Mechanical Engineering Commons^™

Aerodynamic Effects In A Dropped Ping-Pong Ball Experiment, Mark L. Nagurka

Mechanical Engineering Faculty Research and Publications

This paper addresses aerodynamic modeling issues related to a simple experiment in which a pingpong ball is dropped from rest onto a table surface. From the times between the ball-table impacts, the initial drop height and the coefficient of restitution can be determined using a model that neglects aerodynamic drag. The experiment prompts questions about modeling the dynamics of a simple impact problem, including the importance of accounting for aerodynamic effects. Two nonlinear aerodynamic models are discussed in the context of experimental results.

Application Of A Finite Element Model Update Technique To Detect Damage In A Beam Structure, Madhu Kumar Vattipulusu

Masters Theses

"The interest in the ability to monitor a structure and detect damage at the earliest possible stage is pervasive throughout the civil, mechanical and aerospace engineering communities. The thesis focuses on the application of a finite element model updating technique to monitor and detect damage in beams. A Sensitivity Based Element-by- Element (SBEBE) methodology is chosen as the finite element model updating technique. In this method, damage is detected by updating a finite element model with test data obtained from "healthy" and "damaged" structures and observing the relative changes in the updated finite element models. The performance, efficiency and sensitivity …

Evaluation Of Fire-Fighting Helmet Surface Technology For High Radiant Heat Applications, David L. Barnett

University of Kentucky Master's Theses

Protective helmets used by fire-fighters must be designed to minimize the amount of heat transferred to the users head while providing durability, comfort, and affordable costs. This thesis highlights the evaluation of new helmet technology specifically tailored to high radiant heat environments to advance the state-of-the-art in head protection for this application. The research focused on the assessment of the outer shells of helmets and the properties of the surfaces. The development included the evaluation of radiation heat transfer, in a laboratory environment, to various helmet shell surface constructions. Industry standards were considered, and critiqued. Experiments were designed to isolate …

Experimental Investigation Of Separation In A Low Pressure Turbine Blade Cascade Model, Brian Hollon

University of Kentucky Master's Theses

The flow field around a low pressure turbine blade is examined using smoke-wire flow visualization, static surface pressure measurements, and particle image velocimetry (PIV). The purpose of the experimental study is to investigate the transition and separation characteristics on low pressure turbine blades under low Reynolds number (Re) and varying freestream turbulence intensity (FSTI). A cascade model consisting of 6 Pratt andamp; Whitney PAK-B low pressure turbine blades was examined in a wind tunnel using PIV and flow visualization. Smoke-wire visualization was performed for test section exit angles of 93°, 95°, and 97°, in the range Re = …

Measurements In A Rotating Serpentine Duct With Multiple Rib Arrangements, Rahul Bharadwajh

University of Kentucky Master's Theses

The effect of rotation on flow in a gas turbine blade cooling duct model is investigated experimentally. The present work consists of velocity measurements at different locations in a test section with a 180° bend with ribs on one wall. Three geometric rib parameters are considered; rib-rib spacing, rib orientation angle and rib blockage ratio. PIV is used for flow visualization and analysis. Along with the clean duct measurements, ribs with blockage ratios, b/h, of 0.25 and 0.125 were considered. The b/h = 0.25 cases have been comprehensively analyzed while the b/h = 0.125 cases have been studied at …

Study Of The "Poor Man's Navier-Stokes" Equation Turbulence Model, Stewart Andrew Bible

University of Kentucky Master's Theses

The work presented here is part of an ongoing effort to develop a highly accurate and numerically efficient turbulence simulation technique. The paper consists of four main parts, viz., the general discussion of the procedure known as Additive Turbulent Decomposition, the derivation of the "synthetic velocity" subgrid-scale model of the high wavenumber turbulent fluctuations necessary for its implementation, the numerical investigation of this model and a priori tests of said models physical validity. Through these investigations we have demonstrated that this procedure, coupled with the use of the "Poor Mans Navier-Stokes" equation subgrid-scale model, has the potential to be …

Proper Orthogonal Decomposition Of Hartmann Wavefront Sensor Data For A Plane Mixing Layer, Peter J. Szyjka

Mechanical Engineering ETDs

The ''snapshot" proper orthogonal decomposition (POD) was used to analyze the turbulent characteristics of a plane mixing layer. A two-dimensional (2-D) Hartmann wavefront sensor measured optical tilt propagation through a flow field downstream of a splitter plate. The velocity difference across the splitter plate produced roller vortices via the Kelvin-Helmholtz instability. Refractive-index fluctuations were produced by slightly heating the flow on the low-speed side of the splitter plate. The Hartmann sensor detects gradients in refractive index (and thus temperature) in directions perpendicular to its direction of propagation. The measured field of two-dimensional tilt (or optical deflection) is proportional to the …

Nebraska Summary: S438 New Holland Tm190, Nebraska Tractor Test Lab

Nebraska Tractor Tests

ABOUT THE TEST REPORT AND USE OF THE DATA The test data contained in this report are a tabulation of the results of a series of tests. Due to the restricted format of these pages, only a limited amount of data and not all of the tractor specifications are included. The full OECD report contains usually about 30 pages of data and specifications. The test data were obtained for each tractor under similar conditions and therefore, provide a means of comparison of performance based on a limited set of reported data. EXPLANATION OF THE TEST PROCEDURES Purpose The purpose of …

Test 1821: Challenger Mt735 Diesel, Nebraska Tractor Test Lab

Nebraska Tractor Tests

No abstract provided.

Test 1819: John Deere 8120 16-Speed, Nebraska Tractor Test Lab

Nebraska Tractor Tests

ABOUT THE TEST REPORT AND USE OF THE DATA

The test data contained in this report are a tabulation of the results of a series of tests. Due to the restricted format of these pages, only a limited amount of data and not all of the tractor specifications are included. The full OECD report contains usually about 30 pages of data and specifications. The test data were obtained for each tractor under similar conditions and therefore, provide a means of comparison of performance based on a limited set of reported data.

EXPLANATION OF THE TEST PROCEDURES

Purpose

The purpose of …

Tests 2077 & 2095: Case Ih Jx 80u Diesel, Nebraska Tractor Test Lab

Nebraska Tractor Tests

No abstract provided.

Finite Element Analysis And Testing Of An Inkjet Cartridge Die, Dylan Ryan

Theses

This project investigates the application of finite element and experimental analysis in the design and testing of silicon based semiconductor components. In a thermal inkjet printer the ink cartridge contains a print head (or die), the head fires numerous droplets simultaneously to form pixels and letters. The inkjet cartridge die consists of a thin film layer, containing the integrated circuits that make up the thennal inkjets, mounted on a polysilicon substrate structure.

A number of incremental changes to the design and manufacturing processes related to the manufacture of these inkjet cartridge dies is made. In past instances when changes were …

An Air-Filter Sensor For Home-Used Air Conditioners, Cheng Y. Lin, Gary R. Crossman, Alok K. Verma

Engineering Technology Faculty Publications

This paper presents a successful senior project of instrumentation developed in a Mechanical Engineering Technology senior capstone course. Students were encouraged to approach the problem of designing an air-filter sensor and to propose an optimum and practical solution for the problem. Work includes conceptual design and analysis, implementation, tests and modifications. When an air filter is used in a home air conditioner, inhabitants often forget when to replace it until the cooling or heating capacity is obviously reduced. If the filter remains in service, the efficiency of the cooling/heating system will continue decreasing while the electricity bill will significantly increase. …

Mechanical Property Characterization Of Mouse Zona Pellucida, Yu Sun, Kai-Tak Wan, K. P. Roberts, J. C. Bischof, B. J. Nelson

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Previous intracytoplasmic sperm injection (ICSI) studies have indicated significant variation in ICSI success rates among different species. In mouse ICSI, the zona pellucida (ZP) undergoes a "hardening" process at fertilization in order to prevent subsequent sperm from penetrating. There have been few studies investigating changes in the mechanical properties of mouse ZP post fertilization. To characterize mouse ZP mechanical properties and quantitate the mechanical property differences of the ZP before and after fertilization, a microelectromechanical systems-based multiaxis cellular force sensor has been developed. A microrobotic cell manipulation system employing the multiaxis cellular force sensor is used to conduct mouse ZP …

Nonlinear H Infinity Missile Longitudinal Autopilot Design With Θ-D Method, Ming Xin, S. N. Balakrishnan

Mechanical and Aerospace Engineering Faculty Research & Creative Works

In this paper, a new nonlinear control synthesis technique, the theta- D method, is employed to design a missile longitudinal autopilot. The θ-D technique yields suboptimal solutions to nonlinear optimal control problems in the sense that it provides approximate solution to the Hamilton-Jacobi-Bellman (HJB) equation. Semi-global asymptotic stability can be achieved by manipulating the perturbation terms which are added to the cost function in developing a series solution. Furthermore, this method can be used to provide an approximate closed-form solution to the state dependent Riccati equation. The particular θ-D methodology adopted in this paper is referred to as θ-D H …

Multidimensional, Time-Accurate Cfd Simulation Of Adsorption/Desorption In A Carbon Canister, Xingyan Bai, Kakkattukuzhy M. Isaac, D. Klein, R. Banerjee, J. Edson, W. Breig, L. Oliver

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Computational fluid dynamics simulations of fixed-bed adiabatic adsorption/desorption processes are presented in this paper. Linear driving force model is used for heat and mass transfer rates. a two-dimensional cylindrical canister and three-dimensional automotive production canister geometry are used to study the adsorption/desorption processes of carbon dioxide in helium carrier gas on Norit B4 activated carbon. the two-dimensional results compare well with the results of Hwang et al. [1]. Computational results as breakthrough curve, adsorption amount and temperature profiles are provided. Results show that non-adiabatic model should be used to fully utilize the activated carbon bed capacity prior to breakthrough. Copyright …

Innovative Forced Response Analysis Method Applied To A Transonic Compressor, Timothy M. Hutton

Browse all Theses and Dissertations

A set of inlet guide vane (IGV) unsteady surface pressure measurements of a transonic compressor is presented. Using a flexible pressure sensor array, unsteady IGV suction-surface and pressure-surface pressures are acquired for six spanwise by five chordwise locations for various speed lines and throttle settings. Measurements from this sensor array are used to investigate unsteady vane/blade interaction aeromechanical forcing functions in a modern, highly loaded compressor stage. A significant effect is shown on the unsteady forced response of the IGV with changes in compressor operating point and IGV/rotor axial spacing for various span and chord locations. In particular, variations in …

Plastic Dissipation Energy In Mixed-Mode Fatigue Crack Growth On Ductile Bimaterial Interfaces, Jeremy S. Daily

Browse all Theses and Dissertations

A new theory of fatigue crack growth in ductile solids has recently been proposed based on the total plastic energy dissipation per cycle ahead of the crack. This and previous energy-based approaches in the literature suggest that the total plastic dissipation per cycle can be closely correlated with fatigue crack growth rates under Mode I loading. The goal of the current study is to extend the dissipated energy approach to steady-state crack growth under mixed-mode loading conditions, with application to cyclic delamination of ductile interfaces in layered materials. The total plastic dissipation per cycle is obtained by 2-D elastic-plastic finite …

Alloy States In Dilute Gaas1-XNX Alloys (X<1%), X. D. Luo, Jinsong Huang, Z. Y. Xu, C. L. Yang, J. Liu, W. K. Ge, Y. Zhang, A. Mascarenhas, H. P. Xin, C. W. Tu

Department of Mechanical and Materials Engineering: Faculty Publications

A set of GaAs_1-xN_x samples with small nitrogen composition (x<1%) were investigated by continuous-wave photoluminescence (PL), pulse-wave excitation PL, and time-resolved PL. In the PL spectra, an extra transition located at the higher-energy side of the commonly reported N-related emissions was observed. By measuring the PL dependence on temperature and excitation power, the PL peak was identified as a transition of alloy band edge-related recombination in GaAsN. The PL dynamics further confirms its intrinsic nature as being associated with the band edge rather than N-related bound states.

Effect Of Combined Metal-Carbon Additions On The Microstructure And Structure Of Sm2fe17, B. E. Meacham, Jeffrey E. Shield

Department of Mechanical and Materials Engineering: Faculty Publications

The effect of combined alloying additions on the structure and scale of rapidly solidified Sm–Fe alloys was investigated. Transition metal additions tend to promote the formation of the disordered TbCu₇-type structure in Sm₂Fe₁₇ alloys, as determined by monitoring the long-range order parameter. Essentially no order was observed for M = Ti, Zr, V, or Nb. Thus, the structure was close to the prototypical TbCu₇-type structure. With M = Si, a large amount of order was observed (S = 0.62), resulting in a structure closer to the well-ordered Th₂Zn₁₇-type. The …

Production Of Fine Nd-Fe-B Alloy Powder By Pulsed Plasma Atomization, Jeffrey E. Shield, S. Christensen, R. W. Kincaid, F. D. Witherspoon

Department of Mechanical and Materials Engineering: Faculty Publications

Extremely fine (<10 >μm) Nd-Fe-B powder was generated by pulsed plasma atomization processing. The number average was just over 3 μm, as determined by computer-assisted scanning electron microscopy analysis of almost 3000 particles. Despite the fine particle size, alloys of stoichiometric Nd₂Fe₁₄B resulted in the properitectic formation of α-Fe, deleteriously affecting the magnetic properties. Nevertheless, this work shows the possibility of generating extremely fine, isotropic powder for bonded and hybrid magnet applications.

Recent Advances In Solid Hydrogen Storage Systems, B. S. Chao, R. C. Young, V. Myasnikov, Y. Li, F. Gingl, Patrick D. Ferro, V. Sobolev, S. R. Ovshinsky

Mechanical Engineering Faculty Scholarship

Hydrogen energy offers great promise as an energy alternative. Hydrogen technologies can reduce and eliminate the release of carbon dioxide from fossil-fuel combustion, the main cause of global warming. One of the main challenges is hydrogen storage. Storing hydrogen in the solid-state hydride form holds a volumetric advantage over compressed and liquid hydrogen states. Solid hydrogen storage systems also have features of low-pressure operation, compactness, safety, tailorable delivery pressure, excellent absorption /desorption kinetics, modular design for easy scalability, and long cycle life.

In this paper, solid hydrogen storage systems (such as portable power canisters, lightweight fiber wrapped vessels, and aluminum …

Manufacturing And Analysis Of A Liga Heat Exchanger For The Surface Of A Tube: A Cooling Simulation Of The Leading Edge Region Of A Turbine Blade, Christophe Marques

LSU Doctoral Dissertations

Fabricating nickel micro heat exchangers directly on planar or non-planar metal surfaces has been demonstrated using the LIGA micromachining process. These heat exchangers can effectively control the temperature of surfaces in high heat flux applications. Of particular interest is the temperature control of gas turbine engine components. The locations in the gas turbine engine where improved, efficient cooling is required includes gas turbine blades, stator vanes, the turbine disk, and the combustor liner. In this dissertation, the primary application of interest is the use of such heat exchangers to cool airfoils such as turbine blades. In the first part of …

Modeling, Fabrication, And Optimization Of Niobium Cavities: Final Phase, Robert A. Schill Jr., Mohamed Trabia

Transmutation Sciences Materials (TRP)

Niobium cavities are important parts of the integrated NC/SC high-power linacs. Over the years, researchers in several countries have tested various cavity shapes. They concluded that elliptically shaped cells are the most appropriate shape for superconducting cavities. The need for very clean surfaces lead to the use of a buffered chemical polishing produce for surface cleaning to get good performance of the cavities. This is the third and final phase of the study.

The first phase has resulted in improving the basic understanding of multipacting and the process of chemical etching. The second phase has resulted in an experimental setup …

Modeling, Fabrication, And Optimization Of Niobium Cavities, Robert A. Schill Jr., Mohamed Trabia, William Culbreth

Transmutation Sciences Materials (TRP)

One of the key technologies for the deployment of accelerator driven transmutation systems is the accelerator itself. To increase the efficiency of the high-power accelerators needed to support the transmutation mission, the national and international accelerator teams have proposed using elliptical superconducting niobium cavities. This project is tasked with examining the impacts of the design and fabrication technologies for these elliptical niobium cavities on their performance. Niobium was selected primarily due to its behavior at low temperatures.

One of the major sources of energy loss from a superconducting accelerator cavity is a process known as multiple impacting (or “multipacting”) of …

Developing A Sensing System For The Measurement Of Oxygen Concentration In Liquid Pb-Bi Eutectic, Yingtao Jiang, Bingmei Fu, Woosoon Yim

Transmutation Sciences Materials (TRP)

Lead-bismuth eutectic (LBE) is a candidate as a spallation target in sub-critical transmutation systems and as a coolant in nuclear programs. One of the primary concerns with LBE systems is the corrosion of stainless steel, the primary structural material used in nuclear systems. To mitigate this problem, trace levels of oxygen can be introduced into the system, causing the formation of a protective oxide layer at the interface between the LBE and steel. To protect the steel components, this oxide layer must be properly maintained. However, too much oxygen will produce unwanted oxide precipitation within the coolant and elsewhere in …

Effects Of Environmental Variables And Stress Concentration On Target Materials, Sudheer Sama

Transmutation Sciences Materials (TRP)

This paper presents a brief summary on stress corrosion cracking (SCC) behavior of alloy HT 9. The susceptibility of this alloy to SCC was evaluated by using constant load and slow strain rate test techniques in neutral and acidic solutions at ambient temperature and 90°C. A proof ring was used to apply tensile load to the smooth specimen for 30 days in constant load testing. In slow strain rate testing, the specimen was continuously strained in tension at a rate of 3.3 × 10^-6 sec^-1 until fracture.

Effects Of Environmental Variables And Stress Concentration On Cracking Of Spallation Target Materials, Ajit K. Roy, Ramprashad Prabhakaran, Mohammad K. Hossain

Transmutation Sciences Materials (TRP)

This paper presents the results of stress corrosion cracking (SCC) studies of two martensitic target materials, namely Alloy EP-823 and Type 422 stainless steel. The susceptibility to SCC was evaluated by using constantload and slow-strain-rate (SSR) test techniques in neutral (pH: 6-7) and acidic (pH: 2-3) aqueous solutions at ambient temperature and 90^oC. A proof ring was used to apply tensile load to the smooth cylindrical specimen for 30 days in constant-load testing. For SSR testing, the specimen was strained in tension until fracture at a strain rate of 3.3 x 10^-6 sec^-1.

Stress Corrosion Cracking Of Type 422 Stainless Steel, Ramprashad Prabhakaran

Transmutation Sciences Materials (TRP)

This paper presents the results of SCC tests of quenched and tempered martensitic Type 422 SS in neutral and acidic aqueous environments at ambient temperature and 90^oC.The susceptibility of smooth and notched tensile specimens to SCC was evaluated by using constant load (CL) and slow strain rate (SSR) test methods. During CL testing, a calibrated proof ring was used to apply a constant load to the test specimen. The magnitude of the applied stress was based on ambient temperature yield strength of the material. On the contrary, the test specimen during SSR testing was continuously strained in tension …

The Biomechanical Aspects Of Pedestrian Protection, Krishnakanth Aekbote, Peter Schuster, Sunny Kankanala, Srini Sundararajan, Stephen W. Rouhana

Mechanical Engineering

In this paper a biomechanical basis for pedestrian protection is presented based on reviews of epidemiological and biomechanical studies conducted over the last three decades. Epidemiological studies reveal the nature and cause of pedestrian crashes and injuries sustained in the field. The various factors that influence pedestrian crashes and fatalities such as pedestrian demographics, time and location of crash, type of vehicles involved and their design characteristics, impact speeds, and nature and severity of injuries sustained are covered in the epidemiology section. The biomechanical studies identify the injury mechanisms and the biomechanical tolerances. Several biomechanical studies that attempt to identify …