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Modeling And Testing Of Stitched Composite Laminates For Enhanced Interlaminar Strength, Janet M. Wood

Graduate Theses, Dissertations, and Problem Reports

This research assesses the effects of stitching a four-layer E-glass/Epoxy cross-ply laminate with translaminar reinforcement consisting of E-glass yarns. Both experimental characterization and finite element analysis have been employed to accurately predict and analyze the properties of the stitched material.;Tensile and Double Cantilever Beam testing indicated that translaminar stitching degrades the effective extensional modulus of the laminate by about 15.9 percent, while it enhances the opening Mode I interlaminar fracture toughness. This degradation in the effective in-plane stiffness is attributed to the localized damage inflicted on the fiber plies by the needle penetration of the sewing machine used to insert …

Design, Fabrication, And Testing Of A Miniature Impulse Turbine Driven By Compressed Gas, Daniel B. Holt

Theses

A miniature impulse turbine has been developed at the Rochester Institute of Technology. The goal of this project was to design, fabricate, and test a miniature turbine intended to power small vehicles such as micro air vehicles (MAVs). MAVs are vehicles with a maximum dimension of less then 15 cm and are used for surveillance and scouting. Due to the small size of MAVs, weight is a key design parameter. The batteries alone can account for more than 50% of the weight of the entire vehicle. A miniature turbine driven by compressed gas and coupled to a generator has been …

Characterization Of In-Use Emissions From Marine Engines, Sam George

Graduate Theses, Dissertations, and Problem Reports

Recently, exhaust emissions from marine engines have become a cause of growing concern. Emission reduction technologies applicable to marine engines need to be developed and tested so that the emission regulations can be met. A review of emission reduction technologies applicable for marine engines is presented in this study. The experimental results of onboard testing of a high-speed passenger ferry to determine the benefits of low sulfur diesel (LSD) fuel and intake air water injection are presented. Gaseous emissions of oxides of nitrogen (NOx), carbon dioxide (CO2), and particulate matter (PM) emissions were measured using on-board emission measurement systems developed …

Parametric Modeling And Analysis Of Structural Bonded Joints, Sailaja Malladi

Graduate Theses, Dissertations, and Problem Reports

A closed form model of a double lap bonded joint based on the Hart-Smith Model is considered. An extensional link is added to the inner adherend in order to minimize the magnitude of the shear distribution in the adhesive along the overlap length and equations are formulated for this new model. Various parametric studies are performed on the closed form model to observe their effect on the behavior of the shear stress distribution in the adhesive. Overlap length, stiffness of the extensional link, thickness of the adhesive and stiffness of the adherends are varied in the parametric study.;A 2D finite …

Portable Implementation Of Computer Aided Design Environment For Composite Structures, Santosh Kumar Pagadala E.

Graduate Theses, Dissertations, and Problem Reports

Composite materials are widely used due to their low weight, long durability and the ability to tailor their properties to specific design requirements. Their wide range of applications requires a solid understanding of their behavior under different load conditions. The calculations needed for efficient and accurate design of composites could be exhaustive and time consuming. Therefore an efficient computer program which would facilitate effective design becomes a key factor to supporting commercial use of composite materials.;A portable software tool was developed in Java programming environment for design analysis of composite materials. This software tool is superior to its predecessor, the …

Separation Of Small Particles Due To Density Differences In A Cfb Riser System, Jeremy L. Regester

Graduate Theses, Dissertations, and Problem Reports

Common wet density separation processes require large amounts of water, expensive wastewater cleanup, and do not effectively recover fine particles. A circulating fluidized bed riser system was developed as an exploratory system for dry separation by density that will eliminate many problems associated with wet separation. The system sends an air-solid mixture through a vertical riser. The flow pattern in the riser, established by varying gas velocity (Uo) and mass flux (Jp), allowed dense particles to collect at the bottom of the riser while less dense particles were collected through the riser exit at the top. The system was developed …

Fatigue Of Drill Pipes Used In Horizontal Directional Drilling, Feibai Ma

Doctoral Dissertations

Fatigue is the most common cause of mini-HDD drill rod failure. It can occur at stress levels far below the normal operating stress in most drill stem components. Fatigue failures occur because the drill rod, after it has been forced into a curved path, undergoes a cyclic bending stress oscillating from tension to compression in concert with the other stress components caused by torque, thrust, or pullback.

When a rod breaks underground, there is considerable extra cost caused by the delay in “fishing” out the broken rod as well as the cost of replacing the rod. On the other hand, …

Cfd Analysis And Validation For Solution To Micro Air Vehicle Airframes, Taher I. Attari

Theses

Micro Air Vehicles (MAVs) are generally defined as having an airframe with a span less than 6 inches and a mass less than 100 grams. The design of airframes is currently hindered by the lack of thorough understanding of the flow physics of very small aircrafts flying at low speeds. The study investigates the use of Fluent, a licensed CFD code at RTT, for MAV airframe design. This study is carried out in 4 steps. First, 4 different airfoils are selected and tested in CFD. The next step included the simulation of 3-D flat plates and wing models. An external …

Migration Of An Intruder Particle In A Boundary Driven Shear Flow, Jian Liu

Dissertations

This study reports on three-dimensional, discrete element simulations of a single large spherical intruder in a Couette shear flow composed of uniform sized particles. The simulation results are useful in providing a numerical reproduction of the experiments for size segregation and mixing. This in turn has a major importance in many industries which are concerned with handling of particles and powders, such as pharmaceutical manufacturing, agriculture, chemical and mineral processing.

Discrete element simulations are carried out using the "soft sphere" model of Walton, et. al., which provides a method for obtaining the information at a macroscopic level from multi-body collisions …

Simulating Particle Deposition In A Human Replica Lung Model, Pravir Rai

Theses

Tobacco consumption causes a variety of respiratory diseases including lung cancer and chronic obstructive pulmonary disease. These diseases occur when pathogens present in cigarette smoke enter into the respiratory system and deposit in the airways or gas exchanging membranes. Computational Fluid Dynamics (CFD) package FLUENT has been applied to study the deposition patterns of cigarette smoke particles from sidestream and mainstream smoke, as well as carcinogen size specific particles for NNK and BaP. A three dimensional cast of an ideal three generation Weibel lung model and a three dimensional morphologically accurate human replica lung model were used in the analysis. …