to calculate the effective elastic modulus of reinforced concrete beams. The results of the thermal analysis are compared to the experimental results in the literature, and the analytically derived structural results are also compared with experimental data on the flexural behaviors of RC beams exposed to fire. The …

Microstructure Design Of A Two Phase Composite Using Two-Point Correlation Functions, Brent L. Adams, H. Garmestani, G. Saheli

Faculty Publications

This work has been funded under the AFOSR Grant no. F49620-03-1-0011 and Army Research Lab contract no. DAAD17-02-P-0398 and DAAD 19-01-1-0742. Two-point distribution functions are used here as to introduce "Microstructure Sensitive Design" in two-phase composites. Statistical distribution functions are commonly used for the representation of microstructures and also for homogenization of materials properties. The use of two-point statistics allows the composite designer to include the morphology and distribution in addition to the properties of the individual phases and components. Statistical continuum mechanics is used to make a direct link between the microstructure and properties (elastic and plastic) in terms …

Anisotropy And Its Relation To Liquefaction Resistance Of Granular Material, Isao Ishibashi, Omer F. Capar

Civil & Environmental Engineering Faculty Publications

This research establishes quantitative relationships between soil's anisotropy and liquefaction resistance for granular materials. Uniform medium density (D_r = 50%) sand specimens were prepared using three different sample preparation techniques (air pluviated (AP), moist tamped (NIT), and moist vibrated (MV)) to create different initial soil fabrics. Undrained cyclic triaxial tests were then performed to determine the liquefaction resistance of each soil specimen. On the same specimens in the triaxial cell, vertical and horizontal compression wave velocities and vertical shear wave velocity (V_s) were measured using piezoelectric bender elements. Anisotropic (transversely isotropic) elastic constants of the soil specimens were …

Effect Of Sand Ration On The Elastic Modulus Of Self-Compacting Concrete, J. K. Su, S. W. Cho, C. C. Yang, R. Huang

Journal of Marine Science and Technology

In order to study the effect of sand ratio (S/A ratio, fine aggregate volume/total aggregate volume) on the elastic modulus of self-compacting concrete (SCC), concretes with various S/A ratios were cast and tested. Elastic moduli of SCC were compared with those of normal concrete. Slump flow test, slump test, and box test were carried out to evaluate concrete flowability. The flowability of SCC increases with an increase in S/A ratio. However, the elastic modulus of SCC is not significantly affected by S/A ratio when total aggregate volume is kept constant.