Engineering Commons^™

Rc Baja Suspension And Steering, Garrett Bailey

All Undergraduate Projects

The RC Baja team set out to engineer and construct a working remote-control device that can compete in the ASME Baja Competition. The students have a focus on either suspension and steering or drivetrain and chassis. This report is centered on the suspension and steering. First, multiple analyses were completed using engineering methods such as mechanical design, statics, strengths of materials, and dynamics for parts of the device. The calculations found in the analysis are then used to create designs for the parts so that they will meet the requirements and be successful in the competition. After the parts are …

Novel Locomotion Methods In Magnetic Actuation And Pipe Inspection, Adam Cox

Mechanical Engineering Research Theses and Dissertations

There is much room for improvement in tube network inspections of jet aircraft. Often, these inspections are incomplete and inconsistent. In this paper, we develop a Modular Robotic Inspection System (MoRIS) for jet aircraft tube networks and a corresponding kinematic model. MoRIS consists of a Base Station for user control and communication, and robotic Vertebrae for accessing and inspecting the network. The presented and tested design of MoRIS can travel up to 9 feet in a tube network. The Vertebrae can navigate in all orientations, including smooth vertical tubes. The design is optimized for nominal 1.5" outside diameter tubes. We …

Anisotropic Plasticity Modeling Of Thin Sheets And Its Application To Micro Channel Forming Of Steel Foils, Jie Sheng

Mechanical Engineering Research Theses and Dissertations

Thin sheet metals and ultrathin metal foils produced by industrial rolling processes are textured polycrystalline materials and their mechanical behaviors may depend strongly on the orientation of applied loading. Consideration of such plastic anisotropy in advanced modeling of these materials is of the paramount importance in designing optimal manufacturing processes for automotive and other applications using finite element methods. This research addresses several critical issues in anisotropic plasticity modeling and its applications in analyzing micro channel forming of ultrathin stainless-steel foils. An experimental study has first been carried out on the accuracy and sensitivity of measuring the plastic strain ratios …

Homogenization Of Composite And Cellular Materials Incorporating Microstructure And Surface Energy Effects, Ahmad Gad

Mechanical Engineering Research Theses and Dissertations

In the last few decades, the popularity of composite and cellular materials has rapidly increased through their widespread applications in multiple engineering fields including aerospace, automotive, civil and biomedical. However, to a large extent, the success of their practical applications depends on our ability to predict their mechanical behavior by using high-fidelity mechanics models.

Micromechanical modeling of composite and cellular materials is a challenging task due to the heterogeneous nature of such materials and the interactions among various constituent phases at the microscopic level, which result in non-homogeneous deformation, strain and stress fields. Therefore, it is necessary to develop simple …

Stability Analysis, Dynamic Modeling, And Kinematic Analysis Of Hydraulically Amplified Dielectric Elastomer Actuators And Robot Manipulators, Amir Hosein Zamanian

Mechanical Engineering Research Theses and Dissertations

In this dissertation, we have proposed a new dielectric elastomer actuator design and model that couples electrostatics, fluid mechanics, linear and nonlinear elastic deformations. The internal hydraulic pressure can amplify the structural deformation generated by induced electrostatic forces (Maxwell pressure), given the name of this class of actuators, hydraulically amplified dielectric elastomer actuators (HADEAs).

First, we developed novel lumped-parameter models (LPMs) using linear and hyper-elastic material models and second compared the LPM results with finite element analysis in quasi-static simulations. We analytically expressed the conditions for the snap-through instability in the HADEA, which appears after exceeding a certain voltage applied …

Failure Of High Strength Concrete Under Dynamic Uniaxial Compression, Colin Loeffler

Mechanical Engineering Research Theses and Dissertations

The failure strength of concrete materials has been widely shown to be dependent on experimental parameters such as specimen geometry and strain-rate. The effects of specimen geometry have been shown both theoretically and experimentally to be a result of the quasi-brittle nature of concrete. While the failure strength of concrete has been widely reported to increase significantly when deformed at high strain-rates, the physical mechanisms driving this phenomenon remain the source of debate amongst researchers. This means that constitutive models designed to predict this rate dependent behavior are not based on the real physical mechanisms that drive this behavior but …

Investigation Of Fundamental Principles Of Rigid Body Impact Mechanics, Khalid Alluhydan

Mechanical Engineering Research Theses and Dissertations

In impact mechanics, the collision between two or more bodies is a common, yet a very challenging problem. Producing analytical solutions that can predict the post-collision motion of the colliding bodies require consistent modeling of the dynamics of the colliding bodies. This dissertation presents a new method for solving the two and multibody impact problems that can be used to predict the post-collision motion of the colliding bodies. Also, we solve the rigid body collision problem of planar kinematic chains with multiple contacts with external surfaces.

In the first part of this dissertation, we study planar collisions of Balls and …

A Novel Splitting Beam Laser Extensometer Technique For Kolsky Tension Bar Systems, Colin Loeffler

Mechanical Engineering Research Theses and Dissertations

The Kolsky (Split Hopkinson) Bar has become a well-known and established experimental technique for characterizing the mechanical behavior of materials subjected to dynamic loading conditions. Kolsky bar based experimental techniques facilitate the application of controlled and repeatable dynamic loading conditions to a specimen as well as the high resolution measurement of the resulting mechanical response. In recent decades the technique has been refined and adapted to provide more complex dynamic stress-states beyond uniaxial compression. However, the increasing complexity of the experimental apparatus introduces uncertainty to the traditional specimen deformation measurement techniques.

In this thesis, a direct non-contact optical measurement technique …

Non-Classical Plate Models Incorporating Microstructure And Surface Energy Effects: Their Variational Formulations And Applications, Gongye Zhang

Mechanical Engineering Research Theses and Dissertations

In this dissertation research, new non-classical models for Kirchhoff and Mindlin plates are developed and applied to study band gaps for flexural wave propagation in composite plate structures.

In Chapter 2, a new non-classical model for a Kirchhoff plate resting on an elastic foundation is developed using a modified couple stress theory, a surface elasticity theory and a two-parameter elastic foundation model. A variational formulation based on Hamilton’s principle is employed, which leads to the simultaneous determination of the equations of motion and the complete boundary conditions and provides a unified treatment of the microstructure, surface energy and foundation effects. …

Soft-Microrobotics: The Manipulation Of Alginate Artificial Cells, Samuel Sheckman

Mechanical Engineering Research Theses and Dissertations

In this work, the approach to the manipulation of alginate artificial cell soft-microrobots, both individually and in swarms is shown. Fabrication of these artificial cells were completed through centrifugation, producing large volumes of artificial cells, encapsulated with superparamagnetic iron oxide nanoparticles; these artificial cells can be then externally stimulated by an applied magnetic field. The construction of a Permeant Magnet Stage (PMS) was produced to manipulate the artificial cells individually and in swarms. The stage functionalizes the permanent magnet in the 2D xy-plane. Once the PMS was completed, Parallel self-assembly (Object Particle Computation) using swarms of artificial cells in complex …

Blunt And Ballistic Impacts On Human Head Models: An Analytical And Numerical Study, Yongqiang Li

Mechanical Engineering Research Theses and Dissertations

Head injuries, as a leading cause of death, have become a major health care issue for civilians and soldiers. There has been an urgent need to understand mechanisms of such injuries. The objective of this dissertation research is to study some head injuries and related mechanisms using analytical and computational models.

In Chapter 2, a new analytical (non-linear) model for the impact of a solid sphere on a fluid-filled spherical shell is developed by including the stress wave propagation effect in addition to the Hertzian contact deformations and the shell membrane and bending actions. A simplified (linearized) model incorporating the …

Micro-Architectured Metamaterials: Design And Analysis, Li Ai

Mechanical Engineering Research Theses and Dissertations

Metamaterials are engineered materials with unusual properties deriving mainly from their micro-architectures rather than composition. They have attracted increasing attention owing to their tailorable multi-functional properties that cannot be exhibited by naturally-occurring or traditionally-manufactured materials. Materials with a negative Poisson’s ratio (PR) and materials with a non-positive coefficient of thermal expansion (CTE) are examples of mechanical metamaterials. In this dissertation, metamaterials with negative Poisson’s ratios and negative coefficients of thermal expansion are designed using both heuristic approaches and topology optimization methods.

Firstly, based on a star-shaped re-entrant structure, three two-dimensional (2-D) periodic cellular materials are developed, which can be tailored …

Multiple Consecutive Recapture Of Rigid Nanoparticles Using A Solid-State Nanopore Sensor, Jungsoo Lee

Mechanical Engineering Research Theses and Dissertations

Solid‐state nanopore sensors have been used to measure the size of a nanoparticle by applying a resistive pulse sensing technique. Previously, the size distribution of the population pool could be investigated utilizing data from a single translocation, however, the accuracy of the distribution is limited due to the lack of repeated data. In this study, we characterized polystyrene nanobeads utilizing single particle recapture techniques, which provide a better statistical estimate of the size distribution than that of single sampling techniques. The pulses and translocation times of two different sized nanobeads (80 nm and 125 nm in diameter) were acquired repeatedly …

Lightweight Uav Launcher, Ben Miller, Christian Valoria, Corinne Warnock, Jake Coutlee

Mechanical Engineering

This report discusses the design, construction, and testing of a lightweight, portable UAV launcher. There is a current need for a small team of soldiers to launch a US Marine Tier II UAV in a remote location without transport. Research was conducted into existing UAV launcher designs and the pros and cons of each were recorded. This research served as a basis for concept generation during the initial design development stage. It was required that the design weigh less than 110 lbs, occupy a smaller volume than 48" x 24" 18" in its collapsed state, be portable by a single …

Computationally Efficient Representation Of Statistically Described Material Microstructure For Tractable Forming Simulations, Nicholas Landry

Honors Theses and Capstones

The purpose of this project is to reduce a large statistical distribution of metal microstructure orientations to a manageable distribution to be used in metal forming simulations. Microstructure sensitive simulations at the macro-scale are impractical, because with so many state variables associated with material microstructure data, these simulations are extremely computationally expensive.

The goal was to develop a framework to accurately model plastic material response while representing the material microstructure in a more compact form, reducing 106 or more microstructure orientations to a significantly smaller statistical distribution of representative orientations. This will significantly increase the computational efficiency and make the …