Mechanical Engineering Commons^™

Thermomechanical Fatigue Life Prediction Of Notched 304 Stainless Steel, Justin Karl

Electronic Theses and Dissertations

The behavior of materials as they are subjected to combined thermal and mechanical fatigue loads is an area of research that carries great significance in a number of engineering applications. Power generation, petrochemical, and aerospace industries operate machinery with expensive components that undergo repeated applications of force while simultaneously being exposed to variable temperature working fluids. A case of considerable importance is found in steam turbines, which subject blades to cyclic loads from rotation as well as the passing of heated gases. The complex strain and temperature histories from this type of operation, combined with the geometric profile of the …

A Scr Model Based On Reactor And Engine Experimental Studies For A Cu-Zeolite Catalyst, Xiaobo Song

Dissertations, Master's Theses and Master's Reports - Open

A NO_x reduction efficiency higher than 95% with NH₃ slip less than 30 ppm is desirable for heavy-duty diesel (HDD) engines using selective catalytic reduction (SCR) systems to meet the US EPA 2010 NO_x standard and the 2014-2018 fuel consumption regulation. The SCR performance needs to be improved through experimental and modeling studies. In this research, a high fidelity global kinetic 1-dimensional 2-site SCR model with mass transfer, heat transfer and global reaction mechanisms was developed for a Cu-zeolite catalyst. The model simulates the SCR performance for the engine exhaust conditions with NH₃ maldistribution and aging …

Mathematical Model And Experimental Exploration Of The Nanoinjector Lance Array, Nathan C. Toone

Theses and Dissertations

The Nanoinjector Lance Array has been developed to inject foreign material into thousands of cells at once using electrophoresis to attract and repel particles to and from the electrically-charged lances. A mathematical computer model simulating the motion of attracted or repelled proteins informs the design of the nanoinjection lance array system. The model is validated by accurately predicting protein velocity in electrophoresis experiments. A complete analysis of parameters is conducted via simulations and specific research questions regarding the counter electrode of the nanoinjector lance array system are explored using the model. A novel technique for fabricating lance arrays from collapsed …

A Simulation Analysis Of Photovoltaic Ac Module Integrated Converters In Parallel, Under Controlled Edge Shading Conditions, Lynette O'Callaghan, Mick Mckeever, Brian Norton

Conference Papers

A DC and AC power simulation comparison of: a Photovoltaic (PV) array with a modular, parallel, AC converter configuration; and a series, string configuration with a central AC converter, is presented. The systems are simulated using a comprehensive range of edge shading scenarios and irradiance conditions. Power control and transformation circuitry must be designed for shade and module mismatch tolerance to prevent over-proportional power to shade losses, as average losses from Building Integrated PV (BIPV) systems are approximately 20 to 25%, due to shade, mismatch, differences in orientation and inclination, and temperature effects. 59.4% of the simulations showed gains in …

Sae Aero Design Project, Angela N. Mclelland

Honors Theses

The Union College Flying Dutchmen Team aims to compete in the spring 2011, SAE Aero Design® East Competition. This regional event, hosted by the Society of Automotive Engineers International, is a threefold opportunity for teams from around the globe to showcase their understanding of engineering fundamentals. Competing in the SAE Aero Design® competition creates an arena for students to participate in hands-on design, to emphasize technological innovations in a competition setting, and to cooperate in a unique atmosphere where intellectual advancement and teamwork are championed above success. The underlying goal of the SAE Aero Design® competition is to design and …

An Empirical Model For Build-Up Of Sodium And Calcium Ions In Small Scale Reverse Osmosis, Subriyer Nasir

Makara Journal of Technology

A simple models for predicting build-up of solute on membrane surface were formulated in this paper. The experiments were conducted with secondary effluent, groundwater and simulated feed water in small-scale of RO with capacity of 2000 L/d. Feed water used in the experiments contained varying concentrations of sodium, calcium, combined sodium and calcium. In order to study the effect of sodium and calcium ions on membrane performance, experiments with ground water and secondary effluent wastewater were also performed. Build-up of salts on the membrane surface was calculated by measuring concentrations of sodium and calcium ions in feed water permeate and …

An Analytical Model For Rotator Cuff Repairs, A. Aurora, Jorge E. Gatica, Antonie J. Van Den Bogert, J. A. Mccarron, Kathleen A. Derwin

Mechanical Engineering Faculty Publications

Background

Currently, natural and synthetic scaffolds are being explored as augmentation devices for rotator cuff repair. When used in this manner, these devices are believed to offer some degree of load sharing; however, no studies have quantified this effect. Furthermore, the manner in which loads on an augmented rotator cuff repair are distributed among the various components of the repair is not known, nor is the relative biomechanical importance of each component. The objectives of this study are to (1) develop quasi-static analytical models of simplified rotator cuff repairs, (2) validate the models, and (3) predict the degree of load …

Numerical And Analytical Verification Of A Multiscale Computational Model For Impact Problems In Heterogeneous Viscoelastic Materials With Evolving Damage, Bruno Bachiega Araujo

Department of Engineering Mechanics: Dissertations, Theses, and Student Research

Composites are engineered materials that take advantage of the particular properties of each of its two or more constituents. They are designed to be stronger, lighter and to last longer which can lead to the creation of safer protection gear, more fuel efficient transportation methods and more affordable materials, among other examples.

This thesis proposes a numerical and analytical verification of an in-house developed multiscale model for predicting the mechanical behavior of composite materials with various configurations subjected to impact loading. This verification is done by comparing the results obtained with analytical and numerical solutions with the results found when …

Development Of A Model Predictive Controller For Tankless Water Heaters, Gregor P. Henze, David P. Yuill, Andrew H. Coward

David Yuill

This paper describes the development of a novel approach to temperature control of tankless water heaters (TWHs). Conventional methods of controlling TWHs typically allow a high degree of error in the outlet water temperature when subjected to disturbances in flow rate or inlet water temperature. Poor control affects comfort, safety, and energy consumption associ- ated with TWHs. The novel control approach presented here uses model predictive control (MPC) to minimize the outlet temperature error. A dynamic heat transfer model of an electric TWH is developed and validated and used within a MPC-based controller. The controller is interfaced to a physical …

A Dynamic Model Of The Human/Cooling System/Clothing/Environment System, Zhengxiang Pu

Electronic Theses and Dissertations

The human body compensates well for moderate climatic heat stress, but artificial environments often block or overwhelm physiological defense mechanism. Personal protective equipment (PPE) is one of sources of heat stress. It protects individual from chemical, physical, or biological hazards, but the high thermal insulation and low vapor permeability of PPE may also lead to substantial heat stress. Personal cooling is widely used to alleviate heat stress, especially for those situations where ambient environmental cooling is not economically viable or feasible. It is important to predict the physiological responses of a person wearing PPE with personal cooling to make sure …

Flexible Engineering Software: An Integrated Workstation Approach To Finite Element Analysis, Brant Arnold Ross

Theses and Dissertations

One obstacle preventing more engineers from using finite element analysis (FEA) is the difficulty of transferring data between steps in the modeling process. A Fortran computer program, Rosetta.BYU, has been developed to open data paths between finite element preprocessors (mesh generators) and finite element analysis programs, using a custom data structure. It accepts neutral data files, Version 2.0 IGES data files, and Movie.BYU files for input/output. An application of Rosetta is described. A general workstation manager program, Davinci.BYU, is reviewed that provides a support layer between the engineer and the operating system, organizes software and data files, and facilitates on-line …

Finite Element Model Of A Timoshenko Beam With Structural Damping, Louis Ablen Roussos

Mechanical & Aerospace Engineering Theses & Dissertations

A numerical integration technique, a modified version of the Newmark method, is applied to transient motion problems of systems with mass, stiffness, and small nonlinear damping. The nonlinearity is cast as a pseudo-force to avoid repeated recalculation and decomposition of the effective stiffness matrix; thus, the solution technique is dubbed the "pseudo-force Newmark method." Comparisons with exact and perturbation solutions in single-degree-of-freedom problems and with a Gear-method numerical solution in a cantilevered Timoshenko beam finite element problem show the solution technique to be efficient, accurate, and, thus, feasible provided the nonlinear damping is small. As a preliminary step into the …

A Thermal Energy Storage Tank Model For Solar Heating, Robert Arthur Pate

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The results of a combined theoretical and experimental study of the kinetics of a hot-liquid energy-storage tank are presented. A physical model is developed which accurately describes the thermal stratification behavior in a storage tank. The governing differential equations are developed for the physical model. A numerical solution to the system of equations is presented. Some existing models were examined and the predicted results of each are discussed. The concepts developed can be used to predict the thermal stratification behavior in a storage tank under most conceivable operating conditions. These conditions include flow configurations at the top and the bottom …