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Articles 1 - 8 of 8
Full-Text Articles in Engineering
Network Target Coordination For Design Optimization Of Decomposed Systems, Wenshan Wang
Network Target Coordination For Design Optimization Of Decomposed Systems, Wenshan Wang
All Dissertations
A complex engineered system is often decomposed into a number of different subsystems that interact on one another and together produce results not obtainable by the subsystems alone. Effective coordination of the interdependencies shared among these subsystems is critical to fulfill the stakeholder expectations and technical requirements of the original system. The past research has shown that various coordination methods obtain different solution accuracies and exhibit different computational efficiencies when solving a decomposed system. Addressing these coordination decisions may lead to improved complex system design. This dissertation studies coordination methods through two types of decomposition structures, hierarchical, and nonhierarchical.
For …
On Simulation And Modeling Of Turbulent Non-Premixed Reacting Shear Flames At Low And High Pressure, Justin Foster
On Simulation And Modeling Of Turbulent Non-Premixed Reacting Shear Flames At Low And High Pressure, Justin Foster
All Dissertations
A database of simulations of fundamental turbulent H2/O2 and H2/Air shear layer flames has been developed using the direct numerical simulation technique in which all length and time scales of a flow are fully resolved without resort to turbulence modeling. The formulation includes the fully-compressible form of the governing equations, a pressure dependent detailed chemical kinetics scheme (9 species, 19 steps), a cubic real gas equation of state, realistic property models, and generalized heat and mass diffusion models. Simulations were conducted for a temporally developing shear layer geometry and cover a wide range of initial pressures (1 atm < P < 125 atm) and flame Reynolds numbers (850 < Re < 4500). These supercomputing simulations are the largest yet performed for high pressure conditions to the author's knowledge. Computational requirements for the largest simulations included mesh sizes of ~3/4 billion grid points and ~2.2 million CPU-hrs conducted on nearly 4,000 CPU cores on Clemson's Palmetto cluster.
The database …
Applying Chaotic Advection To Rheology: An In Situ Structuring Rheometer, Ramaswami Subrahmanian
Applying Chaotic Advection To Rheology: An In Situ Structuring Rheometer, Ramaswami Subrahmanian
All Dissertations
A prototype In Situ Structuring Rheometer (ISSR) was designed and implemented to study changes in shear viscosity of polymer blends and composites while processing them in such a way as to control the evolution of microstructure. The ISSR is based on a regime of fluid mechanics known as chaotic advection, in which simple time-periodic flow fields can cause fluid particles to move chaotically. Chaotic advection is also the basis of Smart Blending, a technology employed to process polymer blends having a variety of morphologies at a fixed composition, and polymer composites in which the additives have been arranged into layered …
Compressive Strength Of Continuous Fiber Unidirectional Composites, Ronald Thompson
Compressive Strength Of Continuous Fiber Unidirectional Composites, Ronald Thompson
All Dissertations
Dow and Rosen's work in 1965 formed an intellectual framework for compressive strength of unidirectional composites. Compressive strength was explained in terms of micro-buckling, in which filaments are beams on an elastic foundation. They made simplifying assumptions, with a two dimensional idealization and linearized material properties. This study builds on their model, recognizing that the shear mode of instability drives unidirectional compressive strength. As a necessary corollary, the predictive methods developed in this study emphasize correct representation of composite shear stiffness. Non-linear effects related to matrix material properties, fiber misalignment, three dimensional representation, and thermal prestrains are taken into account. …
Clustering And Classification Of Multivariate Stochastic Time Series In The Time And Frequency Domains, Ryan Schkoda
Clustering And Classification Of Multivariate Stochastic Time Series In The Time And Frequency Domains, Ryan Schkoda
All Dissertations
The dissertation primarily investigates the characterization and discrimination of stochastic time series with an application to pattern recognition and fault detection. These techniques supplement traditional methodologies that make overly restrictive assumptions about the nature of a signal by accommodating stochastic behavior. The assumption that the signal under investigation is either deterministic or a deterministic signal polluted with white noise excludes an entire class of signals -- stochastic time series. The research is concerned with this class of signals almost exclusively. The investigation considers signals in both the time and the frequency domains and makes use of both model-based and model-free …
Computational Representation And Reasoning Support For Requirements Change Management In Complex System Design, Beshoy Morkos
Computational Representation And Reasoning Support For Requirements Change Management In Complex System Design, Beshoy Morkos
All Dissertations
Requirements play a critical role within any design process and the activity of identifying and maintaining a system's requirements is essential to. However, design is a complex and iterative process, where requirements are continuously evolving and are volatile. This change, if not managed, may result in undesired uncertainty within the design process leading to monetary losses and time delays, as the changing of requirements has been recognized as a major cause of project failure. In order to mitigate issues that arise due to requirement change propagation, this research presents a computational reasoning tool to help designers and engineers predict change …
Design Of Meta-Materials Outside The Homogenization Limit Using Multiscale Analysis And Topology Optimization, Christopher Czech
Design Of Meta-Materials Outside The Homogenization Limit Using Multiscale Analysis And Topology Optimization, Christopher Czech
All Dissertations
The field of meta-materials engineering has largely expanded mechanical design possibilities over the last two decades; some notable design advances include the systematic engineering of negative Poisson's ratio materials and functionally graded materials, materials designed for optimal electronic and thermo-mechanical performances, and the design of materials under uncertainty. With these innovations, the systematic engineering of materials for design-specific uses is becoming more common in industrial and military uses. The motivation for this body of research is the design of the shear beam for a non-pneumatic wheel. Previously, a design optimization of a finite element model of the non-pneumatic wheel was …
Extending Origami Technique To Fold Forming Of Sheet Metal Products, Ala Qattawi
Extending Origami Technique To Fold Forming Of Sheet Metal Products, Ala Qattawi
All Dissertations
This dissertation presents a scientific based approach for the analysis of folded sheet metal products. Such analysis initializes the examination in terms of topological exploration using set of graph modeling and traversal algorithms. The geometrical validity and optimization are followed by utilizing boundary representation and overlapping detection during a geometrical analysis stage, in this phase the optimization metrics are established to evaluate the unfolded sheet metal design in terms of its manufacturability and cost parameters, such as nesting efficiency, total welding cost, bend lines orientation, and maximum part extent, which aides in handling purposes. The proposed approach evaluates the design …