Mechanical Engineering Commons^™

Tagalong Trail, Sean Wahl, Jason Davis, Quinlan Stephens, Ryan Johnson, Vinh Vo

Mechanical Engineering

The Cal Poly mechanical engineering team working on the Path of Lights and Sounds for the Girl Scouts of California’s Central Coast has now completed their project. In the last quarter of their project, they were able to finalize their tile’s structural design while iterating through several electronics board designs. Through this iteration, they were able to create a final electronics board and designed a water-resistant enclosure to house the board. A new team member was added, allowing them to manufacture 28 tile structures and 30 electronics assemblies over the course of two and a half weeks. This proved to …

Slitter Blade Sharpener, Griffin Buchan, Regan Lane, Kinsale Sproule

Mechanical Engineering

Within this document, our team, “Think Sharpener”, will discuss the following work we have completed since the Critical Design Review: material and part procurement, the manufacturing process for our prototype, and a discussion of our results from testing our final Verification Prototype (VP). To summarize our team’s work during the last portion of this project, our design for the slitter blade sharpening mechanism required us to consult the IME department for materials and manufacturing guidance, order pneumatic components from various online hardware companies, and test our VP to verify we met the engineering design specifications. Our slitter blade sharpening mechanism …

Integrated Actuator, David Hefter, Mathew Smith, Amanda Westmoreland, Akanksha Maddi

Mechanical Engineering

This Final Design Review document outlines the senior project design that we, a team of four mechanical engineering students at California Polytechnic State University, are developing for Charlie Refvem, a lecturer in the mechanical engineering department. The final design has undergone significant modifications since the Critical Design Review, such as a redesigned vertical shaft, material changes, and the incorporation of belt tensioners. These redesigns are thoroughly discussed in the context of testing and assembly error resolution.

The document outlines the detailed steps for the production and testing of the design verification prototype. This includes the procurement and manufacturing of components, …

Maitreya Desalination, Riley Taft, Hudson Kispert, Brendan Dizon

Mechanical Engineering

This document relays the design and manufacture of a dual power input Reverse Osmosis desalination unit. It's power sources are electric drive and human power via recumbent seated cycling. Fresh water outputs range from 4 - 7 GPH for human power inputs of 150 - 280 Watts depending on the selected gearing ratio from the derailleur.

Controlled Manipulation And Transport By Microswimmers In Stokes Flows, Jake Buzhardt

All Dissertations

Remotely actuated microscale swimming robots have the potential to revolutionize many aspects of biomedicine. However, for the longterm goals of this field of research to be achievable, it is necessary to develop modelling, simulation, and control strategies which effectively and efficiently account for not only the motion of individual swimmers, but also the complex interactions of such swimmers with their environment including other nearby swimmers, boundaries, other cargo and passive particles, and the fluid medium itself. The aim of this thesis is to study these problems in simulation from the perspective of controls and dynamical systems, with a particular focus …

Femtosecond Laser Shock Peening And The Dynamics Of Femtosecond Laser-Induced Shock Waves, Yuxin Li

All Dissertations

Laser shock peening (LSP) is an important material surface strengthening technique that uses laserinduced shock waves to cause severe plastic deformation near material surfaces. It can significantly improve material properties like hardness, strength, fatigue life, and corrosion resistance and is widely used in industrial sectors such as automotive, aerospace, nuclear, and medical areas. The conventional nanosecond laser shock peening (ns-LSP) has demonstrated effectiveness but faces challenges such as complex setup, low throughput, high energy consumption, and inflexibility for complex geometries. Femtosecond laser shock peening (fs-LSP) offers a promising alternative to overcome these issues, thanks to its ultra-high laser intensity and …

Impacts Of Connected And Automated Vehicles On Energy And Traffic Flow: Optimal Control Design And Verification Through Field Testing, Tyler Ard

All Dissertations

This dissertation assesses eco-driving effectiveness in several key traffic scenarios that include passenger vehicle transportation in highway driving and urban driving that also includes interactions with traffic signals, as well as heavy-duty line-haul truck transportation in highway driving with significant road grade. These studies are accomplished through both traffic microsimulation that propagates individual vehicle interactions to synthesize large-scale traffic patterns that emerge from the eco-driving strategies, and through experimentation in which real prototyped connected and automated vehicles (CAVs) are utilized to directly measure energy benefits from the designed eco-driving control strategies. In particular, vehicle-in-the-loop is leveraged for the CAVs driven …

Deep Reinforcement Learning For The Design Of Structural Topologies, Nathan Brown

All Dissertations

Advances in machine learning algorithms and increased computational efficiencies have given engineers new capabilities and tools for engineering design. The presented work investigates using deep reinforcement learning (DRL), a subset of deep machine learning that teaches an agent to complete a task through accumulating experiences in an interactive environment, to design 2D structural topologies. Three unique structural topology design problems are investigated to validate DRL as a practical design automation tool to produce high-performing designs in structural topology domains.

The first design problem attempts to find a gradient-free alternative to solving the compliance minimization topology optimization problem. In the proposed …

Process-Structure-Property Relationships Of Nanofibers For Biomedical Applications, Dipasree Bhowmick

Theses and Dissertations

This thesis explores the fabrication, characterization, and applications of nanofiber membranes utilizing Forcespinning® technology. Two distinct nanofiber systems were developed and evaluated, one focusing on pH-responsive Eudragit-baicalin loaded nanofibrous membranes for wound healing and the second one on thermo-responsive nanofiber-hydrogel (PNIPAAm) systems for biosensing applications, specifically dopamine detection. In the first project, nanofiber membranes loaded with Eudragit and baicalin demonstrated superior antibacterial properties against both gram-negative (E. coli) and gram-positive (B. meg) bacteria. Additionally, these membranes exhibited antioxidant properties and enhanced cell proliferation of 3TT cells, making them promising candidates for wound healing dressings. In the second project, a …

Husker Motorsports Active Drag Reduction System, Creighton Hughes, Evan Killian, Micah Busboom, Aj Johnson, Jude Steffen

Honors Program: Senior Projects (Public)

Formula SAE is a multifaceted competition that involves student teams designing and competing with an open-wheel style race car. There are 5 different dynamic events included in the competition. Each event requires a unique aerodynamic setup to have the best performance possible. This design project focuses on a drag reduction system (DRS) that will improve aerodynamic performance, resulting in faster lap times and increased competitiveness. Key features include a direct electronic actuation mechanism that will allow the rear wing to be adjusted during a race. The benefits of the DRS system, include increased speed, improved handling, and greater fuel efficiency …

Quantifying The Effect Of Stable Stratification On Low-Reynolds Number Flow Past A Horizontal Cylinder, Holland Kartchner

All Graduate Theses and Dissertations, Fall 2023 to Present

In this research, we study the behavior of flow around a cylinder in the presence of stable stratification, which refers to variations in density throughout the fluid. This phenomenon is observed in natural and industrial settings. We use computer simulations to analyze how stratification affects the flow patterns created by the cylinder. Specifically, we investigate situations where the stratification is perpendicular to the flow direction, and the wake exhibits two-dimensional characteristics. We use spectral-element method based computational fluids dynamics to simulate the phenomena. During the simulations, we vary two important parameters: the Densimetric Froude Number (Fr) and the …

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 …

Affordances Of Mobile Technology To Facilitate Learning In Undergraduate Thermal-Fluid Sciences, Maeve Raphael Bakic

Boise State University Theses and Dissertations

In recent years, the pandemic has affected learning at all levels, in particular higher education, where higher levels of independence and self-motivation are required during distance learning. In engineering in particular, distance learning adds another degree of difficulty to an already complex field. Comprehension in engineering requires the repeated use of diagrams, high-level charts, and practice problems. Mobile devices, combined with a technology-enhanced curriculum, provide an excellent platform for learning in engineering as it allows for clear illustration and the transfer of complex ideas at any time and place. In alignment with the social-constructivist framework, these facets of mobile technology …

Laser Assisted Direct Writing Of Liquid Metal For Microprinting Applications, Olga Vargas Cruz

Theses and Dissertations

This paper presents a research study for potential printing of a Liquid Metal (LM) Eutectic Gallium Indium alloy (EGaIn) through the applications of the innovative additive manufacturing technology LIFT (Laser Induced Forward Transfer). LIFT is a precise printing technology that allows to create small, detailed printing. The liquid metal in study, EGaIn, has demonstrated great potential for microelectronics applications due to its minimum toxicity and high conductivity. Throughout this research different printing parameters are studied to comprehend the behavior of EGaIn printing with LIFT technique, these include laser energy, laser pulse, receiver material substrate, donor layer thickness, and …

Effects Of The Build Orientation And Support Patterns On The Geometric Accuracy In Printing Parts With Overhang Structure: An Experimental Study, Bala Murali Krishna Mohan

Theses and Dissertations

Additive manufacturing is becoming increasingly popular in industries such as manufacturing due to its ability to use raw materials more efficiently and require less machining than traditional methods(Calignano et al., 2017). However, constructing overhanging structures in additive manufacturing can be challenging, potentially affecting the overall geometric quality of the printed components. The objective of this study was to identify the most effective printing orientation for overhanging designs in Fused Deposition Modeling (FDM) using two different support structures. To achieve this, the researchers used a laser scanner to collect point cloud data and conducted a comparative study to determine the …

Finite Element Analysis On Laser Sintering Of Ceramic Materials, Shardul Sharma

All Theses

Laser sintering of ceramics plays a vital role in advanced additive manufacturing due to its precise fabrication of complex ceramic structures, localized heating and microstructural control. It allows the production of complex and customized ceramic parts for applications such as the aerospace industry and biomedical devices. However, due to the high thermal gradients produced during the process, laser sintering technology faces fundamental challenges, such as thermal stresses and crack formation. Establishing a valid numerical model to guide the ceramic laser sintering process, which predicts the thermal and mechanical behavior of the component, is necessary.

In this work, the modified Skorohod-Olevsky …

Experimental And Numerical Study Of Low-Velocity Impact Damage In Sandwich Panel With Uhmwpe Composite Facings, Bin Yang, Qi Zhou, Juhyeong Lee, Yan Li, Kunkun Fu, Dongmin Yang

Mechanical and Aerospace Engineering Faculty Publications

This paper is concerned with the low-velocity impact (LVI) response behaviour of sandwich composite panels (SCPs) with ultra-high molecular weight polyethylene (UHMWPE) composite facings and Polyvinyl Chloride (PVC)/Polyethylene Terephthalate (PET) foam cores. A series of LVI tests with SCPs subjected to 50 J, 80 J and 110 J were conducted to examine their impact characteristics and damage mechanisms. LVI-induced internal damage in the SCPs were characterised by compute micro-tomography (μCT) analysis. The effects of UHMWPE areal density and foam type on the LVI responses and associated failure modes of the panels were also examined. The experimental results showed that the …

A Digital Triplet For Utilizing Offline Environments To Train Condition Monitoring Systems For Rolling Element Bearings, Ethan Wescoat

All Dissertations

Manufacturing competitiveness is related to making a quality product while incurring the lowest costs. Unexpected downtime caused by equipment failure negatively impacts manufacturing competitiveness due to the ensuing defects and delays caused by the downtime. Manufacturers have adopted condition monitoring (CM) techniques to reduce unexpected downtime to augment maintenance strategies. The CM adoption has transitioned maintenance from Breakdown Maintenance (BM) to Condition-Based Maintenance (CbM) to anticipate impending failures and provide maintenance actions before equipment failure. CbM is the umbrella term for maintenance strategies that use condition monitoring techniques such as Preventive Maintenance (PM) and Predictive Maintenance (PdM). Preventive Maintenance involves …

Improving Sizing Resolution Of Particle Impactors In The Nanoparticle Range, Shivuday Kala

All Dissertations

The application of particle size measurement extends across many fields: air quality measurement, pharmaceutical studies, paint and coating production, and nanoparticle formulation to name a few. Therefore, accurate measurement of nanoparticles is critical to aerosol science. While devices currently exist that can size and count nanoparticles such as electrical mobility spectrometers, dynamic light scattering devices, and small angle X-ray scattering devices, their high costs, complex operation, and lack of outdoor usability, restrict their use in practical applications. Among the devices that can size aerosols down to the nanoscale, cascade impactors stand out because of their robustness, relatively simple design, low …

Examining The Efficacy Of Using Irt As An Nde Method For Cfrp And Ztcfrp Composites, William Wyatt Taylor

Graduate Theses and Dissertations (2019 - present)

A film adhesive is commonly used to form the bond-line between composite parts. The bond-line's quality and performance can be affected by defects such as voids, impurities, and agglomerations. Identifying these defects is possible with non-destructive evaluation testing (NDE). In this thesis, the joule-heating effect (JH) through carbon nanofiber (CNF) and carbon nanotube (CNT) modified film adhesive bonded to control carbon fiber reinforced polymer (CCFRP) was used along with infrared thermography testing (IRT) for bond-line defect inspection as a preliminary study. Due to the difference in the electrical conductivity between the modified epoxy and the defect, JH can cause a …

Additive Manufacturing Of Composites For Sensing And Harsh Environments Application, Md Sahid Hassan

Open Access Theses & Dissertations

Composite materials are made by combining two or more materials, such as fibers and resins to create a material system that has improved mechanical and physical properties compared to its individual components. The use of 3D printing technology in composite manufacturing allows for the creation of complex and custom shapes with precise control over the placement of the materials. This makes it possible to create composite parts with enhanced performance characteristics and reduced weight. The work presented in this dissertation lies in the design and development of highly flexible impact propagation sensor through material extrusion 3D printing technique. By using …

Design And Customization Of 3d Printers For Advanced Materials Printing, Alan Omar Loera Martinez

Open Access Theses & Dissertations

This research is divided into two sections. The first section discusses modificationsperformed to two commercial printers. The first printer was modified from a thermoplastic polymer printer to a pneumatic printer by taking away its heating elements and print head. Circuits were directed to pneumatic dispensing system as well in order to automate the process. The second printer had mechanical modifications performed to be a multi-material gradient printer by controlling two stepper motors through an electronics board. Through code, a mixing ratio changed the motors' rotations to provide the desired gradient of two different materials. The second section of the present …

An Optimization Procedure To Design Nozzle Contours For Hypersonic Wind Tunnels, Omar Antonio Dominguez

Open Access Theses & Dissertations

Supersonic wind tunnels allow scientists and researchers to evaluate and analyze the behaviors of objects under real-life conditions when subjected to supersonic speeds. One of the main complexities when building a wind tunnel is the design of the convergent-divergent nozzle that is used to produce high-speed and high-quality flows. To achieve supersonic speeds, this nozzle adopts a specialized approach that incorporates the complexities of flow compressibility. The compressible effect is accurately evaluated using isentropic relations, allowing for precise determination of stagnation pressure and temperature, and static pressure and temperature relevant to the desired Mach number. Isentropic equations used to define …

Design And Implementation Of Laser Beam Measurements At The Extents Of The Build Platform: Impact Of Beam Location On Melt Pool Geometry, Alexandra Hernandez

Open Access Theses & Dissertations

Laser powder bed fusion (LPBF) is a form of metal additive manufacturing that enables the development of complex parts that cannot readily be made with traditional manufacturing methods. The process utilizes a tightly focused laser beam to selectively melt and fuse layers of powdered metal to create a 3-D part.LPBF is a promising technology, but there are barriers to its adoption in most industries. Mainly, it is difficult to qualify these parts for use, since they are prone to processing defects and part-to-part variation. One source of this is part position on the building plane, especially for multi-part builds where …

Ultra Wide Band Gap Oxides For Advanced Optoelectronics And Supercapacitor Applications: A Case Study Of Intrinsic And Doped Germanium Dioxide, Paul Gaurav Nalam

Open Access Theses & Dissertations

Germanium dioxide (GeO2) is a metal oxide semiconductor with multiple polymorphs that has recently garnered a significant amount of scientific attention owing to its novel ultra-wide band gap and pseudo-capacitive properties, which can potentially transcend current power electronic, optoelectronic, and supercapacitor technologies. However, due to the difficulty in the synthesis of stable crystalline phases of individual polymorphs of GeO2 thin films, this material system demands complex and resource-intensive deposition techniques to synthesize. An attempt was made to develop cost-effective and scalable deposition techniques to stabilize specific crystalline phases of GeO2 thin films. These phases were further structurally fine-tuned to state …

Enhancing Damage Tolerance Of The Constituents Of Sandwich Composites, Zackery Nieto

Open Access Theses & Dissertations

Composite structures have become a lucrative material choice for researchers throughout various sectors such as green energy, arctic travel, and aerospace application due to their light weight, high-bending to stiffness ratio, and job tailorable applications through material selection. With the increasing demand for new and better composite technologies growing each year it is imperative to investigate new materials and analytical options to help the composite field as a whole grow. In this report various materials and statistical applications have been studied regarding the constituent materials in sandwich composites. For core materials an additive manufactured photoreactive resin has been characterized for …

Ultrasonic Non-Destructive Evaluation Of Additively Manufactured Polymer-Ceramic Composites, Christian Alexander Ruiz

Open Access Theses & Dissertations

Digital light processing (DLP) is an attractive additive manufacturing technique due to its ability to create ceramic parts with complex geometries. DLP uses ultraviolet light to polymerize a slurry comprised of ceramic powder and photosensitive resin in layers to create solid parts. Printing parameters such as light intensity and exposure time are critical when producing these parts. Improper parameters can lead to over or under-curing, adversely impacting print quality and strength. Samples were printed at varying layer exposure times and then tested using ultrasonics to determine the degree of conversion. Additionally, ultrasonics were used as a non-destructive technique to obtain …

Exploration Of Advanced Scan Strategy Capabilities On A Commercial Lpbf System Using Intervector Power Ramping, Antonio York

Open Access Theses & Dissertations

Lack of confidence in the quality of materials produced with metal AM has hinged on the unaddressed defects inherent to the process. Studies have worked to determine defect formation mechanisms and provide adjustments to key process controls. However, these advances have typically been developed in-house on research systems which offer increased and transparent control to the operator. A research gap exists in applying changes in approach of scan strategies to existing commercial systems, which can incentivize adoption while furthering development. The focus of this study is the implementation of inter-vector power ramping on a commercial laser powder bed fusion system …

Human-Centric Smart Cities: A Digital Twin-Oriented Design Of Interactive Autonomous Vehicles, Oscar G. De Leon-Vazquez

Theses and Dissertations

Autonomous vehicle (AV) technology is introduced as a solution to improve transportation safety by eliminating traffic accidents caused by human error, which is the leading cause of 90% of accidents. One key feature of AVs is sensing and perceiving their surrounding environment through processing observations collected from the environment. The perception system is essential for an AV to make informed decisions and safely navigate the environment. This study presents an image semantic segmentation algorithm developed in the area of computer vision to improve AV perception. The U-Net-based algorithm is trained and validated using a synthetically generated dataset in a simulation …

Restricted Nonlinear Scales Of Turbulent Secondary Flows Over Spanwise Heterogeneous Roughness, Benjamin A. Minnick, Xiaowei Zhu, Dennice F. Gayme

Mechanical and Materials Engineering Faculty Publications and Presentations

Recent studies, e.g., Wangsawijaya et al. (2020) have revealed the prevalence of streak meandering in turbulent flow over spanwise heterogeneous roughness. Here we exploit the scale decomposition inherent in the Restricted Nonlinear (RNL) modeling approach to further investigate this behavior. The RNL decomposition comprises a large-scale streamwise averaged mean with small-scale fluctuations about that mean defined through a dynamical restriction that leads to computational tractability. The simplified setting facilitates the study of secondary flow interacting with the large-scale streak via one-way coupling, thus enabling additional insight into relevant interaction mechanisms. In agreement with the experimental work, our results indicate that …