Mechanical Engineering Commons^™

Pseudo-Rigid-Body Models For Approximating Spatial Compliant Mechanisms Of Rectangular Cross Section, Issa Ailenid Ramirez

USF Tampa Graduate Theses and Dissertations

The objective of the dissertation is to develop and describe kinematic models (Pseudo-Rigid-Body Models) for approximating large-deflection of spatial (3D) cantilever beams that undergo multiple bending motions thru end-moment loading. Those models enable efficient design of compliant mechanisms, because they simply and accurately represent the bending and stiffness of compliant beams.

To accomplish this goal, the approach can be divided into three stages: development of the governing equations of a flexible cantilever beam, development of a PRBM for axisymmetric cantilever beams and the development of spatial PRBMs for rectangular cross-section beam with multiple end moments.

The governing equations of a …

Thermal Assessment Of A Latent-Heat Energy Storage Module During Melting And Freezing For Solar Energy Applications, Antonio Miguel Ramos Archibold

USF Tampa Graduate Theses and Dissertations

Capital investment reduction, exergetic efficiency improvement and material compatibility issues have been identified as the primary techno-economic challenges associated, with the near-term development and deployment of thermal energy storage (TES) in commercial-scale concentrating solar power plants. Three TES techniques have gained attention in the solar energy research community as possible candidates to reduce the cost of solar-generated electricity, namely (1) sensible heat storage, (2) latent heat (tank filled with phase change materials (PCMs) or encapsulated PCMs packed in a vessel) and (3) thermochemical storage. Among these the PCM macro-encapsulation approach seems to be one of the most-promising methods because of …

Exploration Of Electrodeposition Of Aluminum-Nickel Alloys And Multilayers In Organic Chloroaluminate Ionic Liquids, Ammar Bin Waqar

USF Tampa Graduate Theses and Dissertations

Aluminum-nickel (Al-Ni) alloys and Al/Ni bilayers were successfully electrodeposited from AlCl₃-EMIM-NiCl₂ electrolyte at room temperature. Dissolution of NiCl₂ was shown to be favorable in Lewis basic (with molar ratio of AlCl₃ < 0.5) AlCl₃-EMIM solution. The use of electrochemically active Cu working electrode as opposed to inert W induced additional Cu oxidation and dissolution in the cyclic voltammetry scan. The reduction potentials of Al and Ni were found to be ~ – 0.3 and 0.15 V vs. Al/Al³⁺ respectively. Increasing [NiCl₂] in the electrolyte leads to an increase of Ni concentration in the …

Exergetic Life Cycle Assessment Of Electrospun Polyvinylidene Fluoride Nanofibers, Salman Ali Abbasi

USF Tampa Graduate Theses and Dissertations

Assessing the sustainability of nanomanufacturing products and processes has been difficult to achieve using conventional approaches mainly due to an inadequate inventory, large process-to-process variation, and a dearth of relevant toxicology data for nanomaterials. Since these issues are long term in nature, it is required to create hybrid methodologies that can work towards filling the existing gaps. Merging thermodynamic techniques such as the exergy analysis with environmental assessments can help make better, more informed choices while providing an opportunity for process improvement by enabling to correctly quantify efficiency loss through the waste stream, and by locating the exact areas for …

Analysis And Application Of Passive Gait Rehabilitation Methods, Ismet Handzic

USF Tampa Graduate Theses and Dissertations

Human gait is elegant and efficient in propelling the body forward. While a healthy human gait is symmetric, any deviation from symmetry can cause inefficiencies to the entire body. Such asymmetries may present themselves in hemiplegic patients, prosthetic users, lower limb injuries, limb height and weight discrepancies, or abnormal overground foot rolling. In this dissertation, practical passive methods to alleviate such asymmetric walking dynamics are presented. The novel concepts presented in this manuscript can all be related and applied to passive gait rehabilitation, that is, the rehabilitation of a person's gait through methods that do not require external power. One …

Asymmetric Unilateral Transfemoral Prosthetic Simulator, Tyagi Ramakrishnan

USF Tampa Graduate Theses and Dissertations

amputation, which includes reduced force generation at the knee and ankle, reduced control of the leg, and different mass properties relative to their intact leg. The physical change in the prosthetic leg leads to gait asymmetries that include spatial, temporal, or force differences. This altered gait can lead to an increase in energy consumption and pain due to compensating forces and torques. The asymmetric prosthesis demonstrated in this research aims to find a balance between the different types of asymmetries to provide a gait that is more symmetric and to make it overall easier for an amputee to walk.

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Numerical Simulation Of Flow In Ozonation Process, Jie Zhang

USF Tampa Graduate Theses and Dissertations

In the last two decades, Computational Fluid Dynamics (CFD) has shown great potential as a powerful and cost-efficient tool to troubleshoot existing disinfection contactors and improve future designs for the water and wastewater treatment utilities.

In the first part of this dissertation two CFD simulation methodologies or strategies for computing turbulent flow are evaluated in terms of the predicted hydraulic performance of contactors. In the LES (large eddy simulation) methodology, the more energetic, larger scales of the turbulence are explicitly computed or resolved by the grid. In the less computationally intensive RANS (Reynolds-averaged Navier-Stokes) methodology, only the mean component of …

A 3-D Pseudo-Rigid-Body Model For Rectangular Cantilever Beams With An Arbitrary Force End-Load, Jairo Renato Chimento

USF Tampa Graduate Theses and Dissertations

This dissertation introduces a novel three-dimensional pseudo-rigid-body model (3-D PRBM) for straight cantilever beams with rectangular cross sections. The model is capable of capturing the behavior of the neutral axis of a beam loaded with an arbitrary force end-load. Numerical integration of a system of differential equations yields approximate displacement and orientation of the beam's neutral axis at the free end, and curvatures of the neutral axis at the fixed end. This data was used to develop the 3-D PRBM which consists of two torsional springs connecting two rigid links for a total of 2 degrees of freedom (DOF). The …

A Recreation And Ballistic Evaluation Of Otto Schneeloch's Firearm Curiosity - The .307 Triangular, Amber Nicole Shukitis

USF Tampa Graduate Theses and Dissertations

Otto Scheeloch's U.S. Patent No. 134,442 of 1872 describes a unique firearm that uses triangular bullets. The current research effort evaluates the ballistic performance of Otto's disclosure for the very first time. To achieve this goal it was necessary to seek out surviving artifacts and scour the historical record in search of all the parameters needed to meticulously recreate the curious triangular cartridges and the corresponding gun barrel, with its matching twisted triangular bore. Every aspect of the resulting reproduction ammunition was made to be as authentic as possible, including the use of vintage civil war era bullet lead, bullet …

Quantification Of Transhumeral Prosthetic Socket Residual Limb Interface Movement Using Motion Capture And A Slip Detection Sensor, Matthew Wernke

USF Tampa Graduate Theses and Dissertations

Current literature focusing on the prosthetic socket is limited by measurement techniques and modeling assumptions, leading to a limited understanding of the forces and motions occurring between the residual limb and prosthesis and how they can be used to influence socket design and fitting. Prosthetic socket fitting and prescription would benefit from an elegant method for comparing socket designs. This dissertation focuses on the development and implementation of a 3D motion capture model and a Slip Detection Sensor to quantify rotations and translations at the prosthetic socket-residual limb interface. The 3D motion capture model defines the residual limb bone position …