Applied Mechanics Commons^™

In-Situ Tribology Of Engineered Surfaces With 3d-Printed Micro/Nano-Textures, Mahyar Afshar Mohajer

Graduate Theses and Dissertations

Surface texturing is an effective way to reduce the adhesion and friction between two contacting surfaces by reducing the real area of contact between them, providing a potential solution for adhesion and friction-induced failures, for example, failures in micro-/nano-electromechanical systems (MEMS/NEMS). Surface texturing is also essential to the realization of functional surfaces such as superhydrophobic/philic and icephobic surfaces. However, textures are prone to deformation due to being subjected to higher contact pressures. The advancement of 3D nanoprinting by two-photon lithography (TPL), combined with the ability to make an in-situ observation of the interplay between the forces and the sliding surfaces …

Multiscale Topology Optimization With A Strong Dependence On Complementary Energy, Dustin Dean Bielecki

All Dissertations

A discrete approach introduces a novel deep learning approach for generating fine resolution structures that preserve all the information from the topology optimization (TO). The proposed approach utilizes neural networks (NNs) that map the desired engineering properties to seed for determining optimized structure. This framework relies on utilizing parameters such as density and nodal deflections to predict optimized topologies. A three-stage NN framework is employed for the discrete approach to reduce computational runtime while maintaining physics constraints.

A continuous representation that uses complementary energy (CE) methods to solve a representative element's homogenized properties consists of an embedded structure that is …

Use Of Precious Plastic Method Of Bricks For The Construction Of Tiny Homes, Haylie E. Tallon

Architectural Engineering

Precious Plastics, a Netherlands based company, created an open source project that can be used to create different objects from recycled plastics. The San Luis Obispo area has a large amount of recyclable plastic that is being treated as trash, adding to the pollution of the ocean and the air. This project is to determine the necessary steps to create plastic building blocks, using the Precious Plastic process, as a construction material for low-income, temporary housing. This report covers the process that was used to build two of the machines that will be used to create the bricks. This requires …

Multiple Objective Function Optimization And Trade Space Analysis, Yifan Xu

All Theses

Optimization can assist in obtaining the best possible solution to a design problem by varying related variables under given constraints. It can be applied in many practical applications, including engineering, during the design process. The design time can be further reduced by the application of automated optimization methods. Since the required resource and desired benefit can be translated to a function of variables, optimization can be viewed as the process of finding the variable values to reach the function maxima or minima. A Multiple Objective Optimization (MOO) problem is when there is more than one desired function that needs to …

Gasifier Wall Wash Manifold, Ashley Sieu Che, Gintaras Julius Baipsys, Peyton Joseph Archibald, Michael Thomas Kieran

Mechanical Engineering

The objective of our Gasifier Wall Wash Manifold Project is to design three different manifolds that will uniformly distribute water on the inner diameter of a pressure vessel. Also, the distributed water should completely cover the circumference of the inner walls. From extensive research of current solutions as well as the conduction of technical analyses, we were able to produce three designs that would be able to meet our engineering specifications. Time constraints led to the fabrication of one manifold design along with a test rig. With a fully functional test rig, we saw positive results from our design verification …

Novel Hitch Cargo Cart, Cesilio Sanchez Ramirez, Lance Haidet, Richard Lontoc, Tyler Selinka

Mechanical Engineering

This document presents the engineering design process used to develop, manufacture, and test a new and improved iteration of a hitch cart prototype. This process was performed by a team of four mechanical engineering seniors as part of California Polytechnic State University, San Luis Obispo’s senior design pathway. The goal of this project was to develop a sturdy and reliable iteration of our sponsor’s hitch cart prototype, that integrated the functionality of a vehicle hitch cargo platform and that of a height adjustable cargo cart into a single streamlined and easy to use product. This design could be used by …

Modeling, Control And Estimation Of Reconfigurable Cable Driven Parallel Robots, Adhiti Raman Thothathri

All Dissertations

The motivation for this thesis was to develop a cable-driven parallel robot (CDPR) as part of a two-part robotic device for concrete 3D printing. This research addresses specific research questions in this domain, chiefly, to present advantages offered by the addition of kinematic redundancies to CDPRs. Due to the natural actuation redundancy present in a fully constrained CDPR, the addition of internal mobility offers complex challenges in modeling and control that are not often encountered in literature.

This work presents a systematic analysis of modeling such kinematic redundancies through the application of reciprocal screw theory (RST) and Lie algebra while …

Novelty Ice Cream Assembly Prototype, Mason Sylvester, Logan Williamson, Alvaro Martinez, Adin Gilman-Cohen

Mechanical Engineering

Cool Beans USA is a novelty ice cream startup company founded by Keith Zachow. In the winter of 2022, our team began working with Mr. Zachow to develop a machine to automate parts of the production process for his product. This product consists of two hemispherical ice-cream cone shell halves filled with soft serve ice cream and pressed together. The assembled pods are around the size and shape of a small walnut and are intended to be sold in stores as a frozen finger food. At the time of project inception, this product was in its early stages and was …

Low-Cost, Low-Weight Test Rig Design For A Laboratory-Scale Twin Rotor Wind Turbine, Ahmed Ayoub, Ahmed Elzeedy, Mahmoud Elkordy, Eslam Ayad, Mohamed Waleed, Amira Elkodama, Amr Ismaiel

Future Engineering Journal

Multi-Rotor Wind Turbine (MRWT) has been proven advantageous over Single-Rotor Wind Turbine (SRWT) in many aspects. In order to study the performance of MRWT over SRWT, this work presents a low-cost and low-weight design for a test rig for laboratory-scale wind turbine configurations. The configurations under study are a single-rotor, and a twin-rotor of the same size with a diameter of 30 cm. Aerodynamic loads have been calculated using the Blade Element Momentum (BEM) method, then the loads were used for stress analysis over the test rig proposed. The test rig is designed on Solidworks and the aerodynamic and inertial …

Effet De La Perte Auditive Et Du Port De Protecteurs Auditifs Sur La Perception Et La Localisation Auditive Des Alarmes De Recul, Véronique Vaillancourt, Chantal Laroche, Christian Giguère, Hugues Nélisse

Rapports de recherche scientifique

Chaque année, des travailleurs se font heurter par un véhicule qui manœuvre en marche arrière. Certaines caractéristiques des alarmes de recul conventionnellement utilisées en milieu de travail (alarmes tonales « bip-bip ») compromettent leur performance à avertir adéquatement les travailleurs de l’approche d’un véhicule, du moins comparativement aux plus récentes alarmes à large bande (« pshit-pshit »). On cite trois principaux désavantages de l’alarme tonale, soit une plus grande difficulté à localiser la provenance du signal sonore dans l’espace, un patron de propagation sonore irrégulier derrière le véhicule lourd, ainsi qu’une nuisance sonore (ou pollution sonore) accrue.

Des études antérieures …

Tunable Filtration Of Particles During Dip-Coating, Connor Copeland

All Theses

When a solid substrate is withdrawn from a liquid bath a thin coating is deposited whose thickness is given by the Landau-Levich-Derjaguin (LLD) law. We perform an experimental study of dip coating of particle suspensions showing that particles of a given size can become entrained in the meniscus by the competition between viscous and surface tension forces. This is called capillary filtration and can be used as a tunable dynamic filter. For single particle suspensions, filtration can be in terms of either clumps or single particles, with the relevant entrainment points depending upon the rheology of the working fluid, either …

An Investigation Into The Velocity-Dependence Of The Coefficient Of Friction Between Concrete And Maraging Steel, Trace A. Duncan

Theses and Dissertations

This work investigates the velocity-dependent coefficient of friction between concrete and 300 Maraging steel over short displacements. A modified torsional Hopkinson bar is utilized for rotating thin-walled steel rings in contact with a concrete disk under static precompression. Rotational velocity is varied between tests to determine the velocity dependence of the friction coefficient. Normal force is varied between certain tests to determine the pressure dependence of the friction coefficient between the concrete and steel. Three different types of concrete are tested to deduce any composition effect on the friction coefficient. Dry and greased conditions’ impact on the friction coefficient are …

The Temperature Dependent Mechanical Response Of M250 Maraging Steel And Its Implications On Wire Arc Additive Manufacturing, Frank M. Brinkley Iii

Theses and Dissertations

Wire-arc additive manufacturing (WAAM) is becoming increasingly common for large scale additive manufacturing (AM) applications because of its high deposition rate (2-3 kg/hr.). The rapid temperature changes and subsequent evolution of mechanical properties during AM can lead to large distortion and residual stresses. Finite element modeling of the AM process shows promise to minimize part distortion and residual stresses through improved path planning and process parameter optimization. However, accurate material properties of M250 before and after heat treatment are needed to properly characterize the property evolution from annealed to AM, to aged. Due to limited data on annealed M250, this …

Foundations For Finite-State Modelling Of A Two-Dimensional Airfoil That Reverses Direction, Jake Michael Oscar Welsh

McKelvey School of Engineering Graduate Student Theses & Dissertations

Current 3-D finite-state wake models are incapable of simulating a maneuver in which the sign of the free-stream velocity changes direction and the rotor enters its own wake -- as might occur in the case of a helicopter which ascends and then descends. It is the purpose of this work to create a 2-D finite-state wake model which is capable of handling changes in free-stream direction as a precursor to development of a 3-D model that can do the same.

The 2-D finite-state model used for reentry modifications is an existing model created by Peters, Johnson, and Karunamoorthy. By the …

Creep Behavior Of A Ti-Based Multi-Principal Element Alloy, Benjamin Elbrecht

All Theses

Abstract

The understanding of microstructural damage mechanisms is the foundation of better understanding existing materials and future material development. There are significant challenges to measuring these damage mechanisms in-situ as continuous observation of the state of the microstructure is difficult or impossible for many experimental setups. This thesis presents a method for measuring grain boundary sliding (GBS) and local strain concentrations in-situ via a Heaviside function based algorithm. GBS is the shearing of two grains along their shared grain boundary and is a common damage mechanism in creep which presents as a discontinuity that can be measured with a Heaviside …

Tunable Passive Shock And Vibration Isolators For Rotational Isolation, Chase B. Lemaire

LSU Master's Theses

Shock and vibration isolation are a critical need in helmets, which are widely used to protect athletes, workers, soldiers, and astronauts. Passive vibration isolation systems are a good option when mass and volume should be minimized and when the experienced loadings can be predicted. However, it is frequently challenging to find materials and structures which exhibit the optimal vibration and impact isolation properties for an application. As a case study illustrating a novel design paradigm for rotational shock absorption, a family of optimal solutions for the physical properties of American football helmets is presented. Lumped parameter Simulink models simulate a …

Real-Time Data Analytics For Monitoring Electricity Consumption Using Iot Technology, Waheed Muhammad Sanya, Gaurav Bajpai, Omar Haji Kombo, Evariste Twahirwa

Tanzania Journal of Engineering and Technology (TJET)

Rising electricity bills as a result of climate variability and new home electrical and electronic appliances are becoming a major source of concern for most end users. Consumers are typically unaware of their household electricity consumption patterns and the costs associated with them, making proper planning and budgeting difficult. Monitoring and controlling energy consumption on appliances can reduce energy costs for end-users. The Internet of Things (IoT) has the potential to provide remote monitoring and control of devices via automated monitoring and control. In this study, we propose an IoT-enabled system for monitoring and controlling energy consumption in homes to …

Design Of A Proprioceptive Actuator Utilizing A Cycloidal Gearbox, Craig John Kimball

Master's Theses

Legged robotics creates the demand for high torque compact actuators able to develop high instantaneous torque. Proprioceptive actuator design theory is a design theory that removes the need for a torque feedback device and relies on the stiffness in the leg for absorbing the high Ground Impact Forces created by walking locomotion. It utilizes a high torque density motor paired with a gearbox with a high gear ratio for torque multiplication. Previously work has been done to design a proprioceptive actuator design that utilizes a planetary gearbox to create a modular low-cost actuator for legged robotics. The purpose of this …

Interactive Lego Girl Scout Arm, Christopher Suzuki, Emi Okuyama, Bryson Shores, Karina Sandoval

Mechanical Engineering

This Senior Project Report document outlines the senior design project for Girl Scouts of California’s Central Coast (GSCCC) led by a team of four Mechanical Engineering students at California Polytechnic State University, San Luis Obispo. The project encompasses the researching, designing, prototyping, and testing of a LEGO robotic arm for the Girl Scouts to learn more about STEM (Science, Technology, Engineering, and Mathematics) and provide support to each Girl Scouts cookie sales in their stores. Their goal was to build a LEGO robotic arm that will interact with customers at the Girl Scout stores and promote the girl scouts' interest …

Universal Tread For Power Wheelchairs, Daniel Ceja Gonzalez, Ryan Scarcella, Aaron Rocha, Brian Song

Mechanical Engineering

This project was centered around developing a fully independently driven powered wheelchair attachment that would allow users to traverse non-wheelchair accessible terrain. The initial goal was to create a full-scale model that would allow our user to use and test as a prototype to get over curbs and some light dirt off-roading. However, as the project progressed and limitations of time and money came up, this project was rescoped to a quarter-scale proof of concept model. The goal of this new project was to create a prototype that would carry a scaled-down load and traverse a scaled-down curb. This was …