Digital Commons Network^™

Part Design Geometry-Driven Toolpath Optimization For Additive Manufacturing Energy Sustainability Improvement, David Kolawole Somade

Graduate Research Theses & Dissertations

One of the most promising new manufacturing technologies in the past three decades isadditive manufacturing (AM), also commonly known as three-dimensional (3D) printing or rapid prototyping. The energy consumption problem in AM can be significant when it is adopted at the industrial scale or used under resource-restricted conditions. The energy consumption of an AM process is influenced by several factors including bed heating, filament extrusion, material infill, component cooling, etc. All these factors are further determined by the equipment and the toolpath for a specific printing task. Build orientation and tool-path direction are frequently used to optimize part and process …

Mechanical Behavior Of Metallic Core-Shell Nanoparticles Under Compressive Loading, Phillip Tomich

Graduate Research Theses & Dissertations

Core/shell metallic nanoparticles have been shown to be a promising material type for additive manufacturing in the aerospace and automotive fields. Within additive manufacturing they will be used to accurately make an array of nanoparticles within the grains of metal matrix composites. This in turn will help to strengthen the material while remaining ductility and light weight. In this study, copper/aluminum core/shell nanoparticles are compressed under [100], [110], [111], and [112] directions to showcase their anisotropic material properties. Models of their individual counterparts were also investigated. There are no previous works showing the deformation mechanisms of copper/aluminum core/shell nanoparticles. Molecular …

Artificial Intelligence And Multi-Physics Approach For Electrocoagulation Parameter Selection, Adam Cotton

Graduate Research Theses & Dissertations

Proper treatment of wastewater is crucial to maintain the health of the public and avoid pollution of the environment. Methods like filtering and chemical coagulation have been utilized to treat wastewater, but they have significant limitations such as inefficient treatment of micro-size pollutants, generation of secondary contaminants, and high operation and maintenance costs. The electro-coagulation system which generates coagulants from low-cost aluminum electrodes under the application of a current has received strong attention as a promising water treatment system. However, the EC system has not been fully utilized yet due to lack of understanding and operation guidelines.

In this study, …

Analysis Of The Effect Of Surface Roughness In Additive Manufacturing On Thermo-Hydraulic Performance By Ml Models Supported By Physics-Based Modeling, Kaylen A. Platt

Graduate Research Theses & Dissertations

Heat exchangers (HX) are crucial components of thermal control systems which facilitate proper transfer of heat in systems such as nuclear reactors. This research focuses on the heat transfer-enhancing effect associated with turbulence in fluid flowing conduits. Turbulence can be induced at low flow rates when surface roughness is present on channel walls. Rough surfaces are typically regarded as a flawed product of the Additive Manufacturing (AM) process during the construction of Heat Exchangers. Machining surface finishes onto AM parts is a typical post-processing method used to remove the roughness. Thorough investigations have not yet been published on the effects …

Strategies To Increase Competitive Advantage In The Automotive Manufacturing Supply Chain, Amber Willis

Walden Dissertations and Doctoral Studies

Some automotive manufacturing supply chain leaders lack strategies that are needed to implement information technology (IT) systems. Business leaders are concerned with implementing IT systems to achieve and maintain a competitive advantage. Grounded in the resource-based view theory (RBV), the purpose of this qualitative single case study was to explore information system strategies used by leaders in the automotive manufacturing supply chain to achieve competitive advantage. Participants were five leaders of an automotive manufacturing supply chain organization who implemented IT systems. Data were collected through semistructured interviews and a review of organization project documents. Through thematic analysis, five themes were …

Mechanical And Morphological Characterization Of Energy Materials By Nanoindentation And Scanning Probe Microscopy, Jacob Hempel

Theses and Dissertations--Physics and Astronomy

The demand for robust materials in energy-based applications such as solid electrolytes for batteries, piezoelectric composites for mechanical energy harvesting, or new polymer materials for polymer binders in composite electrodes is on the rise. Mechanical degradation is the most common way for devices to fail in operation, thus a thorough understanding of a material’s mechanical properties is essential for application purposes.

In this dissertation, the mechanical characterization of novel boron cluster solid electrolytes is presented. Therein, we determine the elastic modulus and hardness of these compounds using instrumented indentation. A comparison is made against other solid electrolytes. It is found …

Advances In Precision Microfabrication Through Digital Light Processing: System Development, Material And Applications, Xinhui Wang, Jinghang Liu, Yang Zhang, Per Magnus Kristiansen, Aminul Islam, Michael Gilchrist, Nan Zhang

Articles

Digital Light Processing (DLP) is an advanced additive manufacturing technology which has garnered substantial recognition and has been extensively applications in various fields. This review focuses on the precision microfabrication process of DLP, providing an overview of the DLP 3D printing system, including the digital light engine, project lenses, motorised stage and resin vat for micro-structure fabrication. Additionally, this review paper comprehensively analyses commercially available DLP printers, covering resolution, cost and a detailed discussion on the importance of photopolymer resins, emphasising the monomer, photo-initiator, photoabsorber, etc. Based on the photopolymerisation theory, the DLP high-precision printing process is analysed, which is …

Orbital Stabilization Of Underactuated Systems Using Time Period Regulation, Nilay Kant, Ranjan Mukherjee

Mechanical and Aerospace Engineering Faculty Research & Creative Works

A new approach to orbital stabilization of under-actuated systems with one passive degree-of-freedom (DOF) is presented. Virtual holonomic constraints are enforced using partial feedback linearization; this results in a dense set of periodic orbits on a constraint manifold. Every orbit on the constraint manifold is associated with a unique time-period. A desired orbit is selected, and the impulse controlled Poincaré map (ICPM) approach is utilized to stabilize the orbit by regulating the time-period. By treating the time period as the output, it is possible to design a dead-beat controller that achieves orbital stabilization in a single time-step. The effectiveness of …

Jet Noise Reduction: A Fresh Start, Christopher K. Tam, Fang Q. Hu

Mathematics & Statistics Faculty Publications

Attempts to reduce jet noise began some 70 years ago. In the literature, there have been many publications written on this topic. By now, it is common knowledge that jet noise consists of a number of components. They possess different spectral and radiation characteristics and are generated by different mechanisms. It appears then that one may aim at the suppression of the noise of a single component instead of trying to reduce jet noise overall. The objective of the present project is to reduce large turbulence structures noise. It is the most dominant noise component radiating in the downstream direction. …

Application Of A Variable Path Length Repetitive Process Control For Direct Energy Deposition Of Thin-Walled Structures, Elias B. Snider, Douglas A. Bristow

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Direct Energy Deposition (DED) Additive Manufacturing is Well Suited to Fabricating Large Thin-Walled Metal Structures Such as Rocket Nozzles but Suffers from Layer-To-Layer Defect Propagation. Propagating Defects May Exhibit as Slumping or a Ripple in Bead Geometry. Recent Works Have Used Repetitive Process Control (RPC) Methods for Additive Manufacturing to Stabilize the Layer-Wise Defect Propagation, But These Methods Require Repetition of the Same Path. However, Typical Thin-Wall DED Applications, Sometimes Referred to as Vase Structures, Have Changing Paths with Each Layer Such as Expanding or Contracting Diameters and Changing Profiles. This Paper Presents an Extension to Optimal RPC that Uses …

Feature-Based Learning For Optimal Abort Guidance, Vinay Kenny, Sixiong You, Godfrey Hendrix, Chaoying Pei, Roha Gul, Ran Dai, Jeremy R. Rea

Mechanical and Aerospace Engineering Faculty Research & Creative Works

The abort mission refers to the mission where the landing vehicle needs to terminate the landing mission when an anomaly happens and be safely guided to the desired orbit. This paper focuses on solving the time-optimal abort guidance (TOAG) problem in real-time via the feature-based learning method. First, according to the optimal control theory, the features are identified to represent the optimal solutions of TOAG using a few parameters. After that, a sufficiently large dataset of time-optimal abort trajectories is generated offline by solving the TOAG problems with different initial conditions. Then the features are extracted for all generated cases. …

Analytical Heat Transfer Modeling Of The Microwave Heating Process: A Focus On Carbon Black, Craig Offutt

Graduate Theses, Dissertations, and Problem Reports (ETD)

Electronic waste (e-waste) has become a significant environmental issue due to the rapid advancement of technology, increasing demand for electronic devices, and shorter lifespan of electronics. One critical step in processing the e-waste involves ball milling as a means of preparing the recycling e-waste for the recovery of critical materials. Ball milling is a technique that involves the mechanical crushing and grinding of electronic waste to reduce its size and improve its reactivity during recovery. Our focused recovery technique is based on a microwave recovery technique of these critical materials from e-waste. The size and distribution of the e-waste with …

Development Of Machine Learning Based Approach To Predict Fuel Consumption And Maintenance Cost Of Heavy-Duty Vehicles Using Diesel And Alternative Fuels, Sasanka Katreddi

Graduate Theses, Dissertations, and Problem Reports (ETD)

One of the major contributors of human-made greenhouse gases (GHG) namely carbon dioxide (CO2), methane (CH4), and nitrous oxide (NOX) in the transportation sector and heavy-duty vehicles (HDV) contributing to about 27% of the overall fraction. In addition to the rapid increase in global temperature, airborne pollutants from diesel vehicles also present a risk to human health. Even a small improvement that could potentially drive energy savings to the century-old mature diesel technology could yield a significant impact on minimizing greenhouse gas emissions. With the increasing focus on reducing emissions and operating costs, there is a need for efficient and …

Design And Validation Of An Aerodynamic System For A Formula Sae® Vehicle Using Vehicle Dynamic Simulation And Experimentation, Evan S. Cole

Graduate Theses, Dissertations, and Problem Reports (ETD)

This thesis presents the design, simulation, and experimental validation for the aerodynamic system for a Formula SAE® vehicle. The Society of Automotive Engineers ® (SAE) hosts a collegiate competition annually called Formula SAE® where students design, fabricate, and test a small “formula style” vehicle. The vehicle performs in relatively slow maneuvers, around different courses and tests to evaluate the vehicle’s overall performance. Over the years, collegiate teams have put significant research into the design and manufacturing of the aerodynamics of these vehicles. In order to justify this undertaking for future teams at West Virginia University’s Formula SAE® program, a comprehensive …

Biologically – Plausible Load Feedback From Dynamically Scaled Robotic Model Insect Legs, William Zyhowski

Graduate Theses, Dissertations, and Problem Reports (ETD)

Researchers have been studying the mechanisms underlying animal motor control for many years using computational models and biomimetic robots. Since testing some theories in animals can be challenging, this approach can enable unique contributions to the field. An example of a system that benefits from this modeling and robotics approach is the campaniform sensillum (CS), a kind of sensory organ used to detect the loads exerted on an insect's legs. The CS on the leg are found in groups on high-stress areas of the exoskeleton and have a major influence on the adaptation of walking behavior. The challenge for studying …

Development Of A Quasi-Dimension Gci Combustion Model Aided By Cfd, Jinsu Kim

Graduate Theses, Dissertations, and Problem Reports (ETD)

Advanced combustion strategies have been proposed to improve fuel efficiency while minimizing exhaust emissions. Gasoline compression ignition (GCI) combustion featuring partially premixed compression ignition (PPCI) and diffusion combustion has been recognized as an attractive, viable combustion strategy for its potential and advantages over conventional diesel and gasoline engines. The optimization of the GCI engine system requires the development of a quasi-dimensional GCI combustion model capable of simulating GCI combustion while requesting less computational burden than CFD simulation, which is very critical in engine system simulation. This study developed a quasi-dimension, phenomenological combustion model for PPCI and diffusion combustion to facilitate …

Molecular Dynamics Modeling Of Polymers For Aerospace Composites, Swapnil Sambhaji Bamane

Dissertations, Master's Theses and Master's Reports

Polymer matrix composite materials are widely used as structural materials in aerospace and aeronautical vehicles. Resin/reinforcement wetting and the effect of polymerization on the thermo-mechanical properties of the resin are key parameters in the manufacturing of aerospace composite materials. Determining the contact angle between combinations of liquid resin and reinforcement surfaces is a common method for quantifying wettability. It is challenging to determine contact angle values experimentally of high-performance resins on CNT materials such as CNT, graphene, bundles or yarns, and BNNT surfaces. It is also experimentally difficult to determine the effect of polymerization reaction on material properties of a …

Localization Of People In Gnss-Denied Environments Using Neural-Inertial Prediction And Kalman Filter Correction, Lauren N. Cash

Graduate Theses, Dissertations, and Problem Reports (ETD)

This thesis presents a method based on neural networks and Kalman filters for estimating the position of a person carrying a mobile device (i.e., cell phone or tablet) that can communicate with static UWB sensors or is carried in an environment with known landmark positions. This device is used to collect and share inertial measurement unit (IMU) information — which includes data from sensors such as accelerometers, gyroscopes, and magnetometers — and UWB and landmark information. The collected data, in combination with other necessary initial condition information, is input into a pre-trained deep neural network (DNN) which predicts the movement …

Simulating The Impact Of Emissions Control On Economic Productivity Using Particle Systems And Puff Dispersion Model, Najam Khan

Electronic Theses and Dissertations

A simulation platform is developed for quantifying the change in productivity of an economy under passive and active emission control mechanisms. The program uses object-oriented programming to code a collection of objects resembling typical stakeholders in an economy. These objects include firms, markets, transportation hubs, and boids which are distributed over a 2D surface. Firms are connected using a modified Prim’s Minimum spanning tree algorithm, followed by implementation of an all-pair shortest path Floyd Warshall algorithm for navigation purposes. Firms use a non-linear production function for transformation of land, labor, and capital inputs to finished product. A GA-Vehicle Routing Problem …

Perceptual Anthropomorphic Walking Robot Platform For Navigation In Unstructured And Undifferentiated Environments, Luige Vladareanu, Mihai Rădulescu, Marius Pandelea, Hongbo Wang, Florentin Smarandache, Yongfei Feng, Ionel-Alexandru Gal, Alexandra C. Ciocîrlan

Branch Mathematics and Statistics Faculty and Staff Publications

This scientific presentation studies the VIPRO Platform for control of Anthropomorphic Walking Robots (AWR), the architecture control system of the SiMeLA MP robot motion, and shows several experimental results.

Study Of Nanocomposite Materials Using Molecular Dynamics, Prashik Sunil Gaikwad

Dissertations, Master's Theses and Master's Reports

There is an increase in demand for new lightweight structural materials in the aerospace industry for more efficient and affordable human space travel. Polymer matrix composites (PMCs) with reinforcement material as carbon nanotubes (CNTs) have shown exceptional increase in the mechanical properties. Flattened carbon nanotubes (flCNTs) are a primary component of many carbon nanotube (CNT) yarn and sheet materials, which are promising reinforcements for the next generation of ultra-strong composites for aerospace applications. These flCNT/polymer materials are subjected to extreme pressure and temperature during curing process. Therefore there is a need to investigate the evolution of properties during the curing …

Novel Bayesian Neural Networks And Uncertainty Quantification Of Computational Mechanics Models, Ponkrshnan Thiagarajan

Dissertations, Master's Theses and Master's Reports

Computational and data-driven models suffer from a wide range of uncertainties that impact the reliability of such models. Given the exponential proliferation of machine learning models in real-world systems, establishing a degree of confidence in their predictions becomes paramount. Reliability in predictions takes on utmost significance in domains such as autonomous driving, medical image analysis, etc., where human lives are involved, and inaccuracies in predictions could lead to disastrous outcomes. For these reasons, comprehending and quantifying uncertainties in computational and data-driven models is of utmost importance. A number of techniques have been developed to quantify uncertainties in machine learning models. …

การศึกษาความสบายในการขับขี่ของยานยนต์ไฟฟ้าผ่านการควบคุมแรงขับจากมอเตอร์ในล้อ, ชนกนันท์ บุญลัภยานันท์

Chulalongkorn University Theses and Dissertations (Chula ETD)

วิทยานิพนธ์ฉบับนี้ ได้ทำการศึกษาความสบายในการขับขี่ (Ride Comfort) ของยานยนต์ไฟฟ้าที่มีการติดตั้ง In-Wheel Motor ไว้ที่ล้อทุกล้อบนโปรแกรม MATLAB โดยใช้แบบจำลองแบบครึ่งคัน (Half Car Model) ผ่านการพิจารณาค่า Frequency-Weighted Acceleration ซึ่งถูกนิยามไว้ในมาตรฐานของ ISO 2631 โดยการใช้ Power Spectral Density ของ Road Profile 3 แบบ ซึ่งเป็น Input ของระบบ (ถนนทั้ง 3 แบบถูกจัดอยู่ใน Class A ถึง D ตามมาตรฐาน ISO 8608) จากนั้นจึงคำนวณหาค่า Frequency-Weighted Acceleration ของ 2 กรณี เปรียบเทียบกัน โดยกรณีแรกคือระบบแบบ Open-Loop ที่ไม่ได้มีการติดตั้ง Controller กับอีกกรณีหนึ่งซึ่งเป็นระบบแบบ Closed-Loop ที่มีการติดตั้ง P Controller ไว้ที่ In-Wheel Motor ของล้อทุกล้อ เพื่อให้เกิดการสั่นสะเทือนในแนวดิ่งให้น้อยที่สุด ผ่านการควบคุมแรงขับจาก In-Wheel Motor โดยมีการเปลี่ยนแปลงค่าของ Proportional Gain เพื่อดูผลของ Controller ที่มีต่อค่า Frequency-Weighted Acceleration แล้วจึงพิจารณาประสิทธิภาพของ Controller ว่าสามารถลดการสั่นสะเทือนของยานยนต์ไฟฟ้าได้มากน้อยเพียงใด โดยคำนวณเป็นสัดส่วนของค่า Frequency-Weighted Acceleration ที่ลดลงเมื่อเทียบกับกรณีของระบบ Open-Loop​ ผลการศึกษาพบว่า เมื่อค่า Proportional Gain ของ P Controller มีค่าสูงขึ้น จะทำให้ค่า Frequency-Weighted Acceleration มีค่าลดลงตามไปด้วย ซึ่งจะส่งผลให้การขับขี่มีความสบายมากขึ้น แต่อย่างไรก็ตาม ในกรณีที่ค่า Proportional Gain ของ Controller …

Design And Fabrication Of An Anthropomorphic Robotic Finger With Dual Tendon Drives And Passive Stretch-Driven Elastic Members, Worathris Chungsangsatiporn

Chulalongkorn University Theses and Dissertations (Chula ETD)

Human hands are unparalleled in their dexterity, precision, and versatility, making them ideal models for robotic systems. Conventional robotic hands with standard joints cannot fully replicate human hand biomechanics, often resulting in increased weight, cost, and complexity. The primary objective is to develop a robotic finger that closely mimics anthropomorphic characteristics using computer-aided design (CAD) and rapid prototyping technology and to analyze its force and motion behaviors. The underactuated hybrid design combined soft and rigid elements and emphasizes passive adaptability to achieve dexterity. Rolling contact joints were applied to replicate varied rotational axis biomechanics. Springs and tendon routes were integrated …

Aerostructural Predictions Combining Fenics And A Viscous Vortex Particle Method, Ryan Anderson, Andrew Ning, Ru Xiang, Sebastiaan P. C. Van Schie, Mark Sperry, Darshan Sarojini, David Kamensky, John T. Hwang

Faculty Publications

Electric Vertical Takeoff and Landing (eVTOL) aircraft experience complex, unsteady aerodynamic interactions between rotors, wings, and fuselage that can make design difficult. We introduce a new framework for predicting aerostructural interactions. Specifically, we demonstrate the coupling of a finite element solver with Reissner-Mindlin shell theory for computing deflections and a viscous vortex particle for capturing wakes. We perform convergence studies of the aerodynamics and the coupled aerostructural model. Finally, we share some preliminary results of the dynamic aeroelastic response of Uber’s eCRM-002 main wing, and share some qualitative observations.

An Intrinsic Sensing Ram Extruder With Pressure And Volumetric Flow Control For Liquid Deposition Modeling, Kantawatchr Chaiprabha

Chulalongkorn University Theses and Dissertations (Chula ETD)

In this dissertation, a ram extruder for liquid deposition modeling (LDM) with a flexible actuation system is proposed. The system allows the command of flow through either pressure or volumetric modes. A mathematical model of the extruder is implemented. The actuation system enables real-time monitoring of pressure and material flow rate, providing benefits for precise control and adjustment during the printing process. Additionally, the system allows for the classification of material viscosity characteristics, offering in-depth information on the material for further analysis of the printing process. The prototype provides the advantage of both pressure and volumetric flow, as well as …

Design Of Force Indicator For Ballistic Armor Trauma Pad, William Keenan, Anthony Cinalli, Patrick Kennedy

Williams Honors College, Honors Research Projects

The purpose of the Force Indicator for Ballistic Armor Vests is to obtain an approximate value for the impact a bullet delivers through a trauma pad after the Kevlar layer stops the initial bullet. This approximation will be applied in the field to assist in medical treatment of gunshot wounds. The indicator is made from a pressure-sensitive film located behind the Kevlar layer and trauma pad, and it can be easily removed in the field for examination. The impact vest and force indicator are self-contained for ease of implementation. The device will be tested with 9mm, .22 Long Rifle, and …

Static I-V Based Pim Evaluation For Spring And Fabric-Over-Foam Contacts, Kalkidan W. Anjajo, Yang Xu, Shengxuan Xia, Yuchu He, Haicheng Zhou, Hanfeng Wang, Jonghyun Park, Chulsoon Hwang

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Spring Clips and Fabric-Over-Foams (FOFs) Are Widely Used in Mobile Devices for Electrical Connection Purposes. However, the Imperfect Metallic Connections Tend to Induce Passive Intermodulation (PIM), Resulting in a Receiver Sensitivity Degradation, Known as RP Desensitization. Due to the Complexity of the PIM Characterization, there is Not Yet a Way to Evaluate PIM Performance using a Simple Setup for Environments Like Factories. in This Paper, a Current-Voltage (I-V) Behavior-Based PIM Evaluation Method is Proposed and Validated with Various Metallic Contacts and Contact Forces. the Test Results Demonstrated the Feasibility of the PIM Performance Evaluation based on the Measured Static I-V …

Reinforcement Learning-Guided Quadratically Constrained Quadratic Programming For Enhanced Convergence And Optimality, Chaoying Pei, Zhi Xu, Sixiong You, Jeffrey Sun, Ran Dai

Mechanical and Aerospace Engineering Faculty Research & Creative Works

In the context of Quadratically Constrained Quadratic Programming (QCQP) with dynamic parameters, the effectiveness of various optimization approaches is heavily influenced by the quality of the initial guess. To address this challenge, this paper proposes a novel approach that leverages reinforcement learning (RL) to generate high-performing initial guesses for iterative algorithms, with the dynamic parameters serving as inputs. Our approach aims to accelerate convergence and improve the objective value, thereby enabling efficient and effective solutions to the QCQP problem under variability. In this study, we evaluate the proposed approach by applying it to an iterative algorithm, specifically the Iterative Rank …

Mixed-Input Learning For Multi-Point Landing Guidance With Hazard Avoidance Part I: Offline Mission Planning Based On Multi-Stage Optimization, Chaoying Pei, Sixiong You, Ran Dai, Jeremy R. Rea

Mechanical and Aerospace Engineering Faculty Research & Creative Works

This paper proposes a multi-stage optimization framework based on iterative second-order cone programming (SOCP) to solve the three-dimensional (3D) multi-point landing guidance (MLG) problem with hazard avoidance. The approach is used to generate the offline optimal trajectories for database construction in Part II of this paper, it aims to select a safe landing point while finding an optimal path to the selected landing point with minimum fuel consumption. First, by introducing binary variables associated with quadratic constraints, the MLG problem with hazard avoidance is equivalently reformulated as a quadratically constrained quadratic programming (QCQP) problem. Next, to solve the reformulated QCQP …