Results :: Search Electronic Theses and Dissertations (ETDs)

Your search for Keyword finite element resulted in 46 match(es).

Back to search page

View next 25 results

Nanocomposites: a study of theoretical micromechanical behavior using finite element analysis: Author: Milliren, Eric Carlton; Date: 2009-05-15; Program: Mechanical Engineering; Abstract: Current research in nanotechnology has produced an increasing number of possibilities for advanced materials. Among those materials with potential advanced mechanical properties are fiber-reinforced composite laminates that utilize nanoscale fiber diameters. Through a combination of studying classic micromechanical models and modern computer-aided finite element analysis (FEA), the advantages for utilizing these nanofibers in advanced structural applications, such as space mirror backings, was investigated. The approach for modeling these composite structures was that of a Representative Volum...; Download File | View full details

Animating the Conversion of Nondeterministic finite State Automata to Deterministic finite State Automata: Author: Merryman, William Patrick; Date: 2007-05-15; Program: Computer Science; Abstract: Many students may find the conversion of non-deterministic finite state automata into deterministic finite state automata to be difficult. Since standard computers are deterministic by nature, it is beneficial to understand how to convert nondeterministic finite state automata into equivalent deterministic versions. This conversion process is often inadequately presented in traditional textbooks, though, as static presentations rarely capture the dynamics of the process. This thesis provides a Java applet that will help students better understand the conversion, and may help teachers to better...; Download File | View full details

Analysis and Design of MEMS Scan Mirrors Using Periodically Stiffened Silicon Nitride: Author: Lutzenberger, Bert Jeffrey; Date: 2006-05-15; Program: Civil Engineering; Abstract: This research presents a novel fabrication method combining surface and bulk micromachining techniques to deposit mechanically stiffened silicon nitride films for use in MEMS fabrication. The stiffened silicon nitride film consists of a thin (~1.5 um) top sheet with stiffening fins molded to the back of the film. In the final configuration, the fins extend between 15 um and 40 um vertically from the back of the film. The molded fins are arranged into periodic square and hexagonal cell configurations ranging in size from 10 um to 250 um. The periodic cells significantly increase the bending sti...; Download File | View full details

Internal Damage Characterization for Composite Materials under Biaxial Loading Configuration: Author: Smith, Jay David; Date: 2007-05-15; Program: Mechanical Engineering; Abstract: This thesis contains the results of a composite material database developed for fiber glass laminates using test data from the in-plane loader (IPL). The IPL is a unique multi-axial test machine developed at Montana State University. The research was completed with the aim to improve the reliability of composite materials, namely fiber glass for use in wind turbine blades. An energy method was used to characterize strain-induced damage in fiber glass coupons. The energy dissipated by internal failure mechanisms was employed as a metric of internal damage. Thus, by means of a deconvolution proc...; Download File | View full details

Continuum structural representation of flexure and tension stiffened one-dimensional spacecraft architectures: Author: Larsen, Jeffrey James; Date: 2009-05-15; Program: Mechanical Engineering; Abstract: Spacecraft designs are a result of system properties and design variables that ensure the spacecraft will operate to mission objectives. The focus of this effort is a set of global system variables for frequency, length, total mass and the ratio between the payload mass and the support structure mass. These properties will be explored to observe the behavior of the system and develop relationships that govern the trade-offs between the variables and assist mission planners in future spacecraft design. These variables will be observed in one-dimensional structures where the dominating dimension...; Download File | View full details

Visualizing the Minimization of a Deterministic finite State Automaton: Author: Kshatriya Jagannath, Rajini Singh; Date: 2007-12-15; Program: Computer Science; Abstract: The minimization of deterministic finite state automata is one of the challenging concepts that students of an introductory theory of computation course must master. The minimization algorithm identifies redundant states that may occur in any deterministic finite state automaton and combines them in order to minimize the total number of states. Traditional textbooks provide a static presentation of this process. The average student seems to grasp the process better if it is presented dynamically. In this thesis we visualize every step of a minimization algorithm in sequence through a Java appl...; Download File | View full details

Efficient finite element Modeling Across Optical Length Scales: Author: Harwood, Jason Alan; Date: 2007-08-15; Program: Mechanical Engineering; Abstract: Optical engineers frequently rely on finite element analysis (FEA) to predict the thermal and mechanical performance of an optic before it is produced. These analyses are usually performed by modeling a simplified version of the real structure to obtain the global deformations of the surface of the mirror. This method eliminates the ability to represent localized deformations and strain gradients, resulting from thermal and mechanical loading, which may exceed the mechanical limit of the materials or material interfaces in coated mirrors causing delamination or cracking. The goal of this study...; Download File | View full details

Modeling of In-Plane and Interlaminar Fatigue Behavior of Glass and Carbon Fiber Composite Materials: Author: Wilson, Timothy James; Date: 2007-05-15; Program: Mechanical Engineering; Abstract: This thesis presents the results of a modeling study of the fatigue behavior of fiberglass and carbon fiber reinforced epoxy composite materials intended primarily for wind turbine blades. The modeling effort is based on recent experimental results for infused glass fiber laminates typical of current blades, and hybrid carbon prepreg laminates of potential interest for future blades. There are two focus areas: in-plane performance represented by stress-life (S-N) curves, and out-of-plane ply delamination at details including ply drops and joints, based on fracture mechanics. In-plane fatigue m...; Download File | View full details

An Alternating-Direction Sinc-Galerkin method for elliptic problems on finite and infinite domains: Author: Alonso, Nicomedes III; Date: 2009-05-15; Program: Mathematics; Abstract: Alternating-Direction Implicit (ADI) schemes are a class of very efficient algorithms for the numerical solution of differential equations. Sinc-Galerkin schemes employ a sinc basis to produce exponentially accurate approximate solutions to differential equations even in the presence of singularities. In this dissertation we begin with a broad overview of sinc methods for problems posed on both finite and infinite, one- and two-dimensional domains. We then present a variety of finite difference methods that lead to the introduction of a new Alternating-Direction Sinc-Galerkin scheme based on t...; Download File | View full details

Size Dependence of the Magnetic Properties of Cobalt Oxide Nanoparticles Mineralized in Protein Cages: Author: Resnick, Damon Aaron; Date: 2005-12-15; Program: Physics; Abstract: A major question in the physics of magnetic nanoparticles is how the size affects the magnetic properties in magnetic nanoparticle systems. In particular, the magnetic properties can be affected by finite-size effects or surface effects. It is this author's belief that surface effects and not finite-size effects play the dominate role. This study is a specific example of how to try to answer this question by looking at different sizes of Co₃O₄ nanoparticles. In order to answer this question as well as better understand this system, different antiferromagnetic Co₃Oâ...; Download File | View full details

A Validation Study of the Montana State University In-Plane Loader: Author: Collett, Aaron Bruce; Date: 2006-08-15; Program: Mechanical Engineering; Abstract: Characterizing a polymer composite material's response to loading beyond the elastic region is less well defined than it is for other structural materials such as metals. The Naval Research Laboratory has developed a method that uses dissipated energy as a metric to facilitate this characterization. The method relies on empirical data from material strength tests as well as finite element analysis data to make the prediction. A substantial amount of empirical data from different loading conditions is needed to characterize a material. This warrants a testing machine that can apply several load...; Download File | View full details

Analysis and Design of the Mechanical Systems Onboard a Microsatellite in Low-Earth Orbit: An Assessment Study: Author: Solomon, Dylan Raymond; Date: 2006-05-15; Program: Mechanical Engineering; Abstract: A study of the mechanical systems contributing to the design and performance of a picosatellite's mission in low-Earth orbit (LEO) was performed through design and analysis. The unique architecture of this satellite stems from a form factor established by the internationally recognized CubeSat Program. This CubeSat-Plus architecture limits the satellite's size to be no larger than a 10 x 10 x 15 cm cube with an overall mass not exceeding 2 kg. This satellite would then be launch into LEO and conduct on-orbit GPS measurements while remaining tethered to the second stage booster of a Boeing Delt...; Download File | View full details

Static and Dynamic Behavior of Stress Coated Membranes: Author: Nandurkar, Kuldeep Pandurang; Date: 2006-08-15; Program: Mechanical Engineering; Abstract: Large space mirrors need to be made of ultra-lightweight materials (membranes) that have very low densities and high flexibility (compliance) for packaging. A coating application necessary for optical reflectivity may also impart to these ultra-lightweight materials a desired shape and to help maintain that shape in the harsh environment of space. When a coating is applied on the membrane substrate, stresses develop in the coating due to atomistic processes. These stresses are fundamental to the final shape of the substrate. Coatings applied to the substrate in order to maintain a particular s...; Download File | View full details

Ultrasonic repair of polymers: fundamentals and modeling for self-healing: Author: Sarrazin, John Cody; Date: 2009-05-15; Program: Mechanical Engineering; Abstract: Although current research focuses within self-healing materials are advancing, most pursuits are passive systems, unlike the active biological systems they aim to mimic. In this paper an active method utilizing ultrasonic energy is explored. Ultrasonic inspection has served as an effective means toward nondestructive damage detection for decades. Also, a recent method called time-reversed acoustics allows for the redirection of acoustic waves back towards the source. The active healing method utilizes ultrasonic nondestructive damage detection to locate and categorize damage, and then provide ...; Download File | View full details

Objective Lens for a Miniature Endoscopic Confocal Microscope: Author: El Ferradi, Nabil; Date: 2005-05-15; Program: Electrical Engineering; Abstract: This thesis presents the design and testing of a micro-objective lens for a miniature endoscopic confocal microscope. The advance of confocal endo-microscopy for in-situ imaging can lead to considerable improvements in inspection, analysis, and diagnosis, especially in the biomedical field. The dimensions of the objective lens developed are 4.0 mm long and 2.0 mm in diameter incorporated into a probe that is 2.0 mm in diameter and 10.0 mm long. The size of the probe will allow it to be inserted in some of the smallest channels in an endoscope. The objective lens features a 0.33 numerical apert...; Download File | View full details

A Three Dimensional finite element Model of Biofilm Subjected to Fluid Flow and its Application to Predicting Detachment Potential: Author: Gammelgard, Peter Norman; Date: 2006-08-15; Program: Civil Engineering; Abstract: Microbial biofouling of wetted surfaces can adversely impact the hydrodynamic performance of pressurized conduits. These impacts are due, in part, to the viscoelastic material properties of biofilm. Of particular interest is the response of biofilm to changing hydrodynamic conditions and its effect on potential for biofilm removal. The goal of this research was two fold; 1) to develop a three dimensional numerical model, incorporating the viscoelastic material description of biofilm, to simulate the response of biofilm to varying hydrodynamic conditions and 2) use this model to identify behavi...; Download File | View full details

Application of the Van Der Pauw Structure as a Piezoresistive Pressure Sensor - A Numerical Study: Author: Law, Jesse Townsend; Date: 2007-08-15; Program: Mechanical Engineering; Abstract: This research characterizes a piezoresistive sensor under variations of both size and orientation with respect to the silicon crystal lattice for its application to MEMS pressure sensing. The sensor to be studied is a four-terminal piezoresistive sensor commonly referred to as a van der Pauw (VDP) structure. It is observed that the sensitivity of the VDP sensor is over three times higher than the conventional filament type Wheatstone bridge resistor. With MEMS devices being used in applications which continually necessitate smaller size, characterizing the effect of size and orientation of a V...; Download File | View full details

Rectangular pellicle beam splitter design: Author: Fraser, Jacob Lee; Date: 2008-05-15; Program: Mechanical Engineering; Abstract: This project investigates a pellicle beam splitter of rectangular form. A pellicle is a thin optical membrane and a beam splitter separates one optical path into two. The beam splitter under investigation is used at Arnold Engineering Development Center (AEDC) for optical component testing and mission simulation in cryogenic vacuum chambers. The conventional beam splitter had undesirable optical performance at cryogenic temperatures. The goal of this project was to use analysis to guide development of pellicle beam splitter prototypes to minimize thermal distortion. Engineers commonly use fini...; Download File | View full details

An Inverse Approach to Coefficient of Thermal Expansion Optimization in Optical Structures: Author: Rassi, Erik Michael; Date: 2007-12-15; Program: Mechanical Engineering; Abstract: Optical component performance increasingly demands materials with tailored properties. Optical systems see applications where ambient conditions can drastically reduce performance. Optics used in space, for example, may undergo severe changes in temperature, which results in large thermally induced stresses and distortions. To minimize these thermal effects, it was desired to manipulate the coefficient of thermal expansion (CTE) within the material. However, wholesale reductions in CTE may not be optimum since synthetic manipulation of CTE often leads to undesirable effects on other material p...; Download File | View full details

Position Sensing and Feedback Control for a High Precision Accelerometer: Author: Yu, Feng; Date: 2004-05-15; Program: Electrical Engineering; Abstract: High precision accelerometers have broad applications in space missions and fundamental physics research. However, conventional high precision accelerometers have disadvantages of large volume, high supply voltage and extremely high cost. In this paper, the volume of the sensing element in this accelerometer is reduced on the order of about one hundred. In order to achieve high resolution at the same time when reducing the size of the proof mass, a drag free structure is employed for the sensing element. A capacitive sensing approach is introduced and, in turn, the relationship between the def...; Download File | View full details

Slope scale modeling of snow surface temperature in topographically complex terrain: Author: Staples, James Mark; Date: 2008-12-15; Program: Civil Engineering; Abstract: In mountainous terrain, landscape can influences the thermal state of snow. Snow temperature and mass flux have been calculated using an energy balance model, Radtherm/RT, to account for the effects of topography and meteorological conditions. For a specific location, a terrain model is defined and contains a connected assemblage of elements or facets. Each element has a specified terrain type with assigned thermal properties. Meteorological data are applied, and a one dimensional energy balance is calculated for each element. This energy balance includes conduction, convection, radiation, and...; Download File | View full details

Intergranular Water and Permeability of the Lake Vostok Accretion Ice, Eastern Antarctica: Author: Jepsen, Steven Michael; Date: 2005-12-15; Program: Engineering; Abstract: The relative importance of nonhydrostatic stress and lattice-rejected impurities on the phase equilibrium of intergranular liquid water in the Vostok accretion ice, Eastern Antarctica, was examined in this study. In addition, experiments were conducted to examine the influence of intergranular water in ice on the permeability of a Light Non-Aqueous Phase Liquid (LNAPL) hydrocarbon. Sub-grain scale stresses in the Vostok accretion ice were simulated with anisotropic elastic and elastocreep finite element (FE) models and compared to X-ray dislocation topographs. The phase equilibrium conditions ...; Download File | View full details

Generic Properties of the Infinite Population Genetic Algorithm: Author: Hayes, Christina Savannah Maria; Date: 2006-08-15; Program: Mathematics; Abstract: The infinite population model for the genetic algorithm, where the iteration of the genetic algorithm corresponds to an iteration of a map G, is a discrete dynamical system. The map G is a composition of a selection operator and a mixing operator, where the latter models the effects of both mutation and crossover. This dissertation examines the finiteness and hyperbolicity of fixed points of this model. For a typical mixing operator, the fixed point set of G is finite and all fixed points are hyperbolic....; Download File | View full details

Renovatio: architecture as filter: Author: Woolley, Jeremy Scott; Date: 2008-05-15; Program: Architecture; Abstract: This project set out to investigate the potential for architecture, and architectural systems, to become an element of filtration for contamination in both water and soil. To do this, investigation into Biomimicry, or the use of nature as inspiration, as well as Phytoremediation, the use of plants for the filtration and breakdown of contaminants, was done and then applied to architectural design. The project became the filtration of roughly three million gallons of highly toxic water that enters the Berkley Pit, in Butte, Montana, every day. This particular solution would then prevent the pote...; Download File | View full details

An Autonomic Software Architecture for Distributed Applications: Author: Fuad, Mohammad Muztaba; Date: 2007-08-15; Program: Computer Science; Abstract: Autonomic computing is a grand challenge in computing that aims to produce software that has the properties of self-configuration, self-healing, self-optimization and self-protection. Adding such autonomic properties into existing applications is immensely useful for redeploying them in an environment other than they were developed for. Such transformed applications can be redeployed in different dynamic environments without the user making changes to the application. However, creating such autonomic software entities is a significant challenge not only because of the amount of code transforma...; Download File | View full details

View next 25 results

Back to search page

print-friendly page | mobile-friendly page