Mechanical Engineering Commons^™

Onboard Payload Mass Estimation And Electric Propulsion Modeling For Multicopters With Application In Unmanned Aerial Systems, Abel Martinez Martinez Martinez

Mechanical and Aerospace Engineering Theses - Archive

Unmanned vehicles are the future. The aim of the future online retailers, delivery and transportation companies would be air delivery using unmanned aerial vehicles. Multicopters are becoming rapidly famous because they o er a relatively easy-to-fly platform that is also very stable, and their mechanical simplicity. The possibility of estimating the weight of the multicopter in real time is really useful. A weight estimation system that could be implemented in multicopters with cable suspended payloads without using any extra sensors is presented in this thesis. The weight estimation system uses a functional relationship that correlates Pulse Position Modulation (PPM) signal …

Experimental Analysis For Optimization Of Thermal Performance Of A Server In Single Phase Immersion Cooling, Pravin Ashok Shinde

Mechanical and Aerospace Engineering Theses - Archive

Liquid immersion cooling of servers in synthetic dielectric fluids is an emerging technology which offers significant cooling energy saving and increased power densities for data centers. A noteworthy advantage of using immersion cooling is high heat dissipation capacity which is roughly 1200 times greater than air. Other advantages of dielectric fluid immersion cooling include high rack density, better server performance, even temperature profile, reduction in noise. The enhanced thermal properties of oil lead to the considerable saving of both upfront and operating cost over traditional methods. In this study, a server is completely submerged in a synthetic dielectric fluid. Experiments …

Onboard Payload Mass Estimation And Electric Propulsion Modeling For Multicopters With Application In Unmanned Aerial Systems, Abel Martinez Martinez

Mechanical and Aerospace Engineering Theses - Archive

Unmanned vehicles are the future. The aim of the future online retailers, delivery and transportation companies would be air delivery using unmanned aerial vehicles. Multicopters are becoming rapidly famous because they o er a relatively easy-to-fly platform that is also very stable, and their mechanical simplicity. The possibility of estimating the weight of the multicopter in real time is really useful. A weight estimation system that could be implemented in multicopters with cable suspended payloads without using any extra sensors is presented in this thesis. The weight estimation system uses a functional relationship that correlates Pulse Position Modulation (PPM) signal …

Computational Analysis For Thermal Optimization Of Server For Single - Phase Immersion Cooling, Dhruvkumar Vimalkumar Gandhi

Mechanical and Aerospace Engineering Theses - Archive

Complete immersion of servers in synthetic dielectric fluids is rapidly becoming a popular technique to minimize the energy consumed by data centers for cooling purposes. In general, immersion cooling offers noteworthy advantages over conventional air-cooling methods as synthetic dielectric fluids have high heat dissipation capacities which are roughly about 1200 times greater than air. Other advantages of dielectric fluid immersion cooling include even temperature profile on chips, reduction in noise and addressing reliability and operational enhancements like whisker formation and electro-chemical migration. Nevertheless, lack of data published and availability of long-term reliability data on immersion cooling is insufficient which makes …

Electroextraction Across Droplet-Droplet Interface, Subhadeep Chakraborti

Mechanical and Aerospace Engineering Theses - Archive

Extraction of analytes from solvents is a crucial part of many medical, clinical, industrial and refinery processes. It is required for preconcentration of analytes into other solvents, purification of solvents and detection of harmful or toxic molecules. One of the very important methods of extraction in microfluidics is liquid-liquid extraction (LLE). LLE involves the use of two immiscible liquids for diffusion of analytes across the interface. Recently there has been a growing interest in the coupling of external electric field with LLE to enhance the extraction of charged analytes. This has led to the birth of a new extraction method …

Effect Of Dielectric Inter-Layer In Performance Of The Multi-Functional Material In Mechanical, Thermal And Environmental Loading Conditions, Rauhon Ahmed Shaik

Mechanical and Aerospace Engineering Theses - Archive

The demand for Electrical power storage devices for space shuttle, aircraft, car, bus and marine vehicles increased a great deal to have a greener and safer world. Decades of research has been done on development of light weight and high-performance energy storage devices such as batteries and structural capacitors. The use of structural capacitors can solve the high-performance energy storage requirement with no dead weight and also gives a strong structure. However, these heterogeneous materials experience different thermal expansions across the dielectric and electrodes inter layers due to which the energy storage capacity and mechanical performance evolve over time. Hence, …

Methodology To Develop Artificial Neural Network Based Control Strategies For Multiple Air-Cooling Units In A Raised Floor Data Center, Vibin Shalom Simon

Mechanical and Aerospace Engineering Theses - Archive

A data center consists of a hierarchy of systems with dedicated control algorithms dictating their operational states. We could say, there exists an ensemble of dynamical systems, each executing a control task, while the global objective is to drive the overall system to an optimum i.e. minimum total operational power at desired rack inlet temperatures. The dynamics of the Information Technology Equipment (ITE) workload and the cooling provisioning is non-linear in spatial and temporal parameter space. Data-driven modelling is one method to realistically model such non-linear dynamics and make predictions that are necessary for improved control design of the cooling …

Numerical And Experimental Study On Turbulence Production Of A Selected Mode Of Streamwise Vortex Interaction In Supersonic Flow, Davide Viganó

Mechanical and Aerospace Engineering Dissertations - Archive

The development of effective mixing strategies of air/fuel mixtures in supersonic flows has been the subject of a significant body of research for the last 60 years due to the hindering effects of compressibility. Particular attention has been focused on the introduction of streamwise vortices as a way to enhance molecular mixing both in terms of added source for hydrodynamic instabilities on classical shear-layer flows as well as for transverse jet configurations, aero-ramps and hypermixers. However, a large portion of fundamental knowledge for these complex flows is still missing. This work is centered on a numerical and experimental study of …

Characterization Of 3d Printed Pla With The Help Of Mechanical, Di-Electric And X-Ray Diffraction Techniques, Sai Sri Nidhi Munaganuru

Mechanical and Aerospace Engineering Theses - Archive

Additive manufacturing (AM) revolutionized many industries, i.e., Automotive, Biomedical, Aerospace and Defense. As opposed to traditional manufacturing methods, a part is manufactured layer by layer from 3D CAD models in AM. Though the vision of AM is impressive, there are many challenges that are hindering the widespread use of these complex parts. One of the main challenges is its strength that varies with different manufacturing parameters. We are going to investigate the effect of build parameters on the mechanical, electrical and crystalline properties of the additively manufactured heterogeneous material system. The goal of the thesis is to find a correlation …

Probabilistic Risk Assessment And The Path Planning Of Safe Task-Aware Autonomous Resilient Systems (Staars), Uluhan Cem Kaya

Mechanical and Aerospace Engineering Theses - Archive

Recent advancements on the unmanned systems manifest the potential of these technologies to impact our daily life. In particular, the unmanned aircraft systems (UAS) become ordinary for people in almost any area from aerial photography to emergency responses, from agricultural services to even autonomous deliveries. Increased autonomy and advancements in low-cost high-computing technologies made these compact autonomous solutions accessible to any party with ease. Easiness and affordability to access these systems accelerated the innovations and the novel ideas for the solution of diverse real-life problems. Despite its benefits, however, this widespread availability also resulted in the safety and regulatory concerns …

Simulation Modelling Of Thermal Runaway Propagation In Li Ion Batteries, Dhananjay Mishra

Mechanical and Aerospace Engineering Theses - Archive

Li Ion batteries are highly engineered systems which have become part and parcel of our daily lives. Safety of these systems has been in jeopardy ever since they were created. Mechanical abuse, shot circuit, overcharging or unfavorable working conditions can lead to catastrophic repercussions which might destroy complete battery pack. Previous works have investigated this problem, but many important aspects of design characteristics were left folded. This work not only investigates behavior of a single cell under adverse conditions but also lays emphasis on important factors such as thermal conductivity of the medium and cell gaps in a pack of …

Thermal Destratification Of Air Streams To Improve The Cooling Provisioning Of Air-Cooled Data Centers, Anto Joseph Barigala Charles Paulraj

Mechanical and Aerospace Engineering Theses - Archive

Air side economization is an arrangement of duct, damper and automatic control system which together allow introducing outside air to reduce the mechanical cooling during mild or cold weather thereby decrease the energy consumption. The outside ambient air and heated return air from the information technology (IT) pod is mixed inside a dedicated space to achieve a target cold aisle operating temperature and thereby increase economization. Major constrain faced by the design engineers while designing the Mixing Chamber/ Plenum is the stratification of air stream due to the Temperature gradient in the mixed air stream and this stratification can be …

Vibration Reduction Of Mistuned Bladed Disks Via Piezoelectric-Based Resonance Frequency Detuning, Garrett Lopp

Electronic Theses and Dissertations

Recent trends in turbomachinery blade technology have led to increased use of monolithically constructed bladed disks (blisks). Although offering a wealth of performance benefits, this construction removes the blade-attachment interface present in the conventional design, thus unintentionally removing a source of friction-based damping needed to counteract large vibrations during resonance passages. This issue is further exacerbated in the presence of blade mistuning that arises from small imperfections from otherwise identical blades and are unavoidable as they originate from manufacturing tolerances and operational wear over the lifespan of the engine. Mistuning is known to induce vibration localization with large vibration amplitudes …

Lithium Molybdate-Sulfur Battery., Ruchira Ravinath Dharmasena

Electronic Theses and Dissertations

Rechargeable energy storage systems play a vital role in today’s automobile industry with the emergence of electric vehicles (EVs). In order to meet the targets set by the department of energy (DOE), there is an immediate need of new battery chemistries with higher energy density than the current Li- ion technology. Lithium–sulfur (Li–S) batteries have attracted enormous attention in the energy-storage, due to their high specific energy density of 2600 Wh kg^-1 and operational voltage of 2.0 V. Despite the promising electrochemical characteristics, Li-S batteries suffer from serious technical challenges such as dissolution of polysulfides Li₂S_{x …}

A Comparison Of Discrete Damage Modeling Methods: The Effect Of Stacking Sequence On Progressive Failure Of The Skin Laminate In A Composite Pi-Joint Subject To Pull-Off Load, Joseph Keith Novak

Mechanical and Aerospace Engineering Theses - Archive

Discrete damage modeling of composite failure mechanisms including delamination, matrix cracking, and their interactions was performed for the skin laminate in a composite pi-joint test specimen subject to a pull-off load. The skin laminate stacking sequence was varied, and the pull-off load and path of predicted damage were recorded. Within the study two discrete damage modeling tools were used, Abaqus XFEM with a LaRC05 built-in user subroutine and BSAM. Both tools implement failure criteria developed at the NASA Langley Research Center (LaRC) to predict the location of damage initiation and both tools use similar cohesive zone models to model damage …

Duocel Metal Foam Display Cases, Kate Goldsworthy, Katherina Prodanov, Benjamin Swanson, Syed Hasan

Mechanical Engineering

This Final Design Review (FDR) report outlines the senior design project that was conducted by a team of four mechanical engineering students at California Polytechnic State University-San Luis Obispo for ERG Materials and Aerospace Corporation. The goal of this project was to design displays that showcase the properties of ERG’s Duocel® foam at tradeshows and client meetings. To better understand the needs of our sponsor, the team researched Duocel®’s capabilities, related technologies, and relevant standards and regulations. With this information, we further defined the problem by creating a problem statement and a set of engineering specifications through a Quality Function …

Insulated Solar Electric Cooker With Phase Change Thermal Storage Medium, Justin Brett Unger, Nathan Robert Christler, Matthew Weeman, Marcus Edward Strutz

Mechanical Engineering

This final design review document outlines the senior design project carried out by a team of four mechanical engineering students at the California Polytechnic State University – San Luis Obispo under the sponsorship of Dr. Peter Schwartz of the Cal Poly Physics department. The aim of this project was to improve upon the design of previously developed Insulated Solar Electric Cookers (ISECs) by adding a thermal storage system to allow for quicker cook times and the ability to cook food at non-peak solar hours. The team’s goal was to develop a working prototype utilizing a phase change medium as the …

Framed Human Powered Vehicle Frame, Keyanna Brielle Henderson, Brendon Howard Morey, Kyra Noelle Schmidt, Austin Patrick Henry

Mechanical Engineering

The following is the Final Design Review (FDR) Report for Framed, a team tasked with designing and fabricating the frame of the 2018-2019 Cal Poly Human Powered Vehicle (HPV) Club bike. The bike is to be raced at the 2019 World Human Powered Speed Challenge in Battle Mountain, Nevada with the goal of breaking the American collegiate speed record. The purpose of the FDR Report is to introduce the project’s background and objectives, discuss the final design, and present the results of manufacturing and testing. Prior to beginning work on the design of the frame, the group conducted extensive research …

Vaccine Cooler For The Global Poor, Benjamin J. Larson, Cooper E. Gibson, Eilbron Younan, Cody R. Volk

Mechanical Engineering

Cal Poly physics professors Peter Schwartz and Nathan Heston approached the Solar Freeze team with the problem that remote communities in Africa have limited access to modern-day medicine or vaccines. They suggested that we try and design a cooling device that can keep vaccines cold for multiple days at a time while the medicine is transported to remote villages. Currently, there are vaccine cooler products on the market, but most of them are very expensive or lack portability. Peter and Nate have tasked the Solar Freeze team to come up with a less expensive solution that is also portable and …

Solar Tracking Using A Parallel Manipulator Mechanism To Achieve Two-Axis Position Tracking, Joseph Otto Hubach

Graduate Theses - Mechanical Engineering

A novel solar tracker is presented that uses a parallel manipulator for the tracking mechanism instead of a traditional serial manipulator. The motivation is to create a solar tracker that displays the advantages of two-axis tracking systems (e.g., increased exposure to incident radiation, and enabling the use of efficient concentrating solar cells) while addressing some of the disadvantages of current two-axis tracking systems (e.g., the difficulties associated with having actuators mounted to moving elements within the mechanism). The mobility of the proposed parallel manipulator is examined using Grübler’s Criterion to establish that the manipulator displays the required two degrees of …

Micromechanics-Enriched Finite Element Modeling Of Composites With Manufacturing Or Service-Induced Defects, Alden S. Hyde

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Composite materials are increasingly used in many industries due to the high strength and low weight properties that they exhibit. Since composites are becoming more popular, they are being used in applications such as aircraft, boats, wind turbine blades, and even sports equipment. Composite behavior is complicated since they are made up of two completely different materials such as strong thin fibers and a relatively weaker resin material that hold the fibers together. It is becoming more important to understand how composites behave in different situations so that equipment designers have reliable material information in order to design safe products …

Analysis And Proposed Improvement Of Hamilton County Vw Elab Equipment, Hiroshi Yanagida

Honors Theses

Digital fabrication laboratories have revolutionized project based learning within K-12 STEAM education curriculum. However, classroom utilization of the labs often requires excessive machine hours to accomplish, and this often leads to rapid machine depreciation and disrepair. Many educators do not have the time to repair their equipment while developing curriculum and engaging with their students. This study focuses on building a repair history for common digital fabrication equipment, which includes Prusa i3 Mk2S FDM 3D printers, laser cutters, and CNC routers. Data were collected over a 6 month period to find which machines encountered the most issues. The 3D printers …

Development Of A Multi-Probe Kelvin Scanner Device For Industrially-Relevant Characterization Of Surface-Activated Carbon Fiber Reinforced Thermoplastic Composites, Kirby Simon

McKelvey School of Engineering Graduate Student Theses & Dissertations

Carbon fiber reinforced thermoplastic (CFRTP) composites are becoming increasingly attractive materials in manufacturing due to their lightweight nature, mechanical strength, and corrosion resistance. Surface activation of these materials is usually required during processing to increase the bond strength of assemblies (aerospace and automotive industries) or improve adhesion with implants (biomedical industry). Industrially-relevant, nondestructive quality control methods for assessing the activation state of these materials do not currently exist, however. Applying principles discovered through the use of scanning probe microscopy, a multiple-probe Kelvin scanning (MPKS) device has been developed that can assess the uniformity of the activation state of plasma-treated CFRTP …

Stability Analysis Of A More General Class Of Systems With Delay-Dependent Coefficients, Chi Jin, Keqin Gu, Islam Boussaada, Silviu-Iulian Niculescu

SIUE Faculty Research, Scholarship, and Creative Activity

This paper presents a systematic method to analyse the stability of systems with single delay in which the coefficient polynomials of the characteristic equation depend on the delay. Such systems often arise in, for example, life science and engineering systems. A method to analyze such systems was presented by Beretta and Kuang in a 2002 paper, but with some very restrictive assumptions. This work extends their results to the general case with the exception of some degenerate cases. It is found that a much richer behavior is possible when the restrictive assumptions are removed. The interval of interest for the …

Numerical Investigation Of Coalescence-Induced Self-Propelled Behavior Of Droplets On Non-Wetting Surfaces And Wedged Surfaces., Yan Chen

Electronic Theses and Dissertations

When small drops coalesce on a superhydrophobic surface, the merged drop can jump away from the surface due to the surface energy released during the coalescence. This self-propelled behavior has been observed on various superhydrophobic surfaces and has potential applications in areas related to the heat and mass transfer, such as heat exchangers, anti-icing and anti-frost devices, thermal management and water harvesting. The jumping velocity model was obtained based on published experimental data and the balance of various energy terms described in previous studies. However, the self-propelled mechanism is still not fully understood. In this study, the self-propelled droplet phenomenon …

Impact Of Immersion Cooling On Thermo-Mechanical Properties Of Pcb's And Reliability Of Electronic Packages, Shrinath Shrinivas Ramdas

Mechanical and Aerospace Engineering Theses - Archive

Immersion cooling technique is used for the thermal management of high-density data centers to avoid overheating of components and failure of servers. However, to use this as a viable cooling technique, the effect of dielectric coolants on the reliability of server components needs to be evaluated. Previous work reported contradicting findings for Young’s modulus of PCBs, providing motivation for this work. This study focuses on effect of immersion cooling on the thermos-mechanical properties of printed circuit board (PCB) and its impact on reliability of electronic packages. Changes in thermo-mechanical properties like Young’s modulus (E), Glass transition temperature (Tg), Coefficient of …

Development Of A Single Sensor Approach For Capturing Three-Dimensional, Time Resolved Flame And Velocity Information, Jonathan Reyes

Electronic Theses and Dissertations

Performing non-intrusive measurements is the key to acquiring accurate information representative of what is being observed. The act of measuring often changes the environment being observed altering the information that is being obtained. Due to this, the community of fluid scientists have gravitated towards using laser-based measurements to observe the phenomena occurring in their experiments. The study of fluids has advanced since this point, utilizing techniques such as planar laser induced florescence (PLIF), particle image velocimetry (PIV), laser doppler velocimetry (LDV), particle doppler anemometry (PDA), etc. to acquire chemical species information and velocity information. These techniques, though, are inherently two-dimensional …

Decentralized Consensus-Based Control Allocation For Some Dynamical Systems, August Mark

Electronic Theses and Dissertations

In this dissertation, three separate studies, wherein techniques from graph theory and consensus control are used to address control allocation problems, are presented. In the first study, a decentralized allocator is presented for synthetic jet actuators and control surfaces onboard a small unmanned aerial vehicle to cooperatively generate desired aerodynamic moments. First order linear dynamics are assumed for both the synthetic jet actuators and control surfaces. A weighted consensus algorithm with limited feedback is used for the aerodynamic moment contribution allocator considering constraints. In the second study, the same allocation problem as in the first study is considered, but the …

How Infant Positioning Impacts Hip Motion And The Associated Implications For Babies With Hip Dysplasia, Lauren Buchele

Biomedical Engineering Undergraduate Honors Theses

Developmental dysplasia of the hip (DDH) refers to a group of disorders, ranging from slight instability (Grades 1-3) to a severe dislocation (Grade 4) of the femoral head from the acetabulum [1]. In order to treat DDH in infants, a reduction procedure and the use of a lower body harness to secure the hip joint as the bones and ligaments re-form properly is typically prescribed. The Pavlik Harness is currently the “gold-standard” orthopedic device used to place hips in proper positioning. However, little research has been reported on the biomechanical affects during use of these device types.

Although the Pavlik …

Mechanical Properties Of Brittle Ceramics: Case Study Of Boron Rich Ceramics And Acropora Cervicornis Coral Skeleton, Alejandro Carrasco-Pena

Electronic Theses and Dissertations

Ceramics are ubiquitous in man-made and natural structures. Their mechanical properties highly depend on their composition, microstructure and level of defects in the bulk of the material, the latter affecting the integrity of the components; such is the case of boron-rich ceramics where large agglomerates create high stressed regions, or coral skeleton where porosity determines their strength against hydrodynamic forces present in the ocean tides. Therefore, studying the properties of ceramic materials using invasive and non-invasive methods helps in the understanding of the link between the properties and the performance of the structures. The aim of this research was to …