Mechanical Engineering Commons^™

Peridynamic Modeling Of Ruptures In Biomembranes, Michael Taylor, Irep Gözen, Samir Patel, Aldo Jesorka, Katia Bertoldi

Mechanical Engineering

We simulate the formation of spontaneous ruptures in supported phospholipid double bilayer membranes, using peridynamic modeling. Experiments performed on spreading double bilayers typically show two distinct kinds of ruptures, floral and fractal, which form spontaneously in the distal (upper) bilayer at late stages of double bilayer formation on high energy substrates. It is, however, currently unresolved which factors govern the occurrence of either rupture type. Variations in the distance between the two bilayers, and the occurrence of interconnections (“pinning sites”) are suspected of contributing to the process. Our new simulations indicate that the pinned regions which form, presumably due to …

Non-Destructive Evaluation Of Functional Material Properties Performed On Additively Manufactured Coupons, Devin S. Plagge

Mechanical Engineering ETDs

This thesis presents the development of non-destructive characterization of functional material properties of additively manufactured metals. In particular, this study was focused on the common structural stainless steel alloy, 316L, utilizing a coupon designed specifically for simple modal analysis. Additive manufacturing (AM) has moved to the forefront of the manufacturing world, particularly in aerospace and defense segments because of the potential to produce multi-functional, highly optimized components. The ability to confidently qualify these complex, and thus expensive, components has been lagging behind the advancing technology. The adoption of traditional characterization techniques developed for wrought materials has been most common, and …

The Effects Of The Stratosphere On Materials, Ashley C. Greene, Theresa M. Palandro

Posters-at-the-Capitol

Abstract 1:

Making AND Breaking: How reliable are some water pipes?

Ashley C. Greene.

Three different types of pipes were tested to see at what point in time they would break. The pipes, PVC pipe, PEX pipe, and CPVC pipe, were filled with water and attached to a helium filled weather balloon. The ends of the pipes were sealed to trap the water inside. The pipes were secured onto a payload in a Styrofoam box surrounded by cheese cloth. This frame secured the pipes and ensured that they stayed in one place and could not move around the container. The …

High Altitude Ballooning And The Effect Of Temperature On Balloon Ascent Rate, Christopher D. Young

Posters-at-the-Capitol

Abstract

High Altitude Ballooning and The Effect of Temperature on Balloon Ascent Rate.

Christopher Young

High-altitude balloons are unmanned balloons, usually filled with helium or hydrogen, that after release, ascend into the stratosphere, generally attaining an altitude of between 60,000 to 100,000 feet. The balloon payload includes scientific experiments on organisms, equipment to study radiation, temperature, ultra- violet radiation, and pressure. The balloon flights and experiments are logged by means of video devices and are tracked from the ground through multiple tracking devices. The effect of temperature on the ascent rate of the balloon could change how the balloon expands …

Model Truss Bridge Design, William Spicer Berry, Kaleb Rankin Dyer, Dustin Lee Schultz

Posters-at-the-Capitol

Bridges are one of the most important and costly engineering projects, involving extensive design considerations that try to minimize expenses while insuring the bridge will not fail. Different models of bridges were constructed in order to perform experiments that determined which beams were in compression and how much force was experienced in the beam’s when a static load was applied. Computer simulations were also performed to determine the loads on the different beams. The simulation and calculated results were compared to ensure accuracy of the final results. It was determined that a Howe bridge offers the lowest maximum compression on …

Experimental And Computational Study On Fracture Mechanics Of Multilayered Structures, Hai Thanh Tran

USF Tampa Graduate Theses and Dissertations

Many devices in electronics are in the form of multilayered structures. These structures can fail catastrophically if they contain defects or cracks. Enhancing their fracture properties is therefore critical to improve the reliability of the systems. The interface-dominated fracture mechanics of multilayered structure was studied using experiments and finite element (FE) modeling by considering two examples: thin films on polymer substrates in flexible electronics and Cu leadframe/epoxy molding compound (EMC) in micro-electronics packaging.

In the first example, aluminum-manganese (Al-Mn) thin films with Mn concentration up to 20.5 at.% were deposited on polyimide (PI) substrates. A variety of phases, including supersaturated …

Survey Of Selected Additively Manufactured Propellant For Arc-Ignition Of Hybrid Rockets, Stephen A. Whitmore, Stephen L. Merkley, Louis Tonc, Spencer D. Mathias

Mechanical and Aerospace Engineering Faculty Publications

Results of a testing campaign to assess multiple commercially available three-dimensional printer materials for effectiveness in an arc-ignition system for hybrid rockets are presented. Previously, a form of additive manufacturing known as fused deposition modeling was used to fabricate high-density acrylonitrile butadiene styrene (ABS) fuel grains so that, when properly layered, they possess unique electrical breakdown properties. When subjected to an inductive charge, an electrical arc flows along the layered material surface and seeds combustion when the arc occurs simultaneously with the introduction of an oxidizing flow. This study investigates commercially available three-dimensional printable materials to search for equivalent or …

Sputtering Power Effects On Growth And Mechanical Properties Of Cr2alc Max Phase Coatings, Muhammad Naveed, Aleksei Obrosov, Andrzej Zak, Wlodzimierz Dudzinski, Alex A. Volinsky, Sabine Weiß

Mechanical Engineering Faculty Publications

Coating growth and mechanical properties of nanolamellar Cr₂AlC coatings at various sputtering power were investigated in the present study. Cr₂AlC coating was deposited on the IN 718 superalloy and (100) Si wafers by DC magnetron sputtering at different sputtering powers. The structure and properties were characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and nanoindentation. It was found that coatings had columnar structure with nanocrystalline substructure. Deposition rate increased with the sputtering power. XRD results showed the presence of the Cr₂AlC MAX phase, intermetallic AlCr₂ and Cr_{7 …}

Molybdenum Disulfide-Conducting Polymer Composite Structures For Electrochemical Biosensor Applications, Hongxiang Jia

USF Tampa Graduate Theses and Dissertations

Lactic acid is widely existing in human bodies, animals and microorganisms. Recently, using biosensor to detect the concentration of lactic acid and diagnose disease have attracted great research and development interests. Nanocomposites is one of the best material used for biosensor because their wonderful conductivity, optical and electrochemical properties. In the study, MoS₂ and polypyrrole (PPY) are used for the composite material electrode. To determine whether lactate oxidase (LOD) was helpful for the biosensor’s detective properties, both PPY-MoS₂ film with LOD and PPY-MoS₂ film without LOD are being tested. The fourier transform infrared spectroscopy (FTIR) and Raman …

Simulation And Verification Of Fluid Jet Polishing, Senmiao Hu

USF Tampa Graduate Theses and Dissertations

Fluid jet polishing (FJP) is a new advanced polishing technology that finds applications in many industries, especially in the optics industry. With the broad application of various surfaces in optics, the sub-micrometric scale and the nanometric surface roughness accuracy are major challenges. Fluid jet polishing is a technology developed from abrasive water jet machining. This technology is a water jet cutting technology, which uses high-pressure flow to cut/remove materials.

In this thesis, the working principle, and simulations, as well as verification of fluid jet polishing are thoroughly investigated. The verification of fluid jet polishing in this thesis includes velocity distribution …

Video Capture And Post-Processing Technique For Approximating 3d Projectile Trajectory, Chase M. Pfeifer, Judith M. Burnfield, Guilherme M. Cesar, Max H. Twedt, Jeff A. Hawks

Department of Mechanical and Materials Engineering: Faculty Publications

In this paper we introduce a low-cost procedure and methodology for markerless projectile tracking in three-dimensional (3D) space. Understanding the 3D trajectory of an object in flight can often be essential in examining variables relating to launch and landing conditions. Many systems exist to track the 3D motion of projectiles but are often constrained by space or the type of object the system can recognize (Qualisys, Göteborg, Sweden; Vicon, Oxford, United Kingdom; Opti-Track, Corvallis, Oregon USA; Motion Analysis, Santa Rosa, California USA; Flight Scope, Orlando, Florida USA). These technologies can also be quite expensive, often costing hundreds of thousand dollars. …

25+ Years Of The Hubble Space Telescope And A Simple Error That Cost Millions, Said Shakerin

All Faculty Articles - School of Engineering and Computer Science

A simple mistake in properly setting up a measuring device caused millions of dollars to be spent in correcting the initial optical failure of the Hubble Space Telescope (HST). This short article is intended as a lesson for a physics laboratory and discussion of errors in measurement.

A Robot Platform For Intelligent Ground Vehicle Research, Jihang Li

Theses and Dissertations

This thesis presents a mobile platform developed for further research on the Intellegent Ground Vehicle project which began as a capstone project but without achieving full autonomy. The scope of the current project is to develop Robot Operating System (ROS) based driver libraries to the electronic system and provide application program interfaces (APIs) for higher abstraction level libraries. Prior work had provided a mechanical system and several sensors for the robot. The chassis of the vehicle is fabricated with aluminum tubings and enclosed with aluminum boards to protect internal electronics from environmental conditions. A three-wheel differential drive architecture is used …

Flex-Ro: Design, Implementation, And Control Of Subassemblies For An Agricultural Robotic Platform, Jared Patrick Werner

Department of Agricultural and Biological Systems Engineering: Dissertations, Theses, and Student Research

Automation technology in agriculture is growing, making agricultural robotics viable. Innovative field usable multi-purpose robotic platforms are needed for the successful progression of agricultural robotics. Furthermore, the field of agricultural robotics would benefit from a robotic platform design allowing for variable height, thus accommodating navigation throughout various crop growth stages. A variable height machine, Flex-Ro was developed to accommodate this feature. Multiple sub-assemblies were designed and implemented for Flex-Ro. An electronic control unit (ECU) enabled engine was used to power Flex-Ro. An embedded application program was developed to control engine speed using proprietary Controller Area Network (CAN) messages in conjunction …

Bioaerosol Deposition On An Air-Conditioning Cooling Coil, Yan Wu, Ailu Chen, Irvan Luhung, Elliott T. Gall, Qingliang Cao, Victor Wei-Chung Chang, William W. Nazaroff

Mechanical and Materials Engineering Faculty Publications and Presentations

This study is concerned with the role of a fin-and-tube heat exchanger in modifying microbial indoor air quality. Specifically, depositional losses of ambient bioaerosols and particles onto dry (not cooled) and wet (cool) coil surfaces were measured for different airspeeds passing through the test coil. Total, bacterial and fungal DNA concentrations in condensate water produced by a wet coil were also quantified by means of fluorescent dsDNA-binding dye and qPCR assays. Results revealed that the deposition of bioaerosols and total particles is substantial on coil surfaces, especially when wet and cool. The average deposition fraction was 0.14 for total DNA, …

Distribution Of Mean Kinetic Energy Around An Isolated Wind Turbine And A Characteristic Wind Turbine Of A Very Large Wind Farm, Gerard Cortina, Marc Calaf, Raul Bayoan Cal

Mechanical and Materials Engineering Faculty Publications and Presentations

An isolated wind turbine and a very large wind farm are introduced into large-eddy simulations of an atmospheric boundary layer. The atmospheric flow is forced with a constant geostrophic wind and a time-varying surface temperature extracted from a selected period of the CASES-99 field experiment. A control volume approach is used to directly compare the transfer of mean kinetic energy around a characteristic wind turbine throughout a diurnal cycle considering both scenarios. For the very large wind farm case, results illustrate that the recovery of mean kinetic energy around a wind turbine is dominated by the vertical flux, regardless of …

Material Evaluation: Self Damping Wire Sd/Acsr Conductor Failures, Daniel F. Weyer

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

Following numerous 954 ACSR SD Wire failures from 2010 to 2012, Nebraska Public Power District (NPPD) implemented an inspection program to determine the extent of condition for this type of widely used conductor. NPPD transmission system includes over 2000 miles of this particular conductor.

Transmission line splices are installed every 15-20 spans, with failures being located in a span containing a splice. NPPD worked with Kinectrics to complete electromagnetic field inspections for three days in 2013, with retesting performed in 2015. Throughout this inspection of 54 spans of conductor, 36 were found to have deterioration and corrosion.

Over 80% of …

Feasibility Study Of Hall Thruster Fabrication Using Additive Manufacturing, Ethan Hopping, Gabriel Xu

Von Braun Symposium Student Posters

No abstract provided.

Collapse Resistance Of Moment Resisting Frame And Shear Wall Rc Structural Systems Exposed To Blast, Alaa I. Chehab, Christopher D. Eamon, Joshua Griffin

Civil and Environmental Engineering Faculty Research Publications

Various characteristics of a structure influence its response when subjected to a blast load. This has important implications for survivability and resistance to progressive collapse. In this study, the effect of the type of lateral load resisting system on reinforced concrete building resistance to progressive collapse when exposed to blast load is examined. Fourteen different reinforced concrete structures were considered for analysis, with five structures designed as moment resisting frames and nine designed as shear walls systems. Buildings with 3, 6, and 10 stories with 3, 4, and 5-bay symmetric configurations were considered. The structures were exposed to external and …

Comparison Of The Modes And Mechanisms Of Degradation Of Experimental C-Si Pv Modules With Various Encapsulants, October 2016, Florida Solar Energy Center, Neelkanth Dhere

FSEC Energy Research Center®

Seven modules with different encapsulants, provided by the National Renewable Energy Laboratory (NREL), were installed at the Florida Solar Energy Center (FSEC) outdoor test facility for long-term durability testing in the hot and humid climate of Florida. Along with the modules, NREL also provided corresponding load resistors, junction boxes, and module connections. The modules were installed at latitude tilt, on a south facing rack on March 20, 2014.During project different types of tests such as visual inspection in environmental conditions and infrared imaging and I-V characterization were carried out on the seven module

A Bioinspired Modification For Uas Propeller/Rotor Noise Reduction, Mark N. Callender

ASA Multidisciplinary Research Symposium

This projects presents a bioinspired modification to UAS propellers/rotors for noise reduction. Sound pressure levels (SPL) and thrust for modified propellers were compared to a baseline propeller. The bioinspired modification yielded lower SPL with a requisite increase in rpm in order to maintain a chosen level of thrust.

Behaviour Of A Spd Switchable Glazing In An Outdoor Test Cell With Heat Removal Under Varying Weather Conditions, Aritra Ghosh, Brian Norton, Aidan Duffy

Articles

Suspended particle device (SPD) switchable glazing has potential to control transmission of solar radiation in the visible range by changing its transparency from 55% to 5%. Outdoor test cell characterisation of a SPD switchable glazing offered the dynamic solar heat gain coefficient (SHGC) which varied between 0.05 (when opaque) and 0.38 (when transparent). Reduction of maximum temperature rise of 11% and 15% was possible using SPD “transparent” and “opaque” state compared to same area double-glazing. Insulated test cell with water flow heat exchanger was employed to measure the cooling load reduction potential of SPD glazing while its transmission changed from …

Novel Closed-Loop Control Strategy For Inkjet-Based Additive Manufacturing System, Yunong Shi, Chunsheng Ye

The 8th International Conference on Physical and Numerical Simulation of Materials Processing

No abstract provided.

Study On Criterion Of Fabricating Columnar Dendrite Structure Dz466 Superalloy Based On Lmc Process, Xun Sun

The 8th International Conference on Physical and Numerical Simulation of Materials Processing

No abstract provided.

A Coupled Finite Element-Free Galerkin Method For Simulating Viscous Pressure Bulging, Chunjun Dai

The 8th International Conference on Physical and Numerical Simulation of Materials Processing

No abstract provided.

Study On The Impact Abrasive Wear Of New Super-High Manganese Steel, Wenyan Wang

The 8th International Conference on Physical and Numerical Simulation of Materials Processing

No abstract provided.

Simulation Of Superplastic Forming Of Circular Edge-Welded Envelopes, Olga Tulupova

The 8th International Conference on Physical and Numerical Simulation of Materials Processing

No abstract provided.

Numerical Simulation On The Combustion Characteristic Of Iron Ore Sintering With Flue Gas Recirculation, Gan Wang, Zhi Wen, Guofeng Lou, Ruifeng Dou, Xunliang Liu, Fuyong Su, Sizong Zhang

The 8th International Conference on Physical and Numerical Simulation of Materials Processing

No abstract provided.

A Parallel 3d Phase-Field Simulation Of Multi-Grain Growth Based On The Full Thread Tree, Ya-Jun Yin, Min Wang, Jian-Xin Zhou, Dun-Ming Liao, Xu Shen, Tao Chen

The 8th International Conference on Physical and Numerical Simulation of Materials Processing

No abstract provided.

Study On Criterion Of Fabricating Columnar Dendrite Structure Dz466 Superalloy Based On Lmc Process, Xun Sun, Guoyan Shui, Yang Guan, Guiqiao Su, Bo Yu, Lou Yanchun

The 8th International Conference on Physical and Numerical Simulation of Materials Processing

No abstract provided.