Applied Mechanics Commons^™

Ambient Temperature Strength Degradation Of A Ceramic Matrix Composite Due To Solid Particle Erosion, Jonathan Clawson

Williams Honors College, Honors Research Projects

Solid particle erosion (SPE) is an issue for aircraft exposed to hard, fine particles, such as sand or dust, that can be ingested into the engine at a high velocity without reaching their melting point, resulting in material removal. SPE can be attributed to the intake of particulate debris from the runway or from airborne particulates. The cumulative mass loss from SPE damage affects the structural integrity and performance of the engine; however, its effects on ceramic matrix composites (CMCs), that are being employed in the aerospace industry, are not well understood in literature. The limited SPE research studies that …

Zips Racing Electric Brakes Design, Zachary Koneval, Andrew Thompson, Cory Baczkowski

Williams Honors College, Honors Research Projects

The Zips electric racing team is a collegiate team full of engineering students to make a formula electric car that competes against other universities and their cars. But before the cars make it to competition they go through a series of tests to make sure the car is able to perform in all of the actual competition stages. One of the tests for the cars is the brakes test. Where the car has to lock up all four wheels at once and stop in a square that is on the ground. So in this report we have detailed out our …

Porous Bearing Research Rig, Josh Beranek, Hannah Liggett, Jonathan Lemmon, Brandon Allen

Williams Honors College, Honors Research Projects

Our team has decided to continue the research of fluid bearings, specifically, that of the journal and porous bearing. This will continue off of research currently being done at the University of Akron by graduate student Elizabeth Clifford who has developed a mathematical model for a porous bearing. Our job will be to create a testing rig that will be able to either prove or disprove this model. To do this, the rig will need to be able to take measurements of temperature and pressure at key areas within the bearing. It will also need to be readily capable of …

Directional Dependent Fracture Characteristics Of 3d Printed Mechanical Metamaterials, Thomas Draper

Dissertations, Master's Theses and Master's Reports

Structural metamaterials, such as lattice metamaterials, are engineered cellular structures designed to achieve properties not achievable by natural materials. They enable mechanical properties unattainable by homogeneous solid materials and offer optimal properties for these materials tunable for specific applications in industries such as automotive, medical, and aerospace. Recent findings have revealed unique tunable mechanical properties such as negative Poisson's ratio, high strength-to-weight ratio, anisotropic stiffness, and much more. While the elastic and wave propogation properties of many lattice metamaterials are well investigated, the fracture properties are not well explored. However, their low fracture toughness is a bottleneck for their use …

Analysis Of Variations In Flow-Independent Liquid Jet-In-Crossflow Injections, Michael Scott

Honors Undergraduate Theses

Liquid fuel injection is a critical mechanism for the deliverance of liquid fuel in contemporary aircraft propulsion combustion systems due to its outsized influence in providing optimal combustion conditions and improving overall aircraft efficiency and performance. Despite this, these liquid jet in crossflow (LJIC) systems are highly variable due to conditions in the jet and the surrounding airflow, leading to variability in performance behavior and inconsistency in fuel mixing and combustion efficiency. This has prompted the introduction of solid pintile obstructions of novel designs to provide a more flow-independent fuel injection scheme and decrease variability of the jet properties against …

Impact Of Glottis Area On Airflow Dynamics In The Human Trachea Using A Simplified Stenosis Pipe Model, Amany M. Kamal, Momtaz Sedrak, Abouelmagd Abdelsamie

Trends in advanced sciences and technology

A complex transitional flow is produced in the larynx during air inhalation process, pivotal for fundamental comprehension and medical advancements in treatment methodologies. This study delves into the influence of the glottis region utilizing a simplified stenosis pipe geometry, examining two distinct cases: (1) the axisymmetric case and (2) the eccentric case. Reynolds-averaged Navier–Stokes equations with shear stress transport (SST) 𝑘 − 𝜔 turbulence model with intermittency transition activated with steady, Newtonian, and incompressible airflow have been used. The analysis underscores the significant impact of the eccentricity on the velocity by increasing 0.6% comparing with axisymmetric case, also particularly affecting …

Simulation Of Wave Propagation In Granular Particles Using A Discrete Element Model, Syed Tahmid Hussan

College of Graduate Studies: Theses & Dissertations

The understanding of Bender Element mechanism and utilization of Particle Flow Code (PFC) to simulate the seismic wave behavior is important to test the dynamic behavior of soil particles. Both discrete and finite element methods can be used to simulate wave behavior. However, Discrete Element Method (DEM) is mostly suitable, as the micro scaled soil particle cannot be fully considered as continuous specimen like a piece of rod or aluminum. Recently DEM has been widely used to study mechanical properties of soils at particle level considering the particles as balls. This study represents a comparative analysis of Voigt and Best …

Linear Actuator Using Electromagnetic Brake For Damping Modulation In Physical Human-Robot Interaction, Zahid Ullah

Chulalongkorn University Theses and Dissertations (Chula ETD)

Improving the transparency of high-transmission-ratio linear actuators is essential for enhancing the safety and performance of high-force robotic systems that engage in physical contact with humans in unstructured environments. However, achieving this goal presents significant challenges. A proposed solution for active body weight support systems involves a linear actuator design, combining a high-force unit with an agile, highly back-drivable unit, using an electrorheological-fluid brake. This dissertation introduces an approach that utilizes an electromagnetic (EM) brake with a reduced rotor inertia to address these challenges. The EM brake's increased torque capacity allows for integration with a low-gear-ratio linear transmission. The mini …

ระบบการเรียนปฏิบัติการร่วมกันจากระยะไกลร่วมกับโมเดลภาษาขนาดใหญ่บนเว็บแอปพลิเคชันสำหรับการทดลองสอบเทียบเทอร์โมคัปเปิล, ภูมิรพี เมเยอร์

Chulalongkorn University Theses and Dissertations (Chula ETD)

แม้การระบาดของโควิด-19 จะผ่านพ้นไปแล้ว แต่การพัฒนาและเพิ่มความสามารถของห้องปฏิบัติการระยะไกลให้ทันสมัยและพร้อมใช้งานยังคงมีความสำคัญ งานวิจัยนี้นำเสนอระบบ Telepresence Laboratory ที่รวมการควบคุมการทดลองจากระยะไกลผ่าน Web Application กับการใช้งาน Large Language Model (LLM) เพื่อสร้างผู้ช่วยอัจฉริยะสำหรับการทดลองสอบเทียบเทอร์โมคัปเปิล ระบบนี้สนับสนุนการเรียนรู้ผ่านการคำนวณค่าพารามิเตอร์ ตอบคำถาม และแนะนำขั้นตอนการทดลองในแบบเรียลไทม์ การประเมินระบบครอบคลุมสามด้าน ได้แก่ คุณสมบัติและประโยชน์เปรียบเทียบกับการทดลองแบบดั้งเดิม, ประสิทธิภาพของ LLM ในการสนับสนุนการทดลอง และความพึงพอใจจากผู้ทดลอง ผลการประเมินพบว่าระบบช่วยเพิ่มการเข้าถึง ลดภาระผู้สอน และลดเวลาในการคำนวณ แม้ว่าจะยังมีข้อจำกัดในด้านการมอบประสบการณ์สัมผัสจริงและความล่าช้าในการตอบสนองของ LLM สรุปได้ว่าระบบเหมาะสำหรับการเรียนที่มุ่งเน้นความเข้าใจทฤษฎีและกระบวนการทดลอง แต่ไม่เหมาะสำหรับการเรียนรู้การใช้งานเครื่องมือที่ซับซ้อน

Machine Learning-Assisted Multiscale Simulation And Design Optimization Of Composite Jackets Under Low-Velocity Impacts, Masoud Mohammadi

Graduate Theses, Dissertations, and Problem Reports (ETD)

This research presents the development of a data-driven machine learning-assisted approach to simulate and optimize the design of composite materials subjected to low-velocity impacts. It focuses on a specific type of hybrid composite comprised of fiberglass and Kevlar fabrics stitched with Kevlar threads. The study begins by creating a multiscale finite element simulation for the composite under a low-velocity impact, which operates across three scales: microscale, mesoscale, and macroscale. This simulation accepts various inputs, such as different layer configurations and orientations, and provides impact outputs including maximum load and energy absorption capacity and displacement at failure.

Python and MATLAB scripts …

Reducing Food Scarcity: The Benefits Of Urban Farming, S.A. Claudell, Emilio Mejia

Journal of Nonprofit Innovation

Urban farming can enhance the lives of communities and help reduce food scarcity. This paper presents a conceptual prototype of an efficient urban farming community that can be scaled for a single apartment building or an entire community across all global geoeconomics regions, including densely populated cities and rural, developing towns and communities. When deployed in coordination with smart crop choices, local farm support, and efficient transportation then the result isn’t just sustainability, but also increasing fresh produce accessibility, optimizing nutritional value, eliminating the use of ‘forever chemicals’, reducing transportation costs, and fostering global environmental benefits.

Imagine Doris, who is …

Inverted Pendulum With Swing-Up And Center-Stabilization System Design, Caleb Osmond

Honors Program: Senior Projects (Public)

The inverted pendulum is a classic problem for testing control techniques. This paper details the implementation of multiple PID control schemes and the overall design of an inverted pendulum capable of swing-up and center stabilization.

Mechanical Characterization Of Functionally Graded M300 Maraging Steel Cellular Structures, Bradley Jay Sampson

Theses and Dissertations

Traditional methods for increasing the energy absorption of a structure involve using a stronger material or increasing the volume of the structure, resulting in a higher cost or additional weight. Additive manufacturing (AM) can be used to maximize the energy absorption of materials with the ability to create complex geometries such as cellular structures. Previous work has shown that the energy absorption of additively manufactured parts can be improved through functionally graded cellular structures; however, this strategy has not been applied to ultra-high strength steel materials. This work characterizes the effect of multiple functional-grading strategies (e.g. uniform, rod-graded, size-graded) on …

Development Of A Prototype Satellite-Tracking Telescope For Ground-Based Spectroscopy, Charles Smith

Graduate Theses and Dissertations

Spectroscopy is the practice of determining the chemical composition of a gas through analyzing the light that is filtered by the gas. Spectroscopy is commonly used by astronomers to deduce the atmospheric composition of planets. This process is done by initially measuring the spectrum of light from the star that the planet orbits, and then measuring it again once the planet is in between the observer and the star. The spectrum light that is filtered out is dependent on the chemical composition of the gas, and so this information can be used to determine the chemical composition of the atmosphere …

Silver Sintering Reliability And Its Enhancement For Use In High-Density Power Modules, Alicia Medina Garcia

Graduate Theses and Dissertations

This master's thesis is dedicated to enhancing the reliability of silver sinter die attachments, a pivotal component within the dynamic realm of power electronics. The study is meticulously organized into four distinct chapters, each contributing to a comprehensive understanding of silver sinter die attachment reliability and its implications for contemporary electronic packaging. In Chapter 1, an introduction is provided to the significance of silver sinter die attachment in the context of power electronics, underlining the imperatives associated with miniaturization, weight reduction, and heightened efficiency. The compelling need to investigate die attachment properties, particularly in high-temperature and high-power-density environments, is emphasized. …

An Apparatus To Quantify Lengthwise Flexural Rigidity Profiles Of Endovascular Devices, Charles B. Suskin

McKelvey School of Engineering Graduate Student Theses & Dissertations

Endovascular procedures require access to distal anatomical sites through the vasculature using catheters and guidewires. Quantitative frameworks for device behavior during procedures hold the potential to drive device design through greater understanding of the mechanical behavior of endovascular devices, and offer the potential to personalize care based on a patient's particular vascular anatomy. However, data that would facilitate this technology are lacking, partly due to undisclosed material properties from manufacturers and partly due to the intricate variations along the length of each device due to material changes and the intersections between them. We developed a three-point bend test methodology on …

Deep Ocean Vehicle Applications And Modifications, Nichole "Nikki" T. Arm

Master's Theses

This project had two primary goals: (1) to explore opportunities to further a deep-ocean vehicle’s reach using alternative pressure spheres, and (2) to implement an existing deep-ocean vehicle (lander) in active scientific research.

I gained a greater understanding of the limitations and design choices made for existing pressure spheres using Finite Element Analysis (FEA). My simplified FEA model predicted sphere failure for the existing 30% Fiber Glass 70% Nylon injection molded spheres at an external pressure of 3,954psi or 2,690m ocean-depth (only a 7.38% error compared to the tested minimum failure depth), so I determined it a valid model. I …

Accelerated Testing Of Solder Spheres Under Combined Temperature, Current, And Shear Stresses To Estimate Reliability, Collin Ruby

Graduate Theses and Dissertations

With the densification of power electronics in the pursuit of decreased size and weight and increased efficiency, the need to investigate the properties of solder in packages with higher working temperatures and power densities is becoming apparent. Many research groups have conducted accelerated testing using methods such as thermal aging, shear or tensile stress tests, or electromigration tests, but relatively little research exists that considers the impact of several stresses in a combined study. This work aims to produce a novel method for estimating the lifetime of SAC305 solder joints under a combined stress scenario, which more accurately depicts the …

The Generation Of A Physics Informed Machine Learning Model To Predict Defect Evolution In Materials & On The Thermally Activated Regime Of Dislocation Motion: A Simulation Driven Study On The Mechanical Behavior Of Crystals, Liam Myhill

All Theses

Line defects in crystals, known as dislocations, govern the mechanisms of plastic deformation at the micro-meso scale. The study of dislocations has proliferated the field of materials science and engineering for since the 1950’s, and modern studies show increasing utilization of computational methods to model the evolution of line defects in material systems. In keeping with modern research practice, the studies herewith demonstrate the use of advanced computing to generate models which can be used to better understand the behaviors of dislocations within crystal matrices. An advanced high-throughput model for a physically informed machine learning graph neural network (PIML-GNN) is …

Cfrp Delamination Density Propagation Analysis By Magnetostriction Theory, Brandon Eugene Williams

All Dissertations

While Carbon Fiber Reinforced Polymers (CFRPs) have exceptional mechanical properties concerning their overall weight, their failure profile in demanding high-stress environments raises reliability concerns in structural applications. Two crucial limiting factors in CFRP reliability are low-strain material degradation and low fracture toughness. Due to CFRP’s low strain degradation characteristics, a wide variety of interlaminar damage can be sustained without any appreciable change to the physical structure itself. This damage suffered by the energy transfer from high- stress levels appears in the form of microporosity, crazes, microcracks, and delamination in the matrix material before any severe laminate damage is observed. This …