Engineering Commons^™

Fire Resistance Of Steel Connectors Of Precast Lightweight Concrete Walls, Jen-Hao Chi, Maochieh Chi, Yue-Lin Huang

Journal of Marine Science and Technology–Taiwan

In this study the fire test was performed to investigate the mechanic behaviors and failure patterns of precast normal weight concrete (NWC) and lightweight concrete (LWC) walls with three types of commonly used steel connectors, namely dry (61), wet (81), and bearing (56E) connectors. For the LWC wall specimens, on lateral application of tension, the cracking load values of the dry, wet, and bearing-type connectors were 95.1%, 86.3%, and 83.0%, respectively, of the original loads, and their ultimate load values were 81.6%, 90.7%, and 85.0%, respectively, of the original. In the shearing test after the fire resistance test, the cracking …

Differential Evolution Algorithm For Ship Path Planning In Open Waters, Yu-Tao Kang, Wei-Jiong Chen, Jin-Hui Wang

Journal of Marine Science and Technology–Taiwan

A general approach to the derivation of simple yet accurate formulas for identifying bandpass nonlinear channels in or-thogonal frequency-division multiplexing (OFDM) systems is proposed in this paper. The OFDM is an widely adopted tech-nique for wideband communication applications. An OFDM signal could be highly vulnerable to nonlinearities in a com-munication link. This makes proper estimation of the nonlin-ear channel essential for an OFDM system. A nonlinear bandpass communication channel is commonly described by a complex Voletrra series, in which the task of nonlinear channel identification is to determine the Volterra kernels. This task can become very difficult when the order …

Integrated Simulation Of Virtual Prototypes And Control Algorithms Of Unmanned Surface Vehicles Based On A Robot Operating System, Hye-Won Lee, Joo-Hyun Woo, Myung-Il Roh, Seung-Ho Ham, Luman Zhao, Sol Ha, Nak-Wan Kim, Chan-Woo Yu

Journal of Marine Science and Technology–Taiwan

Unmanned surface vehicles (USVs) require autonomous software with a high level of liberalization and automation to complete various missions. Therefore, experimental verification and validation of this software at the initial design stage are essential. However, such experiments are impossible before the actual hardware is developed, and the creation of an external environment for the mission requires substantial cost and time. In this study, virtual prototypes of the mission environment and hardware for the USV are developed. Then, a simulation environment for testing the control algorithms in the autonomous software is constructed. Data communication with the USV hardware is necessary for …

Identification Of Nonlinear Channels In Bandpass Communication Systems With Ofdm Inputs, Jen-Ho Cheng, Ching-Hsiang Tseng

Journal of Marine Science and Technology–Taiwan

A general approach to the derivation of simple yet accurate formulas for identifying bandpass nonlinear channels in or-thogonal frequency-division multiplexing (OFDM) systems is proposed in this paper. The OFDM is an widely adopted tech-nique for wideband communication applications. An OFDM signal could be highly vulnerable to nonlinearities in a com-munication link. This makes proper estimation of the nonlin-ear channel essential for an OFDM system. A nonlinear bandpass communication channel is commonly described by a complex Voletrra series, in which the task of nonlinear channel identification is to determine the Volterra kernels. This task can become very difficult when the order …

Metasurface Cloaks To Decouple Closely Spaced Printed Dipole Antenna Arrays Fed By A Microstrip-To-Balanced Transmission-Line Transition, Doojin Lee, Alexander B. Yakovlev

Faculty and Student Publications

In this work, we present a numerical study of 1D and 2D closely spaced antenna arrays of microstrip dipole antennas covered by a metasurface in order to properly cloak and decouple the antenna arrays operating at neighboring frequencies. We show that the two strongly coupled arrays fed by a microstrip-to-balanced transmission-line transition are effectively decoupled in 1D and 2D array scenarios by covering the dipole antenna elements with an elliptically shaped metasurface. The metasurface comprises sub-wavelength periodic metallic strips printed on an elliptically shaped dielectric cover around the dipole antennas and integrated with the substrate. We present a practical design …

Characterizing Behaviors And Functions Of Joints For Design Of Origami-Based Mechanical Systems, Nathan Chandler Brown

Theses and Dissertations

This thesis addresses a number of challenges designers face when designing deployable origami-based arrays, specifically joint selection, design, and placement within an array. In deployable systems, the selection and arrangement of joint types is key to how the system functions. The kinematics and performance of an array is directly affected by joint performance. This work develops joint metrics which are then used to compare joint performances, constructing a tool designers can use when selecting joints for an origami array. While often a single type of joint is used throughout an array, this work shows how using multiple types of joints …

Thermal Barrier Coating For Carbon Fiber-Reinforced Composite Materials, Heejin Kim, Jungwon Kim, Juhyeong Lee, Min Wook Lee

Mechanical and Aerospace Engineering Faculty Publications

Carbon fiber-reinforced plastic (CFRP) composites are widely employed in lightweight and high performance applications including supercars, aero-vehicles, and space components. However, although carbon fibers are thermally stable, the low thermal endurance of the matrix materials remains a critical problem in terms of the performance of the material. In this study, we proposed a new, Al₂O₃-based thermal barrier coating (TBC) for the CFRP composites. The TBC comprised α-phase Al₂O₃ particles with a mean diameter of 9.27 μm. The strong adhesion between the TBC and the CFRP substrate was evaluated using a three point bending …

Layered Double Hydroxide-Based Nanocomposite Scaffolds In Tissue Engineering Applications, Burcin Izbudak, Berivan Cecen, Ingrid Anaya, Amir K. Miri, Ayca Bal-Ozturk, Erdal Karaoz

Henry M. Rowan College of Engineering Departmental Research

Layered double hydroxides (LDHs), when incorporated into biomaterials, provide a tunable composition, controllable particle size, anion exchange capacity, pH-sensitive solubility, high-drug loading efficiency, efficient gene and drug delivery, controlled release and effective intracellular uptake, natural biodegradability in an acidic medium, and negligible toxicity. In this review, we study potential applications of LDH-based nanocomposite scaffolds for tissue engineering. We address how LDHs provide new solutions for nanostructure stability and enhance in vivo studies' success.

Submicron Metal 3d Printing By Ultrafast Laser Heating And Induced Ligand Transformation Of Nanocrystals, Chinmoy Podder, Xiangtao Gong, Xiaowei Yu, Wan Shou, Heng Pan

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Currently, light-based three-dimensional (3D) printing with submicron features is mainly developed based on photosensitive polymers or inorganic-polymer composite materials. To eliminate polymer/organic additives, a strategy for direct 3D assembly and printing of metallic nanocrystals without additives is presented. Ultrafast laser with intensity in the range of 1 x 1010 to 1 x 1012 W/cm2 is used to nonequilibrium heat nanocrystals and induce ligand transformation, which triggers the spontaneous fusion and localized assembly of nanocrystals. The process is due to the operation of hot electrons as confirmed by a strong dependence of the printing rate on laser pulse duration varied in …

Algorithm Of The Estimation Of The Moving The Raw Cotton On Surfaces Of The Pallet Of The Mechanism Of The Presenting Ginning Machines, M Х. Aхmedov, T O. Tuychiev, A A. Ismoilov, Sh A. Xusanova

Scientific-technical journal

In article are brought algorithm of searching for parameter unceasing moving the raw cotton on surfaces of the pallet of the mechanism of the presenting ginning machines, management and provision rational parameter, as well as results called on numerically-experimental studies. The broughted results called on numerically-experimental studies on estimations of the dependencies of the corner , factor of friction, primary velocity and time for displacement centre raw cotton in feedersof saw gin.

Rainbow Trapping Effect In 2d Axisymmetric Broadband Acoustic Energy Harvesters, Louis Alexander Gormley

Theses and Dissertations

Acoustic energy harvesters (AEHs) collect otherwise unused ambient acoustic waves for conversion into useful electrical energy. This promising technology has potential applications ranging from grid-independent electronics to structural health monitoring systems. AEHs capture specific acoustic frequencies of interest using structures with frequency-matched component geometries. Despite the multitude of potential geometries suitable for AEH structures, existing AEH research has predominantly focused on the acoustic wave trapping performance of unidimensional or linear bidimensional AEH structures.

This study intended to broaden AEH bandwidth and capture efficiency by investigating the acoustic rainbow trapping performance of a novel 2D axisymmetric AEH design. A Finite Element …

Comparison Of Theoretical And Multi-Fidelity Optimum Aerostructural Solutions For Wing Design, Jeffrey D. Taylor, Douglas F. Hunsaker

Mechanical and Aerospace Engineering Student Publications and Presentations

As contemporary aerostructural research for aircraft design trends toward high-fidelity computational methods, aerostructural solutions based on theory are often neglected or forgotten. In fact, in many modern aerostructural wing optimization studies, the elliptic lift distribution is used as a benchmark in place of theoretical aerostructural solutions with more appropriate constraints. In this paper, we review several theoretical aerostructural solutions that could be used as benchmark cases for wing design studies, and we compare them to high-fidelity solutions with similar constraints. Solutions are presented for studies with 1) constraints related to the wing integrated bending moment, 2) constraints related to the …

Mechanism Design And Analysis: Developing An Understanding Of Mechanism Motion Through Graphical Modeling, Andrew J. Hughes, Chris Merrill

Educational Leadership & Technology Faculty Publications

The intention of this article is to provide Technology and Engineering Educators with foundational knowledge of mechanism design and analysis and the ability to develop middle and high school students' mechanism knowledge during practical hands-on learning activities in the STEM classroom. Technology and Engineering Educators' implementation of mechanism design and analysis could promote students' increased depth of mechanical knowledge and ability to apply this knowledge during engineering design challenges. In this article, the authors present an introduction to four-bar mechanism design and analysis using CAD software to produce graphical representations. After designing mechanisms graphical, students should be allowed to produce …

Thermal Vacuum Chamber Modification, Testing, And Analysis, Jared C. Lehmann

Master's Theses

This work discusses the modification and analysis of the Blue Thermal Vacuum Chamber (TVAC) located at the Space Environments Lab at California Polytechnic State University, San Luis Obispo. The modified design has a cylindrical test section and can accommodate 6U Cubesats or larger for educational or research purposes. The sizing process for the modified shroud cooling system and modular heating plates is discussed. The modified cooling system uses existing nitrogen plumbing into the chamber and control systems with a new copper shroud. The modified heating system uses modular heater plates, which utilize the existing three heater strips. The modified system …

Fourth-Order Adjoint Sensitivity And Uncertainty Analysis Of An Oecd/Nea Reactor Physics Benchmark: I. Computed Sensitivities, Ruixian Fang, Dan Gabriel Cacuci

Faculty Publications

This work extends the investigation of higher-order sensitivity and uncertainty analysis from 3rd-order to 4th-order for a polyethylene-reflected plutonium (PERP) OECD/NEA reactor physics benchmark. Specifically, by applying the 4th-order comprehensive adjoint sensitivity analysis methodology (4th-CASAM) to the PERP benchmark, this work presents the numerical results of the most important 4th-order sensitivities of the benchmark’s total leakage response with respect to the benchmark’s 180 microscopic total cross sections, which includes 180 4th-order unmixed sensitivities and 360 4th-order mixed sensitivities corresponding to the largest 3rd-order ones. The numerical results obtained in this work reveal that the number of 4th-order relative sensitivities that …

Stabilization Of Energy Level Sets Of Underactuated Mechanical Systems Exploiting Impulsive Braking, Nilay Kant, Ranjan Mukherjee, Hassan Khalil

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Recent investigations of underactuated systems have demonstrated the benefits of control inputs that are impulsive in nature. Here we consider the problem of stabilization of energy level sets of underactuated systems exploiting impulsive braking. We consider systems with one passive degree-of-freedom (DOF) and the energy level set is a manifold where the active coordinates are fixed and the mechanical energy equals some desired value. A control strategy comprised of continuous inputs and intermittent impulsive braking inputs is presented. The generality of the approach is shown through simulation of a three-DOF Tiptoebot; the feasibility of implementation of impulsive control using standard …

Testing And Characterization Of Polymer Laminates For Swelling, Absorption, And Cracking, Matthew W. Carlson

Master's Theses

A polymer laminate consisting of multiple layers of proprietary blends of Ethylene Vinyl Alcohol (EVOH) and Thermoplastic Polyurethane (TPU) and used in the construction of air bladders was evaluated for hygroscopic effects driving delamination and multiple layer fragmentation. These air bladders are observed to suffer delamination during a manufacturing process that involves immersion in an alcohol/water solution. A plausible underlying mechanism is differential swelling and absorption by the laminate constituents. Both room and elevated temperature swelling tests were carried out to find the absorption and swelling coefficients of the constituents. These coefficients served as input into a Finite Element Analysis …

Vacuum Infusion Of Composites: Durability Of Hybrid Large Area Additive Tooling For Vacuum Infusion Of Composites, Nathan Northrup, Jason Weaver, Andy R. George

Faculty Publications

The durability of a hybrid large area additively manufactured fiberglass ABS mold for vacuum infusion of composites was evaluated. The validation was done by designing and fabricating a mold for a custom test artifact and analyzing the surface geometry over the course of multiple infusions until tool failure. After printing and machining, the mold required a sealer to maintain vacuum integrity. The mold was able to produce 10 parts successfully before the sealed tool surface began to tangibly roughen, resulting in increased difficulty of demolding and a rougher surface finish. After the 14th infusion, the part required destructive force to …

Physical-Based Training Data Collection Approach For Data-Driven Lithium-Ion Battery State-Of-Charge Prediction, Jie Li, Will Ziehm, Jonathan W. Kimball, Robert Landers, Jonghyun Park

Electrical and Computer Engineering Faculty Research & Creative Works

Data-Driven approaches for State of Charge (SOC) prediction have been developed considerably in recent years. However, determining the appropriate training dataset is still a challenge for model development and validation due to the considerably varieties of lithium-ion batteries in terms of material, types of battery cells, and operation conditions. This work focuses on optimization of the training data set by using simple measurable data sets, which is important for the accuracy of predictions, reduction of training time, and application to online estimation. It is found that a randomly generated data set can be effectively used for the training data set, …

Coalescence Characteristics Of Bulk Nanobubbles In Water: A Molecular Dynamics Study Coupled With Theoretical Analysis, Eric Bird, Eric Smith, Zhi Liang

Mechanical and Aerospace Engineering Faculty Research & Creative Works

The Coalescence of Two Nanobubbles (NBs) in Water is a Process of Great Importance to Many Industrial Applications. in This Work, We Study the Coalescence of Two Equal-Sized Nitrogen NBs in Water using Molecular Dynamics (MD) Simulations and Continuum-Based Theoretical Analysis. We Vary the NB Diameter from 30 to 50 Nm and Study the Coalescence Characteristics Including the Expansion Speed of the Capillary Bridge between Two Coalescing NBs, the Dynamic Regime of NB Coalescence, the Diameter of Fully Merged NBs, and the Temperature Variation of NBs during the Coalescence Process. for All Cases, We Show the MD Simulation Results Can …

Deep Learning-Based Penetration Depth Prediction In Al/Cu Laser Welding Using Spectrometer Signal And Ccd Image, Sanghoon Kang, Minjung Kang, Yong Hoon Jang, Cheolhee Kim

Mechanical and Materials Engineering Faculty Publications and Presentations

In the laser welding of thin Al/Cu sheets, proper penetration depth and wide interface bead width ensure stable joint strength and low electrical conductance. In this study, we proposed deep learning models to predict the penetration depth. The inputs for the prediction models were 500 Hz-sampled low-cost charge-coupled device (CCD) camera images and 100 Hz-sampled spectral signals. The output was the penetration depth estimated from the keyhole depth measured coaxially using optical coherence tomography. A unisensor model using a CCD image and a multisensor model using a CCD image and the spectrometer signal were proposed in this study. The input …

Electrostatic Flocking Of Salt-Treated Microfibers And Nanofiber Yarns For Regenerative Engineering, Alec Mccarthy, Kossi Loic M. Avegnon, Phil A. Holubeck, Demi Brown, Anik Karan, Navatha Shree Sharma, Johnson V. John, Shelbie Weihs, Jazmin Ley, Jingwei Xie

Mechanical Engineering Faculty Publications

Electrostatic flocking is a textile technology that employs a Coulombic driving force to launch short fibers from a charging source towards an adhesive-covered substrate, resulting in a dense array of aligned fibers perpendicular to the substrate. However, electrostatic flocking of insulative polymeric fibers remains a challenge due to their insufficient charge accumulation. We report a facile method to flock electrostatically insulative poly(ε-caprolactone) (PCL) microfibers (MFs) and electrospun PCL nanofiber yarns (NFYs) by incorporating NaCl during pre-flock processing. Both MF and NFY were evaluated for flock functionality, mechanical properties, and biological responses. To demonstrate this platform's diverse applications, standalone flocked NFY …

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 …

Atomistic Simulation Of Desalination, Ian David Durr

Symposium of Student Scholars

Atomistic Simulation of Desalination

Ian Durr, Matheus Prates, and Jungkyu Park

Kennesaw State University

In this research, we investigate the desalination capacity of three-dimensional (3D) carbon nanostructures using molecular dynamics simulations. 3D carbon nanostructures proposed here will filter seawater efficiently because of their multiple layers with holes of tunable sizes. The structure is designed to be flexible, allowing mechanical deformation during daily use. The 3D carbon nanostructure will still possess high thermal conductivity, enabling easy recycle through a simple heating process. Here, we employ LAMMPS, Large-scale Atomic/MolecularMassively Parallel Simulator distributed by Sandia National Laboratories to measure salt ion flux through …

Using Comprehensive Finite Element Analysis To Simulate A Special Connection In Post-Tensioned Concrete, Joshuah Leljedal

Symposium of Student Scholars

Finite element analysis (FEA) uses differential equations to determine a computer-based solution that explains interactive behaviors within models of complex structural and mechanical systems, subjected to various loading and environmental conditions. Those systems are partitioned into finite elements consisting of a linear mesh with nodes at each end point, and FEA determines relationships, such as force-displacement, between each of the finite elements. This apportioned model allows systems to be evaluated under multiple loading scenarios. Computer-based FEA offers significant benefits that reduce cost and the time required to perform alternative analysis for complex structural systems. In this research project, a comprehensive …

The Influence Of Mechanical Properties Associated With Exercise Equipment Padding On Maximizing Performance And Minimizing Potential Soft-Tissue Injury When Performing High-Intensity Weight Lifting Exercises, Robert Hewston

Symposium of Student Scholars

The intention of this study is the measurement of mechanical properties such as resilience and compressibility associated with exercise equipment padding in order to determine the ability to minimize potential soft-tissue injuries while performing high-intensity weight lifting exercises. ASTM standards were used to test the resilience and compressibility of five different exercise equipment padding specimens. The specimens consisted of standard bench press foam, composite foam, polyethylene foam, a single yoga mat foam, and double yoga mat foam. The resilience and compressibility are tested to determine the amount of deformation each sample can experience and the level of energy returned back …

Contact Angle Measurement Using A Hele-Shaw Cell: A Proof-Of-Concept Study, Haipeng Zhang, Jacob Gottberg, Sangjin Ryu

Department of Mechanical and Materials Engineering: Faculty Publications

Contact angle is an important property to quantify the wettability of a solid surface with a liquid, which characterizes interactions of the solid-liquid pair. Generally, to measure contact angle, special instruments such as a goniometer are necessary, but they are not readily available in certain research settings. In this study, an alternative method to measure contact angle based on a Hele-Shaw cell, microscopy imaging, and image processing is suggested. In this method, a liquid drop is injected into a transparent Hele-Shaw cell, the meniscus of the drop is captured in the top or bottom view using a brightfield microscope, and …

Stable Thermally-Modulated Nanodroplet Ultrasound Contrast Agents, Anastasiia Vasiukhina, Javad Estraghi, Adib Ahmadzadegan, Craig J. Goergen, Pavlov P. Vlachos, Luis Solorio

School of Mechanical Engineering Faculty Publications

Liquid perfluorocarbon-based nanodroplets are stable enough to be used in extravascular imaging, but provide limited contrast enhancement due to their small size, incompressible core, and small acoustic impedance mismatch with biological fluids. Here we show a novel approach to overcoming this limitation by using a heating–cooling cycle, which we will refer to as thermal modulation (TM), to induce echogenicity of otherwise stable but poorly echogenic nanodroplets without triggering a transient phase shift. We apply thermal modulation to high-boiling point tetradecafluorohexane (TDFH) nanodroplets stabilized with a bovine serum albumin (BSA) shell. BSA-TDFH nanodroplets with an average diameter under 300 nanometers showed …

Flow Interaction Between Turbomachine Blade Row And Flow Resistance Medium, Tong Lin

Dissertations - ALL

This research investigates the fluid-dynamic interaction between close-coupled axial turbomachines and surrounding components, e.g., heat-exchangers, filters, or cooling fins in high-density computer servers, and its effects on turbomachine and system performance. The importance of this research is that the flow interaction effect occurs in every scenario that requires system compactness.

Firstly, a combined experimental and 3-D computational study on an off-the-shelf server cooling fan is performed, showing that the fan performance has little changed. However, the system performance can be very different since the server cooling has a large hub-to-tip radius ratio, which effectively blocks the high resistance media's (HRM) …

Molecular Interfaces And Heterogeneous Bubble Nucleation From Heated Surfaces At Nanoscale, Manish Gupta

Dissertations - ALL

Heat transfer from a solid surface to fluid occurs in numerous applications, such as boilers, refrigerators, power electronics, etc., and include various underlying phenomena of thin-film evaporation, boiling, condensation, surface wetting, and droplet evaporation. Several studies show that heat transfer can be enhanced significantly by incorporating micro and nanoscale features onto surfaces. Phase change heat transfer plays an important role in dissipating energy from hot surfaces and distributing it to bulk liquid due to high latent heat of liquids. Boiling, a phase change heat transfer phenomenon, happens when the surface is heated to a temperature above the saturation temperature of …