Applied Mechanics Commons^™

Complicating Factors In Hydraulic Jumps: The Effects Of Earth's Rotation, Muveno Pascoal Elias Mucaza

Electronic Thesis and Dissertation Repository

Hydraulic jumps at the interface of stratified rotating fluids are studied. The flow is de- fined with continuous density and velocity profiles, with the velocity in each layer changing (upstream shear). The study is conducted in jumps defined by an imposed velocity transition, and jumps developing over a topography.

The numerical simulations conducted showed the qualitative structure of the flow changing in the cross-width direction, as well as the size and amount of turbulence of the jumps. Mixing in these jumps was shown to increase towards the side of the domain where the jumps were larger and more turbulent. The …

Design And Development Of A Novel Soft Gripper Manipulated By A Robotic Arm, Derek Price

Symposium of Student Scholars

This study presents the design and development of a tendon-driven soft gripper manipulated by a 4 DOF robotic arm. The proposed robotic arm and the gripper explore the new areas focusing on increasing the grasping performance of the gripper as well as the workspace. The gripper is designed as a 3 finger and driven by tendons using two servo motors. The tension of the strings is adjusted using a pulley mechanism and a string. The opening and grasping of the soft gripper are accomplished by each motor. The wide opening allows the gripper to grasp wide objects. The parallel robotic …

Nonlinear Dynamics Of A Class Of Ring-Based Angular Rate Sensing And Energy Harvesting Systems, Ibrahim F Abdelhamid Gebrel

Electronic Thesis and Dissertation Repository

This research is classified into two broad sections: ring-based MEMS (Micro-electro Mechanical Systems) and macro gyroscopes and novel bi-stable/monostable nonlinear energy harvesting systems. In both cases, models and solution methods are based on ring structural dynamics considering comprehensive nonlinear formulations. The investigation of nonlinear and linear dynamic response behavior of MEMS and macro ring gyroscopes forms the basis of the first study. This class of MEMS/macro ring-based vibratory gyroscopes requires oscillatory nonlinear electrostatic/electromagnetic excitation forces for their operation. The partial differential equations that govern the ring dynamics are reduced to a set of coupled nonlinear ordinary differential equations by assuming …

A Manufacturing-To-Response Pathway For Formed Carbon Fiber Reinforced Polymer Composite Structures, Madhura Limaye

All Theses

Over the past decade, there has been an increased adoption of thermoplastic and thermoset based continuous carbon fiber reinforced polymer (CFRP) composites for structural applications in several industries. Among the different manufacturing methods, thermoforming process for thermoplastic based continuous CFRP’s offer a major advantage in reducing cycle times for large scale productions. Similarly, out-of-autoclave curing process for thermoset based continuous CFRP’s using heated tooling enables production of large composite structures. However, these manufacturing processes can have a significant impact on the structural performance of parts by inducing undesirable effects. These effects include inhomogeneous fiber orientations, thickness variations, and residual stresses …

Thermomechanical Modeling In Laser Powder Bed Fusion Additive Manufacturing Using Graph Theory: Application To Prediction Of Recoater Crash, Md Humaun Kobir

Department of Mechanical and Materials Engineering: Dissertations, Theses, and Student Research

This work pertains to the laser powder bed fusion (LPBF) additive manufacturing process. The objective of this thesis is to predict a frequently occurring type of thermal-induced process failure in LPBF called recoater crash. To ascertain the likelihood of a recoater crash before the part is printed, we develop and apply a computationally efficient thermomechanical modeling approach based on graph theory.

Despite its demonstrated ability to overcome the design and processing constraints of conventional subtractive and formative manufacturing, the production-level scaleup of LPBF is hindered by frequent build failures. For example, the part often deforms as it is being printed …

Anisotropic Plasticity Modeling Of Thin Sheets And Its Application To Micro Channel Forming Of Steel Foils, Jie Sheng

Mechanical Engineering Research Theses and Dissertations

Thin sheet metals and ultrathin metal foils produced by industrial rolling processes are textured polycrystalline materials and their mechanical behaviors may depend strongly on the orientation of applied loading. Consideration of such plastic anisotropy in advanced modeling of these materials is of the paramount importance in designing optimal manufacturing processes for automotive and other applications using finite element methods. This research addresses several critical issues in anisotropic plasticity modeling and its applications in analyzing micro channel forming of ultrathin stainless-steel foils. An experimental study has first been carried out on the accuracy and sensitivity of measuring the plastic strain ratios …

Development Of Novel Battery Materials For Lithium-Ion Batteries And Beyond, Jiyu Cai

Graduate Theses and Dissertations

As fossil fuels are depleting and causing environmental issues, it becomes imperative to widely implement renewable energies (e.g., solar and wind power). In this context, electrical energy storage (EES) systems are essential to accommodate the intermittent supply and uneven distribution of renewable energies. To this end, high-energy-density EES devices are highly demanded, such as rechargeable batteries. This dissertation presents my efforts in developing novel battery materials for lithium-ion batteries (LIBs), sodium-ion batteries (SIBs), and solidstate lithium batteries (SSLBs). These efforts include electrochemical evaluations of battery materials, surface modifications of electrodes via atomic layer deposition (ALD), and advanced characterizations of batteries …

Phase-Field Modeling Of The Polymer Membrane Formation Process For Micro- And Ultra-Filtration, Michael Rosario Cervellere

Graduate Theses and Dissertations

Porous polymer membrane filters are widely used in separation and filtration process. Micro- and ultra-filtration membranes are commonly used in biopharmaceutical applications such as filtering viruses and separating proteins from a carrier solution. The formation of these membrane filters via phase inversion is a complex and interconnected process where varying casting conditions can have a wide variety of effects on the final membrane morphol- ogy. Tailoring membrane filters for specific performance characteristics is a tedious and time consuming process. The time and length scales of membrane formation make it extremely difficult to experimentally observe membrane formation. Modeling the membrane formation …

Influence Of Extracellular Matrix Stiffness And Topography On Neuronal Cell Behavior And Neurite Outgrowth, Mohan Yasodharababu

Graduate Theses and Dissertations

The focus of regeneration therapy for traumatic brain injuries and Alzheimer's disease is on the promotion and growth of neuronal cells. In vitro research attempts to improve this by modifying the stiffness and topography of the extracellular matrix (ECM). However, the limitations of in vitro experiments make it difficult to control the individual factors influencing neuronal cell growth. A computational model can be used to decouple individual factors and study them individually to gain a better understanding of the mechanics between the neuronal cell and ECM, which will aid in the design of in vitro experimental studies.

This study develops …

Material Property Heterogeneity In Dimensional Lumber And Its Relationship To Mass Timber Performance, Fiona O'Donnell

Doctoral Dissertations

According to the Environmental Protection Agency, buildings account for 38% of the United States' carbon dioxide emissions, providing architects and structural engineers a unique opportunity to mitigate a significant factor driving climate change by implementing innovative and sustainable technology in infrastructure design. Wood and mass timber products are becoming an increasingly popular alternative building material due to their economic and environmental benefits. The natural growth of wood leads to highly heterogeneous material properties. Defects such as checks, knots, and localized slope of grain contribute to some of this variation; however, wood properties vary significantly even in clear wood. Using mass …

Harnessing The Mechanics Of Thin-Walled Metallic Structures: From Plate-Lattice Materials To Cold-Formed Steel Shear Walls, Fani Derveni

Doctoral Dissertations

Thin-walled structures have received a lot of interest during the last years due to their light weight, cost efficiency, and ease in fabrication and transportation, along with their high strength and stiffness. This dissertation focuses on the mechanical performance of thin-walled metallic structures from cold-formed steel shear walls and connections (PART I) to plate-lattice architected materials (PART II) via computational, experimental, and probabilistic methods. Cold-formed steel (CFS) shear walls subjected to seismic loads is the focus of PART I of this dissertation. An innovative three-dimensional shell finite element model of oriented strand board (OSB) sheathed CFS shear walls is introduced …

Fluid-Structure Interaction Of Nrel 5-Mw Wind Turbine, Mohamed Sayed Elkady Abd-Elhay

Theses and Dissertations

Wind energy is considered one of the major sources of renewable energy. Nowadays, wind turbine blades could exceed 100 m to maximize the generated power and minimize produced energy cost. Due to the enormous size of the wind turbines, the blades are subjected to failure by aerodynamics loads or instability issues. Also, the gravitational and centrifugal loads affect the wind turbine design because of the huge mass of the blades. Accordingly, wind turbine simulation became efficient in blade design to reduce the cost of its manufacturing. The fluid-structure interaction (FSI) is considered an effective way to study the turbine's behavior …

Adjustable Head Tube Angle Headset, Glenn Petersen, Ben Harper, Josh Martin, Dylan Prins

Mechanical Engineering

This final design review report describes the design, manufacture, and test process of a bicycle headset capable of quickly and easily adjusting the effective head tube angle. The evolution of mountain bike geometry has forced bike designers to compromise between climbing and descending performance when choosing a head tube angle. A headset capable of quickly adjusting the effective head tube angle would allow riders to optimize their bike’s geometry for different stages of riding. This report details the research, idea generation, concept development and selection, design, manufacturing, and testing of our adjustable head tube angle headset.

Tensile Testing Environmental Chamber – Structural, Michael Ingel, Erik Soldenwagner, Austin Marshall, Lauren Schirle

Mechanical Engineering

Environmental chambers for tensile testing machines are used to study how a multitude of materials behave in extreme temperatures. These chambers provide the necessary information to innovate cutting edge technology for materials in fields such as aerospace. These chambers are often heavy and expensive requiring a significant amount of time and money just in the installation process alone. This report will serve to outline and define the design and fabrication of an environmental chamber, conducted by a team of four senior mechanical engineering students at California Polytechnic State University, San Luis Obispo. The goals of the project include a low-weight …

Cnc Feed Drive Control, Ryan J. Funchess, Caleb P. O'Gorman, Nick J. Desimone, Juan M. Majano, Samuel K. Wong

Mechanical Engineering

This document serves as the Final Design Report (FDR) for a senior project developed by our team: four senior Mechanical Engineering students and one computer engineering student at California Polytechnic State University, San Luis Obispo (Cal Poly). While the project was completed for, and sponsored by, Professor Simon Xing of Cal Poly, the remainder of the university’s controls professors will be indirectly benefited from this project. Our goal was to design and implement a functional CNC Feed Drive to be used for educational demonstrations and data collection. This document discusses our early product research and benchmark goals, which established constraints …

Adaptive Vehicle Control, Brian L. Finger, Maria Vargas, Jacob T. Larson, Christopher J. Villa

Mechanical Engineering

This report presents the final design for our device made for Mrs. Laura Jagels. Mrs. Jagels, who has an above the knee amputation, needed a device that would allow her to operate a manual car in a safe and reliable way that still gives her the traditional driving experience. This report takes into consideration the shortcomings of current market devices that enable amputees to operate vehicles. From this research and through interviews with Mrs. Jagels, we were able to decide on our device specifications, giving us a basis to objectively evaluate designs. Ideation and concept prototype building was performed for …

F34 Beekeeper Assist, Kyle Ladtkow, Javier Guerra, Jose Velazquez, Ryan Heryford

Mechanical Engineering

Alejandro Jauregui is a veteran who now works as a commercial beekeeper. He lost both of his legs during his service. While his current prostheses allow him to fully complete his work, he has found that inspection of the bee boxes causes him severe hip and back pain. Bee box inspection is a critical task for beekeeping, especially since he maintains about 200 hives every day. Our senior project team was tasked with designing and building a device that would help him move the top bee box out of the way to allow for inspection. We performed preliminary research into …

Configurable Seat Track Latching Mechanism, Emily Sun, Kai Quizon, Rick Hall, Daniel Turn, Nicholas Holman, Alexander Kuznik, Jacob Winkler, Audrey Trejo, Phoebe Zeiss, Steven Kam

Mechanical Engineering

The reconfigurable seating system is a flexible seating solution for transit vehicles that allows operators to change the configuration of the floor plan in a timely manner in order to accommodate change in needs. This project consists of three senior project teams each working on a component of the design: system, track & latch, and articulation. Descriptions of the responsibilities of each team will be discussed below.

Composite Pegboard, Asa J. Cusick, Luis Corrales, Joelle Hylton, Wyatt Pauley

Mechanical Engineering

Many of those with mobility limitations who are told they will need a wheelchair for the rest of their lives can actually begin to stand and walk again given the proper tools and support. The current design for a wheelchair seeking to support this process is overly complex, heavy, and exhibits some features that could potentially pose a serious health hazard to those using it. The scope of this project is to aid in the design of an adaptable composite wheelchair frame that can be both lightweight and strong, while still allowing for physical diversity of potential users. Through research …

Hands-On 3d Printed Dynamics Activities, Dakota Baker, Jacob Lindberg, Andrew Meyenberg, Junnior Rodriguez

Mechanical Engineering

The advancement of 3D printing has allowed everyday individuals to rapid prototype and manufacture in a more efficient, cost-effective, and timely manner. This has paved the way for a more adaptable educational model, by allowing instructors to easily access alternative instruments for teaching. By providing students with tangible tools, they will better be able to grasp complex principles. Dynamics professors need a way in which they can easily access these academic tools, transport them to and from class, and teach multiple dynamics principles through variations of a single 3D printed kit. Interviews with professors and students were conducted to gain …

Prediction Of In-Plane Stiffnesses And Thermomechanical Stresses In Cylindrical Composite Cross-Sections, Bryson M. Chan

Master's Theses

Accurate mechanical analysis of composite structures is necessary for the prediction of laminate behavior. Cylindrical composite tubes are a mainstay in many structural applications. The fundamental design of circular composite cross-sections necessitates the development of a comprehensive composite lamination theory. A new analytical method is developed to characterize the behavior of thin-walled composite cylindrical tubes using a modified plate theory. A generated numerical solver can predict properties such as axial stiffness, bending stiffness, layer stresses, and layer strains in composite tubes subjected to combined mechanical loading and thermal effects. The model accounts for the curvature by transforming and translating the …

Computational Design Of Nonlinear Stress-Strain Of Isotropic Materials, Askhad M.Polatov, Akhmat M. Ikramov, Daniyarbek Razmukhamedov

Chemical Technology, Control and Management

The article deals with the problems of numerical modeling of nonlinear physical processes of the stress-strain state of structural elements. An elastoplastic medium of a homogeneous solid material is investigated. The results of computational experiments on the study of the process of physically nonlinear deformation of isotropic elements of three-dimensional structures with a system of one- and double-periodic spherical cavities under uniaxial compression are presented. The influence and mutual influence of stress concentrators in the form of spherical cavities, vertically located two cavities and a horizontally located system of two cavities on the deformation of the structure are investigated. Numerical …

Motor Control-Based Assessment Of Therapy Effects In Individuals Post-Stroke: Implications For Prediction Of Response And Subject-Specific Modifications, Ashley Rice

Doctoral Dissertations

Producing a coordinated motion such as walking is, at its root, the result of healthy communication pathways between the central nervous system and the musculoskeletal system. The central nervous system produces an electrical signal responsible for the excitation of a muscle, and the musculoskeletal system contains the necessary equipment for producing a movement-driving force to achieve a desired motion. Motor control refers to the ability an individual has to produce a desired motion, and the complexity of motor control is a mathematical concept stemming from how the electrical signals from the central nervous system translate to muscle activations. Exercising a …

Process-Structure-Property Relationships In 3d-Printed Epoxy Composites Produced Via Material Extrusion Additive Manufacturing, Nadim S. Hmeidat

Doctoral Dissertations

Extrusion-based additive manufacturing (AM) technologies, such as direct ink writing (DIW), offer unique opportunities to create composite materials and novel multi-material architectures that are not feasible using other AM technologies. DIW is a novel 3D-printing approach in which viscoelastic inks, with favorable rheological properties, are extruded through fine nozzles and patterned in a filament form at room temperature.

Recent developments in DIW of polymer composites have led to expanding the range of materials used for printing, as well as introducing novel deposition strategies to control filler orientation and create improved functional/structural composite materials. Despite these substantial advancements, the successful and …

An Investigation Of Testing Parameters On The Frictional Properties Of Patterned Core-Shell Nanostructures, Colin Phelan

Graduate Theses and Dissertations

Friction tests are a beneficial means to analyze the tribological characteristics and advantages of materials and textured surfaces. However, the selected test parameters can significantly influence the results. This work explores the significance of the friction testing parameters on the frictional performances of core-shell nanostructure-textured surfaces (CSNTSs). Several applied normal loads (10 μN, 100 μN, and 500 μN) and diamond counterface indenter tip radii (1 μm, 5 μm, and 20 μm) were selected for the testing of Al/diamond-like-carbon (DLC) and Al/amorphous silicon (a-Si) CSNTSs. The measured friction values of the CSNTSs were then compared to a matching Al/DLC film and …

Mathematical Modeling Of A Two Wheeled Robotic Base, Kathryn Remell

Mechanical Engineering Undergraduate Honors Theses

This thesis presents the concept of using a two wheeled robot on the moon and briefly explores the requirements for successful long term operation in a lunar environment. The mathematical model for the motion of a robot with two fixed wheels on a differential drive with in a global reference frame. The robot is assumed to be balancing a platform so the mathematical model to balance the platform with wheel motors is also developed and briefly evaluated.

Correlating Fracture Toughness And Surface Roughness For A Ductile Epoxy Adhered To Aluminum Substrates, Kurt Ryan Smith

Masters Theses

Adhesively bonded joints are used across multiple disciplines as an efficient and cost effective method for reinforcing, repairing, or creating new structures. Sufficient understanding of the bond line characteristics of the adhesive is necessary to properly design a reliable bonded joint and ensure a long service life. It is well understood that surface preparation has a significant impact on these interface characteristics as a given level of surface roughness achieves mechanical interlocking between the resin and metal and is important to prevent premature interfacial failure [1]. The goal of this study is to characterize the fracture toughness values for an …

Project Blipper, Peter Jacobs, Preston Delaware, Ryan Foster

Senior Design Project For Engineers

This project was sponsored by Clorox to design and create an automatic bottle-unscrambling system for possible implementation at their bottling plant in Chile. The objective was to use a robotic arm to unscramble bottles from an incoming conveyor belt and place them upright on an outbound conveyor belt. Throughout the research, design, and testing of solutions for this project, several design alternatives were found for each discipline, and will be presented to Clorox so that they can make an informed decision for how and if they want to move forward with implementation of this project.

The project was split into …

Kennesaw State University And United Alloy Corporation Robotic Pick And Place Project, Kathryn Bharadwaj, Logan Spencer, Tharkun Hudlow

Senior Design Project For Engineers

United Alloy Corporation (UAC), a company specializing in unique aluminum parts for aeronautics, needed a fix to their error prone, labor-intensive billet press operation. The process has a problem of adding the wrong size or wrong alloy billet to the induction oven, which results in a waste of raw materials. The billets range from ten to thirty-seven inches in length and weigh up to three hundred pounds. Currently, an operator uses a gantry crane to check and lift the billets from a rack onto the magazine of an induction oven. The magazine can hold up to three billets safely and …

Free Vibration Analysis Of Rotating Beams Based On The Modified Couple Stress Theory And Coupled Displacement Field, Alireza Babaei, Masoud Arabghahestani

Mechanical Engineering Graduate Research

In this paper, transverse vibration analysis of rotating micro-beam is investigated based on the modified couple stress theory. The simply-supported micro-beam is modeled utilizing Euler-Bernoulli and Timoshenko beam theories. The system is rotating around a fixed axis perpendicular to the axial direction of the beam. For the first time, displacement filed is introduced as a coupled field to the translational field. In other words, the mentioned rotational displacement field is expressed as a proportional function of translational displacement field using first (axial), second (lateral), and third (angular or rotational) velocity factors. Utilizing Hamilton’s approach as a variational method, dynamic-vibration equations …