Mechanical Engineering Commons^™

The Effects Of Micro-Dimple Texture On The Friction And Thermal Behavior Of A Point Contact, Utsav Kamleshbhai Parmar

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This study investigates the effects of the micro-dimple texture on the friction and surface temperature performances of a ball-on-disk contact, operating under the speed and load ranges that cover typical gearing applications. Circular shaped micro-dimple arrays with different dimple center distances and dimple depths are implemented on the ball surface to quantify the impacts of these two parameters on the friction coefficient and the maximum ball surface temperature. In addition, the contacts of three surface texture combinations, namely micro-dimpled and polished ball surface versus polished disk surface, polished ball surface versus polished disk surface and ground ball surface versus ground …

Hybrid Particle Image Velocimetry With The Combination Of Cross-Correlation And Optical Flow Method, Mark Bradley Johnson

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Particle Image Velocimetry (PIV) has been of relevant discussions lately as the equipment used to obtain temporally and spatially resolved flow fields have advanced rapidly. Despite these advancements, the accuracy of evaluating these images have yet to exceed expectations. Current techniques typically utilize one method, either correlation based (frequently) or optical flow (non-frequently), and both are vulnerable to specific conditions incorporated in the PIV images. Only through the combination of two methods, cross correlation and optical flow, can a technique benefit from the strengths of each method while concealing the flaws each individual method contains. The Hybrid Particle Image Velocimetry …

Locally Optimized Covariance Kriging For Non-Stationary System Responses, Daniel Lee Clark Jr.

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In this thesis, the Locally-Optimized Covariance (LOC) Kriging method is developed. This method represents a flexible surrogate modeling approach for approximating a non-stationary Kriging covariance structures for deterministic responses. The non-stationary covariance structure is approximated by aggregating multiple stationary localities. The aforementioned localities are determined to be statistically significant utilizing the Non-Stationary Identification Test. This methodology is applied to various demonstration problems including simple one and two-dimensional analytical cases, a deterministic fatigue and creep life model, and a five-dimensional fluid-structural interaction problem. The practical significance of LOC-Kriging is discussed in detail and is directly compared to stationary Kriging considering computational …

Feasibility Of Attaining Fully Equiaxed Microstructure Through Process Variable Control For Additive Manufacturing Of Ti-6al-4v, Sarah Louise Kuntz

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One of the greatest challenges in additive manufacturing is fabricating titanium structures with consistent and desirable microstructure. To date, fully columnar deposits have been achieved through direct control of process variables. However, the introduction of external factors appears necessary to achieve fully equiaxed grain morphology using existing commercial processes. This work introduces and employs an analytic model to relate process variables to solidification thermal conditions and expected beta grain morphology at the surface of and at the deepest point in the melt pool. The latter is required in order to ensure the deposited microstructure is maintained even after the deposition …

Scalability Of Microscale Fractal-Like Branching Channel Networks, James R. Miller Iii

Honors College Theses

Fractal-like branching channel networks have been shown to offer the advantages of reduced pumping power and lower maximum wall temperatures when employed in the design of microscale heat sinks. Unfortunately, previous literature has been limited to microscale flow networks. In this paper, a microscale flow network will be scaled up to result in a mesoscale flow network and a macroscale flow network. In order to compare the pressure drop across the flow networks of varying scales the results will be nondimensionalized in the form of the Euler number. For a laminar inlet Reynolds number the microscale, mesoscale, and macroscale fractal-like …

Development Of Learning Objectives For An Undergraduate Computer-Aided Drafting And Design Animation Using The Delphi Technique, Gavin M. Wilk

Masters Theses

This study reflects on learning objectives created for an advanced computer aided drafting (CAD) learning module(s) or course with the emphasis on simulation and engineering animations. These objectives were derived by using the Delphi technique by access the support of a panel of subject matter experts (SME) from academia and industry that are interested in CAD. The results of this study are intended for the use of creating instructional modules for undergraduate studies.

A panel of experts were chosen through an electronic listserv of engineering and technology supporters. Two rounds of two different Delphi survey instruments were utilized to complete …

Optimal Configuration Of Inspection And Rework Stations In A Multistage Flexible Flowline, Md. Shahriar Jahan Hossain

LSU Master's Theses

Inspection and rework are two important issues of quality control. In this research, an N-stage flowline is considered to make decisions on these two issues. When defective items are detected at the inspection station the items are either scrapped or reworked. A reworkable item may be repaired at the regular defect-creating workstation or at a dedicated off-line rework station. Two problems (end-of-line and multistage inspections) are considered here to deal with this situation. The end-of-line inspection (ELI) problem considers an inspection station located at the end of the line while the multistage inspection (MSI) problem deals with multiple in-line inspection …