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Tribological Behavior Of Duplex Nitrogen Diffusion/Dlc Coating Treatments., Yan Liu
Tribological Behavior Of Duplex Nitrogen Diffusion/Dlc Coating Treatments., Yan Liu
LSU Historical Dissertations and Theses
Diamond-like carbon (DLC) coatings have high potential for developing advanced tribological systems and the overall objective of the present research is to provide a framework to theoretically design and experimentally develop and study such systems of interest. The present research concentrates on the following specific aspects: the fundamental wear mechanism of DLC coatings; finite element (FE) modeling to understand the stress distribution in coating/substrate system under indentation and friction; and the influence of graded interface on the tribological behavior of DLC coatings. The experimental results showed that DLC films possess low friction coefficient ($f\sb{init}$: 0.12-0.20, $f\sb{fin}$: 0.06-0.08) and low wear …
Performance Of Composite Piping Systems: Thermal, Fire Endurance, And Joining Characteristics., Michael Andre Stubblefield
Performance Of Composite Piping Systems: Thermal, Fire Endurance, And Joining Characteristics., Michael Andre Stubblefield
LSU Historical Dissertations and Theses
Composite piping systems are becoming the "System of Choice" in many applications previously the domain of metallic piping systems. For full acceptability and usage of these composite piping systems, new innovative approaches must be developed. Three areas of development are addressed; (i) thermal efficiency, (ii) fire endurance, and (iii) joining techniques. In the development of the energy conserving composite pipe, the thermal contact resistance acts as an additional insulating layer. A model and device to predict and measure the contact resistance for a pipe system has been developed. A corrugated layer, which acts as an enhanced contact resistance layer, forms …
Development Of A Prototype Computer-Assisted Well Control System For Deep Ocean Drilling Environments., Orville Allen Kelly
Development Of A Prototype Computer-Assisted Well Control System For Deep Ocean Drilling Environments., Orville Allen Kelly
LSU Historical Dissertations and Theses
An advanced prototype computer-assisted deep water drilling well control system was developed using process control technology. The goal of the system was to improve rig safety by reducing the potential for surface and underground blowouts through providing enhanced bottom hole and casing seat pressure control during the well kill process. The system developed is capable of full computer control of the fluid pump and drilling choke control functions during normal well control operations. The system provides computer-assistance in collecting and curve fitting slow circulation rate pump pressure data, in developing a well kill program (kill sheet), and in detecting anomalies …
The Recycling Potential Of Out-Of-Service Utility Poles For Engineered Wood Products., Han Roliadi
The Recycling Potential Of Out-Of-Service Utility Poles For Engineered Wood Products., Han Roliadi
LSU Historical Dissertations and Theses
This study on the recycling potential of out-of-service poles for use in engineered wood products involved determination of basic properties of used southern pine (Pinus sp.) utility poles and also manufacture of glued-laminated beams from these poles. Most of the defect-free portions of 25-year treated poles still retained adequate strengths comparable to those of freshly treated poles and untreated southern pine. Creosote contents, however, diminished with pole ages. The reduction in creosote content was correlated with lower decay resistance, poorer dimensional stability, and lower lumber recovery, but better gluability. The spectrometry method for creosote content determination was explored as an …
Feature-Based Models For Three-Dimensional Data Fitting., Gregory Todd Dobson
Feature-Based Models For Three-Dimensional Data Fitting., Gregory Todd Dobson
LSU Historical Dissertations and Theses
There are numerous techniques available for fitting a surface to any supplied data set. The feature-based modeling technique takes advantage of the known, geometric shape of the data by deforming a model having this generic shape to approximate the data. The model is constructed as a rational B-spline surface with characteristic features superimposed on its definition. The first step in the fitting process is to align the model with a data set using the center of mass, principal axes and/or landmarks. Using this initial orientation, the position, rotation and scale parameters are optimized using a Newton-type optimization of a least …
A Micro-Mechanical Fatigue Damage Model For Uni-Directional Metal Matrix Composites., Rainer Echle
A Micro-Mechanical Fatigue Damage Model For Uni-Directional Metal Matrix Composites., Rainer Echle
LSU Historical Dissertations and Theses
A micro-mechanical damage model for high cycle fatigue loading based on thermo-dynamical principles is developed for uni-directional continuous fiber reinforced metal matrix composites. The model uses a micro-mechanical based theory to predict the fatigue damage evolution in the individual constituents of the composite material, namely the fibers and the matrix, from which the overall fatigue damage evolution in the composite is obtained. The micro-mechanical analysis is performed for each individual constituent using stress and strain concentration tensors based on the Mori-Tanaka method. A fatigue damage criterion based on thermo-dynamical principles is developed and applied to each of the constituents. Fatigue …
Development Of An Analysis System For Discontinuities In Rigid Airfield Pavements., Michael Ivan Hammons
Development Of An Analysis System For Discontinuities In Rigid Airfield Pavements., Michael Ivan Hammons
LSU Historical Dissertations and Theses
The response of the rigid pavement slab-joint-base structural system is complex, and accurately predicting the response of such a system requires a significant degree of analytical sophistication. The research reported in this dissertation has defined some essential features required to adequately model the system and has demonstrated a technique to develop a comprehensive three-dimensional (3D) finite element model of the rigid pavement slab-joint-foundation structural system. Analysis of experimental data from the 1950s confirms that explicit modeling of dowels is not required to model the structural response of the system. Additional experimental data gathered as a part of this research indicates …