Open Access. Powered by Scholars. Published by Universities.®

Engineering Commons

Open Access. Powered by Scholars. Published by Universities.®

Mechanical Engineering

Discipline
Institution
Publication Year
Publication
Publication Type
File Type

Articles 1 - 30 of 735

Full-Text Articles in Engineering

Utilizing The Product Development Process To Bring An Idea From Concept To Production, Sydney Ferguson, Jackson Sneed May 2020

Utilizing The Product Development Process To Bring An Idea From Concept To Production, Sydney Ferguson, Jackson Sneed

Honors Theses

The purpose of this thesis is to document and discuss the five-stage product development process starting with defining a problem and resulting in manufacturing a final product for sale as it was implemented in the Portable Fire Pit Center for Manufacturing Excellence Senior Capstone Project. This project was carried out over the course of the Fall 2019 and Spring 2020 semesters by a team consisting of three Undergraduate Mechanical Engineering majors and two Undergraduate Accountancy majors. The ultimate goal of the project was to carry out a full production run of the Portable Fire Pit outputting fifteen units meeting retail ...


Failure Of High Strength Concrete Under Dynamic Uniaxial Compression, Colin Loeffler Dec 2019

Failure Of High Strength Concrete Under Dynamic Uniaxial Compression, Colin Loeffler

Mechanical Engineering Research Theses and Dissertations

The failure strength of concrete materials has been widely shown to be dependent on experimental parameters such as specimen geometry and strain-rate. The effects of specimen geometry have been shown both theoretically and experimentally to be a result of the quasi-brittle nature of concrete. While the failure strength of concrete has been widely reported to increase significantly when deformed at high strain-rates, the physical mechanisms driving this phenomenon remain the source of debate amongst researchers. This means that constitutive models designed to predict this rate dependent behavior are not based on the real physical mechanisms that drive this behavior but ...


Graphene-Based Water Desalination Using Atomistic Simulations, Thanh Chinh Nguyen Oct 2019

Graphene-Based Water Desalination Using Atomistic Simulations, Thanh Chinh Nguyen

Mechanical Engineering Research Theses and Dissertations

My research focused on investigating saltwater transport through nanoporous graphene membranes using molecular dynamics (MD) simulations. Particularly, in this dissertation, we focused on pressure-driven flows of salt water through uncharged and charged nanoporous graphene membranes for water desalination applications. In the first study, desalination performance of uncharged single-layer nanoporous graphene membranes was observed based on volumetric flow rate, required pressure drop, and salt rejection efficiency. A functional relationship between the volumetric flow rate, pressure drop, pore diameter, and the dynamic viscosity of saltwater was also examined. In further studies, transport of salt ions through positively and negatively charged single-layer nanoporous ...


Development Of A Robotized Laser Directed Energy Deposition System And Process Challenges, Meysam Akbari Oct 2019

Development Of A Robotized Laser Directed Energy Deposition System And Process Challenges, Meysam Akbari

Mechanical Engineering Research Theses and Dissertations

Metal additive manufacturing (AM) is a disruptive technology, enabling fabrication of complex and near net shaped parts by adding material in a layer-wise fashion. It offers reduced lead production time, decreased buy-to-fly ratio, and repair and remanufacturing of high value components. AM processes are finding applications in many industrial sectors such as aerospace, automotive, biomedical and mold tooling. However, beside tremendous advantages of AM, there are still some challenges that prevent the adoption of this technology into high standard applications. Anisotropy and inhomogeneity in mechanical properties of the as-built parts and existence of pores and lack-of-fusion defects are considered as ...


Investigation Of The Electrode Polarization Effect For Biosensor Applications, Anil Koklu Aug 2019

Investigation Of The Electrode Polarization Effect For Biosensor Applications, Anil Koklu

Mechanical Engineering Research Theses and Dissertations

My research focuses on electrokinetic transport. Particularly, in this dissertation, we focus on fabrication and testing of micro electrodes with nanostructured surfaces to minimize the electrode polarization (EP) effects for biosensor applications. In the first study, electrochemical deposition of gold nanoparticles on to planar gold electrodes was used to generate rough surfaces. Dendritic nanostructures that reduced EP up to two orders of magnitude was obtained by optimizing the deposition conditions. These structures also enhanced dielectrophoresis (DEP) response of our bio-chips, making them usable in physiological buffers. In further studies we discovered a universal scaling of EP in the frequency domain ...


The Axisymmetric Harmonic Element Including Gyroscopic Effects: A Complete Derivation, Zachary Charles Glick Aug 2019

The Axisymmetric Harmonic Element Including Gyroscopic Effects: A Complete Derivation, Zachary Charles Glick

Graduate Theses - Mechanical Engineering

Various types of finite elements have been used in the prediction of critical speeds of turbomachinery. Among these, axisymmetric harmonic elements provide both accurate natural frequency prediction and computational speed. Yet, a full derivation of such an element including gyroscopic effects is not widely available in the relevant literature. In this work, the finite elements for rotordynamics available in the literature are reviewed. Derivations necessary for the axisymmetric harmonic element mass, gyroscopic damping, and stiffness matrices and the equations of motion are clearly expounded using Hamilton’s principle. The formulation is applied to two model shafts, and the comparison of ...


Investigation Of Fundamental Principles Of Rigid Body Impact Mechanics, Khalid Alluhydan Jul 2019

Investigation Of Fundamental Principles Of Rigid Body Impact Mechanics, Khalid Alluhydan

Mechanical Engineering Research Theses and Dissertations

In impact mechanics, the collision between two or more bodies is a common, yet a very challenging problem. Producing analytical solutions that can predict the post-collision motion of the colliding bodies require consistent modeling of the dynamics of the colliding bodies. This dissertation presents a new method for solving the two and multibody impact problems that can be used to predict the post-collision motion of the colliding bodies. Also, we solve the rigid body collision problem of planar kinematic chains with multiple contacts with external surfaces.

In the first part of this dissertation, we study planar collisions of Balls and ...


Impedance-Based Microfluidic Platform For Quantitative Biology, Amin Mansoorifar Jul 2019

Impedance-Based Microfluidic Platform For Quantitative Biology, Amin Mansoorifar

Mechanical Engineering Research Theses and Dissertations

Dielectric properties of biological cells are functions of cellular structure, content, state, and phenotype. Dielectric spectroscopy (DS) is a nondestructive method to characterize dielectric properties by measuring impedance data over a frequency range. This method has been widely used for various applications such as counting, sizing, and monitoring biological cells and particles. Recently, this method has been suggested to be utilized in various stages of the drug discovery process due to its low sample consumption and fast analysis time.

In this thesis, we have developed a lab-on-a-chip device that uses an electro-activated microwells array for capturing, making DS measurements on ...


Graphs And Cad: Analyzing The Experience Of A Mechanical Engineering Intern, Matthew Des Biens Jun 2019

Graphs And Cad: Analyzing The Experience Of A Mechanical Engineering Intern, Matthew Des Biens

Celebration of Learning

A reflection on the experiences of a mechanical engineering intern at Bergstrom Inc., this presentation, by Senior Matt Des Biens, will discuss what it was like working for a manufacturing and design company making HVAC units for large customers across the world. The highlights will be on the projects he worked on, the things that he learned, and his views on working for the company as a whole.


Design Of An Urban Garden Aquaponics System, Riley Albright-Borden, James Wang, Sydney Thompson Jun 2019

Design Of An Urban Garden Aquaponics System, Riley Albright-Borden, James Wang, Sydney Thompson

Interdisciplinary Design Senior Theses

The project objective is to create a durable, off-the-grid, large-scale aquaponics system consisting of over 90 sq. ft of growing space, a 650-gallon fishpond, and four types of sensors to transmit water quality data to the internet for remote water quality monitoring. The end goal of the project is to supplement produce grown in the garden to further increase fresh, nutritional options available in meals cooked and distributed by Loaves and Fishes Family Kitchen to combat food insecurity in San Jose. This report presents the need for a system, details the various subsystems, and the rationale for the designs. It ...


Design And Control Of Fiber Encapsulation Additive Manufacturing, Matt Saari May 2019

Design And Control Of Fiber Encapsulation Additive Manufacturing, Matt Saari

Mechanical Engineering Research Theses and Dissertations

This work presents the design, development, and analysis of the Fiber Encapsulation Additive Manufacturing (FEAM) system developed at the Laboratory for Additive Manufacturing Robotics \& Automation at the Lyle School of Engineering at Southern Methodist University. The innovation introduced by FEAM is the ability to insert a continuous fiber of different material into the flowing extrudate. Correctly positioning the fiber feed inside the extrudate while turning the fiber in arbitrary directions is a critical aspect of the technology. This will allow for the full exploitation of the capabilities of the FEAM technology to produce robotic components that actuate and sense. Several ...


Fault Adaptive Workload Allocation For Complex Manufacturing Systems, Charlie B. Destefano May 2019

Fault Adaptive Workload Allocation For Complex Manufacturing Systems, Charlie B. Destefano

Theses and Dissertations

This research proposes novel fault adaptive workload allocation (FAWA) strategies for the health management of complex manufacturing systems. The primary goal of these strategies is to minimize maintenance costs and maximize production by strategically controlling when and where failures occur through condition-based workload allocation.

For complex systems that are capable of performing tasks a variety of different ways, such as an industrial robot arm that can move between locations using different joint angle configurations and path trajectories, each option, i.e. mission plan, will result in different degradation rates and life-expectancies. Consequently, this can make it difficult to predict when ...


The Effects Of Scale On Granular Mixing In A Double Screw Pyrolyzer, Breanna L. Marmur Apr 2019

The Effects Of Scale On Granular Mixing In A Double Screw Pyrolyzer, Breanna L. Marmur

Breanna L. Marmur

Granular mixing processes are important to many industries including the pharmaceutical, agricultural, and biotechnology industries. These processes often require both a high degree of homogeneity and a high degree of customizability. As granular mixing processes are so widely employed, a thorough understanding of the mixing dynamics is necessary to understand and control the resulting products. Research into granular mixing processes has been, thus far, largely focused on laboratory scale mixers with simple geometries, while actual industrial processes often require large mixers with complex geometries. Moreover, granular mixing processes are often very sensitive to changes in operating conditions and any solutions ...


Human-Centered Electric Prosthetic (Help) Hand, Jamie Ferris, Shiyin Lim, Michael Mehta, Evan Misuraca Apr 2019

Human-Centered Electric Prosthetic (Help) Hand, Jamie Ferris, Shiyin Lim, Michael Mehta, Evan Misuraca

Interdisciplinary Design Senior Theses

Through a partnership with Indian non-profit Bhagwan Mahaveer Viklang Sahayata Samiti, we designed a functional, robust, and and low cost electrically powered prosthetic hand that communicates with unilateral, transradial, urban Indian amputees through a biointerface. The device uses compliant tendon actuation, a small linear servo, and a wearable garment outfitted with flex sensors to produce a device that, once placed inside a prosthetic glove, is anthropomorphic in both look and feel. The prosthesis was developed such that future groups can design for manufacturing and distribution in India.


Hybrid Laser/Arc Welding Of Difficult-To-Weld Thick Steel Plates In Different Joint Configurations: Issues And Resolutions, Nima Yazdian Apr 2019

Hybrid Laser/Arc Welding Of Difficult-To-Weld Thick Steel Plates In Different Joint Configurations: Issues And Resolutions, Nima Yazdian

Mechanical Engineering Research Theses and Dissertations

Difficult-to-weld steels are ferrous alloys that are characterized by a low thermal conductivity, and large thermal expansion coefficient. These intrinsic features contribute to a high level of distortion and cracking susceptibility during joining of these types of steels. In an effort to address the issues associated with difficult-to-weld steels, highly concentrated beam spots like electron and laser beam welding were developed. Usage of tightly focused heat sources have been accompanied by several challenges. An extremely precise fit-up requirement was considered as the most significant issue corresponding to application of either laser or electron beam. Recently, it was found that the ...


Analytical And Experimental Study Of Laser Cladding Of Ni/Wc Metal Matrix Powders Reinforced With Rare Earth Elements Using A High Power Direct Diode Laser, Mohammed Sayeed Apr 2019

Analytical And Experimental Study Of Laser Cladding Of Ni/Wc Metal Matrix Powders Reinforced With Rare Earth Elements Using A High Power Direct Diode Laser, Mohammed Sayeed

Mechanical Engineering Research Theses and Dissertations

The corrosion and wear are major limiting factors for steel in the harsh environments and can be controlled by depositing protective passive coatings. Nickel based alloy cladding of steel offers a solution by enabling better corrosion and wear resistance, and high bonding strength. The laser surface cladding of steel was conducted using a high power direct diode laser. Layers of tungsten carbide in Ni (40%Ni-60%WC) combined with 1% and 2% Lanthanum Oxide (La2O3) and Cerium Oxide (CeO2) were deposited on ASTM A36 steel substrate. The X-ray diffraction and scanning electron microscopy were employed to ...


Thermal Transport In Layer-By-Layer Assembled Polycrystalline Graphene Films, David Estrada, Alondra Perez Mar 2019

Thermal Transport In Layer-By-Layer Assembled Polycrystalline Graphene Films, David Estrada, Alondra Perez

Materials Science and Engineering Faculty Publications and Presentations

New technologies are emerging which allow us to manipulate and assemble 2-dimensional (2D) building blocks, such as graphene, into synthetic van der Waals (vdW) solids. Assembly of such vdW solids has enabled novel electronic devices and could lead to control over anisotropic thermal properties through tuning of inter-layer coupling and phonon scattering. Here we report the systematic control of heat flow in graphene-based vdW solids assembled in a layer-by-layer (LBL) fashion. In-plane thermal measurements (between 100 K and 400 K) reveal substrate and grain boundary scattering limit thermal transport in vdW solids composed of one to four transferred layers of ...


Cal Poly Supermileage Electric Vehicle Drivetrain And Motor Control Design, Clarisa Joy Howe, Christopher Joseph Mclaughlin, Erik Alvarado, Enyi Liang Mar 2019

Cal Poly Supermileage Electric Vehicle Drivetrain And Motor Control Design, Clarisa Joy Howe, Christopher Joseph Mclaughlin, Erik Alvarado, Enyi Liang

Mechanical Engineering

The Cal Poly Supermileage Vehicle team is a multidisciplinary club that designs and builds high efficiency vehicles to compete internationally at Shell Eco-Marathon (SEM). Cal Poly Supermileage Club has been competing in the internal combustion engine (ICE) category of the competition since 2007. The club has decided it is time to expand their competition goals and enter their first battery electric prototype vehicle. To this end, a yearlong senior design project was presented to this team of engineers giving us the opportunity to design an electric powertrain with a custom motor controller. This system has been integrated into Ventus, the ...


Open-Source Automated Chemical Vapor Deposition System For The Production Of Two-Dimensional Nanomaterials, Lizandra Williams-Godwin, Dale Brown, Richard Livingston, Tyler Webb, Lynn Karriem, Elton Graugnard, David Estrada Jan 2019

Open-Source Automated Chemical Vapor Deposition System For The Production Of Two-Dimensional Nanomaterials, Lizandra Williams-Godwin, Dale Brown, Richard Livingston, Tyler Webb, Lynn Karriem, Elton Graugnard, David Estrada

Materials Science and Engineering Faculty Publications and Presentations

The study of two- dimensional (2D) materials is a rapidly growing area within nanomaterials research. However, the high equipment costs, which include the processing systems necessary for creating these materials, can be a barrier to entry for some researchers interested in studying these novel materials. Such process systems include those used for chemical vapor deposition, a preferred method for making these materials. To address this challenge, this article presents the first open-source design for an automated chemical vapor deposition system that can be built for less than a third of the cost for a comparable commercial system. The materials and ...


Theoretical Study Of Fano Resonance In A Mechanical System, Alex Alberts Jan 2019

Theoretical Study Of Fano Resonance In A Mechanical System, Alex Alberts

Williams Honors College, Honors Research Projects

Resonance conditions are a major area of study in theoretical and experimental investigation. Normally, a resonance condition is characterized by a symmetric shape on either side of the resonance. In some cases, we can observe an asymmetric resonance shape, which is called a Fano resonance. We will study the appearance of Fano resonance in a purely mechanical system. The frequency response of the primary system is approximated using the method of multiple scales focusing on the location of the resonance condition. Then, curve fitting is used to approximate the Fano parameter associated with the system, which provides a measurement of ...


Pick-And-Place Robot For The 2019 Asme Student Design Competition, Riniah A. Foor, Megan Schmit, Aaron Urban, Jeanetta Davidsaver, Daniel Mugongo Jan 2019

Pick-And-Place Robot For The 2019 Asme Student Design Competition, Riniah A. Foor, Megan Schmit, Aaron Urban, Jeanetta Davidsaver, Daniel Mugongo

Williams Honors College, Honors Research Projects

This project was undertaken as an opportunity to participate in a holistic experience of designing, building, and competing as an engineering design team. In the ASME Student Design Competition, undergraduate students are able to experientially learn the process of design inception, manufacture, and product performance in addition to the development of critical project management skills. This is done through a creative design challenge to build a device capable of accomplishing a “pick-and-place” task in a fast and efficient manner.


Analytical And Experimental Investigation Of Time-Variant Acceleration Fields, Justin A. Williams Jan 2019

Analytical And Experimental Investigation Of Time-Variant Acceleration Fields, Justin A. Williams

Browse all Theses and Dissertations

Devices expected to operate in elevated or non-standard acceleration fields are often tested in similar conditions prior to deployment. Typically these tests only simulate steady-state acceleration fields in one direction. However, real acceleration fields often vary both directionally and temporally. Designing experiments to produce these conditions requires careful forethought and analysis in order to understand the emergent acceleration components that result from the methodology. An experiment was designed and executed on a horizontal centrifuge in which the radial acceleration varied sinusoidally between -10 < a_r < 10 g. Negative acceleration was achieved by rotating the test article relative to the radial acceleration vector using a servo motor. A model was developed that predicted the acceleration field at every point along the test article. The model provided important information such as the acceleration magnitude and direction anywhere on the test device at any point in time. This model was then used to optimize the velocity profile of the servo motor to minimize experimental artifacts.


Power/Thermal Interaction Within An Adaptive Turbine Engine, Andrew K. Desomma Jan 2019

Power/Thermal Interaction Within An Adaptive Turbine Engine, Andrew K. Desomma

Browse all Theses and Dissertations

Usually power take off (PTO) with a two-spool turbofan engine has been accomplished via the high pressure (HP) shaft and bleed air from the high-pressure compressor (HPC). The PTO is used to run various aircraft components such as generators and hydraulic pumps, which also produce waste heat. To better understand the coupled transient nature of balancing engine thrust, power take off and thermal management, a transient variable cycle three stream turbofan engine model has been developed to investigate the integrated behavior. The model incorporates many dynamic features including a third-stream heat exchanger as a heat sink for thermal management and ...


Design And Implementation Of Periodic Unsteadiness Generator For Turbine Secondary Flow Studies, Nathan James Fletcher Jan 2019

Design And Implementation Of Periodic Unsteadiness Generator For Turbine Secondary Flow Studies, Nathan James Fletcher

Browse all Theses and Dissertations

A primary source of periodic unsteadiness in low-pressure turbines is the wakes shed from upstream blade rows due to the relative motion between adjacent stators and rotors. These periodic perturbations can affect boundary layer transition, secondary flow, and loss generation. In particular, for high-lift front-loaded blades, the secondary flowfield is characterized by strong three-dimensional vortical structures. It is important to understand how these flow features respond to periodic disturbances. A novel approach was taken to generate periodic unsteadiness which captures some of the physics of turbomachinery wakes. Using stationary pneumatic devices, pulsed jets were used to generate disturbances characterized by ...


Unsteady Effects Of A Pulsed Blowing System On An Endwall Vortex, Molly Hope Donovan Jan 2019

Unsteady Effects Of A Pulsed Blowing System On An Endwall Vortex, Molly Hope Donovan

Browse all Theses and Dissertations

The low-pressure turbine is an important component of a gas turbine engine, powering the low-pressure spool which provides the bulk of the thrust in medium- and high-bypass engines. It is also a significant fraction of the engine weight and complexity as it can comprise up to a third of the total engine weight. One way to drastically reduce the weight of the low-pressure turbine is to utilize high lift blades. To advance high-lift technology, the Air Force Research Laboratory (AFRL) designed the L2F blade profile, which was implemented in the linear cascade at AFRL/RQT’s low speed wind tunnel ...


Design And Manipulation Of A Power-Generating System With High-Temperature Fuel Cells For Hypersonic Applications, Jack Randolph Chalker Jan 2019

Design And Manipulation Of A Power-Generating System With High-Temperature Fuel Cells For Hypersonic Applications, Jack Randolph Chalker

Browse all Theses and Dissertations

Current hypersonic vehicles tend to be incapable of producing onboard power with traditional generators due to their use of supersonic combusting ramjets (scramjets). Because of this, they seek additional energy sources for supporting advanced electronics or other auxiliary power-dependent devices while requiring elaborate thermal management systems to combat temperatures exceeding 700ºC. The incorporation of Solid Oxide Fuel Cell (SOFCs) stacks is an efficient solution, capable of generating large quantities of power through the use of natural fuel sources at high temperatures. Developments in this thesis include the design, construction, and support of a system operating at hypersonic-environment conditions with a ...


Using Cfd To Improve Off-Design Throughflow Analysis, Troy J. Lanchman Jan 2019

Using Cfd To Improve Off-Design Throughflow Analysis, Troy J. Lanchman

Browse all Theses and Dissertations

In turbomachinery design, complex internal flows give rise to significant losses and blockage whose effects are difficult to properly analyze without detailed computational fluid dynamics (CFD) methods or experiments. In a typical design method, CFD is used in conjunction with simpler throughflow or cascade codes to hasten the process. However, the lesser physical accuracy of the design codes demands the inclusion of models to improve the accuracy of the throughflow codes. This thesis aims to use CFD data to generate improved loss and blockage models for a 2D compressor throughflow code by matching throughflow data to CFD data using optimizations ...


Development Of A Computer Program For Transient Heat Transfer Coefficient Studies, Sri Prithvi Samrat Samayamantula Jan 2019

Development Of A Computer Program For Transient Heat Transfer Coefficient Studies, Sri Prithvi Samrat Samayamantula

Browse all Theses and Dissertations

At the present time, the magnitude of transient convective heat transfer is approximated using heat transfer coefficient correlations developed for steady state conditions. This is done by necessity, as transient heat transfer correlations are not readily available. There is a rare transient heat transfer correlation found in the literature, but the number of correlations available can be counted on one hand. In addition, the literature does provide some plots of Nusselt numbers for specific cases of transient convective heat transfer, but these are limited to the specific case for which they were developed. The work presented in this thesis is ...


As-Manufactured Modeling Of A Mistuned Turbine Engine Compressor Evaluated Against Experimental Approaches, Daniel L. Gillaugh Jan 2019

As-Manufactured Modeling Of A Mistuned Turbine Engine Compressor Evaluated Against Experimental Approaches, Daniel L. Gillaugh

Browse all Theses and Dissertations

As-manufactured rotors behave quite differently than nominal, as-designed rotors due to small geometric and material property deviations in the rotor, referred to as mistuning. Traditional integrally bladed rotor (IBR) modeling approaches assume each blade is identical. State-of-the-art IBR dynamic response predictions can be accomplished using asmanufactured models (AMM) generated via optical topography measurements and mesh morphing. As-manufactured models account for geometric deviations occurring through the machining process, material deviations and field wear, allowing each blade to respond differently. Rotor designs are intended to avoid resonance crossings throughout an engine’s operating range, but total avoidance is challenging. This has led ...


Aerodynamics Of Fan Blade Blending, Clint J. Knape Jan 2019

Aerodynamics Of Fan Blade Blending, Clint J. Knape

Browse all Theses and Dissertations

Blending is a method of fan and compressor blade repair. The goal of the blending process is to remove stress concentration points such as cracks and nicks along the leading, trailing, or tip edges of the blade. The stressed areas are typically removed by grinding or cropping away the surrounding material. For integrally bladed rotor (IBR) disks, repairing a damaged blade is much more economical than replacing the entire disk. However, the change in shape of the blade will change the local aerodynamics and result in mistuning, both structurally and aerodynamically. In a worst case scenario, the change in the ...