A thermodynamic framework was presented for the development of powderconstitutive models. The process of powder compaction through Equal ChannelAngular Extrusion (ECAE) at room temperature was modeled using the finiteelement analysis package ABAQUS. The simulation setup was used to conduct aparametric study involving varying the process parameters of ECAE, aimed ataiding the process design.Two powder compaction models, the Gurson model and the Duva and Crowmodel, were used to test their efficacy in modeling this process. Thethermodynamic framework was applied to derive the constitutive equations of theDuva and Crow model. Modeling parameters like friction coefficients, interactionconditions were determined by comparing the simulations for solid billet and anempty can with actual experimental runs for loads, shear angle and workpiece geometry. The simulations using the two powder constitutive models showed nosignificant difference in the stress in the powder during the extrusion.The results obtained from the 3-D simulations were also compared toexperiments conducted to compact copper powder with a size distribution of 10mto 45m. It was found through experiments that the powder does not fullyconsolidate near the outer corner of the workpiece after the first ECAE pass and theresults from the simulations were used to rationalize this phenomenon.Modifications made to the process by applying a back pressure during thesimulations resulted in a uniformly compacted powder region.Further, simulations were carried out by varying the process parameters likethe crosshead velocity, the friction coefficient between the walls of the die and thecan, can dimensions and material, shape of the can cross section etc and the effectof each of these parameters was quantified by doing a sensitivity analysis.

Predicting the performance of wells in compartmentalized reservoirs can be quite challenging to most conventional reservoir engineering tools. The purpose of this research is to develop a Compartmentalized Gas Depletion Model that applies not only to conventional consolidated reservoirs (with constant formation compressibility) but also to unconsolidated reservoirs (with variable formation compressibility) by including geomechanics, permeability deterioration and compartmentalization to estimate the OGIP and performance characteristics of each compartment in such reservoirs given production data. A geomechanics model was developed using available correlation in the industry to estimate variable pore volume compressibility, reservoir compaction and permeability reduction. The geomechanics calculations were combined with gas material balance equation and pseudo-steady state equation and the model was used to predict well performance. Simulated production data from a conventional gas Simulator was used for consolidated reservoir cases while synthetic data (generated by the model using known parameters) was used for unconsolidated reservoir cases. In both cases, the Compartmentalized Depletion Model was used to analyze data, and estimate the OGIP and Jg of each compartment in a compartmentalized gas reservoir and predict the subsequent reservoir performance. The analysis was done by history-matching gas rate with the model using an optimization technique. The model gave satisfactory results with both consolidated and unconsolidated reservoirs for single and multiple reservoir layers. It was demonstrated that for unconsolidated reservoirs, reduction in permeability and reservoir compaction could be very significant especially for unconsolidated gas reservoirs with large pay thickness and large depletion pressure.

Thesis (Ph. D.)--University of Missouri-Columbia, 2003. / Typescript. Vita. Includes bibliographical references (leaves 153-156). Also available on the Internet.

Thesis (Ph. D.)--University of Missouri-Columbia, 2003. / Typescript. Vita. Includes bibliographical references (leaves 153-156). Also available on the Internet.

A novel method of producing die compacted powder metallurgy components with fully en-closed internal structures was developed. The physical characteristics of the compacts were evaluated by measuring bulk density, internal density gradients and compressive green strength. Additionally, a finite element simulation was developed to evaluate the compaction process of the internal structure compact. The internal structure compact displayed the anticipated lower bulk densities due to the less dense internal structure than a conventional powder metallurgy compact, however; higher local densities were found within the internal structure compact at all compaction pressures. Compressive green strength characteristics showed unique results where the strength in-creased up to 300 MPa compaction pressure, however; at 400 MPa there was a distinct plat-eau in green strength. This phenomenon was attributed to an increase in differential shear stress around the internal structure with a minimal increase in density from 300 MPa to 400 MPa.

Thesis (M.S.)--Ohio University, November, 1999. / Title from PDF t.p.

Thesis (M.S.)--Missouri University of Science and Technology, 2008. / Vita. The entire thesis text is included in file. Title from title screen of thesis/dissertation PDF file (viewed October 20, 2008) Includes bibliographical references.

Thesis (M.S.)--University of Missouri-Columbia, 2004. / Typescript. Includes bibliographical references. Also available on the Internet.

Thesis--Auburn University, 2009. / Abstract. Vita. Includes bibliographical references (p. 58-59).

Thesis--Auburn University, 2008. / Abstract. Includes bibliographic references.