Fabrication And Characterization Of Low-Density Polymeric Materials With 3d Microstructures,
2015
University of Texas at Arlington
Fabrication And Characterization Of Low-Density Polymeric Materials With 3d Microstructures, Hakan Arslan
Mechanical and Aerospace Engineering Theses - Archive
Low-density polymeric materials with octet-truss and quad-truss 3D microstructures were studied. The materials with 3D microstructures were created using digital light processing technology with polyethylene glycol (PEG). The mechanical properties of the materials with different relative densities were characterized in air and water. The experimental results were also compared and analyzed with the results from simulation studies. This work reveals that the material with octet-truss microstructures stand at least three times higher deformation than the materials with quad-truss microstructures. The polymeric material with internal 3D microstructures also shows a higher water absorption rate than the same material without internal microstructures.
Non Thermal Reliability Considerations For Oil Cooled Data Centers And Its Serviceability,
2015
University of Texas at Arlington
Non Thermal Reliability Considerations For Oil Cooled Data Centers And Its Serviceability, Sahithi Reddy Nagilla
Mechanical and Aerospace Engineering Theses - Archive
The interest in Oil immersion cooling is increasing day by day which can be attributed to the recent research that shows the potential of its performance when compared to other techniques that add a little more expenses to the organization. Even though the performance of oil immersion cooling has its own capabilities and advantages, this technique is not widely adopted and there is limited published information regarding the important aspects of the design of the system. This paper presents the non-thermal aspects of oil immersion cooling and explains the chemistry of mineral oil and the factors that affect its performance. …
Quantitative Evaluation Of A Thrust Vector Controlled Transport At The Conceptual Design Phase,
2015
University of Texas at Arlington
Quantitative Evaluation Of A Thrust Vector Controlled Transport At The Conceptual Design Phase, Vincent Patrick Ricketts
Mechanical and Aerospace Engineering Theses - Archive
The impetus to innovate, to push the bounds and break the molds of evolutionary design trends, often comes from competition but sometimes requires catalytic political legislature. For this research endeavor, the ‘catalyzing legislation’ comes in response to the rise in cost of fossil fuels and the request put forth by NASA on aircraft manufacturers to show reduced aircraft fuel consumption of +60% within 30 years. This necessitates that novel technologies be considered to achieve these values of improved performance. One such technology is thrust vector control (TVC). The beneficial characteristic of thrust vector control technology applied to the traditional tail-aft …
Thermal Analysis Of Disk Brake In Order To Study The Brake Fluid Vaporization Phenomenon Of A Formula Sae Car,
2015
University of Texas at Arlington
Thermal Analysis Of Disk Brake In Order To Study The Brake Fluid Vaporization Phenomenon Of A Formula Sae Car, Anurag Dey
Mechanical and Aerospace Engineering Theses - Archive
The brake system is inarguable one of the most critical aspect of a vehicle safety. It has always been the major concern for design engineers to develop a system that gives a steady performance with respect to time. In order to achieve that feat, one of the most common problems that arises in maintaining a brake is the problem of brake fluid vaporization. Brake fluids, being hygroscopic in nature, absorb moisture over a period of time. It is one of the prime reasons for reducing the longevity of brake fluid volume inside the brake caliper as the boiling point of …
Automatic Carrier Landing System For V/Stol Aircraft Using L1 Adaptive And Optimal Control,
2015
University of Texas at Arlington
Automatic Carrier Landing System For V/Stol Aircraft Using L1 Adaptive And Optimal Control, Shashank Hariharapura Ramesh
Mechanical and Aerospace Engineering Theses - Archive
This thesis presents a framework for developing automatic carrier landing systems for aircraft with vertical or short take-off and landing capability using two different control strategies - gain-scheduled linear optimal control, and L1 adaptive control. The carrier landing sequence of V/STOL aircraft involves large variations in dynamic pressure and aerodynamic coefficients arising because of the transition from aerodynamic-supported to jet-borne flight, descent to the touchdown altitude, and turns performed to align with the runway. Consequently, the dynamics of the aircraft exhibit a highly non-linear dynamical behavior with variations in flight conditions prior to touchdown. Therefore, the implication is the need …
The Effect Of Temperature And Relative Humidity On The Corrosion Rates Of Copper And Silver In Electronic Equipment In The Presence Of Sulfur Environment,
2015
University of Texas at Arlington
The Effect Of Temperature And Relative Humidity On The Corrosion Rates Of Copper And Silver In Electronic Equipment In The Presence Of Sulfur Environment, Kanan Pujara
Mechanical and Aerospace Engineering Theses - Archive
Data center consume a significant amount of energy for the continuous air-conditioning of the servers with high internal heat loads and to maintain the indoor temperatures within recommended operating levels as recommended by ASHRAE. As an alternate source to air-conditioning, air-side economizers are used to reduce power consumption. However, there is a reluctance in using this technique due to undetermined equipment reliability by introducing outside air pollutants which over time could cause failures. There is a need to know the degree of reliability degradation when the equipment is operated, outside the recommended range, in the allowable temperature-humidity range in geographies …
Additive Manufacturing And Stress Analysis Of Naturally And Artificially Optimized Celullar Structures,
2015
University of Texas at Arlington
Additive Manufacturing And Stress Analysis Of Naturally And Artificially Optimized Celullar Structures, Sachin Jose
Mechanical and Aerospace Engineering Theses - Archive
The main objective of our research is to manufacture topology optimized cellular structures using 3D printing and polymer infusion and obtain their structural response. First, we have obtained topology optimized cellular structure of beam using an in-house topology optimization tool. The Solid Isotropic material with Penalization (SIMP) method of optimization is used for finding the optimal topology. Since we require a continuous structure where we can take advantage of additive manufacturing, a no-penalty approach was chosen. For 3D printing, first the optimized condition for manufacturing was determined. Important parameters on which manufacturing depend are Number of Shells, Infill percentage and …
Experimental Analysis Validating A Control Scheme To Develop A Dynamic Cooling Solution For Non-Uniform High Powered Electronic Devices In Data Center,
2015
University of Texas at Arlington
Experimental Analysis Validating A Control Scheme To Develop A Dynamic Cooling Solution For Non-Uniform High Powered Electronic Devices In Data Center, Ruturaj Kiran Kokate
Mechanical and Aerospace Engineering Theses - Archive
The trend towards higher heat fluxes and non-uniform power distribution continues as we follow Moore’s law with technology nodes now approaching 10nm. Cooling is always designed for maximum junction temperature and as such it is important to mitigate hot spots. All cold plates have a static design by nature and do not possess the capability to respond to non-uniform heat dissipation. The unique “dynamic cold plate” concept aims to improving on conventional static designs through implementation of sensing and control, by redistributing the liquid across its body to counter varying power dissipation across the device being cooled.
Smart Bed And Contact Impact Of Flexible Bodies Using Energy Compensation Method,
2015
University of Texas at Arlington
Smart Bed And Contact Impact Of Flexible Bodies Using Energy Compensation Method, Pranav Parikh
Mechanical and Aerospace Engineering Theses - Archive
This work investigates robotic means to prevent pressure ulcers in human bodies. The smart bed is intended to act as an intelligent assistant to a care-giver that relieves some of the physical and mental burden involved in preventing pressure ulcers. This type of device is needed because of a labor shortage in the nursing field. The smart bed distinguishes itself from the current available measures by redistributing pressure and minimizing shear forces acting on the skin in contact. This is done by using data from the sensor grid installed on the bed surface and actuating the degrees of freedom associated …
Cfd Modeling And Parametric Study Of Vapor Chamber As Heat Spreaders For High-Power Electronic Devices,
2015
University of Texas at Arlington
Cfd Modeling And Parametric Study Of Vapor Chamber As Heat Spreaders For High-Power Electronic Devices, Dhanraj Arun Patil
Mechanical and Aerospace Engineering Theses - Archive
Technological developments have resulted in a growing demand for high power electronic devices. Although these high power devices meet the high performance requirements, they also generate a very large amount of heat which adversely affects their operating efficiency. Most part of the heat within a package is generated at the chip and hence it is imperative to keep junction temperature as low as possible. This is commonly achieved by using heat sinks mounted directly on top of the package. Heat sinks provide a significant enhancement in cooling by increasing the surface area. However, base thickness of heat sinks limits its …
The Effect Of Material Strain Hardening On The Buckling Strength Of A Perforated Plate Under Uniaxial Loading,
2015
University of Texas at Arlington
The Effect Of Material Strain Hardening On The Buckling Strength Of A Perforated Plate Under Uniaxial Loading, Mayuri Suresh Patil
Mechanical and Aerospace Engineering Theses - Archive
Plates or members containing plate elements have been used in the offshore, aerospace and construction industry. Cutouts are often located to lighten the weight of the structure, but these cutouts reduce the ultimate strength of the plate. A number of studies have taken place for determining the buckling strength of a perforated plated but few discuss the effect of material strain hardening on the buckling strength of a perforated plate. Buckling strength is often considered as an important criterial to determine the serviceable limit of the perforated plate in the offshore structure. The aim of the present study is to …
Estimation Of Fracture Mechanics Parameters In 3d Tsv Package During Chip Attachment Process,
2015
University of Texas at Arlington
Estimation Of Fracture Mechanics Parameters In 3d Tsv Package During Chip Attachment Process, Mohammed Shahid Ali
Mechanical and Aerospace Engineering Theses - Archive
Nowadays, the packaging of electronic products is becoming revolutionized, since the packages are becoming more and more complex, dense, thinner and lighter for greater portability. Miniaturization of packages is being taken to the next level, and hence, 3D packaging has become a hot topic in the present research area. Three dimensional chips stacking with TSV technology has gained momentum to meet such requirements of significant miniaturization and power reduction which result in increased performance. However, the unique issues related to yield and reliability of critical areas in TSV based 3D ICs need to be evaluated. Therefore, Reliability of such electronic …
Cfd Based Design And Modelling Of Wind Fence To Mitigate High-Speed Wind Loading On A Modular Data Center,
2015
University of Texas at Arlington
Cfd Based Design And Modelling Of Wind Fence To Mitigate High-Speed Wind Loading On A Modular Data Center, Devi Prasad Gorrepati
Mechanical and Aerospace Engineering Theses - Archive
A Modular Data Center (MDC) is a portable method of deploying a data center’s capacity. As an alternative to the traditional data center, an MDC can be placed anywhere data capacity is required. But this comes at the cost of making the MDC operable at any desired location with the environmental factors such as earthquakes and heavy winds. This study focuses on mitigating high-speed wind loading on the MDCs by designing a wind fence to reduce wind speed. Although wind fences are used in many agricultural and farming practices, their usage pertaining to MDCs is very limited. The challenge is …
Enhancement Of Fog-Collection Efficiency Of A Raschel Mesh Using Surface Coatings And Geometric Changes,
2015
University of Texas at Arlington
Enhancement Of Fog-Collection Efficiency Of A Raschel Mesh Using Surface Coatings And Geometric Changes, Mithun Rajaram
Mechanical and Aerospace Engineering Theses - Archive
In a few countries, such as Chile, a Raschel mesh is widely used in the field to collect fog. In this work, we explored the possibility of enhancing fog-collection efficiency of a typical Raschel mesh through surface modification and geometric changes. We demonstrated about 100% enhancement in the fog-collection efficiency.
Tbi Induced Rate Dependent Viscoelastic Response Of Axon: Predictions From A Mathematical Model,
2015
University of Texas at Arlington
Tbi Induced Rate Dependent Viscoelastic Response Of Axon: Predictions From A Mathematical Model, Manikanta Jonnalagadda
Mechanical and Aerospace Engineering Theses - Archive
Traumatic brain injury (TBI) accounts to almost one fifth of total fatal injuries. Even though there are various mechanisms hypothesized for the causes leading to TBI, diffuse axonal injury (DAI) is found to be the most observed criterion. The reason for axonal failure in DAI has been studied extensively using experimental and computational models. It was found that axons behave like viscoelastic materials, thus exhibiting rate dependent behavior under loading. This viscoelastic behavior of axons is believed to drive the failure of axons and its substructures. It was observed that axon failure is caused by failures and distortions in axonal …
The Relationship Of Life Prediction For Quad Flat N0-Lead Package (Qfn )Packages Using 4 Point Bend Test And Thermal Cycle Testing,
2015
University of Texas at Arlington
The Relationship Of Life Prediction For Quad Flat N0-Lead Package (Qfn )Packages Using 4 Point Bend Test And Thermal Cycle Testing, Monisha Mohan
Mechanical and Aerospace Engineering Theses - Archive
In the structural design of the Printed Circuit Boards, the stiffness modulus of the involved Fr4 and Cu layers play an important role. The 4 point bend test is one of the few test methods which is included in the JEDEC standard for the Monotonic Bend characterization for board level interconnects. The study in the past has shown that the damage mechanism of these two testing methods is similar. And also, correlation had been drawn by observation of failure mechanism through Scanning Electron Microscope (SEM). The purpose of this study is to create a methodology for co-relating 4 point bend …
Parametric Study Of An Igbt Cold Plate And Affect Of Device Level Modelling On System Level Thermal Predictions,
2015
University of Texas at Arlington
Parametric Study Of An Igbt Cold Plate And Affect Of Device Level Modelling On System Level Thermal Predictions, Abhishek Raj Urs Kadaba Nagaraja Urs
Mechanical and Aerospace Engineering Theses - Archive
In power electronics, as there is continuous increase in performance of the electronic devices, simultaneously the size of the components used in these devices keep on decreasing. This has resulted in increased power densities and the requirements for excellent cooling as well in order to avoid the failure of those devices. Traditionally, while designing a cooling system for a device, uniform heat flux is assumed throughout the components. In many cases this method may not be accurate for a particular model design. There are chances that the heat flux distribution around the components are non-uniform and requires a more accurate …
Additive Manufacturing Methodologies For Multi Process And Multi Material Scenarios,
2015
University of Texas at Arlington
Additive Manufacturing Methodologies For Multi Process And Multi Material Scenarios, Tushar Saini
Mechanical and Aerospace Engineering Theses - Archive
Additive Manufacturing processes have been developing and continuously improving but are primarily constrained to single materials, albeit some commercial multi extrusion 3D printers do exist where by it is possible to print with multi-colored fluidic polymers or at most two filaments of the same type. 3D printing an object with volumetric varying properties requires manual modification of the G-Code, not a feasible option considering the average size of G-Code generated by the slicing software. This research focuses on developing a post processing methodology that modifies the large G-Code files generated by the slicing software according to user requirements. The proposed …
Board Level Flexural Reliability Testing And Failure Analysis Of Printed Circuit Boards With Wcsp Packages,
2015
University of Texas at Arlington
Board Level Flexural Reliability Testing And Failure Analysis Of Printed Circuit Boards With Wcsp Packages, Guruprasad Shrikant Shinde
Mechanical and Aerospace Engineering Theses - Archive
Printed circuit boards, widely known as PCBs; are the skeleton behind every technology today. Electronics have integrated with every other engineering domain to improve the outcomes. It is very important that they remain intact in slightly extreme physical conditions. They are used in wide range applications which may lead to mechanical stress-strain in some conditions. There are various boards with different kinds of packages on them. A 0.7mm thick board with WCSP; Wafer chip scale package is a prime specimen for my work. The research includes designing exact replica of given PCB into ANSYS and its reliability testing. A 3-point …
Evaluating And Augmenting Fuel-Saving Benefits Obtained In Aircraft Formation Flight,
2015
University of Texas at Arlington
Evaluating And Augmenting Fuel-Saving Benefits Obtained In Aircraft Formation Flight, Wendy Awele Okolo
Mechanical and Aerospace Engineering Dissertations - Archive
When an aircraft flies, it generates wake vortices, which induce a non-uniform wind distribution in its wake. A trail aircraft, placed in the wake of a lead's aircraft vortices experiences this non-uniform wind distribution with varying directions and magnitudes, depending on the location within the wake. It has been demonstrated that there is a "sweet spot" within the wake of a leader in which a trail can experience upwash which leads to reduced drag. Through this mechanism, aircraft can save significant amounts of fuel by flying at the sweet spot of the lead aircraft's wake. This dissertation provides two metrics …
