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Dynamic Project Time And Cost Evaluation Under The Combined Influence Of Contract, Quality, And Uncontrollable Change, Thomas V. Hammock

Mechanical & Aerospace Engineering Theses & Dissertations

This dissertation proposes a method that quantifies the dynamics caused by disruptions due to multiple changes that can occur during the progression of a large scale project. To begin, equations consisting of multiple parallel event sequences are derived that define the relationship between individual process events and the final project completion time. Matrix notation and a precedence matrix concept are used in this derivation to produce equations that are best suited for computer programming applications. This relationship is the foundation upon which the equations are built to calculate the variation impact on each event of a large scale project. Pursuing …

Multiple Point Constraint (Mpc)-Based Variable Node Super-Element, Mohamad Eftekharjoo

Mechanical & Aerospace Engineering Theses & Dissertations

The multiple point constraint (MPC)-based variable node element is introduced in this study to handle mismatched meshes between sub-domains in finite element analysis. The MPC-variable node element is a collection of a group of elements. The compatibility condition along the interface boundary is imposed along the edge of these elements through Lagrange multipliers. The Elimination method is then used to remove the effects of the dependent nodes in these elements to produce a single MPC-based variable node element. The derived variable node elements are applied to solve two plane strain problems in order to validate the accuracy of the proposed …

Nano Scale Mechanical Analysis Of Biomaterials Using Atomic Force Microscopy, Diganta Dutta

Mechanical & Aerospace Engineering Theses & Dissertations

The atomic force microscope (AFM) is a probe-based microscope that uses nanoscale and structural imaging where high resolution is desired. AFM has also been used in mechanical, electrical, and thermal engineering applications. This unique technique provides vital local material properties like the modulus of elasticity, hardness, surface potential, Hamaker constant, and the surface charge density from force versus displacement curve. Therefore, AFM was used to measure both the diameter and mechanical properties of the collagen nanostraws in human costal cartilage. Human costal cartilage forms a bridge between the sternum and bony ribs. The chest wall of some humans is deformed …

Constrained Discrete Phase Control Of A Heaving Wave Energy Converter In Irregular Seas Using Reinforcement Learning, Praveen D. Malali

Mechanical & Aerospace Engineering Theses & Dissertations

Designed for offshore deployment in irregular seas, the point absorber wave energy conversion (WEC) system is promisingly attractive amongst the currently available WEC technologies. The effectiveness of phase control when applied to a heaving point absorber through a hydraulic power take-off (PTO) system is systematically investigated in both regular and irregular waves. For this purpose, two phase control accumulators are utilized in the hydraulic PTO system. Simulations are performed in MATLAB® using the Cummins equation to model the dynamics of the heaving point absorber in the time domain.

For a given sea state, the opening instant of the control valves …

Isogeometric Analysis For Electromagnetism, Tahsin Khajah

Mechanical & Aerospace Engineering Theses & Dissertations

The combination of numerical analysis with the scanning technology has been seeing increased use in many research areas. There is an emerging need for high-fidelity geometric modeling and meshing for practical applications. The Isogeometric Analysis (IGA) is a comprehensive computational framework, which integrates geometric modeling and meshing with analysis. Different from other existing numerical methods, the IGA can generate analysis ready models without loss of geometrical accuracy. In IGA, the continuity and the quality of a solution can be conveniently controlled and refined. These features enable IGA to integrate modeling, analysis, and design in a unified framework, the root idea …