Mechanical Engineering Commons^™

Frequency Based Noise Coherence-Function Extension And Application To Passive Bottom-Loss Estimation, Lanfranco Muzi, Martin Siderius, Peter L. Nielsen

Electrical and Computer Engineering Faculty Publications and Presentations

Accurate modeling of acoustic propagation in the ocean waveguide is important to SONAR-performance prediction. Particularly in shallow waters, a crucial contribution to the total transmission loss is the bottom refection loss, which can be estimated passively by beamforming the natural surface-noise acoustic field recorded by a vertical line array of hydrophones. However, the performance in this task of arrays below 2 m of length is problematic for frequencies below 10 kHz" role="presentation" style="display: inline; line-height: normal; word-spacing: normal; word-wrap: normal; white-space: nowrap; float: none; direction: ltr; max-width: none; max-height: none; min-width: 0px; min-height: 0px; border: 0px; padding: 0px 2px 0px …

Haptic Shape-Based Management Of Robot Teams In Cordon And Patrol, Samuel Jacob Mcdonald

Theses and Dissertations

There are many current and future scenarios that require teams of air, ground or humanoid robots to gather information in complex and often dangerous environments, where it would be unreasonable or impossible for humans to be physically present [1-6]. The current state of the art involves a single robot being monitored by one or many human operators [7], but a single operator managing a team of autonomous robots is preferred as long as effective and time-efficient management of the team is maintained [8-9]. This is limited by the operator's ability to command actions of multiple robots, be aware of robot …

Quantification Of Frictional Drag Due To Biofouling On In-Service Ships, John Travis Hunsucker

Theses and Dissertations

The purpose of this research was to improve the quantification of frictional drag due to biofouling on in-service ships by advancing the knowledge and methodology used to study the interactions between fouling communities and the surrounding environment. This research examined the influence of hydrodynamic stress on the development and frictional drag of fouling communities that developed on a fouling release coating; investigated the reliability of using ship performance monitoring to detect changes in the hull and propeller condition; and evaluated the feasibility of developing a field deployable instrument capable of measuring the local frictional resistance on a ship hull in …

Bioink Properties Before, During And After 3d Bioprinting, Katja Hölzl, Shengmao Lin, Liesbeth Tytgat, Sandra Van Vlierberghe, Linxia Gu, Aleksandr Ovsianikov

Department of Mechanical and Materials Engineering: Faculty Publications

Bioprinting is a process based on additive manufacturing from materials containing living cells. These materials, often referred to as bioink, are based on cytocompatible hydrogel precursor formulations, which gel in a manner compatible with different bioprinting approaches. The bioink properties before, during and after gelation are essential for its printability, comprising such features as achievable structural resolution, shape fidelity and cell survival. However, it is the final properties of the matured bioprinted tissue construct that are crucial for the end application. During tissue formation these properties are influenced by the amount of cells present in the construct, their proliferation, migration …

High-Performance Self-Powered Photodetectors Based On Zno/Zns Core-Shell Nanorod Arrays, Hailing Lin, Lin Wei, Cuncun Wu, Yanxue Chen, Shishen Yan, Liangmo Mei, Jun Jiao

Mechanical and Materials Engineering Faculty Publications and Presentations

In recent years, there is an urgent demand for high-performance ultraviolet photodetectors with high photosensitivity, fast responsivity, and excellent spectral selectivity. In this letter, we report a self-powered photoelectrochemical cell-type UV detector using the ZnO/ZnS core-shell nanorod array as the active photoanode and deionized water as the electrolyte. This photodetector demonstrates an excellent spectral selectivity and a rapid photoresponse time of about 0.04 s. And the maximum responsivity is more than 0.056 (A/W) at 340 nm, which shows an improvement of 180 % compared to detectors based on the bare ZnO nanorods. This improved photoresponsivity can be understood from the …

Scenario Analysis For Techno-Economic Model Development Of U.S. Offshore Wind Support Structures, Rick Damiani, Andrew Ning, Ben Maples, Aaron Smith, Katherine Dykes

Faculty Publications

Challenging bathymetry and soil conditions of future U.S. offshore wind power plants might promote the use of multimember, fixed-bottom structures (or “jackets”) in place of monopiles. Support structures affect costs associated with the balance of system (BOS) and operation and maintenance. Understanding the link between these costs and the main environmental design drivers is crucial in the quest for a lower levelized cost of energy (LCOE), and it is the main rationale for this work. Actual cost and engineering data are still scarce; hence, we evaluated a simplified engineering approach to tie key site and turbine parameters (e.g., water depth, …

The Feasibility Of Utilising Compressed Natural Gas As Part Of A Systematic Approach To Establishing The Necessary Groundwork For The Hydrogen Based Transport Economy, James Brunton, John Howlett, David Kennedy

Conference Papers

One key objective for vehicle manufacturers is to develop technology and infrastructure to facilitate the progression from combustion to conversion by the year 2050. In the short to medium term however, the combustion of fossil fuels such as petrol and diesel, coupled with advanced transmission innovations and emission control technology that are governed by strict Euro VI regulations appears to be the main path forward for the transport sector and the environment. This paper presents the feasibility of utilising the developing compressed natural gas network capabilities as part of a systematic approach to establishing the necessary groundwork for a hydrogen …

Realization Of Point Planar Elastic Behaviors Using Revolute Joint Serial Mechanisms Having Specified Link Lengths, Shuguang Huang, Joseph M. Schimmels

Mechanical Engineering Faculty Research and Publications

This paper presents methods for the realization of 2 × 2 translational compliance matrices using serial mechanisms having only revolute joints, each with selectable compliance. The link lengths of the mechanism and the location of the compliant frame relative to the mechanism base are arbitrary but specified. The realizability of a given compliant behavior is investigated, and necessary and sufficient conditions for the realization of a given compliance with a given mechanism are obtained. These realization conditions are interpreted in terms of geometric relationships among the joints. We show that, for an appropriately sized 3R serial mechanism, any single 2 …

Performance Prediction Of Drying Process In Residential Clothes Dryer Using Multiphysics Modeling And Simulation, Molly Shircliff

Mahurin Honors College Capstone Experience/Thesis Projects

The clothes dryer is the second highest consumer of electricity among household appliances in the U.S. However, few improvements have been made to the overall design of dryers since the 1970s. For this reason, energy efficiency research in domestic clothes dryers is a promising topic. In order to effectively and accurately research and test efficiency and design of new prototypes of the dryer, a mathematical model of the air-vented, residential dryer was created in the Energy Systems Lab at Western Kentucky University, using the text-based environment of MATLAB. This model was developed and simulated using numerical solver techniques. This model …

Optical Patterning Of Trapped Charge In Nitrogen-Doped Diamond, Harishankar Jayakumar, Jacob Henshaw, Siddharth Dhomkar, Daniela Pagliero, Abdelghani Laraoui, Neil B. Manson, Remus Albu, Marcus W. Doherty, Carlos A. Meriles

Department of Mechanical and Materials Engineering: Faculty Publications

The nitrogen-vacancy (NV) centre in diamond is emerging as a promising platform for solid-state quantum information processing and nanoscale metrology. Of interest in these applications is the manipulation of the NV charge, which can be attained by optical excitation. Here, we use two-colour optical microscopy to investigate the dynamics of NV photo-ionization, charge diffusion and trapping in type-1b diamond. We combine fixed-point laser excitation and scanning fluorescence imaging to locally alter the concentration of negatively charged NVs, and to subsequently probe the corresponding redistribution of charge. We uncover the formation of spatial patterns of trapped charge, which we qualitatively reproduce …

An Engineering Approach To Industrial Research And Development Of Pillows, Wesley Patterson

Mahurin Honors College Capstone Experience/Thesis Projects

Comfort during sleep, though taken for granted, involves a great amount of research and engineering. Few give it a second thought, but nearly one-third of a person’s life is spent with their head on a pillow, thus making them a point for increased quality. Having been approached by a tier-1 bedding manufacturer, a team of both mechanical and electrical engineers was been tasked with the goal of creating a valid research tool that the customer, Tempur-Sealy, will utilize in the company’s research and development of high-end pillows. The team sought to tackle this project utilizing tools and knowledge gained throughout …

Front Dynamics And Entrainment Of Finite Circular Gravity Currents On An Unbounded Uniform Slope, ‪Nadim Zgheib, A. Ooi, S. Balachandar

Mechanical Engineering Faculty Publications

We report on the dynamics of circular finite-release Boussinesq gravity currents on a uniform slope. The study comprises a series of highly resolved direct numerical simulations for a range of slope angles between 5∘ and 20∘ . The simulations were fixed at Reynolds number Re=5000 for all slopes considered. The temporal evolution of the front is compared to available experimental data. One of the interesting aspects of this study is the detection of a converging flow towards the centre of the gravity current. This converging flow is a result of the finite volume of the release coupled with the presence …

Sensitivity Studies On The Shear Lag Parameter Β Using Analytical And Numerical Techniques, George Thomas Avery

Theses and Dissertations

The strength of fiber-reinforced composites is dependent on the strength of the fiber-matrix interface bond. Thermal, chemical, and other means have been used to modify the surface of fibers, resulting in increased fiber-matrix interface bond strength. However, researchers are still dependent on empirical methods to relate surface modifications to composite performance. Additional efforts are required to develop physics-based models for micro-mechanical effects on interfacial bond strength that will be needed for the improved design and processing of fiber reinforced composites. It is anticipated that experimental, numerical, and analytical efforts will be needed to contribute toward this endeavor.

A numerical approach …

Two-Temperature Dual-Phase-Lags Theory In A Thermoelastic Solid Half-Space Due To An Inclined Load, Ashraf M. Zenkour, Ahmed E. Abouelregal, Khaled A. Alnefaie, Nidal H. Abu-Hamdeh, Abdulmalik A. Aljinaidi, Elias C. Aifantis

Michigan Tech Publications, Part 1

This article addresses the thermoelastic interaction due to inclined load on a homogeneous isotropic half-space in context of two-temperature generalized theory of thermoelasticity with dual-phase-lags. It is assumed that the inclined load is a linear combination of both normal and tangential loads. The governing equations are solved by using the normal mode analysis. The variations of the displacement, stress, conductive temperature, and thermodynamic temperature distributions with the horizontal distance have been shown graphically. Results of some earlier workers have also been deduced from the present investigation as special cases. Some comparisons are graphically presented to estimate the effects of the …

Designing And Building An Automatic Chamfer Grinder, William Johnson

Mahurin Honors College Capstone Experience/Thesis Projects

Modern day manufacturing is a demanding environment with a constant need for process improvement. As automation becomes more advanced, there are fewer jobs that must be completed by a human. In the case of Stupp Bridge Company, a local manufacturer of steel bridge girders, their workforce is highly skilled, so replacing mundane tasks with automation allow the skilled workers to focus on the difficult jobs. One such task is grinding a chamfer onto every leading edge of each girder flange, eight edges in total, ranging from 20 to 200 feet long. The purpose of this project was to design an …

On Event-Triggered Adaptive Architectures For Decentralized And Distributed Control Of Large-Scale Modular Systems, Ali Albattat, Benjamin C. Gruenwald, Tansel Yucelen

Mechanical and Aerospace Engineering Faculty Research & Creative Works

The last decade has witnessed an increased interest in physical systems controlled over wireless networks (networked control systems). These systems allow the computation of control signals via processors that are not attached to the physical systems, and the feedback loops are closed over wireless networks. The contribution of this paper is to design and analyze event-triggered decentralized and distributed adaptive control architectures for uncertain networked large-scale modular systems; that is, systems consist of physically interconnected modules controlled over wireless networks. Specifically, the proposed adaptive architectures guarantee overall system stability while reducing wireless network utilization and achieving a given system performance …

A Fuzzy Data Envelopment Analysis Framework For Dealing With Uncertainty Impacts Of Input–Output Life Cycle Assessment Models On Eco-Efficiency Assessment, Gokhan Egilmez, Serkan Gumus, Murat Kucukvar, Omer Tatari

Mechanical and Industrial Engineering Faculty Publications

The uncertainty in the results of input–output-based life cycle assessment models makes the sustainability performance assessment and ranking a challenging task. Therefore, introducing a new approach, fuzzy data envelopment analysis, is critical; since such a method could make it possible to integrate the uncertainty in the results of the life cycle assessment models into the decision-making for sustainability benchmarking and ranking. In this paper, a fuzzy data envelopment analysis model was coupled with an input–output-based life cycle assessment approach to perform the sustainability performance assessment of the 33 food manufacturing sectors in the United States. Seven environmental impact categories were …

Computational Fluid Dynamics Modeling And Simulations Of Fluidized Bed Reactors For Chemical Looping Combustion, Subhodeep Banerjee

McKelvey School of Engineering Graduate Student Theses & Dissertations

Chemical looping combustion (CLC) is a next generation combustion technology that shows great promise as a solution for the need of high-efficiency low-cost carbon capture from fossil fueled power plants. To realize this technology on an industrial scale, the development of high-fidelity simulations is a necessary step to develop a thorough understanding of the CLC process. Although there have been a number of experimental studies on CLC in recent years, CFD simulations have been limited in the literature.

In this dissertation, reacting flow simulations of a CLC reactor are developed using the Eulerian approach based on a laboratory-scale experiment of …

Open-Loop Electrowetting Actuation With Micro-Stepping, Qi Ni, Daniel E. Capecci, Nathan B. Crane

Faculty Publications

Microfluidic-driven mechanical actuation opens new possibilities for positioning and manipulating delicate small components. However, existing microfluidic actuation methods are not well-suited to positioning with high resolution. This paper reports a method for precise, open-loop control of droplet position in finite steps by varying the duty cycle of the input signal in electrowetting actuation. When wetted to a solid object, both the droplet and the solid can be actuated. Unlike conventional electrowetting actuation methods, positioning resolution in our proposed method can be much smaller than the size of the underlying electrodes without requiring closed loop feedback control system. Using a leaky …

Sound Data Collection And Transmission Noise Reduction, Bradley Cockrel

Mahurin Honors College Capstone Experience/Thesis Projects

The WKU Engineering Department Senior Student Team, The Synchronizers, has been contracted to modify a MTD transmission’s sound characteristics. This project entails developing a sound data acquisition apparatus and method, developing a sound test stand which will fully load the transmission and load characteristics, and suggesting modes of sound modification. The Sound Data Acquisition method entails using a specialized microphone calibrated to operate on IOS devices to measure Sound Intensity. The sound intensity will be found over a collective area, in order to evaluate to the sound power generated. The sound test stand will consist of a system designed to …

Optimizing An Organizational Program For Halton Company, Chandler Clark

Mahurin Honors College Capstone Experience/Thesis Projects

A team of WKU Mechanical Engineering students is collaborating with Halton Company to create an organizational system for their plant. Each job performed at Halton is custom, leading to several different processes needing to be accounted for at once. The team is designing a program in Visual Studio that will be used to control the progression of the plant as well as store data to optimize future processes involved. Visual Studio will be implemented by summer of 2016 in order to give the team and company time to troubleshoot the program and insert optimizing options into the c ode of …

Mechanisms And Solutions To The Brittle Solder Joint In Electroless Ni Plating, Xuan Wang, C. Key Chung

Industrial and Manufacturing Engineering

Brittle solder joints in Electroless Ni electroless Pd immersion Au (ENEPIG) surface finishes are one of the key reliability issues in electronics assembly. Previous characterization of the reflow process has indicated that interfacial voids formed after solder reflow are responsible for the decreases in solder joint strength. However, the mechanisms behind the formation of these voids in the ENEPIG process remain unclear. In this paper, the interaction between various aspects of the ENEPIG process and solder joint strength were investigated. Surface roughness, morphology, and nano-pitting at the interface between electroless Pd and Ni-P were characterized. The size and density of …

Nonaffine Rearrangements Of Atoms In Deformed And Quiescent Binary Glasses, Nikolai V. Priezjev

Mechanical and Materials Engineering Faculty Publications

The influence of periodic shear deformation on nonaffine atomic displacements in an amorphous solid is examined via molecular dynamics simulations. We study the three-dimensional Kob-Andersen binary mixture model at a finite temperature. It is found that when the material is periodically strained, most of the atoms undergo repetitive nonaffine displacements with amplitudes that are broadly distributed. We show that particles with large amplitudes of nonaffine displacements are organized into compact clusters. With increasing strain amplitude, spatial correlations of nonaffine displacements become increasingly long-ranged, although they remain present even in a quiescent system due to thermal fluctuations.

Investigation Of Heat-Affected 304l Ss Powder And Its Effect On Built Parts In Selective Laser Melting, Caitlin S. Kriewall, Austin T. Sutton, Ming-Chuan Leu, Joseph William Newkirk, Ben Brown

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Selective laser melting (SLM) is a powder bed based additive manufacturing process in which a layer of powder is laid over the surface of a substrate and a laser with sufficient energy is employed to selectively melt particles to build a part layer by layer. During the SLM process, dark smoke was observed coming off of the powder bed surface where the laser was interacting with powder. This phenomenon resulted from heat-affected powder that was visibly different than the base powder. Since the concentration of the heat-affected powder differs throughout the build chamber as a result of the recirculating argon …

Modeling And Experimental Investigation Of Pre-Mixed Multi-Powder Flow In Fabricating Functional Gradient Material By Laser Metal Deposition Process, Wei Li, Jingwei Zhang, Sreekar Karnati, Yunlu Zhang, Frank W. Liou, Joseph William Newkirk, Karen M. Brown Taminger, W. L. Seufzer

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Laser Metal Deposition (LMD) is an effective process to fabricate Functionally Graded Material (FGM) from pre-mixed powders. Since the supplied multi-powder directly affects the deposited FGM’s composition, investigation on Pre-Mixed Multi-Powder (PMMP) flow during LMD is greatly needed. This paper presents a comprehensive numerical PMMP flow model. By solving discrete particle force balance equations coupled with continuity equations and momentum equations for carrier gas, the dynamic behavior of PMMP flow through powder feeder tube and out of nozzle was calculated. With this model, the particle sizes of multi-powder were optimized to obtain considered FGM composition. To verify the modeling results, …

Investigation Of Tensile Properties Of Bulk And Slm Fabricated 304l Stainless Steel Using Various Gage Length Specimens, Sreekar Karnati, I. Axelsen, Frank W. Liou, Joseph William Newkirk

Mechanical and Aerospace Engineering Faculty Research & Creative Works

The complex solidification dynamics and thermal cycling during Selective Laser Melting process is expected to result in non-equilibrium material characteristics. There is an essential need for characterization techniques which are critical towards the estimation of anisotropies. The current investigation is targeted towards establishing tensile testing methodologies and their relation to differing gage lengths. Dog-bone shaped specimen designs with gage lengths of 1”, 0.3” and 0.12” were employed in this research. The characterization was performed on hot rolled-annealed 304 stainless and SLM fabricated 304L stainless. It was theorized that smaller gage length specimens would be instrumental in mapping material property anisotropy …

A Novel Extrusion-Based Additive Manufacturing Process For Ceramic Parts, Amir Ghazanfari, Wenbin Li, Ming-Chuan Leu, Greg Hilmas

Mechanical and Aerospace Engineering Faculty Research & Creative Works

An extrusion-based additive manufacturing process, called the Ceramic On-Demand Extrusion (CODE) process, for producing three-dimensional ceramic components with near theoretical density is introduced in this paper. In this process, an aqueous paste of ceramic particles with a very low binder content ( < 1 vol%) is extruded through a moving nozzle at room temperature. After a layer is deposited, it is surrounded by oil (to a level just below the top surface of most recent layer) to preclude non-uniform evaporation from the sides. Infrared radiation is then used to partially, and uniformly, dry the just-deposited layer so that the yield stress of the paste increases and the part maintains its shape. The same procedure is repeated for every layer until part fabrication is completed. Several sample parts for various applications were produced using this process and their properties were obtained. The results indicate that the proposed method enables fabrication of large, dense ceramic parts with complex geometries.

Selective Laser Sintering Of Low Density, Low Coefficient Of Thermal Expansion Silica Parts, John M. Hostetler, Jonathan T. Goldstein, Augustine M. Urbas, Rodrigo E. Gutierrez, Theresa E. Bender, Charles S. Wojnar, Edward C. Kinzel

Mechanical and Aerospace Engineering Faculty Research & Creative Works

This paper presents a study of selective laser sintering of silica-gel. The objective of this work is to investigate a technique to create free-form, low to zero coefficient of thermal expansion structures. This offers potential cost savings over the conventional casting of large pieces of glass-ceramic followed by machining lightening features. In this paper, A CO₂ laser is coupled through a gantry system and focused onto a binder-free silica-gel powder bed (15-40 μm particles). Prior to writing each layer, powder is dispensed by sifting it onto the build platform as opposed to a conventional wiper system. This avoids contacting …

Bubble Formation In Additive Manufacturing Of Borosilicate Glass, Junjie Luo, Theresa Bender, Douglas A. Bristow, Robert G. Landers, Jonathan T. Goldstein, Augustine M. Urbas, Edward C. Kinzel

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Entrapped bubbles are an important problem in conventional glass manufacturing. It is also a significant factor determining the quality of glass products produced using additive manufacturing (AM). This paper reports on the bubble formation and entrapment in filament-fed AM printing of borosilicate glass. This process involves maintaining a local molten region using a CO₂ laser. A 2 mm filament is fed continuously into the molten region while CNC stages position the workpiece relative to the laser and filament feed. Two different bubble regimes are identified in experiments with borosilicate glass. These regimes can be related to different physical phenomena, …

3d Printing Of A Polymer Bioactive Glass Composite For Bone Repair, Caroline Murphy, Krishna C. R. Kolan, M. Long, Ming-Chuan Leu, Julie A. Semon, D. E. Day

Mechanical and Aerospace Engineering Faculty Research & Creative Works

A major limitation of synthetic bone repair is insufficient vascularization of the interior region of the scaffold. In this study, we investigated the 3D printing of adipose derived mesenchymal stem cells (AD-MSCs) with polycaprolactone (PCL)/bioactive glass composite in a single process. This offered a three-dimensional environment for complex and dynamic interactions that govern the cell’s behavior in vivo. Borate based bioactive (13-93B3) glass of different concentrations (10 to 50 weight %) was added to a mixture of PCL and organic solvent to make an extrudable paste. AD-MSCs suspended in Matrigel was extruded as droplets using a second syringe. Scaffolds measuring …