Mechanical Engineering Commons^™

Theoretical And Experimental Analysis And Optimization Of Thermal Conduction In Electrochemical And Latent Heat Energy Storage Systems, Amirhossein Mostafavi

Mechanical and Aerospace Engineering Dissertations - Archive

Phase change materials (PCMs) are used commonly for energy storage purposes. Thermal energy can be stored in a PCM with a variety of configurations such as PCM slabs, cartesian and cylindrical finned systems. Heat transfer in PCM storage systems can be from a heat transfer fluid (HTF) or a heat source at constant temperature to adjacent PCM. The rate of heat transfer is limited by thermal properties. Fin insertion can improve the heat transfer inside the PCM. Chapters 2 and 3 derive and solve the governing energy equations to determine the transient temperature distribution in the PCM due to the …

Rotor Performance Model (Rpm), Chadwick Scott Balfantz

Mechanical and Aerospace Engineering Theses - Archive

Rotorcraft performance modeling is of high interest with multiple industry codes in existence, many of which are high-fidelity and are comprehensive in the analyses that are achievable. Along with the high-fidelity and the comprehensive nature of the industry codes comes an equally high level of complexity in the inputs required to extract meaningful results. The ever-increasing fidelity in the existing codes creates a need for an analysis code that is built to be highly flexible, designed from the top down and implemented from the bottom up in a structured format. The Rotor Performance Model (RPM) was developed to provide high-fidelity …

Object Classication, Detection And State Estimation Using Yolo V3 Deep Neural Network And Sensor Fusion Of Stereo Camera And Lidar, Kamalkumar Bharatkumar Mehta

Mechanical and Aerospace Engineering Theses - Archive

Real-time object classification, localization, and detection with region-based convolution neural network (R-CNN) require high computational power, or it consumes a tremendous amount of time with the use of the available onboard computer system. Therefore, either of those ways is not practical in real-time object detection. In contrast, the YOLO-v3 network, which stands for you only look once, that uses the YOLO algorithm seems to be practical in live object classification, localization, and detection, since the YOLO algorithm seems to work faster than the sliding window algorithm used by R-CNN. Sensor fusion in this context requires estimation and association of information …

Design, Development, And Testing Of Research Payloads On Various Suborbital Flight-Test Platforms, Vijay Vishal Duraisamy

Doctoral Dissertations and Master's Theses

With recent advances in the commercial space industry, suborbital payload launches have become more common and accessible to researchers actively seeking solutions for problems involving prolonged space travel and future missions to Moon and Mars. Suborbital payload missions compared to orbital launches are less expensive and offer faster turnaround times; however, the novelty of this domain provides unique challenges. This multidisciplinary research effort aims to tackle some of these challenges by detailing the design, development, and testing techniques followed in the successful launch and recovery of payload experiments in currently active and upcoming suborbital launch vehicles. The research methodology involves …

Fully Coupled Internal Radiative Heat Transfer For The 3d Material Response Of Heat Shield, Raghava S. C. Davuluri, Rui Fu, Kaveh A. Tagavi, Alexandre Martin

Mechanical Engineering Faculty Publications

The radiative transfer equation (RTE) is strongly coupled to the material response code KATS. A P-1 approximation model of RTE is used to account for radiation heat transfer within the material. First, the verification of the RTE model is performed by comparing the numerical and analytical solutions. Next, the coupling scheme is validated by comparing the temperature profiles of pure conduction and conduction coupled with radiative emission. The validation study is conducted on Marschall et al. cases (radiant heating, arc-jet heating, and space shuttle entry), 3D Block, 2D IsoQ sample, and Stardust Return Capsule. The validation results agree well for …

Fixed Bottom Wind Turbine Wave-Wake Interaction, Ondrej Fercak

Dissertations and Theses

The interest and benefits of offshore wind energy has also brought along legitimate design challenges for engineers. Most notably, the complex interaction between wind and turbine is further complicated by the addition of dynamic ocean waves. This dynamic coupling between wind, wave, and turbine is not fully understood. Even small improvements in wind turbine performance are welcome, so characterizing a fundamental dynamic in offshore energy is necessary to optimize design. Experimentation and simulation have been used to characterize inflow and turbine wakes and separately, wind-wave interactions. But only simulations have just begun to look at the wind, wave, and turbine …

Review: Factors Affecting Composite Laminates Against Lightning Strikes, Aaryan Manoj Nair

Publications and Research

Lightning strike protection (LSP) have recently been a newly developing field particularly with the emergence of graphene thin film integration into carbon fiber composite structures. This technology has a widespread application in airplanes, wind turbines, and other instruments which are susceptible to frequent lightning strikes. Electrical discharge of the instrument in a safe manner is vital for the safety of the passengers (in the case of flights) as well as the integrity of the aircraft structures because of their specific mechanical and structural properties, which are essential for their functioning. The purpose of the study is to fabricate graphene thin …

Analysis Of A Non-Equilibrium Vortex Pair As Aircraft Trailing Vortices, Manuel Ayala

Mechanical & Aerospace Engineering Theses & Dissertations

Shortly after the roll-up evolution of the vortex sheet behind the wings of an aircraft, a coherent counter-rotating vortex pair emerges. Presence of this vortex pair in the downstream of an aircraft, creates unsafe conditions for other aircraft, especially near airport runways. Fundamental knowledge of the physics that govern the formation, duration and dissipation of aircraft wake vortices is desirable in order to improve aircraft operational safety. This study uses non-equilibrium pressure theory to develop an accurate model describing the physical behavior of the vortex pair created by an aircraft in the early to mid-field vortex regime. An isolated aircraft …

Development And Applications Of Adjoint-Based Aerodynamic And Aeroacoustic Multidisciplinary Optimization For Rotorcraft, Ramiz Omur Icke

Mechanical & Aerospace Engineering Theses & Dissertations

Urban Air Mobility (UAM) is one of the most popular proposed solutions for alleviating traffic problems in populated areas. In this context, the proposed types of vehicles mainly consist of rotors and propellers powered by electric motors. However, those rotary-wing components can contribute excessively to noise generation. Therefore, a significant noise concern emerges due to urban air vehicles in or around residential areas. Reducing noise emitted by air vehicles is critically important to improve public acceptance of such vehicles for operations in densely populated areas.

Two main objectives of the present dissertation are: (1) to expand the multidisciplinary optimization to …

The Effect Of Through Thickness Reinforcement On Debonding Behavior Of Skin/Stringer Configuration, Yogaraja Sridhar

Mechanical & Aerospace Engineering Theses & Dissertations

Investigation of this study is to the determine the crack propagation and disbonding in the bonded region of the skin and stringer specimen. An adhesive layer has been used to bond the skin and stringer by using a heat press operation. After the bonding, a drilling method has been adopted to install the through thickness reinforcement in the specimen. The key role of the through thickness reinforcement is to increase the stiffness and strength of the panels and to prevent the crack propagation or disbonding of the panels. The reinforcement was installed in pure (Pristine) samples and in defect samples …

Fluid-Structure Interaction Of Nrel 5-Mw Wind Turbine, Mohamed Sayed Elkady Abd-Elhay

Theses and Dissertations

Wind energy is considered one of the major sources of renewable energy. Nowadays, wind turbine blades could exceed 100 m to maximize the generated power and minimize produced energy cost. Due to the enormous size of the wind turbines, the blades are subjected to failure by aerodynamics loads or instability issues. Also, the gravitational and centrifugal loads affect the wind turbine design because of the huge mass of the blades. Accordingly, wind turbine simulation became efficient in blade design to reduce the cost of its manufacturing. The fluid-structure interaction (FSI) is considered an effective way to study the turbine's behavior …

Bibliometric Analysis On Artificial Compressibility Method Based Cfd Simulations, Bhavna Hemraj Joshi Miss, Chandrakant R. Sonawane Dr, Priyambada Bada Praharaj Mrs, Anand Kumar Pandey Dr

Library Philosophy and Practice (e-journal)

This bibliometric analysis in this paper aims to study the quantitative progress done in the artificial compressibility (AC) method-based CFD simulation and analyze its potential in solving incompressible flow simulations in computational fluid dynamics smoothly. The sector of CFD is enhancing more and more maturely due to advancements in computing architecture, numerical methods, and simulation tools. There have been various attempts to solve the pressure-velocity coupling issue in the Navier-Stokes equation. The artificial compressibility method (ACM), as opposed to pressure-correction methods, solves the incompressible equation in a non-segregated manner. With the introduction of the ACM, the system of the equation …

Nasa Micro-G Next Challenge: Sample Container Dispensing Device, Kristin G. Kraybill-Voth, Kelsey L. Mickelson, Oscar D. Popravka

Mechanical Engineering

This Final Design Review (FDR) report outlines a Cal Poly San Luis Obispo senior design project developing a sample container dispensing device for NASA Johnson Space Center’s Micro-g NExT design challenge, a competition for university students. NASA aims to bring the first woman and next man to the moon through the Artemis missions beginning in 2024. The Micro-g NExT 2021 challenges focus on developing equipment which will support the Artemis mission, where Astronauts will conduct extensive geological sampling to further the scientific understanding of the moon. Our team designed, built, and tested a device that holds sample bags as they …

Toward Cost-Effective Residential Energy Reduction And Community Impacts: A Data-Based Machine Learning Approach, Adel Naji, Badr Al Tarhuni, Jun-Ki Choi, Salahaldin Alshatshati, Seraj Ajena

Mechanical and Aerospace Engineering Faculty Publications

Many U.S. utilities incentivize residential energy reduction through rebates, often in response to state mandates for energy reduction or from a desire to reduce demand to mitigate the need to grow generating assets. The assumption built into incentive programs is that the least efficient residences will be more likely take advantage of the rebates. This, however, is not always the case. The main goal of this study was to determine the potential for prioritized incentivization, i.e., prioritizing incentives that deliver the greatest energy savings per investment through an entire community. It uses a data mining approach that leverages known building …

3-Axis Reaction Wheel System For Cubesats, Alexandra Mae Lee, Daniel Leon, Christopher Pablo Casillas, Rose Mccarver

Mechanical Engineering

Reaction wheels are a common, but expensive, component used in CubeSats, that can accurately position a satellite using an imparted momentum (or impulse) from a rotating flywheel to adjust a satellite’s attitude. This document serves as the final design review and report for the 3-Axis Reaction Wheel Senior Design Project in the Mechanical Engineering Department of California Polytechnic State University, San Luis Obispo. The goal of this project is to produce a functional, low-cost 3-axis reaction wheel system based on previous research done by a master’s student at Cal Poly to be implemented in future CubeSats in the Cal Poly …

Space Suit Attachment Quick Release System, Elyse C. Gillis-Smith, Andres I. Elzaurdia, Cole H. Stanton, Michael T. Roth

Mechanical Engineering

NASA plans to make it back to the Moon by 2024 with their Artemis Program, and stay there for a longer period of time to conduct research which will support the future of space exploration. While on the lunar surface, astronauts need to maximize their efficiency by carrying tools on their Exploration Extravehicular Mobility Unit (xEMU), and to accommodate this need, the Extravehicular Activity (EVA) Tools Team is pursuing a utility belt concept. The objective of this project is to develop a system capable of interfacing between the utility belt and any given tool, while also accommodating numerous restrictions and …

Uav For Medical Equipment Distribution, Richard Barakat, Logan Christensen, Brandon Halebsky, Justin Slavick

Mechanical Engineering

This Final Design Review report documents the senior project participating in the Vertical Flight Society’s 38th Annual Student Design Competition sponsored by The Boeing Company. The goal of this project and competition is to develop an unmanned vertical lift for medical equipment distribution capable of safely delivering a 50 kg payload over distances up to 200 km. This system must be autonomous and have a backup plan to land if any part of the system malfunctions. We discuss the research and justification that drove the selection of the aircraft configuration, a winged quadcopter with a rear propeller. Furthermore, we document …

Prediction Of In-Plane Stiffnesses And Thermomechanical Stresses In Cylindrical Composite Cross-Sections, Bryson M. Chan

Master's Theses

Accurate mechanical analysis of composite structures is necessary for the prediction of laminate behavior. Cylindrical composite tubes are a mainstay in many structural applications. The fundamental design of circular composite cross-sections necessitates the development of a comprehensive composite lamination theory. A new analytical method is developed to characterize the behavior of thin-walled composite cylindrical tubes using a modified plate theory. A generated numerical solver can predict properties such as axial stiffness, bending stiffness, layer stresses, and layer strains in composite tubes subjected to combined mechanical loading and thermal effects. The model accounts for the curvature by transforming and translating the …

Analytical, Numerical, And Computational Methods To Analyze The Time To Empty Open, Closed, And Variable-Topped Inverted Bottles, Callen Schwefler

Master's Theses

Recent unexpected experimental observations of the emptying of inverted bottles with perforations has generated interest in modeling and simulation of this phenomenon. It was observed that as a perforation, i.e., a small hole at the "top" of the inverted bottle, is added and enlarged, the overall emptying time first increases to a maximum value and then decreases until it reaches a lower limit. The change in emptying time is associated with a transition from jetting, where only water exits the neck, to glugging, a competition between air and water flows at the neck of the bottle.

This paper develops analytical …

Electric Field Induced Self-Assembly Of Mesoscale Structured Materials And Smart Fluids, Suchandra Das

Dissertations

This dissertation aims to study the forces that drive self-assembly in binary mixtures of particles suspended in liquids and on fluid-liquid interfaces when they are subjected to a uniform electric or magnetic field. Three fluid-particle systems are investigated experimentally and theoretically : (i) Suspensions of dielectric particles in dielectric liquids; (ii) Suspensions of ferromagnetic and diamagnetic particles in ferrofluids; and (iii) Dielectric particles on dielectric fluid-liquid interfaces. The results of these studies are then used to estimate the parameter values needed to assemble materials with desired mesoscale microstructures.

The first fluid-particle system studied is an electrorheological (ER) fluid formed using …

Energy-Based Orbital Stabilization Of Underactuated Systems Using Impulse Controlled Poincaré Maps, Nilay Kant, Ranjan Mukherjee

Mechanical and Aerospace Engineering Faculty Research & Creative Works

The problem of energy-based orbital stabilization of underactuated mechanical systems with one passive degree-of-freedom is addressed. The orbit is a manifold where the active generalized coordinates are fixed, and the total mechanical energy is equal to some desired value. A hybrid control strategy comprised of continuous and intermittent impulsive inputs is presented. The continuous controller is designed using partial feedback inearization to converge the active generalized coordinates to their desired values. The choice of desired energy characterizes a unique orbit which is stable but not asymptotically stable. To stabilize the desired orbit, a Poincaré section is constructed at a fixed …

Numerical Simulation Of Flow Past An Airfoil With Ice Accretion On Leading Edge, Boyu Wang

McKelvey School of Engineering Graduate Student Theses & Dissertations

The focus of this research is on aerodynamic simulation of flow past NACA 23012 airfoil with clean surface and with ice accretion on its leading edge by using the commercial CFD solver ANSYS Fluent. Reynolds-Averaged Navier-Stokes (RANS) computations are performed using Spalart-Allmaras (SA) and Wray-Agarwal (WA) turbulence models. ANSYS mesh package ICEM is used to model the geometry and generate the mesh. The computations are performed at 0, 2, 4, 6, 8, 10, and 12 degrees angle of attack which are compared with experimental data. For the case of ice accretion at the leading edge, the physical geometry becomes more …

Rehology And Electrical Conductivity Of Particulate Composites In Additive Manufacturing, Bin Xia

Mechanical Engineering Research Theses and Dissertations

Extrusion-based multi-functional additive manufacturing (AM) has been a rapidly developing area in AM recently. Particulate composites are widely used in this area to provide different functionalities with different types of particulate additives. However, there is no systematic understanding of the behavior of particulate composites during extrusion (especially in small nozzles) or of their properties once deposited in the build. This work investigates the properties of the type of particulate composites usually used in additive manufacturing, composed of a polymer matrix material and particulate additives within the micrometer scale. The focus is on the material rheology in the nozzle/capillary (for the …

Real-Time Material State Assessment Of Composites Using Artificial Intelligence And Its Challenges, Muthu Ram Prabhu Elenchezhian

Mechanical and Aerospace Engineering Dissertations - Archive

Over several decades of careful experimental investigation and exhaustive development of discrete damage analysis methods including integrated computational mechanics methods, our community knows a great deal about how discrete defects such as matrix cracks and defect growth (e.g. delamination) can be predicted in structural composites. For many practical situations controlled by laminated multiaxial composite structures, the loss of performance and “sudden death” end of life is controlled by defect coupling which becomes a precursor to fracture plane development. These interaction sequences are highly dependent on local details of manufacture, design configurations, and loading for a given application material and influenced …

Cooling Efficiency Improvement Of A Data Center Using Optimized Cabinet Design And Hybrid Cooling With High Inlet Conditions Of Single-Phase Coolant And Air, Uschas Chowdhury

Mechanical and Aerospace Engineering Dissertations - Archive

The objective of this study is to improve and optimize the cooling efficiency of liquid and air cooling from server to room level while applying best practices in the industry. The effect of increased air and coolant temperature has been explored through a literature survey and studies are conducted from device level to room level for air and liquid cooling. Three major aspects are considered. A closed-form air cooling solution is proposed for high-powered racks in a modular data center equipped with in-row coolers. Direct-to-chip liquid cooling technology is extensively studied at the server level for raised air and coolant …

Impact Of Material Models On Immersion Cooled Electronics Packages And Reliability Assessment For Chip-Package Interaction, Tushar Jashvantbhai Chauhan

Mechanical and Aerospace Engineering Dissertations - Archive

The immersion cooling for IT equipment has been around for decades. From thermal energy management perspective, immersion cooling is better than traditional cooling technology. However, there is need for more work in open literature when it comes to impact of immersion cooling on the reliability of IT equipment to make it commercially implemented. Detailed study of material compatibility of the various electronics packaging materials for immersion cooling is essential to understand their failure modes and reliability. The stiffness and thermal expansion are critical material properties for electronics mechanical design. This part of the study mainly focuses on two things. The …

Development Of A Test Method For Characterizing An Indirect Evaporative Cooling Module For Data Center Cooling Application, Abhijit Rajendra Bhosale

Mechanical and Aerospace Engineering Theses - Archive

Evaporative cooling is a smarter way of maintaining optimum operating conditions in data centers. Indirect Evaporative Cooling (IEC) provides the advantage of cooling without changing the humidity of the Data Center (DC) air. We analyze and develop a method of testing to help build IEC modules at larger scales with improved characterization that is intended to help DC engineers achieve stringent Power Utilization Efficiency (PUE) targets by expending minimum power. We study the design parameters pertinent to sizing an IEC module used in DC cooling and develop a test method while technically selecting the components involved. The module is planned …

Sensitivity Study Of Calibrated Data Center Models To Minimize Site Survey Time Using Cfd, Saurabh Singh

Mechanical and Aerospace Engineering Theses - Archive

Data center (DC) consists of components like cooling pipes, data cables, power conduits, etc. To analyze the thermal behavior of DC using computational fluid dynamics, virtual model of DC is required. To build this virtual model, data is required regarding the different components like size, location and defining parameters. Site surveys are required to collect this data. Data collection is important to build an accurate model. There is lack of guidance with respect to which components are crucial to achieve level of accuracy in computational model. Sensitivity study can be used to determine accuracy achieved by introducing simplification in component …

Effectiveness Of Closed-Loop Inverse-Kinematic Landmark Navigation Method On Drifting And Heading Errors Of Imprecise Multi-Legged Robots, Thong Quang Nguyen

Mechanical and Aerospace Engineering Theses - Archive

This work addresses the effectiveness of a closed-loop inverse-kinematic control methodology on alleviating drifting and heading errors in the walking and turning of a hexapod robot. Most work in this area focuses on stability, hardware design, and control. This work is aimed at controlling imprecise hardware on unknown structured environments. The proposed controller uses a camera and an ultrasonic sensor as sensory feedback. It also uses the well-known tripod gait for locomotion, implemented with the closed-loop inverse-kinematic method. Experimental results show the effectiveness of this approach in walking and turning the hexapod on an unknown surface.

Thermal Design Analysis Of Server Chassis Manifolds For Liquid Cooled Servers Using Cfd, Kaustubh Kantilal Adsul

Mechanical and Aerospace Engineering Theses - Archive

Direct-to-chip liquid cooling is one of the most popular methods in data center thermal management when it comes to cooling high chip power densities. A cold plate-based liquid cooling system contains various components such as pumps, data center room, and rack-level manifolds, and server chassis-level manifold. Efficient coolant distribution to the heat-dissipating cold plates plays an important role in both the thermal and hydraulic performance of the server. It is, thus, very important to design and manufacture server chassis manifold geometry that can perform efficiently under the anticipated heat loads and coolant flow rates. In the present thesis, two such …