Mechanical Engineering Commons^™

A Thermomechanical Analysis Of An Ultrasonic Bonding Mechanism, Chunbo Zhang

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

A systematic experimental and numerical combined study of the thermomechanical bonding mechanisms in the ultrasonic welding (UW) process was conducted. A fully coupled thermomechanical finite element model has been built to fully understand the evolution and coupling between the in-process thermomechanical variables. The severe, localized, plastic deformation at the bond region is believed to be the major phenomenon for bond formation in ultrasonic welding. The influences of substrate dimensions on bond formation were studied and explained with an analytical vibration model. The formation of banded and cyclic stress-strain maxima in the substrate was found to be caused by superposition of …

Dislocation Density-Based Finite Element Method Modeling Of Ultrasonic Consolidation, Deepankar Pal

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

A dislocation density-based constitutive model has been developed and implemented into a crystal plasticity quasi-static finite element framework. This approach captures the statistical evolution of dislocation structures and grain fragmentation at the bonding interface when sufficient boundary conditions pertaining to the Ultrasonic Consolidation (UC) process are prescribed.

The hardening is incorporated using statistically stored and geometrically necessary dislocation densities (SSDs and GNDs), which are dislocation analogs of isotropic and kinematic hardening, respectively. Since the macroscopic global boundary conditions during UC involves cyclic sinosuidal simple shear loading along with constant normal pressure, the cross slip mechanism has been included in the …

Discharge Coefficients Of Oblique Weirs, Samuel Egnew Tingey

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Oblique weirs are those weirs placed at an angle with respect to the channel centerline. They can be used in canal applications where more discharge is needed, but there is limited freeboard. The discharge coefficients were determined for 54 different weirs by measuring total head for various flows over each weir. These weirs included sharp, half round and quarter-round-crested weirs. There were 18 weirs for each crest shape with three weir heights for each angle tested. The oblique angles tested were 10°, 15°, 25°, 45°, 60°, and 90° with respect to the channel centerline, with the nominal weir heights being …

Efficient, Accurate, And Non-Gaussian Error Propagation Through Nonlinear, Closed-Form, Analytical System Models, Travis V. Anderson

Theses and Dissertations

Uncertainty analysis is an important part of system design. The formula for error propagation through a system model that is most-often cited in literature is based on a first-order Taylor series. This formula makes several important assumptions and has several important limitations that are often ignored. This thesis explores these assumptions and addresses two of the major limitations. First, the results obtained from propagating error through nonlinear systems can be wrong by one or more orders of magnitude, due to the linearization inherent in a first-order Taylor series. This thesis presents a method for overcoming that inaccuracy that is capable …

Fracture Analyses Of Aging Aircraft Structures And Human Aorta, Ananth Ram Mahanth Kasavajhala

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

Understanding the behavior of fracture due to preliminary flaws in materials is essential to escalate the life and reliability of a structure. The present work is focused on investigating the influence of various structural parameters on the pre-crack growth stress state, initiation and propagation of flaws in two distinct fields of engineering that is, aging aircraft structural repair (aerospace) and the human aortic dissection (life sciences). Three dimensional finite element methodologies, coupled with linear elastic fracture mechanics (LEFM) formulation was utilized in both the cases.

A model of pre-cracked Al 7075 T6 plate was used to analyze pre- and post- …

Automating The Fret Slotting Process Using A Plc Controlled 1.5 Axis Mill, James Stratton

Purdue Polytechnic Masters Theses

Stratton, James A. M.S., Purdue University, August 2011. Automating the Fret Slotting Process Using a PLC Controlled 1.5 Axis CNC Mill. Major Professor: Richard Mark French.

Can automation assist small job shops and hobbyists in the production of stringed instruments? This research set out to answer the question using a quantitative approach to determine if an economical CNC machine could be produced in such a fashion as to seamlessly join the workshop as an affordable, yet precise instrument to aid in the production of stringed instruments. The key was to incorporate common industrial automation equipment into the operation of the …

Stereoscopic Vision's Impact On Spatial Ability Testing, George Takahashi

Purdue Polytechnic Masters Theses

A look into spatial ability testing tools and the variations that past researchers made to focus on key factors that affect test scores, will demonstrate the need for tuning traditional testing methods to accommodate a wider demographic and provide more accurate results. Due to technological limitations of the time, a large variety of past spatial tests were developed by hand-drawings. Within this research, the addition of stereoscopic vision is analyzed to determine the value of said changes on human perception of spatial entities.

Polarization Sensitive Near-Complete Reflection From Photonic Crystal Slab In Centered Rectangular Lattice, Simon Padron, Kris Ohlinger, Karen Lozano, Yuankun Lin

Mechanical Engineering Faculty Publications

In this study, reflective properties have been systematically calculated for two-dimensional photonic crystal slabs in centered rectangular lattices with elliptical patterns for transverse electric polarization along perpendicular x- and y-directions. The slab structures can be geometrically optimized for a near-complete reflection over a broad wavelength range. The reflection from the photonic crystal slabs is polarization selective, allowing a complete reflection for one polarization and complete transmission for the other polarization, which could be useful for a laser cavity mirror without using Brewster windows. The dependence of the reflection on the slab thickness and the structural parameters demonstrates the effect of …

Direct Numerical Simulation Of Transonic Wake Flow In The Presence Of An Adverse Pressure Gradient And Streamline Curvature, Jeffrey Reed Gibson

Theses and Dissertations

Wakes are present in many engineering flows. These flows include internal flows such as mixing chambers and turbomachinery as well as external flows like flow over high-lift or multi-element airfoils. Many times these wakes are exposed to flow conditions such as adverse pressure gradients and streamline curvature that alter the mean flow and turbulent structure of the wake. The ability to understand how pressure gradients and streamline curvature affects the structure of the wake is essential to predicting how the wake will affect the performance of the application in which it is found. The effects of pressure gradients and curvature …

Skin Cell Regeneration, Polette Cortez^, Maria Yanez, Thomas Boland*

COURI Symposium Abstracts, Summer 2011

No abstract provided.

Design And Analysis Of A Flapping Wing Mechanism For Optimization, Ryan Brandon George

Theses and Dissertations

Furthering our understanding of the physics of flapping flight has the potential to benefit the field of micro air vehicles. Advancements in micro air vehicles can benefit applications such as surveillance, reconnaissance, and search and rescue. In this research, flapping kinematics of a ladybug was explored using a direct linear transformation. A flapping mechanism design is presented that was capable of executing ladybug or other species-specific kinematics. The mechanism was based on a differential gear design, had two wings, and could flap in harsh environments. This mechanism served as a test bed for force analysis and optimization studies. The first …

Artificial Lateral Line Canal For Hydrodynamic Detection, Yingchen Yang, Adrian Klein, Horst Bleckmann

Mechanical Engineering Faculty Publications

Fish use their lateral line system to detect minute water motions. The lateral line consists of superficial neuromasts and canal neuromasts. The response properties of canal neuromasts differ from those of superficial ones. Here, we report the design, fabrication, and characterization of an artificial lateral line canal system. The characterization was done under various fluid conditions, including dipolar excitation and turbulent flow. The experimental results with dipole excitation match well with a mathematical model. Canal sensors also demonstrate significantly better noise immunity compared with superficial ones. Canal-type artificial lateral lines may become important for underwater flow sensing.

Artificial Lateral Line Canal For Hydrodynamic Detection, Yingchen Yang, Adrian Klein, Horst Bleckmann, Chang Liu

Mechanical Engineering Faculty Publications

Fish use their lateral line system to detect minute water motions. The lateral line consists of superficial neuromasts and canal neuromasts. The response properties of canal neuromasts differ from those of superficial ones. Here, we report the design, fabrication, and characterization of an artificial lateral line canal system. The characterization was done under various fluid conditions, including dipolar excitation and turbulent flow. The experimental results with dipole excitation match well with a mathematical model. Canal sensors also demonstrate significantly better noise immunity compared with superficial ones. Canal-type artificial lateral lines may become important for underwater flow sensing.

Automated Multidisciplinary Optimizations Of Conceptual Rocket Fairings, Ronald S. Smart

Theses and Dissertations

The purpose of this research is to develop and architect a preliminary multidisciplinary design optimization (MDO) tool that creates multiple types of generalized rocket fairing models. These models are sized relative to input geometric models and are analyzed and optimized, taking into account the primary objectives, namely the structural, thermal, and aerodynamic aspects of standard rocket flights. A variety of standard nose cone shapes is used as optimization proof of concept examples, being sized and compared to determine optimal choices based on the input specifications, such as the rocket body geometry and the specified trajectory paths. Any input models can …

Analytical Modeling And Optimization Of A Thermoelectric Heat Conversion System Operating Betweeen Fluid Streams, Stephen H. Taylor

Theses and Dissertations

Analytical, closed-form solutions governing thermoelectric behavior are derived. An analytical model utilizing a thermal circuit is presented involving heat transfer into, through, out of, and around a thermoelectric device. A nondimensionalization of the model is presented. Linear heat transfer theory is applied to the model to obtain a series of closed form equations predicting net power output for the thermoelectric device. Fluid streams flowing through shrouded heat sinks with square pin fins are considered for the thermal pathways to and from the device. Heat transfer and pressure drop are characterized in a manner conducive to an analytical model using previously …

Spinal Implant With Customized And Non-Linear Stiffness, Eric Ray Dodgen

Theses and Dissertations

There is a need for spinal implants that have nonlinear stiffness to provide stabilization if the spine loses stiffness through injury, degeneration, or surgery. There is also a need for spinal implants to be customizable for individual needs, and to be small enough to be unobtrusive once implanted. Past and ongoing work that defines the effects of degeneration on the torque rotation curve of a functional spinal unit (FSU) were used to produce a spinal implant which could meet these requirements. This thesis proposes contact-aided inserts to be used with the FlexSuRe™ spinal implant to create a nonlinear stiffness. Moreover, …

Vertical Track Modulus Trending, Shane Michael Farritor, Sheng Lu

Department of Mechanical and Materials Engineering: Faculty Publications

Systems and methods for determining a trend in Vertical track modulus are disclosed in accordance with embodiments of the present invention. Vertical deflection data is collected along a particular section of railroad track. A first set of Vertical track modulus is determined, based in part, on the collected vertical deflection data. At a second time, vertical deflection data is again collected along the particular section of railroad track to be used in determining a second set of vertical track modulus. At least the first and second sets of Vertical track modulus are analyzed to determine a math ematical algorithm that …

Mechanical Characterization Of The Interspinous Ligament Using Anisotropic Small Punch Testing, Rachel Jane Bradshaw

Theses and Dissertations

Objective: The objective of this work was to characterize the nonlinear anisotropic material constitutive response of the interspinous ligament (ISL).

Methods: Cadaveric test samples of the interspinous ligament were tested using the anisotropic small punch test. The measured force-displacement response served as experimental input into a system identification optimization routine to determine the constitutive material parameters that replicated the measured material response.

Results: The constitutive behavior of the ISL is notably different from that reported for knee, shoulder, and hip ligaments. Specifically, the high collagen fiber content and unique collagen architecture provided a stiffer material response. The results from the …

Characterization Of The Mechanical Response Of The Lumbar Spine, Shannon Alisa Zirbel

Theses and Dissertations

The primary objective of this research is to associate lumbar segmental mechanical response with intervertebral disc degeneration under physiologic testing conditions. Because no mathematical model exists for lumbar spine segmental rotations, a portion of this thesis evaluates potential methods for curve fitting the torque-rotation curves. The Dual Inflection Point (DIP) Boltzmann equation was developed during the course of this research and is presented here as a method for fitting spinal motion data wherein a physical meaning can be assigned to each of the model coefficients. This model can tell us more about the effects of degeneration, testing conditions, and other …

Florida Solar Atlas, Florida Solar Energy Center, Charles Cromer

FSEC Energy Research Center®

The direct beam and direct global solar resource values for any geographical location in Florida were found by using actual data taken at the Florida Solar Energy Center (FSEC) for 2010 and correlating those values against clearness values derived from NOAA geostationary satellite data. Using the correlations developed, eleven years of satellite data (2000 - 2010) were used to provide expected monthly average solar resource values for any location in Florida. These values as provided in watts per meter square per day, were matched to colors with the lowest values of the full range of average values representing the deepest …

A Digital Hydraulic Valve, Actuated Using A Piezoelectric Linear Motor, Brian C. Bevill

Purdue Polytechnic Directed Projects

Proportional control in hydraulics is widely utilized. The most widely used current types of proportional valves utilize solenoid technology. While this technology has been around for decades and has been proven an effective means of control, there is always a demand for improved performance of advancing technologies. Integrating piezoelectric devices as a means to control hydraulic systems helps advance control for hydraulic systems.

Piezoelectric stack devices have been used to control hydraulic systems with success. Advantages of these stacks include being relatively small with a high power to weight ratio, using less energy than solenoid operations, and being fast acting. …

Development Of A Second-Stage Novice Driver Education And Training Program, John Wagner, M Jensen, F Switzer, K Alexander, P Pidgeon

Publications

Novice drivers are overrepresented in traffic crashes and fatalities. Traffic crashes are the leading cause of death for 16 to 20 year olds and account for one in three deaths in this age group (NHTSA, 2008; CDC, 2010). Significant research has been conducted developing and analyzing driver education and training and education programs. Effective programs identify their target audiences and tailor the program paradigm and methods to their developmental needs. This paper develops a second-stage safe driver program for novice drivers focusing on classroom and behind-the-wheel instruction for four common driving skills and situations: braking, avoiding obstacles, losing control, and …

A Study On Facility Planning Using Discrete Event Simulation: Case Study Of A Grain Delivery Terminal, Sarah M. Asio

Department of Industrial and Management Systems Engineering: Dissertations, Theses, and Student Research

The application of traditional approaches to the design of efficient facilities can be tedious and time consuming when uncertainty and a number of constraints exist. Queuing models and mathematical programming techniques are not able to capture the complex interaction between resources, the environment and space constraints for dynamic stochastic processes. In the following study discrete event simulation is applied to the facility planning process for a grain delivery terminal. The discrete event simulation approach has been applied to studies such as capacity planning and facility layout for a gasoline station and evaluating the resource requirements for a manufacturing facility. To …

Astro Camp Presentation, Get Away Special Team 2011

Education and Outreach

No abstract provided.

Perfectly Matched Layer Absorbing Boundary Conditions For The Discrete Velocity Boltzmann-Bgk Equation, Elena Craig

Mathematics & Statistics Theses & Dissertations

Perfectly Matched Layer (PML) absorbing boundary conditions were first proposed by Berenger in 1994 for the Maxwell's equations of electromagnetics. Since Hu first applied the method to Euler's equations in 1996, progress made in the application of PML to Computational Aeroacoustics (CAA) includes linearized Euler equations with non-uniform mean flow, non-linear Euler equations, flows with an arbitrary mean flow direction, and non-linear clavier-Stokes equations. Although Boltzmann-BGK methods have appeared in the literature and have been shown capable of simulating aeroacoustics phenomena, very little has been done to develop absorbing boundary conditions for these methods. The purpose of this work was …

Marine Pollution And Energy Calculation Study Of Impacts Of Speed Reduction And Hull Roughness, Aditi Patil

Mechanical & Aerospace Engineering Theses & Dissertations

About 3.3% of global air ermss1ons m 2007 were due to international shipping operations. If no policies are enacted, the Green House Gas (GHG) emissions would increase by a factor of 2-3 by 2050.

In order to reduce Global Warming, international institutions such as the International Marine Organization and European Maritime Authorities are implementing policies for reduction of NO_x and SO_x by 2020. Regulations for these gases are indicated in MARPOL Annex VI.

There are four fundamental ways of reducing emissions:

• Improving energy efficiency by modifying ship design or operation strategy

• Using renewable energy sources for …

The Transfer Of Laser-Machined Micro-Structured Patterns From Silicon To Polymethyl Methacrylate, Warren E. Withrow

Mechanical & Aerospace Engineering Theses & Dissertations

This research project's purpose was transferring a micro-scaled pattern from a silicon wafer to a polymethyl methacrylate (PMMA), or acrylic, substrate through light absorption generated heat. The secondary objective was to determine if the pattern on the silicon wafer could then be transferred to silica (i.e. a microscope glass slide) through light absorption generated heat. Once this pattern-transfer technique is developed for the micro scale, it could be instituted on the nano scale. The experiment was designed to find an alternate method to that currently being used to mass-produce compact discs (CDs). The most popular method employs a stamping process …

Muscle Contributions To Frontal And Transverse Plane Whole-Body Angular Momentum, Richard R. Neptune, Craig P. Mcgowan, Allison Kinney

Mechanical and Aerospace Engineering Faculty Publications

The purpose of this study was to build upon previous work by analyzing how gravity and individual muscles contribute to frontal and traverse plane whole-body angular momentum. Identifying which muscles are responsible for generating angular momentum has important implications for the diagnosis and treatment of movement disorders.

On The Opening Of A Class Of Fatigue Cracks Due To Thermo-Mechanical Fatigue Testing Of Thermal Barrier Coatings, M. T. Hernandez, D. Cojocaru, M. Bartsch, Anette M. Karlsson

Mechanical Engineering Faculty Publications

The evolution of fatigue cracks observed in thermal barrier coatings (TBCs) subjected to an accelerated test scheme is investigated via numerical simulations. The TBC system consists of a NiCoCrAlY bond coat and partially yttria stabilized zirconia top coat with a thermally grown oxide (TGO) between these two coatings. The cracks of interest evolve in the bond coat parallel and near the interface with the TGO during thermo-mechanical fatigue testing. In their final stage, the cracks lead to partial spallation of the TBC. This study focuses on why the cracks open to their characteristic shape. To this end, finite element simulations …

Heat And Mass Transfer Correlations For Steam Methane Reforming In Non-Adiabatic, Process-Intensified Catalytic Reactors, Adam Stephen Kimmel

Master's Theses (2009 -)

Because of its high energy density, hydrogen is a desirable energy source for the achievement of a renewable energy landscape. Though production methods like thermolysis, electrolysis and biomass conversion, among others, are thought to be long term renewable solutions, catalytic steam methane reforming (SMR) is currently the predominant mechanism to produce hydrogen on an industrial scale. The highly endothermic, transport-limited reforming process has also been scaled down through process intensification to create efficient small-scale hydrogen-generating systems. One proposed geometry utilizes a catalytic finned cylinder that provides a manufacturable solution to enable high-efficiency heat exchange and SMR reaction. An accurate representation …