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Full-Text Articles in Mechanical Engineering

Wave Energy Converter For Marine Vessels And Isolated Communities, Leo Kirshenbaum, Owen Pyle, Gage Howard, Charlie Camilli, Jonathan Ma, Emigdio Islas, Joseph Bonafede Jun 2023

Wave Energy Converter For Marine Vessels And Isolated Communities, Leo Kirshenbaum, Owen Pyle, Gage Howard, Charlie Camilli, Jonathan Ma, Emigdio Islas, Joseph Bonafede

Mechanical Engineering

California Polytechnic State University’s 2023 Marine Energy Collegiate Competition team, Surf Supply, has developed a floating dock that transduces wave energy into electricity. The following report aligns with MECC requirements, and our design changes since CDR are present in the User Manual in Appendix F. Our primary market research of the Blue Economy identified electric marine vessel charging and isolated communities as early adopters that could benefit most from the first generation of our wave energy converter (WEC). Surf Supply’s design concept provides a reliable, affordable, and renewable energy source that reduces dependency on conventional fossil fuels, allowing blue economy …


Headlamp/Bike Light Damping System, Ethan Reece Clark, Alec Stonehouse, Omeed Ostry, Mitchel Anderson Jun 2023

Headlamp/Bike Light Damping System, Ethan Reece Clark, Alec Stonehouse, Omeed Ostry, Mitchel Anderson

Mechanical Engineering

The task for this project is to design a headlamp and/or bike light that absorbs the impact shocks from the user’s actions. The user that the system is being designed for may be riding a bike or running on a trail in the evening or early in the morning where the light needs to be stabilized and their path must be illuminated. This report presents the final design chosen after months of prototyping and design iteration. It encompasses the system design, design verification through testing, implementation, future recommendations, and lessons learned throughout the process. The chosen design utilizes a fully …


Flexible Water Cooling, Joshua Terlaje, Andrew Lin, Nicholas Morales, Tanner Parrott Jun 2023

Flexible Water Cooling, Joshua Terlaje, Andrew Lin, Nicholas Morales, Tanner Parrott

Mechanical Engineering

The goal of this project is to develop and deploy a water-cooling system to reduce the danger of heat exhaustion among communities of farmworkers. Currently, it is difficult to keep chilled water available throughout the workday when using portable water coolers. The idea uses a refrigeration system to chill the water supply by using the power take-off (PTO) on farm equipment and a corresponding generator to get around this restriction.

The project places a strong premium on keeping the chilled water supply at a maximum temperature of 59°F to ensure compliance with the California Department of Industrial Relations' requirements. Each …


In-Situ Mechanical Tester, Andrrew Murach, Gustavo Marquez, Kosimo Tonn, Jake Vormbaum Jun 2023

In-Situ Mechanical Tester, Andrrew Murach, Gustavo Marquez, Kosimo Tonn, Jake Vormbaum

Mechanical Engineering

Over the course of the 2022-23 Cal Poly SLO school year, a small tensile tester device was developed specifically for Dr. Long Wang to test thin film materials under a microscope and generate accurate force versus displacement graphs. A tensile tester was manufactured using purchased and machined components, electronics were consolidated in a separate box and connected, and a program and user interface were written to control the motion, provide custom inputs, and organize useful data for the researcher. Tests were conducted to compare the performance of the device to universal tensile testers available in the Composites lab. The device …


Therapeutic Mechanical Horse Project, Broghan Martin, Carson Roff, Zach Barnisham, Lydia Barnes Jun 2023

Therapeutic Mechanical Horse Project, Broghan Martin, Carson Roff, Zach Barnisham, Lydia Barnes

Mechanical Engineering

This project team created a simple mechanical model of a horse that disabled children could ride on to feel more comfortable partaking in equine therapy. This project was sponsored by Jack’s Helping Hand as part of their equine therapy program. The team went through the entire design process of researching, ideating, prototyping, and testing to create the final product. Finite element analysis of the structural members of the horse was performed. The forces used in that model were later validated through testing of the strength of those same members after manufacturing. In the end, a self-actuating single degree of freedom …


Bespoke Bicycle Enclosure, Thomas Link, Kyle Mcafee, Marc Monier, Hunter Walden Jun 2023

Bespoke Bicycle Enclosure, Thomas Link, Kyle Mcafee, Marc Monier, Hunter Walden

Mechanical Engineering

Brian Higgins is an American veteran with retinitis pigmentosa who relies on cycling for transportation. The motivation for this project is to design and manufacture a refined prototype bicycle attachment to support him while biking in the rain and cold. The attachment will serve to enclose him for optimal protection from inclement weather, while maintaining sufficient mobility for daily cycling. Mr. Higgins’ bicycle is equipped with an attached sensor system which assists his visual impairment by using an ultrasonic sensor. Therefore, the attachment cannot adversely affect the function of the sensor system. The project timeline is set at approximately 7 …


Disc Golf Throwing Robot, Nevada S. Schultz, Sydney M. Lewis, Erick Edmundo Daza, Rachel Alysse Greenberg, Peter M. Kean Jun 2023

Disc Golf Throwing Robot, Nevada S. Schultz, Sydney M. Lewis, Erick Edmundo Daza, Rachel Alysse Greenberg, Peter M. Kean

Mechanical Engineering

Disc golf companies need better methods to test disc flight. The scope of this project is to create a disc throwing robot that can throw a disc golf driver 450-500 feet, with control over the speed, spin, and release angle. Research shows that multiple disc-throwing products exist; however, none meet the full requirements of this project. The Cal Poly senior project design team created a proof-of-concept machine. This prototype started as a two-wheel mechanism. Eventually, a third wheel was added, allowing for complete control over disc spin. The three-wheel prototype reached 62 mph when perfectly calibrated. The prototype is accurate, …


Baja Sae Semi-Active Suspension, Cameron Paul Jones, Ethan Jacobi Mikel, Joshua Macguire Wright, Aditya Garg Jun 2023

Baja Sae Semi-Active Suspension, Cameron Paul Jones, Ethan Jacobi Mikel, Joshua Macguire Wright, Aditya Garg

Mechanical Engineering

This document outlines the design and justification for the final design of the Baja SAE Semi-Active Suspension Senior Project. The goal of the project was to build a base valve that can adjust suspension damping rates on the fly. This document details the ideation, design, manufacturing, design verification results, and detailed drawing package for the project. Additionally, this document includes information regarding the pressure drop calculator, O-ring calculations, and CAD. The manufacturing processes used to create the valve and the testing and evaluation of the valve are included as well. Finally, the methods that were used to manage this project …


Mechanics Desktop Lab Equipment, Dante Azpilcueta, Quentin F. Mormann, Arfan Ansar Jun 2023

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 Jun 2023

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 Jun 2023

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 …


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 Jun 2023

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, Ac1 and Ac3, 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. …


Implementation Of Topology Optimization Into The Mechanical Design Process, Nolan Clapp Jun 2023

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 …


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 Jun 2023

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 Jun 2023

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 …


Optimal Domain-Partitioning Algorithm For Real-Life Transportation Networks And Finite Element Meshes, Jimesh Bhagatji, Sharanabasaweshwara Asundi, Eric Thompson, Duc T. Nguyen Jun 2023

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 …


Wave Energy Converters With Rigid Hull Encapsulation: A Review, Mahmodul Hasan Maheen, Yingchen Yang Jun 2023

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 …


Sky Survey Radio Telescope, Jack E. Mcguigan Jun 2023

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 …


Programmable Vibration Table Retrofit With Eagle Medical, Jonathan Ilagan, Madhav Asok, Max Lewter Jun 2023

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 Jun 2023

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 …


Weed Robot, Kaela Stern, Lewis Kanagy, Claire Franz, Carlos Rodriguez Orozco, Jackie Chen, Sachi Hiji, Ayush Kakkanat, William Ta Jun 2023

Weed Robot, Kaela Stern, Lewis Kanagy, Claire Franz, Carlos Rodriguez Orozco, Jackie Chen, Sachi Hiji, Ayush Kakkanat, William Ta

Mechanical Engineering

Team Weed Scouts has completed our work on a weed-cutting robot for the Girl Scouts of California’s Central Coast. The final robot build provides a solid foundation that can be built and improved upon by future teams. We have completed the robot base and structure, including the chassis, drivetrain, and robot shell. We also completed manufacturing a weed storage bin and canvas cover for the robot. Additionally, we have built a weed scooper, the mechanism that cuts weeds and transports them into a storage compartment. The electronics and programming for remote control of the robot are also implemented. After some …


Metamaterial-Based Soft Actuators, Savannah June Cheney, Nathan Kessenich, Marco Leen, Merek Mcgill Jun 2023

Metamaterial-Based Soft Actuators, Savannah June Cheney, Nathan Kessenich, Marco Leen, Merek Mcgill

Mechanical Engineering

For this project the team was tasked with designing a soft actuator that incorporated aspects of mechanical metamaterials. The team’s goal was to demonstrate the feasibility of structural metamaterials in the field of soft robotics and demonstrate a novel response with a final assembly. Also included in the team's discussion are the manufacturing steps, protype tests & results, and suggested future next steps. Following the previous report (critical design review) the team chose to follow the path of designing a continuum robot with metamaterials incorporated into the design. A continuum robot consists of a soft cylindrical body with rigid evenly …


3d Printed Aircraft, Matthew Nagy, Charles D'Amico, Alexis Salgado Medina Jun 2023

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 …


3d Printed Poly Lactic Acid Structures For Cell Growth And Nanoparticle Transport-Simulation And Experimental Validation, Shrikrushna Vinayak Sonawane Jun 2023

3d Printed Poly Lactic Acid Structures For Cell Growth And Nanoparticle Transport-Simulation And Experimental Validation, Shrikrushna Vinayak Sonawane

Masters Theses

In today's world, 3D printing or additive manufacturing (AM) is being widely used in various fields due to its benefits such as rapid prototyping, reduced material waste and energy usage, lower cost, and more. Even the tissue engineering field is utilizing this technology. This study focused on examining the compatibility of 3D printed Lab-on-a-Chip structures made of Poly Lactic Acid (PLA) for in-vitro applications. In this research, the Lab-on-a-Chip structures were designed and created using 3D printing. To achieve the required bio-functionality scaffold surface was customized by post-printing processes such as mechanical polishing, hydrolysis (Wet Chemical Etching), and ultraviolet light …


A Study On The Design And Production Of A Desktop Vaccuum Cleaner, Aaryan Manoj Nair, Emanuel Pichardo, Isaiah Ortiz, Naeem Kotadia Jun 2023

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 …


Computational Study On The Acoustic Footprint Of Stenosis In Larger Arteries, Ahmed Abdelnabi Jun 2023

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.


Measurement Of Polycyclic Aromatic Hydrocarbons (Pahs) On Indoor Materials: Method Development, Aurélie Laguerre, Elliott T. Gall Jun 2023

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 …


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 Jun 2023

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.


Gradient-Based Trade-Off Design For Engineering Applications, Lena A. Royster, Gene Hou Jun 2023

Gradient-Based Trade-Off Design For Engineering Applications, Lena A. Royster, Gene Hou

Mechanical & Aerospace Engineering Faculty Publications

The goal of the trade-off design method presented in this study is to achieve newly targeted performance requirements by modifying the current values of the design variables. The trade-off design problem is formulated in the framework of Sequential Quadratic Programming. The method is computationally efficient as it is gradient-based, which, however, requires the performance functions to be differentiable. A new equation to calculate the scale factor to control the size of the design variables is introduced in this study, which can ensure the new design achieves the targeted performance objective. Three formal approaches are developed in this study for trade-off …


Unmanned Aerial Vehicle-Based Computer Vision For Structural Vibration Measurement And Condition Assessment: A Concise Survey, Kai Zhou, Zequn Wang, Yi Qing Ni, Yang Zhang, Jiong Tang Jun 2023

Unmanned Aerial Vehicle-Based Computer Vision For Structural Vibration Measurement And Condition Assessment: A Concise Survey, Kai Zhou, Zequn Wang, Yi Qing Ni, Yang Zhang, Jiong Tang

Michigan Tech Publications

With the rapid advance in camera sensor technology, the acquisition of high-resolution images or videos has become extremely convenient and cost-effective. Computer vision that extracts semantic knowledge directly from digital images or videos, offers a promising solution for non-contact and full-field structural vibration measurement and condition assessment. Unmanned aerial vehicles (UAVs), also known as flying robots or drones, are being actively developed to suit a wide range of applications. Taking advantage of its excellent mobility and flexibility, camera-equipped UAV systems can facilitate the use of computer vision, thus enhancing the capacity of the structural condition assessment. The current article aims …