Mechanical Engineering Commons^™

Gas Metal Arc Welding With Undermatched Filler Wire For Hot-Press-Formed Steel Of 2.0 Gpa Strength: Influence Of Filler Wire Strength And Bead Geometry, Dong-Yoon Kim, Cheolhee Kim, Tae Hyen Lee, Minjung Kang, Junhong Park

Mechanical and Materials Engineering Faculty Publications and Presentations

Commercial welding filler wires have less strength than hot-press-forming (HPF) steels. As the 2.0 GPa-HPF steel sheets have been released, their lap welding characteristics were investigated using gas metal arc welding in this study. The base metal was 1.1 mm-thick 2.0 GPa-HPF steel sheets, and three filler metal wires considered in this study (W540, W920, and W980) had tensile strengths of 540, 920, and 980 MPa, respectively. Gas metal arc welding was performed under a controlled short-circuit mode, and the wire feed speed (WFS) was selected as a process parameter. Tensile-shear test and microscopy were performed to evaluate the joint …

Spheroidization Heat Treatment Conditions With Data Analysis In Medium Carbon Cr-Mo Steel For Ultra High Strength Cold Heading, Yong Deok Jo, Sung Yi, Byoung Lok Jang

Mechanical and Materials Engineering Faculty Publications and Presentations

The degree to which parameters affect the spheroidization heat treatment of steel was calculated by setting the spheroidization heat treatment conditions of Cr-Mo steel and using data analysis such as S/N ratio and ANOVA. After analyzing the transformation temperatures of the steel, A_c1 and A_c3, using a DSC, the conditions were set accordingly. The surface hardness was measured for the conditions and used as an evaluation index. The correlation was analyzed by comparing the spheroidized volume fraction and the surface hardness, and the Pearson correlation coefficient was -0.88, proving that a correlation existed between the two values. …

Measurement Of Polycyclic Aromatic Hydrocarbons (Pahs) On Indoor Materials: Method Development, Aurélie Laguerre, Elliott T. Gall

Mechanical and Materials Engineering Faculty Publications and Presentations

Wildfire smoke penetrates indoors, and polycyclic aromatic hydrocarbons (PAHs) in smoke may accumulate on indoor materials. We developed two approaches for measuring PAHs on common indoor materials: (1) solvent-soaked wiping of solid materials (glass and drywall) and (2) direct extraction of porous/fleecy materials (mechanical air filter media and cotton sheets). Samples are extracted by sonication in dichloromethane and analyzed with gas chromatography–mass spectrometry. Extraction recoveries range from 50–83% for surrogate standards and for PAHs recovered from direct application to isopropanol-soaked wipes, in line with prior studies. We evaluate our methods with a total recovery metric, defined as the sampling and …

Mechanics Desktop Lab Equipment, Dante Azpilcueta, Quentin F. Mormann, Arfan Ansar

Mechanical Engineering

This paper overviews the design, implementation and testing of a senior project designed to fix the issue of there being no lab equipment or space for content pertaining to mechanic of materials topics. This is of concern as Cal Poly is reorganizing content as it switches to the semester system and is in need of labs for this material. The solution found was to create a portable miniature universal test machine that could be carted into non-lab classrooms. The goal was to create a device that was low-cost, modifiable, durable, easy to manufacture and repair as these were the qualities …

Valve Efficiency Testing Device, Jake Robert Rydberg, Andrew Keith Willardson, Jake Ben Jezier, Emily Marie Wannenmacher

Mechanical Engineering

This document serves as the official Final Design Review (FDR) for the mechanical engineering team on the Valve Efficiency Testing Device project for the Phillips 66 Rodeo Refinery. The team attends California Polytechnic State University, San Luis Obispo. The project involved designing and building a valve efficiency testing device. The goal was to create a finished test device that can be used in the Phillips 66 Rodeo Refinery machine shop to test reciprocating compressor valves before they are installed. The purpose of this document is to describe the manufacturing and design verification activities that have been completed since Critical Design …

The Center For Centering Dome, Olek Piechaczek, Ryan M. Scharf

Architectural Engineering

The Center for Centering seeks to create a large-scale healing center, conducive to individual centering of the mind and body. This mobile installation provides a relaxing, enclosed space while still maintaining a connection to the outdoors. The clients liked the idea of having a pop-up installation that could be easily set up as a touring display. With a deadline for installation looming in June 2022, a team of students had five months to design and manufacture the structure.

In winter 2022, the students developed custom geometry to minimize the number of individual parts and built a ¼ scale model of …

Optimal Domain-Partitioning Algorithm For Real-Life Transportation Networks And Finite Element Meshes, Jimesh Bhagatji, Sharanabasaweshwara Asundi, Eric Thompson, Duc T. Nguyen

Civil & Environmental Engineering Faculty Publications

For large-scale engineering problems, it has been generally accepted that domain-partitioning algorithms are highly desirable for general-purpose finite element analysis (FEA). This paper presents a heuristic numerical algorithm that can efficiently partition any transportation network (or any finite element mesh) into a specified number of subdomains (usually depending on the number of parallel processors available on a computer), which will result in “minimising the total number of system BOUNDARY nodes” (as a primary criterion) and achieve “balancing work loads” amongst the subdomains (as a secondary criterion). The proposed seven-step heuristic algorithm (with enhancement features) is based on engineering common sense …

Computational Study On The Acoustic Footprint Of Stenosis In Larger Arteries, Ahmed Abdelnabi

Theses and Dissertations

We identify a new (acoustic) frequency-stenosis relations whose frequencies fall within the recommended auscultation threshold for stethoscopy (< 120 Hz) in this study. We demonstrate that these relations can be used to extend the application of phonoangiography (the measurement of the degree of stenosis from bruits) to stethoscopes that are broadly available. The First relationship is successfully identified using an analysis limited to the acoustic signature of the von Karman vortex street, which we automatically isolate using a metric based on an area-weighted average of the Q-criteria for the post-stenotic region. Specifically, we conduct LES-CFD simulations on simplified 2D internal flow geometries that represent blood vessels with varying degrees of stenosis. Then, using the Ffowcs Williams-Hawkings (FW-H) equation, we extract their emitted acoustic signals, which we subtract from a pure signal (stenosis-free) at the same heart rate. Next, we transform this differential signal to the frequency domain and meticulously classify its acoustic signatures according to six stenosis-invariant flow phases of a cardiac cycle. Using our Q-criterion-based metric, we then automatically restrict our acoustic analysis to the noises emitted by the von Karman vortex street (phase 4). Our analysis of its acoustic signature demonstrates a strong linear relationship between the degree of steno- sis and its dominant frequency, which differs significantly from the break frequency and heart rate (previously identified dominant frequencies). For the Second relationship, we develop a frequency-stenosis scaling law for particularly supravalvular aortic stenosis that falls within the preferred frequency range (30-120 Hz) for echocardiography. We expand to 3D patient specific geometry using Simulia’s Living Heart Human Model (LHHM), which has an anatomically accurate aorta geometry. This LHHM geometry is modified with stenoses ranging from 30 to 80 percent (moderate to severe). For physiologically consistent hemodynamic boundary conditions, we expand the study to employ the Windkessel model, which has been implemented on Fluent using UDF. We demonstrate that physiological boundary conditions reduce simulation time significantly compared to static boundary conditions. The FW-H model extracted the flow-generated acoustic signal of the stenotic geometries and analysed it at clinically relevant receiver locations. A preferred receiver location consistent with clinical practise is determined, and a correlation between the degree of stenosis and the prevalent acoustic frequency (within the frequency range of 70-120 Hz) is established. The obtained second scaling law is shown to be clinically reliable in assessing stenotic severity. Future research will investigate incorporating the vibroacoustic role of adjacent organs and tissue to expand the clinical applicability of our findings. Expansion of clinical and numerical datasets will be pursued in future research to enhance the reliability of our scaling law, possibly by leveraging much-needed ML-based acceleration schemes.

Thermohydraulic Performance Of 3d Printed Metal Heat Exchanger With Zig-Zag Minichannels, Aysha Rashed Alshamsi

Theses

This work proposes using zig-zag minichannels in heat exchangers for enhancing its performance while operating under balanced (heat capacity ratio of unity) and unbalanced flow (heat capacity ratio of 0.5) conditions for counter flow and parallel flow configurations. The performance of the heat exchangers is quantified in terms of effectiveness and pressure drops and studies are done for hot fluid Reynolds number ranging from 50 to 1500. This work employs a numerical study to investigate the performance of the heat exchanger with zig-zag minichannels.
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Novel Approach For Non-Invasive Prediction Of Body Shape And Habitus, Emma Young

Electronic Theses and Dissertations

While marker-based motion capture remains the gold standard in measuring human movement, accuracy is influenced by soft-tissue artifacts, particularly for subjects with high body mass index (BMI) where markers are not placed close to the underlying bone. Obesity influences joint loads and motion patterns, and BMI may not be sufficient to capture the distribution of a subject’s weight or to differentiate differences between subjects. Subjects in need of a joint replacement are more likely to have mobility issues or pain, which prevents exercise. Obesity also increases the likelihood of needing a total joint replacement. Accurate movement data for subjects with …

Sky Survey Radio Telescope, Jack E. Mcguigan

Electrical Engineering

This document outlines the design of a radio telescope designed to perform hydrogen line sky surveys. The telescope produces radio images mapping the intensity and relative velocities of hydrogen concentrations to their sky coordinates. Over the course of a day, the telescope images the regions of space visible to it, allowing sky survey imagery to be updated daily. Sky survey images are comprised of an array of pixels corresponding to specific sky coordinates. Each 8-bit RGB pixel contains information on the concentrations of hydrogen in the brightness and relative velocity in the color. Radio images mapping the concentrations and velocities …

The Role Of High-Order Anharmonicity And Off-Diagonal Terms In Thermal Conductivity: A Case Study Of Multi-Phase Cspbbr3, Xiangdong Ding, Guimei Zhu, Yi Xia, Jie Ren, Jun Sun, Multiple Additional Authors

Mechanical and Materials Engineering Faculty Publications and Presentations

We investigate the influence of three- and four-phonon scattering, perturbative anharmonic phonon renormalization, and off-diagonal terms of coherent phonons on the thermal conductivity of CsPbBr3 phase change perovskite, by using advanced implementations and first-principles simulations. Our study spans a wide temperature range covering the entire structural spectrum. Notably, we demonstrate that the interactions between acoustic and optical phonons result in contrasting trends of phonon frequency shifts for the high-lying optical phonons in orthorhombic and cubic CsPbBr3 as temperature varies. Our findings highlight the significance of wavelike tunneling of coherent phonons in ultralow and glasslike thermal conductivity in halide perovskites.

A Study On The Design And Production Of A Desktop Vaccuum Cleaner, Aaryan Manoj Nair, Emanuel Pichardo, Isaiah Ortiz, Naeem Kotadia

Publications and Research

The goal of this project was to design a desk-top vacuum cleaner that is compact, portable, and effective in cleaning desktops and tabletops. Two concepts were proposed and compared using Quality Function Deployment (QFD) and various metrics, including in-use purposes and market, technical feasibility, ease of use, durability, and cost. The two concepts were a lifting design with hydraulics and a differently sized offset wheel design. After thorough analysis, it was determined that the lifting design with hydraulics was the better concept due to its adjustability and ability to reach different heights and angles on tabletops. The proposed product title …

Biomechanical Knee Joint For Exoskeleton, Gabriel Ireton Ahern, Calloway Miller, Christianna Altamura, Eric Mailes

Mechanical Engineering

Our senior design project consisted of designing and manufacturing a biomechanically accurate, actuated knee joint to be integrated into an exoskeleton being developed by the Lower Limb Exoskeleton Assist Project (LLEAP), a part of the EMPOWER student association at Cal Poly, San Luis Obispo. As the human knee flexes and extends throughout gait motion, the center of rotation changes. Currently marketed exoskeletons have one point of rotation, which over constrains the knee and causes misalignment between the user and the suit [1]. Our goal was to mimic natural knee joint motion by changing the center or rotation, thus reducing misalignment …

Turbine Integrated Pitching System, Elizabeth Costley, Josephine Maiorano, Jeff Larson, Cameron Jackson

Mechanical Engineering

The Cal Poly Wind Power Club (CPWP) tasked this senior project to design, manufacture, test, and deliver a mechanism to pitch the blades for their small-scale horizontal axis wind turbine. CPWP competes in the Collegiate Wind Competition (CWC) against schools across the country, and as such it was critical to comply with the provided competition rules in addition to the design requirement from CPWP. The purpose of the pitching mechanism is to improve the performance and efficiency of the wind turbine by allowing the blades to adjust angles with different wind speeds. Specifically, this project aimed to minimize hub size, …

Prove Primary Battery Structure, John D. Burkhart, Andy Mccormick, Ryan Yu, Soren Barclay

Mechanical Engineering

In conjunction with Prototype Vehicle (PROVE) Laboratory, our group designed, manufactured, and tested a prototype structure to house the battery boxes for PROVE’s endurance vehicle. Our structure was designed to support the batteries during normal use, and in the event of a front crash. Our design is comprised of a secondary composite box to house the battery boxes, a bottom plate to affix the secondary box to the chassis floor, a horizontal plate fastened to the chassis, and a brace structure welded to the chassis. From the outset, we chose to use a secondary box, the primary battery boxes must …

Rapid Composter, Shannon Shinozaki, Avin Atencio, Jonathan Fraser, Lukas Kolbl, Russell Occhipinti

Mechanical Engineering

This project was created with the intent of automatically composting equine bio waste to be reused as plant fertilizer. The system consists of four subsystems: power generation and storage, automatic controls, aeration, and structure. Each subsystem may be manufactured independently, then put together. This system will not have access to power outlets, so it was designed to be solar-powered.

Parametric Bicycle Yoke, Colin Reay, Walter Minehart, Robby Harrigan, Jordan Olson

Mechanical Engineering

This report outlines the entire design, fabrication, and validation process of a parametric yoke design that addresses the packaging problem of the bottom-bracket chainstay junction in modern bicycle frames. The goal was to create an elegant, space-efficient solution that is accessible to the Cal Poly Bike Builders Club. The report includes documentation of the three-part fixture system, manufacturing process, and testing results for the yoke.

Our yoke design outperforms traditional round-tube weldments in torsional and vertical stiffness. Additionally, all manufacturing fixtures and machining operations function as intended, resulting in a finished yoke that meets all required tolerances in under an …

Treadmill Platform For Quadrupedal Robots, Baxter J. Bartlett, Jack F. Butler, Phillip A. Shafik, Tarun S. Ganamur

Mechanical Engineering

Cal Poly Legged Robots, led by Professor Refvem and Professor Xing, has been leading Cal Poly’s attempts to simulate, produce, and test their legged robots. The initial testing of the locomotion of these robots can be dangerous to the robot since any bugs in the code could cause the robot to fall over and harm itself. Our responsibility as a team was to deliver a portable platform for testing the locomotion capabilities containing a fall prevention mechanism. In short, we have designed a platform for this purpose that consists of a treadmill surrounded by a wheeled chassis with a system …

Perforated Groove Cam Lock, Matthew J. Redmond, Samuel A. Potter, Dylan Weiglein, Andrew Reese

Mechanical Engineering

NASA Artemis III astronauts need a way to attach and detach various tools to an extension handle to be used during lunar EVA sample collection. Because lunar dust is so harsh and abundant, mechanisms must be designed to function regardless of the number of contact particulates. Past designs used on the Apollo missions proved to be problematic for their operators, opening the door for innovative improvement. A new mechanism has been proposed that directly addresses the performance issues of the original handle extension mentioned in NASA’s Apollo mission reports. The new mechanism boasts an open design that promotes dust tolerance …

3d Printed Aircraft, Matthew Nagy, Charles D'Amico, Alexis Salgado Medina

Mechanical Engineering

This project is to design, build, and test a 3D-printable aircraft. The goal is to create a final design that will be able to fly for the longest duration possible, around 20 seconds. To determine the correct preliminary design and manufacturing process for a 3D printed RC aircraft, an analysis of multiple design options and manufacturing materials was performed. This allowed for a variety of choices for aircraft type, airfoil design, structure, among other topics to be narrowed down to the most promising option. It has been found that the aircraft will follow a design similar to industry motor-gliders, with …

Backflow Relief Valve Test Stand, Olivia Mcnulty, Wiill Halvorsen, Ryan Dubois, David Leaman

Mechanical Engineering

This Final Design Review (FDR) document details the final design, manufacturing, testing, and results of the Zurn Wilkins Backflow Relief Valve Test Stand Project under the sponsorship of Brian Yale and Rueben Westmoreland. This project involves simulating real-world conditions of static pressure and water hammer cycling. The stand will give Zurn Wilkins’ engineers a method by which to test their relief valves prior to a rigorous, yearlong University of Southern California (USC) testing procedure. Our design involves using city water, a pump, a Zurn backflow preventer, and a control system to apply specific pressures to each end of the relief …

Saver: Surface Autonomous Vehicle For Emergency Rescue, Lucas Je Sandsor, Michelangelo Coltelli, Brian Wong, Sebastion Rivero, Kobe Hayashi

Mechanical Engineering

The design, fabrication, and testing of an unmanned surface vehicle for the NASA Micro-G NExT SAVER challenge. This device features a radio direction finding phase array to autonomously navigate to an emergency distress beacon to deliver emergency supplies.

Wave Energy Converters With Rigid Hull Encapsulation: A Review, Mahmodul Hasan Maheen, Yingchen Yang

Mechanical Engineering Faculty Publications

Highlights

• WECs with rigid hull encapsulation are water-tight and robust.

• Diverse internally embedded power take-off designs are summarized.

• Various mechanisms and strategies for frequency tuning are formulated.

• Typical WEC testing methods are discussed.

• Some future research considerations are suggested.

Abstract

Ocean wave energy has a great potential in mitigating energy and sustainability crises of the 21st century. The lack of mature and cost-competitive wave energy converter (WEC) technologies, however, has become a major roadblock for WEC products entering the marketplace. A harsh ocean environment, which includes extreme waves, strong biological activities, and chemical transformations, adds to the maintenance cost and …

Patient Movement Monitoring Based On Imu And Deep Learning, Mohsen Sharifi Renani

Electronic Theses and Dissertations

Osteoarthritis (OA) is the leading cause of disability among the aging population in the United States and is frequently treated by replacing deteriorated joints with metal and plastic components. Developing better quantitative measures of movement quality to track patients longitudinally in their own homes would enable personalized treatment plans and hasten the advancement of promising new interventions. Wearable sensors and machine learning used to quantify patient movement could revolutionize the diagnosis and treatment of movement disorders. The purpose of this dissertation was to overcome technical challenges associated with the use of wearable sensors, specifically Inertial Measurement Units (IMUs), as a …

Programmable Vibration Table Retrofit With Eagle Medical, Jonathan Ilagan, Madhav Asok, Max Lewter

Biomedical Engineering

This project aimed to repair and upgrade a vibration table used for package testing for the sponsor, Eagle Medical - a medical packaging and sterilization company based in Paso Robles, California. The current vibration table is not programmable and lacks circuit diagrams, making it difficult to repair. In addition, it is not functional due to internal circuitry issues and power requirements. To address these issues, the team will implement several upgrades to improve the product and allow for better random cyclic vibration testing. A full assessment of the existing vibration table will be conducted to ensure the viability of these …

Neuroevolution Application To Collaborative And Heuristics-Based Connected And Autonomous Vehicle Cohort Simulation At Uncontrolled Intersection, Frederic Jacquelin, Jungyun Bae, Bo Chen, Darrell Robinette

Michigan Tech Publications

Artificial intelligence is gaining tremendous attractiveness and showing great success in solving various problems, such as simplifying optimal control derivation. This work focuses on the application of Neuroevolution to the control of Connected and Autonomous Vehicle (CAV) cohorts operating at uncontrolled intersections. The proposed method implementation’s simplicity, thanks to the inclusion of heuristics and effective real-time performance are demonstrated. The resulting architecture achieves nearly ideal operating conditions in keeping the average speeds close to the speed limit. It achieves twice as high mean speed throughput as a controlled intersection, hence enabling lower travel time and mitigating energy inefficiencies from stop-and-go …

User Guide For Urban Canopy Modeling In Wrf. Version 1.0, Corey L. Smithson, Natalie J. White, Hans R. Klomp, Eric C. Monson, Bradley R. Adams

Faculty Publications

Researchers at Brigham Young University (BYU) have developed this guide for running a WRF simulation using a single layer urban canopy model (UCM). This was developed specifically for the Greater Salt Lake Area but is adaptable to other urban areas. This guide includes information on running WRF simulations to study theoretical urban growth scenarios.

Vortex Particle Method For Electric Ducted Fan In Non-Axisymmetric Flow, Eduardo Alvarez, Cibin Joseph, Andrew Ning

Faculty Publications

The vortex particle method has been reformulated in recent work as a large eddy simulation (LES) in a scheme that is both meshless and numerically stable, solving long-standing issues of numerical stability. In this study, we build upon this meshless LES scheme to create a simulation framework for electric ducted fans. This poses the challenge of introducing solid boundaries in the vorticity form of the Navier-Stokes equations without a mesh. Rotor blades are introduced in our computational domain through an actuator line model (ALM) following well-established practices for LES. A novel, vorticity-based, actuator surface model (ASM) is developed for the …

Implementation Of Topology Optimization Into The Mechanical Design Process, Nolan Clapp

Master's Theses

Topology Optimization is a lightweighting method based on finite element analysis that produces a part with optimum material distribution in the design space. Results from topology optimization often have organic shapes and curves that are difficult if not impossible to machine with traditional subtractive manufacturing methods. This paper analyzes the implementation of the Solidworks® Topology Optimization add-in into the mechanical design process and discusses required postprocessing to ensure manufacturability of the optimized part though a case study on two example parts. Results of traditional optimization, topology optimization and “selective” optimization (optimization using the results from topology optimization to selectively remove …