Mechanical Engineering Commons^™

Numerical Simulation Of The Evolution Of Solidification Microstructure In Laser Deposition, Zhiqiang Fan, Todd E. Sparks, Frank W. Liou, Anand Jambunathan, Yaxin Bao, Jianzhong Ruan, Joseph William Newkirk

Mechanical and Aerospace Engineering Faculty Research & Creative Works

A predictive model is developed to simulate the evolution of the solidification microstructure during the laser deposition process. The microstructure model is coupled with a comprehensive macroscopic thermodynamic model. This model simulates dendritic grain structures and morphological evolution in solidification. Based on the cellular automata approach, this microstructure model takes into account the heterogeneous nucleation both within the melt pool and at the substrate/melt interface, the growth kinetics, and preferential growth directions of dendrites. Both diffusion and convection effects are included. This model enables prediction and visualization of grain structures during and after the deposition process. This model is applied …

Laser Deposition Cladding On-Line Inspection Using 3-D Scanner, Yu Yang, Todd E. Sparks, Jianzhong Ruan, Lan Ren, Frank W. Liou

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Laser deposition directly deposits metal cladding to fabricate and repair components. In order to finish the fabrication or repair, 3-D shape of the deposition needs to be inspected, and thus it can be determined if it has sufficient cladding to fabricate a part after deposition process. In the present hybrid system in the Laser Aided Manufacturing Lab (LAMP) at the University of Missouri - Rolla, a CMM system is used to do the inspection. A CMM requires point-by-point contact, which is time consuming and difficult to plan for an irregular deposition geometry. Also, the CMM is a separate device, which …

Development Of An Integrated Opto-Electric Biosensor To Dynamically Examine Cytometric Proliferation And Cytotoxicity, Chang Kyoung Choi

Doctoral Dissertations

My doctoral research has focused on the development of microscale optical techniques for examining micro/bio fluidics. Preliminary work measured the velocity field in a microchannel, by optical slicing, using Confocal Laser Scanning Microscopy (CLSM). Next, Optical Serial Sectioning Microscopy (OSSM) was applied to examine thermometry by detecting the free Brownian motion of nano-particles suspended in mediums at different temperatures. An extension of this work used objective-based Total Internal Reflection Fluorescence Microscopy (TIRFM) to examine the hindered Brownian motion of nano-particles that were very close to a solid surface (within 1 mm).

An optically transparent and electrically conductive Indium Tin Oxide …

A Pre-Crash Simulator To Evaluate Vehicle Collision Prediction Algorithms, Dana Desrosiers, Charles Birdsong, Peter Schuster

Mechanical Engineering

This paper describes a software simulator for pre-crash collision predictions. The simulator is a surrogate test bed for evaluating the performance of proposed pre-crash algorithms. It reads data from a file, transfers distance and angular position of a target to a test algorithm, and then records the algorithm’s predictions. To illustrate the simulator functionality, a simplified test algorithm is also described. This algorithm predicts collision risks based on assumptions about the size and acceleration of a target object, and the turning and braking limits of the host vehicle. The test algorithm is shown to be effective for cases where both …

Effect Of Length On The Performance Of Lean NoX Traps, Vitaly Y. Prikhodko

Masters Theses

The effect of monolith length on the NO_x performance of two different Lean NO_x Traps has been investigated using a bench flow reactor (BFR). The washcoat composition of one of the catalysts consists of Pt/K/γ-Al₂O₃; the major components of the other catalyst include Pt, Pd, Rh, barium, ceria and zirconia supported on γ-alumina washcoat. Samples of 2.22-cm in diameter and length of 2.54, 5.08 and 7.62-cm within each LNT were evaluated with long and short-cycle experiments at a fixed gas hourly space velocity, and results were compared between samples of different lengths. No significant …

Treating Water Contamination Using Ultraviolet Radiation To Control Cryptosporidium And E.Coli, Michael O'Hehir, David Kennedy, Thomas Dunphy

Articles

Concerns about the quality of drinking water in Ireland have come into sharp focus with the recent Cryptosporidium outbreak in Galway City. This article looks at how ultraviolet radiation can offer a potential solution in the control of Cryptosporidium contamination.

Experiments In Cooperative Timing For Miniature Air Vehicles, Timothy Mclain, Derek R. Nelson, Randal W. Beard

Faculty Publications

This paper presents experimental results for two cooperative timing missions carried out using a team of three miniature air vehicles (MAVs). Using a cooperative timing algorithm based on coordination functions and coordination variables, the MAV team executed a series of simultaneous arrival and cooperative fly-by missions. In the presence of significant wind disturbances, the average time difference between the first and last vehicle in the simultaneous arrival experiments was 1.6 s. For the cooperative fly-by experiments, the average timing error between vehicle arrivals was 0.6 s. These results demonstrate the practical feasibility of the cooperative timing approach.

Obstacle Avoidance Using Circular Paths, Timothy Mclain, Randal W. Beard, Jeffery Brian Saunders

Faculty Publications

This paper develops a method of obstacle avoidance for fixed-wing miniature air vehicles (MAV) using a series of circular oscillating paths and a single point laser ranger. The laser ranger is a low power, light-weight device used to report the distance to an object in a single direction of the body frame of a MAV. The oscillating paths allow the laser ranger to scan for obstacles and possible escape paths for the MAV in the case of obstacle detection. The circular paths are generated along waypoint paths and transition between waypoint paths without loss of scanning capabilities. Obstacle avoidance is …

Experiments In Cooperative Timing For Miniature Air Vehicles, Derek R. Nelson, Timothy W. Mclain, Randal W. Beard

Faculty Publications

This paper presents experimental results for two cooperative timing missions carried out using a team of three miniature air vehicles (MAVs). Using a cooperative timing algorithm based on coordination functions and coordination variables, the MAV team executed a series of simultaneous arrival and cooperative fly-by missions. In the presence of significant wind disturbances, the average time difference between the first and last vehicle in the simultaneous arrival experiments was 1.6 s. For the cooperative fly-by experiments, the average timing error between vehicle arrivals was 0.6 s. These results demonstrate the practical feasibility of the cooperative timing approach.

Comparison Of Material Properties And Microstructure Of Specimens Built Using The 3d Systems Vanguard Hs And Vanguard Hiq+Hs Sls Systems, T.J. Silverman, Allison Kinney, W. Yong, J.H. Koo

Mechanical and Aerospace Engineering Faculty Publications

The HiQ upgrade to the 3D Systems Vanguard selective laser sintering (SLS) machine incorporates a revised thermal calibration system and new control software. The paper compares the tensile modulus, tensile strength, elongation at break, flexural modulus, Izod impact resistance and microstructure of two batteries of standard specimens built from recycled Duraform PA (Nylon 12). The first set is built on a Vanguard HS system and the second on the same system with the HiQ upgrade installed. The upgrade reduces user intervention, decreases total build time and improves surface finish. However, using the default processing parameters, tensile, flexure and impact properties …

Intrustive Probe Measurements In A High-Temperature Mach Two Flow, Sonya Renee Nelson

Masters Theses

To acquire heat transfer measurements of a high temperature Mach two flow a water-cooled calorimeter was placed in the flow and the water temperature rise was used to calculate the heat transfer rate and the recovery temperature of the gas. In addition, a graphite rod with a stainless steel tube at its core was used to measure the total pressure of the flow. This pressure probe was swept through the flow for two test runs to acquire a stagnation pressure profile of the gas flow. All results were compared to NASA CEA computer simulation code results. The heat transfer and …

Influence Of The Sampling Procedure On Extracted Jet Engine Exhaust Gas Emission Samples, Ashley Dawn Owens

Masters Theses

The purpose of this thesis is to analyze the effects of an intrusive sample extraction process on the thermo-chemistry of extracted gas samples taken from exhaust of a GE-J85-H turbojet engine. The engine testing took place at University of Tennessee Space Institute in Tullahoma, TN, where the J85 was installed in a test bay of a research facility. The results of the analysis validate that testing methods used had a low probability of disturbing the exhaust chemistry. The tools used to analyze the thermal history of the extracted samples were the NASA CEA and LSENS programs. Several different cases of …

High Temperature Heat Exchanger Project: Quarterly Progress Report April 1, 2007 Through June 30, 2007, Anthony Hechanova

Publications (NSTD)

• Ceramatec Sulfuric Acid Decomposer. Modeling with different reacting flow channel configurations (ribbed-surface channels, hexagonal channels, and diamond-shaped channels) was performed. The probability of failure for the one channel geometry with different reacting flow channel configurations was calculated to be zero in the three principal directions for all of the cases.

• Bayonet Heat Exchanger. The Matlab code for calculating the probability of failure using a two-dimensional axisymmetric model of the bayonet decomposer was developed. The probability of failure was calculated for the inner and outer SiC walls, and the intermediate quartz wall of the decomposer and found to be …

Development Of A Multiple Microphone Probe Calibrator, Jonathan Reed Oldham

Theses and Dissertations

This paper presents the theory, design, and validation of a microphone calibrator used to calibrate multiple microphones simultaneously. This work was done in conjunction with the development of an acoustic energy density probe, which was used to validate the calibrator. The probe uses multiple microphones to acquire the data needed to compute the acoustic energy density. The probe microphones are 0.006 m diameter electret microphones which typically do not have an ideal “flat" response over a wide range of frequencies as compared to precision condenser microphones. The probe microphone characteristics prompted the need for simultaneous, multi-microphone magnitude calibration. The idea …

Elliptical Rolling Link Toggle Mechanisms For Passive Force Closures With Self-Adjustment, Jacob Ross Montierth

Theses and Dissertations

This thesis presents elliptical rolling contact joints as an alternative to circular rolling contact and conventional revolute joints where high quality force transmission "low friction and backlash" with variable output are desired. Parameters specific to the joint and its position are developed in terms of relative link angles and elliptical surface geometry. These parameters are used to generate the basic forward kinematics for elliptical rolling link toggle mechanisms with oscillatory motion and high mechanical advantage. As large compressive loads are characteristic of such mechanisms, stress conditions are identified and principles for joint stability with variable, precision outputs are discussed. Finally, …

Introducing New Engineering Students To Mechanical Concepts Through An “Energy Cube” Project, Micheal O'Flaherty, Shannon Chance, Fionnuala Farrell, Christopher Montague

Conference papers

The objective of this paper is to describe a problem based learning module, called the “Energy Cube”, offered by Technological University Dublin that is designed to teach mechanical, building services and manufacturing engineering concepts to first year engineering students.

The Energy Cube project gives students hands-on experience in areas ranging from heat transfer, lighting and energy efficiency to industrial and product design. In the Energy Cube, students design and construct (using cardboard, clear plastic, and glue) a model of a building that admits as much daylight as possible while being energy efficient and aesthetically pleasing.

The students, working in teams …

Introducing New Engineering Students To Mechanical Concepts Through An “Energy Cube” Project, Micheal P. O'Flaherty, Shannon Chance, Fionnuala Farrell, Chris Montague

Shannon M. Chance

The objective of this paper is to describe a problem based learning module, called the “Energy Cube”, offered by Dublin Institute of Technology that is designed to teach mechanical, building services and manufacturing engineering concepts to first year engineering students. The Energy Cube project gives students hands-on experience in areas ranging from heat transfer, lighting and energy efficiency to industrial and product design. In the Energy Cube, students design and construct (using cardboard, clear plastic, and glue) a model of a building that admits as much daylight as possible while being energy efficient and aesthetically pleasing. The students, working in …

A Geometry-Based Motion Planner For Direct Machining And Control, Robert M. Cheatham

Theses and Dissertations

Direct Machining And Control (DMAC) is a new method of controlling machine tools directly from process planning software. A motion planning module is developed for the DMAC system that operates directly off path geometry without pre-tessellation. The motion planner is developed with the intent to process Bezier curves. The motion planning module includes a deterministic predictor-corrector-type curve interpolator, a dynamics limiting module, and a two-pass jerk-limited speed profiling algorithm. The methods are verified by machining an automotive surface in a clay medium and evaluating the resultant machine dynamics, feed rate, and chordal error throughout the machining process.

Investigation Of Particle Velocity And Drag With Spherical And Non-Spherical Particles Through A Backward Facing Step, Kyle Frederick Larsen

Theses and Dissertations

Numerous practical applications exist where dispersed solid particles are transported within a turbulent accelerating or decelerating gaseous flow. The large density variation between phases creates the potential for significant differences in velocity known as velocity slip. Flow over a backward facing step provides a well characterized, turbulent, decelerating flow useful for measuring the relative velocities of the solid and gaseous phases in order to determine velocity slip and particle drag. Numerous investigations have been conducted to determine the gas phase velocity in a backward facing step for both laminar and turbulent flows and therefore the gas phase flow is well …

Autonomic Product Development Process Automation, John E. Daley

Theses and Dissertations

Market globalization and mass customization requirements are forcing companies towards automation of their product development processes. Many task-specific software solutions provide localized automation. Coordinating these local solutions to automate higher-level processes requires significant software maintenance costs due to the incompatibility of the software tools and the dynamic nature of the product development environment. Current automation methods do not provide the required level of flexibility to operate in this dynamic environment. An autonomic product development process automation strategy is proposed in order to provide a flexible, standardized approach to product development process automation and to significantly reduce the software maintenance costs …

Comparing The Feasibility Of Cutting Thin-Walled Sections From Five Commonly Used Metals Utilizing Wire Electric Discharge Machining, Richard C. Stephenson

Theses and Dissertations

Wire Electric Discharge Machining (wire-EDM) is a non-traditional machining process. Controlled electric sparks are successively used to vaporize part of a workpiece along a programmed path in order to machine a desired part. Because there is no tool that comes in direct contact with the workpiece, it is possible to machine thin, delicate parts. This thesis was designed to observe and analyze the differences in cutting capabilities for a conventional wire-EDM machine when cutting thin-walled sections from five commonly used metals utilizing a variation of roughing and finishing passes. The five metals that were used in this study are: Aluminum …

Mechanical Behavior Of Fuel Cell Membranes Under Humidity Cycles And Effect Of Swelling Anisotropy On The Fatigue Stresses, Ahmet Kusoglu, Anette M. Karlsson, Michael H. Santare, Simon Cleghorn, William B. Johnson

Mechanical Engineering Faculty Publications

The mechanical response of proton exchange membranes in a fuel cell assembly is investigated under humidity cycles at a constant temperature (85°C). The behavior of the membrane under hydration–dehydration cycles is simulated by imposing a humidity gradient from the cathode to the anode. Linear elastic, plastic constitutive behavior with isotropic hardening and temperature and humidity dependent material properties are utilized in the simulations for the membrane. The evolution of the stresses and plastic deformation during the humidity cycles are determined using finite element analysis for two clamping methods and various levels of swelling anisotropy. The membrane response strongly depends on …

Development Of Deployable Wings For Small Unmanned Aerial Vehicles Using Compliant Mechanisms, Steven D. Landon

Theses and Dissertations

Unmanned Air Vehicles (UAVs) have recently gained attention due to their increased ability to perform sophisticated missions with less cost and/or risk than their manned counterparts. This thesis develops approaches to the use of compliant mechanisms in the design of deployable wings for small UAVs. Although deployable wings with rigid-link mechanisms have been used in the past to maintain flight endurance while minimizing required storage volume, compliant mechanisms offer many advantages in manufacturability and potential space savings due to function sharing of components. A number of compliant, deployable wing concepts are generated and a classification system for them is formed. …

Friction Stir Welding Of High-Strength Automotive Steel, Eric Michael Olsen

Theses and Dissertations

The following thesis is a study on the ability to create acceptable welds in thin-plate, ultra-high-strength steels (UHSS) by way of friction stir welding (FSW). Steels are welded together to create tailor-welded blanks (TWB) for use in the automotive industry. Dual Phase (DP) 590, 780, and 980 steel as well as Transformation-Induced Plasticity (TRIP) 590 steel with thicknesses ranging from 1.2 mm to 1.8 mm were welded using friction stir welding under a variety of processing conditions, including experiments with dissimilar thicknesses. Samples were tested under tensile loads for initial determination if an acceptable weld had been created. Acceptable welds …

Modelamiento, Diseño Y Automatización De Un Modelo Genérico De Secador De Polen, Erika Johana Ibarra Erazo, Julio Enrique Fernandez Gutierrez

Ingeniería en Automatización

No abstract provided.

Articular Cartilage Mechanical And Biochemical Property Relations Before And After In Vitro Growth, Timothy Ficklin, Gregory Thomas, James C. Barthel, Anna Asanbaeva, Eugene J. Thonar, Koichi Masuda, Albert C. Chen, Robert L. Sah, Andrew Davol, Stephen M. Klisch

Mechanical Engineering

The aim of this study was to design in vitro growth protocols that can comprehensively quantify articular cartilage structure–function relations via measurement of mechanical and biochemical properties. Newborn bovine patellofemoral groove articular cartilage explants were tested sequentially in confined compression (CC), unconfined compression (UCC), and torsional shear before (D0, i.e. day zero) and after (D14, i.e. day 14) unstimulated in vitro growth. The contents of collagen (COL), collagen-specific pyridinoline (PYR) crosslinks, glycosaminoglycan, and DNA significantly decreased during in vitro growth; consequently, a wide range of biochemical properties existed for investigating structure–function relations when pooling the D0 and D14 groups. All …

Design Integrated In The Mechanical Engineering Curriculum: Assessment Of The Engineering Clinics, Jennifer Kadlowec, Krishnan Bhatia, Tirupathi R. Chandrupatla, John C. Chen, Eric Constans, Harriet Hartman, Anthony J. Marchese, Paris Von Lockette, Hong Zhang

Mechanical Engineering

At Rowan University, design has been infused into the curriculum through an eight-semester course sequence called the Engineering Clinics. Through this experience, students learn the art and science of design in a multidisciplinary team environment and hone their design skills throughout their 4-year career. This paper describes the objectives of the clinics, types of projects, and how the clinics complement traditional core courses in the curriculum. Impacts and benefits of the clinics on students and faculty are discussed, including retention and graduate study rates comparing Rowan University mechanical engineering students to their peers nationally. An assessment of the clinics is …

Thermal Fatigue Test Apparatus For Large Superconducting Coils, J.T. Kephart, B.K. Fitzpatrick, John Chen, J. Lopez, M. Miller, L. Wong, M. Zimmerman, J. Kostic, C. Rakus

Mechanical Engineering

The United States Navy has a continued interest in the development of High Temperature Superconductivity (HTS) to provide power dense, efficient propulsion and electrical power generation. These machines have large HTS rotor coils that will undergo many thermal cycles during the life of the ship. Thermal fatigue tests for large coils are necessary to understand any degradation and life issues that could arise. The Naval Surface Warfare Center Carderock Division (NSWCCD) has sponsored Rowan University to design and build a device that will assist in the thermal fatigue testing of a superconducting coil. It was designed to be autonomous with …

Fiber-Optic Strain Gauge With High Resolution And Update Rate, Fernando Figueroa, Ajay Mohan Mahajan, Mohammad Sayeh, Bradley Regez

Mechanical Engineering Faculty Research

An improved fiber-optic strain gauge is capable of measuring strains in the approximate range of 0 to 50 microstrains with a resolution of 0.1 microstrain. (To some extent, the resolution of the strain gauge can be tailored and may be extensible to 0.01 microstrain.) The total cost of the hardware components of this strain gauge is less than $100 at 2006 prices. In comparison with prior strain gauges capable of measurement of such low strains, this strain gauge is more accurate, more economical, and more robust, and it operates at a higher update rate. Strain gauges like this one are …

"Smart" Sensor Module, Ajay Mohan Mahajan

Mechanical Engineering Faculty Research

An assembly that contains a sensor, sensor-signal-conditioning circuitry, a sensor-readout analog-to-digital converter (ADC), data-storage circuitry, and a microprocessor that runs special-purpose software and communicates with one or more external computer(s) has been developed as a prototype of "smart" sensor modules for monitoring the integrity and functionality (the "health") of engineering systems. Although these modules are now being designed specifically for use on rocket-engine test stands, it is anticipated that they could also readily be designed to be incorporated into health-monitoring subsystems of such diverse engineering systems as spacecraft, aircraft, land vehicles, bridges, buildings, power plants, oilrigs, and defense installations. The …