Mechanical Engineering Commons^™

Post-Traumatic Elbow Contracture Characterization And Physical Therapy-Based Treatment Strategies In A Preclinical Model, Alex Reiter

McKelvey School of Engineering Graduate Student Theses & Dissertations

The elbow is the most commonly dislocated joint in the pediatric population and second most common in adults. As one of the most congruous joints in the body, slight changes in biomechanics due to injury can lead to drastic reductions in range of motion causing potential quality of life issues. Post-traumatic joint contracture occurs in 12% of patients following elbow dislocation or fracture, and it is characterized by a loss in ROM, joint stiffness, and pain. Preventing joint contracture and functional deficits from occurring is one of the primary goals when managing these injuries. A rat model of joint contracture …

Design And Optimization Of An Array Of Hollow Micropillar Structures For Enhanced Evaporative Cooling, Zhikai Yang

McKelvey School of Engineering Graduate Student Theses & Dissertations

With the increasing demand for higher-performance chips, the architecture of these semiconductor devices becomes more complex, leading to the need for higher-performance cooling technologies. For example, 3D stacked chips offer several advantages, including mixed functionality, reduced signal delay, and a smaller footprint. However, these devices yield higher heat densities due to the heat compounded from one stacked die to the next. While traditional single-phase cooling technologies can dissipate large heat fluxes, its performance is inversely proportional to its hydraulic diameter leading to larger required pumping powers. Two-phase cooling is a promising technique for dissipating high heat fluxes by utilizing the …

Analysis Of Fluid Flow In Redox Flow Batteries, Erfan Asadipour

McKelvey School of Engineering Graduate Student Theses & Dissertations

Redox flow batteries (RFB) hold great potential for large-scale stationary energy storage. However, their low energy density compared to other energy storage systems must improve for feasibility. Electrolyte flow distribution affects current density distribution and providing a uniform current density distribution is one way to improve RFB performance. Additionally, reducing the power consumption of the electrolytes’ pump as a source of energy loss in RFB systems increases their efficiency. Investigating both subjects requires analysis of the fluid dynamics in RFB cells.

In this thesis, a novel, computationally cost-effective hydraulic-electrical analogous model (HEAM) was developed to study fluid dynamics by implementing …

Mems 411: Lift Demonstration, Dean Ryan-Simmons, Marketa Riley, Puja Chhetri

Mechanical Engineering Design Project Class

A portable lift demonstration was requested to get children interested and thinking about what happens with fluid movement. The demonstration had size and weight requirements, which were both met. Accuracy of lift force representation was not requested, but simple force and flow visualizations were required. The demonstration had variable wind speeds, and showed the change in force with change in angle of attack.

Mems 411: Fast Pill Cutter, Andrew Brown, Isaac Sasser, Aaron Manuel, Quan Chau

Mechanical Engineering Design Project Class

This design project attempted to create a new pill-cutting device to help pharmacy technicians split pills quickly, precisely, and safely. The product was intended to occupy a competitive niche with current devices on the market, prioritizing increased cutting speed with potentially greater cost.

Mems 411: Portable Bridge Crane With Pulleys, Daniel Shen, Man Kit Mau, Haoxiang Lu, Kaijun Xu

Mechanical Engineering Design Project Class

The bridge crane demonstrates dynamics behavior that the flexible mode has a natural frequency depending on the string length. In this project, a portable bridge crane is designed and made to demonstrate this dynamical phenomena by changing speed and string length. The portable bridge crane requires a light mass and a small size. At the same time, because it needs to be observed in a two-dimensional plane, the trolley must be able to move horizontally on a bridge with tracks, and the speed of the trolley needs to be controlled by a speed controllable motor. The crane needs to suspend …

Mems 411: The Adjustable Bit Brace, Alex Levy, Alex Dutton, Daniel Luberda, Aidan Murphy

Mechanical Engineering Design Project Class

This group set out to create an open-source adjustable bit brace as a tool to lower the barrier to entry for smaller individuals looking to pick up tools and work on DIY projects. The brace is designed to highlight 3D printed parts, as well as components that can be fabricated at home by an experienced maker. The design uses standard adjustment mechanisms such as button clips and bolts to bring the bit brace from full size down to 2/3 scale in seconds. The device is advised by engineering models, FEA analysis, stiffness/strength targets, and destructive testing protocols to create a …

Mems 411: Creation Of A 3-Axis Camera System For Various Imaging Modalities, Ethan Meitz, Julia Flores, Ashley Linderman, Madison Larkin

Mechanical Engineering Design Project Class

The Lake Lab at Washington University in St. Louis faces challenges when setting up their camera systems for experiments. The Three Axis Camera system aims to optimize the experience by automating the movement and creating a user-friendly design. The current set-up requires the camera position to be adjusted manually and is “not liked” by most users. This wastes their time since the lab must set the location for the camera first and if the camera positioning is moved then the experiment will be ruined. Thus, the lab asked us specifically to help them automate these movements with our design and …

Mems 411: Compact Sewing Pin Dispenser, Jacob L. Weinstein, Eric Y. Lu, Nick J. Armanino

Mechanical Engineering Design Project Class

Sewing pins are small and hard to handle, and managing the pins can be very distracting (or painful) for a sewist. Our goal was to design a simple and easy sewing pin dispenser for a home sewist that can dispense small headed dressmaker pins. For our design to be a viable product, it would have to dispense pins very quickly, accurately, and safely. Additionally, it has to handle many pins at the same time so it does not have to be reloaded during use. Based on the design of a toothpick dispenser, our prototype small, lightweight, and portable device that …

Mems 411; Ground Work Station, Samuel Wille, Daniel Renbaum-Koss

Mechanical Engineering Design Project Class

This project aims to design a support mechanism for ecological field researchers who interact with plants and other samples from the forest floor for long periods. The design aims to recreate the functionality of bending over for long periods of time, while protecting the backs, hips and knees.

Mems 411: Portable Bridge Crane, Alex Eckels, Will Hurley, Zarya Desouza, Troy Bauer

Mechanical Engineering Design Project Class

The team designed and built a portable bridge crane for use in class demonstrations. The design was be based off a typical gantry crane, which consists of a trolley spanning across two horizontal parallel beams that are part of a gantry with a payload hanging from the trolley. The group also needed to design the gantry itself and ensure it was both stable enough to support the trolley and payload at the desired operation speeds as well as scaled properly for the desired use.

Mems 411: Portable Ground Work Station - Group C, Samantha Hudson, Valeria Pinedo Chipana, Valentina Harding, Luis Acosta

Mechanical Engineering Design Project Class

Build a ergonomic, portable, and weather resistant ground work station for members of the department of Biology to use during field research.

Mems 411: The Amazing Renewable Race, Kayla Murphy, Alitzel Yépiz, Daryl Wilson, Rebecca Davis

Mechanical Engineering Design Project Class

The project’s goal was to convey the importance of renewable energy to a 6 through 12 years old audience. This demo was designed to be installed at the St. Louis Science Center. To engage a younger audience, the renewable energy demonstration had to be interactive. As a result, a design similar to a carnival game was chosen. There are 3 stations that represent wind, hydroelectric, and solar energy. In this design, it is a multiplayer interactive race that portrays renewable energy. The initial design was to have each form of energy produced by the users. The user at the hydro …

Mems 411: The Pill Cutter, Alex Posly, Alex Austin, Drew Marolf, Dylan Stubbs

Mechanical Engineering Design Project Class

The goal of this design project was to improve the current method of pill cutting for STL Hills Pharmacy. Pharmacists and other medical professionals cut hundreds of pills weekly. Their current methods can only cut one pill at a time with an error rate of 50%. Pills are often split without enough precision and need to be thrown out. Our project was designed to have a 10% maximum error rate, require 1/4 of the force, and split pills 4 times as fast.

Mems 411: Ground Work Station Design Project, Jakub A. Gawedzki, Mark H. Wood, John B. Campoverde

Mechanical Engineering Design Project Class

Researchers from Washington University had requested us to design and develop a ground work station that allows them to work comfortable in the field for our senior design class.

Mems 411: Arliss Canister Vehicle, Patrick Smith, Brannon Boyd, Matthew Donaldson, Kieran Natarajan

Mechanical Engineering Design Project Class

To design, build, and test an autonomous canister vehicle to compete in the ARLISS competition. Design must autonomously drive to a given set of GPS coordinates, record and store GPS data during operation, survive a parachute drop, and traverse rough, uneven terrain.

Mems 411: Automatic Sewing Pin Dispenser, Edric Choi, Enrico Milletti, Adrian Odamtten, Chad Picerni

Mechanical Engineering Design Project Class

The aim of our project is to design and embody an automatic pin dispenser for our customer, Melanie, a recreational sewer. Namely, our pin dispenser design aims to address the need for sewers to safely receive and handle dressmaker pins with one hand whilst working with garments. We have identified three main performance goals for an automatic pins dispenser: Store at least 50 pins at a time, produce at least 1 pin every 2-3 seconds, and present at least 90% of all sorted pins in an upward orientation to the user. These performance goals were identified by interviewing our customer …

Mems 411: Self Lacing Shoes, Peter Pigatti, Bryce Roberts, Al-Amin Yusuf

Mechanical Engineering Design Project Class

For our senior design project we have chosen to design and prototype a pair of self lacing shoes with the initial target audience being people with disabilities who are limited in their ability to tie their own shoes for a variety of reasons. However, we hope that this product will catch on in popularity and become normalized for all people. These shoes will allow the wearer to easily slip them on and then secure the shoes to the foot with the push of a button rather than tying laces as in conventional shoes. This process will be driven by a …

Mems 411: St. Louis Science Center Vibration Station, Allie Periman, Hailey Hayes, Brian Higgins

Mechanical Engineering Design Project Class

Student groups work on an open-ended mechanical design problem and finish the semester with a physical prototype, a design report, and a presentation delivered to an external review board. Groups are guided through the engineering design process by completing a set of project deliverables. The quality of these deliverables provides a basis for the evaluation of individual and team performance. This course emphasizes the importance of user-centric design, communication and presentation skill, consideration of real-world constraints, sketching and creativity, prototyping, and data-driven decision-making using engineering models and analyses.

Mems 411: Dressmaker Pin Dispenser, Alex Goertz, Henry Holtz, Seamus Boyle, Youngjin Hong

Mechanical Engineering Design Project Class

The goal of this project was to design, manufacture, and test a machine which can dispense dressmaker pins in a consistent orientation, allowing the user can easily, and safely remove them one at a time. The purpose of the machine is to increase the efficiency and safety of sewers who may use dressmaker pins daily.

Mems 411: Lost Grains Winnower, Seth Jack, Matthew Finer, Alex Maggioni, Kristian Nilsen

Mechanical Engineering Design Project Class

This project involved designing an upgrade for the grain winnower in Dr. Mueller’s anthropology lab at Washington University in St. Louis. A winnower is a device that separates chaff from usable grain after harvesting and threshing. Many such devices exist, from industrial-scale winnowers sorting high volumes of grain to personal coffee bean winnowers. However, the constraints of the lab space and the specialized nature of the grain being winnowed presented specific constraints. An interview with Dr. Mueller was necessary to determine a ranked list of needs for use in the final product. After creating these rankings, a mock-up was used …

Mechanical Strength Of Germanium Doped Low Oxygen Concentration Czochralski Silicon And The Effect Of Oxygen On Nitrogen Dissociation In Silicon, Junnan Wu

McKelvey School of Engineering Graduate Student Theses & Dissertations

During the Czochralski growth of silicon, it is inevitable for oxygen to be incorporated into the silicon crystal from the quartz crucible. Interstitial oxygen improves the mechanical strength of silicon by pinning and locking dislocations, but also generates thermal donors during device processes, shifting the electrical resistivity. For silicon wafers used in radio frequency (RF) applications, it is important to ensure the high resistivity of the substrates for good RF characteristics. Therefore, the oxygen level in these high resistivity silicon wafers is kept very low (< 2.5 × 1017 atoms/cm3) by carefully controlling the Czochralski growth conditions, in order to reduce the thermal donor concentration to an acceptable level. Silicon on insulator (SOI) substrates made from high resistivity wafers have been widely used for RF applications. SOI manufacturing includes multiple high temperature thermal cycles (1000 – 1100 °C), during which the high resistivity wafers are prone to slip and warpage. Therefore, it is technologically important to recover some of the lost mechanical strength due to the lack of oxygen by introducing electrically inactive impurities to suppress the dislocation generation and mobility in silicon. Germanium (Ge) as an isovalent impurity is 4% larger in size and forms a solid solution with silicon in the entire concentration range. Previous works have shown Ge doping at high concentrations above 6 × 1019 atoms/cm3 increased mechanical strength of silicon with high oxygen concentration (~ 1 × 1018 atoms/cm3). In this work, we explore the effect of Ge doping (7 - 9 × 1019 atoms/cm3) on the mechanical strength of low oxygen concentration (< 2 × 1017 atoms/cm3) silicon, where the oxygen associated dislocation locking and pinning are very low. A mechanical bending test was used to study the average dislocation migration velocity and the critical shear stress of dislocations motion at 600 – 750 °C for Ge doped, nitrogen doped, and undoped low oxygen samples, as well as nitrogen doped float-zone and un-doped high oxygen concentration samples. Next, we fabricated SOI substrates using these high resistivity wafers and compared their slip generation rates and the slip-free epitaxial grow temperature windows after the high temperature thermal cycles (> 1000 °C). Our results indicate at lower temperature Ge doesn’t affect the dislocation mobility …

Aging Effects On Arterial Mechanics And Matrix Remodeling, Jie Hawes

McKelvey School of Engineering Graduate Student Theses & Dissertations

Large elastic arteries are a composite structure composed of cells and extracellular matrix proteins. Passive arterial mechanical behavior is determined by the composition of extracellular matrix proteins, in particular elastin and collagen. Elastin provides reversible elasticity to the large elastic arteries during cyclic loading and dampens the pulsatile flow from the left ventricle, reducing the workload on the heart and protecting the end organs. Disorganization and insufficiency of elastin alters the passive mechanical behavior of the large arteries. The arterial wall responds to changes in elastin organization or amount through matrix remodeling. Aging causes elastin fragmentation and degradation which changes …

New Modeling Approaches For The Prediction Of Combustion Pollutants, Phillip R. Johnson

McKelvey School of Engineering Graduate Student Theses & Dissertations

Combustion processes are ubiquitous to human technological development and provide many benefits such as large-scale power generation for electricity and transportation along with residential and commercial heating for manufacturing, cooking, and warmth. However, these various processes can also have harmful effects on human health and the environment via emission of CO2 and other pollutants such as NOx and particulate matter (PM; often in the form of soot). For these reasons, there is a continued need for controlling, improving, and optimizing combustion processes. Modeling of these processes provides powerful insights into system-level dynamics and their control. Due to the size and …

Particle Studies In The Lab And Pilot-Scale Coal Combustion Systems, Dishant Khatri

McKelvey School of Engineering Graduate Student Theses & Dissertations

In the past century, coal contributed more to the global electricity supply than any other source. Currently, it alone accounts for over 35% of the global electricity supply. Though coal is globally well-distributed and can provide cheap, stable, and reliable energy on demand, it emits a large amount of carbon dioxide—a greenhouse gas responsible for global warming. Additionally, it is a major source of particulate matter (PM) pollution. Thus, in recent years, to reduce the impact of coal on climate, several policies have been introduced to phase out coal. However, replacing coal with intermittent renewables has led to a reduction …

Large Face Shield, Michael Stieven, Dylan Huddleston, Timothy Bragg

Washington University / UMSL Mechanical Engineering Design Project JME 4110

The large face shield is designed to help stop the spread of COVID-19 Coronavirus in occupational environments where close contact is necessary.

Blood Flow Simulation Of Particle Trapping In Models Of Arterial Bifurcations, Qihang Xu

McKelvey School of Engineering Graduate Student Theses & Dissertations

This thesis describes the particle trapping mechanism in blood flow in different arterial bifurcation models. For validation of CFD calculations, a T-junction model and a Y-junction model are analyzed. In both the models, there is one inlet pipe with two outlet pipes creating a symmetric bifurcation at some angle from the centerline of the inlet pipe. Naiver-Stokes (RANS) equations are solved for single phase laminar flow using the commercial CFD software ANSYS Fluent. After validation, Eulerian simulations are performed by using the Discrete Phase Model (DPM) for two-phase flow with particles injected in different bifurcation models with bifurcation angle of …

Development And Application Of Elliptic Blending Lag K-Omega Sst Standard And Wall-Distance-Free Turbulence Model, Wenjie Shang

McKelvey School of Engineering Graduate Student Theses & Dissertations

In recent decades, Computational Fluid Dynamics (CFD) has become the most widely used technology to understand the fundamental complex fluid dynamics of turbulent flows as well as for modeling of turbulent flows in industrial applications. In industrial applications, the widely used methodology is to solve Reynolds-Average Navier-Stokes Equations (RANS) equations in conjunction with a turbulence model since it strikes a balance between accuracy and computational cost compared to other high fidelity approaches namely the Large Eddy Simulation (LES) and Direct Numerical Simulation (DNS), There are a large number of turbulence models proposed in past five decades, majority of them are …

Exploring Attacks And Defenses In Additive Manufacturing Processes: Implications In Cyber-Physical Security, Nicholas Deily

McKelvey School of Engineering Graduate Student Theses & Dissertations

Many industries are rapidly adopting additive manufacturing (AM) because of the added versatility this technology offers over traditional manufacturing techniques. But with AM, there comes a unique set of security challenges that must be addressed. In particular, the issue of part verification is critically important given the growing reliance of safety-critical systems on 3D printed parts. In this thesis, the current state of part verification technologies will be examined in the con- text of AM-specific geometric-modification attacks, and an automated tool for 3D printed part verification will be presented. This work will cover: 1) the impacts of malicious attacks on …

Design And Validation Of A Dynamic Pressure-Based Loading Device And 3d Strain Tracking Protocol For Ventral Hernia Modeling, Griffin Kivitz

McKelvey School of Engineering Graduate Student Theses & Dissertations

It is estimated that 350,000-500,000 ventral hernia repair surgeries are performed each year in the United States. While the long-term recurrence rate of ventral hernia repairs is not yet known, when tissues are exposed to the trauma of surgery, there is always the chance of recurrence. Commonly used ex vivo testing methods for determining the mechanical properties of the abdominal wall and biomaterials for hernia repair consist primarily of uniaxial and biaxial testing, which are not physiologically relevant loading environments. The need for a testing device that can exert physiologically relevant loads ex vivo to an abdominal wall is crucial …