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Full-Text Articles in Mechanical Engineering

Developing Motion Platform Dynamics For Studying Biomechanical Responses During Exercise For Human Spaceflight Applications, Kaitlin Lostroscio Mar 2018

Developing Motion Platform Dynamics For Studying Biomechanical Responses During Exercise For Human Spaceflight Applications, Kaitlin Lostroscio

Graduate Theses and Dissertations

In future human spaceflight missions, with prolonged exposure to microgravity, resistive and aerobic exercises will be countermeasures for bone loss, muscle loss, and decreased aerobic capacity. Two of the exercises of interest are squats and rowing. The cyclic forces produced during these exercises are at relatively low frequencies which are likely to excite structural resonances of space vehicles. Vibration Isolation Systems (VIS) are being designed to be paired with future exploration exercise devices in order to prevent these cyclic exercise forces from impacting the space vehicle. The VIS may be configured such that a platform supports the human and exercise ...


A Planar Pseudo-Rigid-Body Model For Cantilevers Experiencing Combined Endpoint Forces And Uniformly Distributed Loads Acting In Parallel, Philip James Logan Jan 2015

A Planar Pseudo-Rigid-Body Model For Cantilevers Experiencing Combined Endpoint Forces And Uniformly Distributed Loads Acting In Parallel, Philip James Logan

Graduate Theses and Dissertations

This dissertation describes the development and effectiveness of a mathematical model used to predict the behavior of cantilever beams whose loading conditions include parallel combinations of evenly distributed loads and endpoint forces. The large deflection of cantilever beams has been widely studied. A number of models and mathematical techniques have been utilized in predicting the endpoint path coordinates and load-deflection relationships of such beams. The Pseudo-Rigid-Body Model (PRBM) is one such method which replaces the elastic beam with rigid links of a parameterized pivot location and torsional spring stiffness. In this paper, the PRBM method is extended to include cases ...


Pseudo-Rigid-Body Models For Approximating Spatial Compliant Mechanisms Of Rectangular Cross Section, Issa Ailenid Ramirez Nov 2014

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

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 ...


A 3-D Pseudo-Rigid-Body Model For Rectangular Cantilever Beams With An Arbitrary Force End-Load, Jairo Renato Chimento Apr 2014

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

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 ...


Shield Design For Maximum Deformation In Shape-Shifting Surfaces, Daniel Eduardo Perez Jan 2013

Shield Design For Maximum Deformation In Shape-Shifting Surfaces, Daniel Eduardo Perez

Graduate Theses and Dissertations

This research presents the initial studies and results on shield design for Shape-Shifting Surfaces (SSSs) seeking maximum compression and maximum expansion of a unit-cell. Shape-Shifting Surfaces (SSSs) are multilayered surfaces that are able to change shape while maintaining their integrity as physical barriers. SSSs are composed of polygonal unit-cells, which can change side lengths and corner angles. These changes are made possible by each side and corner consisting of at least two different shields, or layers of material. As the layers undergo relative motion, the unit-cell changes shape. In order for the SSS to retain its effectiveness as a barrier ...


Multistable Shape-Shifting Surfaces (Mssss), Paul Joseph Montalbano Jan 2012

Multistable Shape-Shifting Surfaces (Mssss), Paul Joseph Montalbano

Graduate Theses and Dissertations

This paper presents designs for Multistable Shape-Shifting Surfaces (MSSS) by introducing bistability into the Shape-Shifting Surface (SSS). SSSs are defined as surfaces that retain their effectiveness as a physical barrier while undergoing changes in shape. The addition of bistability to the SSS gives the surface multiple distinct positions in which it remains when shifted to, i.e. by designing bistability into a single SSS link, the SSS unit cell can change into multiple shapes, and stabilize within the resulting shape, while maintaining integrity against various forms of external assaults normal to its surface. Planar stable configurations of the unit cell ...


A Mechanized Horseback Riding Simulator As An Aid To Physical Therapy, Jennifer Lott Jul 2006

A Mechanized Horseback Riding Simulator As An Aid To Physical Therapy, Jennifer Lott

Graduate Theses and Dissertations

Equine-assisted therapy is a nontraditional form of physical therapy that involves riding horses as a form of rehabilitation. Limited access to these riding programs justifies a need to develop a horseback riding simulator capable of simulating the gaits, bend, and collection of the horse. Research involving the development of horseback riding simulators is limited, but the available research does show promising results in the ability to aid in physical therapy.

A two-dimensional model and simulation was developed using MATLAB. Using the results from the simulation, a horseback riding simulator was designed, fabricated and tested. The physical simulator was capable of ...