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The Effect Of Humeral Short Stem Positioning, Humeral Head Contact, And Head Positioning On Bone Stress Following Total Shoulder Arthroplasty, Amir Tavakoli

Electronic Thesis and Dissertation Repository

Uncemented humeral stems cause stress shielding which result in bone resorption when used in total shoulder arthroplasty (TSA). Shorter length stems show a decrease in stress shielding, however the effect of humeral short stem positioning and humeral head contact and positioning on bone stress is currently not known, hence CT-based tools and Finite Element (FE) methods are used to quantify the effects of the mentioned variables on bone stresses after TSA.

Eight male cadaveric humeri were virtually constructed from computed tomography (CT) data, with a generic short humeral short stem as the implant.

The results of this work show that …

An Investigation On The Influences Of Radial Head Hemiarthroplasty Stem Fixation Techniques On Articular Mechanics, Jakub Szmit

Electronic Thesis and Dissertation Repository

Radial head hemiarthroplasty design has been extensively studied with a focus on utilizing the geometrical characteristics of the native radial dish as a guide of implant placement and design. Although implant design has been studied, optimal radial head implant fixation technique remains unknown. This thesis focused on the effect of stem fit on radiocapitellar contact mechanics, using both finite element and experimental bench-top approaches. Additionally, investigation into the impact of varus/valgus malalignment of the radial head in both the native state and following hemiarthroplasty was conducted. It was found that loose fitting a smooth stem axisymmetric radial head implant through …

Experimental Investigation Of Liquid Height Estimation And Simulation Verification Of Bolt Tension Quantification Using Surface Acoustic Waves, Hani Alhazmi

USF Tampa Graduate Theses and Dissertations

In this dissertation, two separate applications that are related to surface acoustic waves in a solid media are presented. The first study concerns simulating and validating an experimentally study for quantifying the bolt tension in the bolted joints using the surface acoustic wave. The second study experimentally investigates measuring the level of a liquid existing on a solid surface via surface acoustic waves and exploring the effect of liquid existence on the propagation of surface acoustic waves over the solid surface.

Quantifying bolt tension and ensuring that bolts are appropriately tightened for large-scale civil infrastructures are crucial. This study investigates …

Acoustic And Ultrasonic Beam Focusing Through Aberrative And Attenuative Layers, Hossain Ahmed

Theses and Dissertations

Ultrasonic nondestructive evaluation (NDE) is a well-established technique to assess material properties and material state in noninvasive way. However, conventional NDE technologies are limited by the thick top coatings over the structure and, therefore, require time consuming removal and replacement of the coatings to perform the inspection. In biological application, although ultrasonic NDE is a safer method in compared to other radioactive non-invasive techniques, aberration of acoustic beams is more common as it encounters multiple tissue layers of complex geometry with nonhomogeneous properties. These limit the use of ultrasonic NDE in engineering and biological applications. To alleviate this problem, recently …

Cal Poly Prove Lab Endurance Car Composite Body Paneling Design, Emma Wheelock, Sarah Rutland, Noah Fisher, Brian Menard

Mechanical Engineering

The Cal Poly Prototype Vehicles Laboratory (PROVE Lab) needs a body paneling design for their Endurance Car aeroshell which optimizes strength, weight and accessibility while minimizing complexity. Additionally, a low-complexity, accurate manufacturing process for the PROVE Lab Endurance Car aeroshell needs to be developed. PROVE Lab designed the shape of the aeroshell. The aeroshell will serve to reduce the aerodynamic drag on the car at high speed, and is not a structural component of the car. Due to the high-strength and lightweight nature of composites, PROVE Lab requests the senior project team investigate using composites for automotive body paneling applications. …

Strategies For Ultraprecise Single Point Cutting Of V-Grooves, Delfim A C Joao

Electronic Thesis and Dissertation Repository

V-groove microstructures have found numerous functionalization applications in mechanical, electronic, photonic, biomechanical and optical components. However, despite their wide use, the manufacturing processes associated with their fabrication are limited to axial strategies with a constant depth of cut that do not allow the control of the cutting force and cutting time, and therefore leading to significant micro-burrs as well as an inability to fabricate high aspect ratio grooves. The current thesis addresses this problem with the development of three cutting strategies that make use of a single point cutting process. The study to be detailed herein includes analytical, numerical and …

Experimental And Computational Studies Of Heat Transfer In Flexible Two-Dimensional Woven Fiber Ceramic Materials, Rodrigo Penide Fernandez

Graduate College Dissertations and Theses

Flexible thermal protection materials made from two-dimensional woven ceramics fibers are of significant interest for hypersonic inflatable aerodynamic decelerators being developed by NASA for future missions on Mars and other planets. A key component of the thermal shield is a heat-resistant outer ceramic fabric that must withstand harsh aero-thermal atmospheric entry conditions. However, a predictive understanding of heat conduction processes in complex woven-fiber ceramic materials under deformation is currently lacking. This dissertation presents a combined experimental and computational study of thermal conductivity in alumina-based Nextel-440 and silicon carbide Hi-Nicalon 5-harness-satin woven fabrics, using the hot-disk transient plane source method and …

Buckling Load Study On Pop Nut (Rivet) Using Finite Element Analysis, Saurabh Shankar Shegokar

Dissertations, Master's Theses and Master's Reports

This study highlights the material behavior in riveting operation that includes buckling load analysis using ABAQUS. Finite Element Analysis is used to find the buckling load vs. Displacement results and validated with the results obtained in physical testing of rivet (POP Nut). A mesh sensitivity study is performed using ABAQUS to understand the optimum mesh size for this analysis. An axisymmetric model with contact properties is created and simulated to reduce the simulation time using ABAQUS. The results obtained through Finite Element Analysis show a good resemblance with the testing results. Design changes were suggested to achieve better results that …

Autonomous Guided Vehicle Frame For Outdoor Use, Thomas Mcgrath

Williams Honors College, Honors Research Projects

The overall goal for my project is to design a durable Autonomous Guided Vehicle (AGV) frame intended for carrying a heavy load over outdoor terrain. I will not be designing a complete vehicle, only the basic structure that can be used to build a complete AGV on. There will be complete 3D models of the design and its individual parts. I also would like to provide limited Finite Element Analysis of the design using ANSYS software to determine weaknesses and methods for improvement. The design I create is meant to be used as a framework for complete outdoor AGV designs. …