Applied Mechanics Commons^™

A Study Of Golf Club Head Kinematics Near Impact, Stephen James Murphy, David Wadsworth Lavelle, Kevin Philip Melancon

Mechanical Engineering

No abstract provided.

Atomic Force Microscopy For Better Probing Surface Properties At Nanoscale: Calibration, Design And Application, Yu Liu

Electronic Thesis and Dissertation Repository

To measure force by AFM with high resolution requires accurate calibration of optic – lever detection sensitivity and spring constant. On biological AFM force mode, the coupling effects of the liquid environment, spot size of laser beam and laser spot location on AFM cantilever backside, must be considered to correlate the static sensitivities from force curves in air and in liquid for calibration. An effective model has been developed first and experimentally elucidated to calibrate the static sensitivity in liquid. The proposed model eliminates inconvenience of static sensitivity calibration in liquid with possible contamination sources.

The static sensitivity based on …

Reliability Estimation Of Complex Numerical Problems Using Modified Conditional Expectation Method, Christopher D. Eamon, Bulakorn Charumas

Civil and Environmental Engineering Faculty Research Publications

A simulation-based structural reliability analysis method is presented. It is intended as an alternate approach to estimate reliability for problems for which most-probable point of failure methods fail and when computational resources are limited. The proposed method combines conditional expectation and estimating the PDF or CDF of a selected portion of the limit state. In the proposed approach, complex limit state functions are simplified to two random variable problems. The success of the simplification depends on the quality of the CDF estimate. Results indicate that the method may provide accurate and efficient solutions for some difficult reliability problems.

Reducing Whole Body Vibration Levels In Off-Road, Heavy-Duty Vehicles: A Case Study With Computer Modelling, Shaun Mcfadden, Matthieu Morhan, Brian Hurley

Conference Papers

This paper describes a case study involving the dynamic ride performance of a 30-ton, articulated dumper vehicle. The vehicle in question was originally fitted with a front-end, solid axle with leading arm mechanism. After an engineering design program, the vehicle was custom-fitted with a Timoney Independent suspension system. Extensive testing and modelling activities using LMS Virtual.lab Motion® were undertaken to determine the productivity levels of each vehicle. It was demonstrated that the vehicle fitted with a Timoney suspension could achieve a productivity increase of up to 50%. A health analysis is also presented which shows the Timoney Independent suspension system …

Stochastic Optimal Control In Nonlinear Systems, Celestin Nkundineza

Mechanical (and Materials) Engineering -- Dissertations, Theses, and Student Research

Stochastic control is an important area of research in engineering systems that undergo disturbances. Controlling individual states in such systems is critical. The present investigation is concerned with the application of the stochastic optimal control strategy developed by To (2010) and its implementation as well as providing computed results of linear and nonlinear systems under stationary and nonstationary random excitations. In the strategy the feedback matrix is designed based on the achievement of the objectives for individual states in the system through the application of the Lyapunov equation for the system. Each diagonal element in the gain or associated gain …

Sae Baja: Final Drive Gearbox, Michael Mccausland, Michael Watkins, Ian Masterson, Andrew Sommer

Mechanical Engineering

This paper presents the results of a manual transmission project for SAE Baja. A full engineering process is documented, including problem definition, scheduling, conceptualization, decision theory, synthesis, analysis, manufacturing, and testing. A comparison is made between existing and potential mechanical power train solutions. The final design is analyzed in dynamic simulations, AGMA stress, predicted FFT spectrums, and shifting rod buckling. A number of complicated parts are manufactured through investment casting and direct CNC machining. Issues in the final assembly have prevented the project from being fully realized, recommendations are made for future SAE Baja teams.

Pole Arrangements That Introduce Prismatic Joints Into The Design Space Of Four- And Five-Position Rigid-Body Synthesis, David H. Myszka, Andrew P. Murray

Mechanical and Aerospace Engineering Faculty Publications

Although a general five-position, rigid-body guidance problem admits a discrete number of revolute–revolute (RR) dyads, this paper identifies arrangements of five task positions that result in a center-point curve. For these special arrangements, a one-dimensional set of revolute-prismatic (RP) dyads exist to achieve the task positions. Other five-position arrangements are identified where a one-dimensional set of prismatic-revolute (PR) dyads exist to achieve the task positions. For a general case of five task positions, neither PR nor RP dyads are possible. In a general case of four-position rigid-body guidance problems, a unique PR dyad and RP dyad exist. Four-position arrangements are …

On Macroscopic Constitutive Relations And Microstructure Evolution In Multi-Scale Viscoplastic Composites, Michalis Agoras

Publicly Accessible Penn Dissertations

The determination of the effective or macroscopic properties of composite materials from the corresponding local properties of the constituent phases and the underlying sub-structure constitutes the fundamental problem in Mechanics of Composites. This problem is motivated from the remarkable physical observation that the constitutive properties of these materials appear to be homogeneous or uniform at the length scale of practical applications, despite the sharp variation of their local properties at the length scale of the heterogeneity and the fairly complex spatial distribution of their phases. This dissertation is concerned with the macroscopic mechanical properties of “multi-scale” viscoplastic composites, i.e., composite …

A Generalized Finite Element Formulation For Arbitrary Basis Functions: From Isogeometric Analysis To Xfem, D. J. Benson, Y. Bazilevs, E. Deluycker, Ming-Chen Hsu, M. Scott, T. J. R. Hughes, T. Belytschko

Ming-Chen Hsu

Many of the formulations of current research interest, including iosogeometric methods and the extended finite element method, use nontraditional basis functions. Some, such as subdivision surfaces, may not have convenient analytical representations. The concept of an element, if appropriate at all, no longer coincides with the traditional definition. Developing a new software for each new class of basis functions is a large research burden, especially, if the problems involve large deformations, non-linear materials, and contact. The objective of this paper is to present a method that separates as much as possible the generation and evaluation of the basis functions from …

Newsletter 42 Issue 2 - Summer 2010 - Nuts And Bolts, Tractor Museum

Friends of the Larsen Tractor Museum

No abstract provided.

The Bending Strip Method For Isogeometric Analysis Of Kirchhoff–Love Shell Structures Comprised Of Multiple Patches, J. Kiendel, Y. Bazilevs, Ming-Chen Hsu, R. Wuchner, K. U. Bletzigner

Ming-Chen Hsu

In this paper we present an isogeometric formulation for rotation-free thin shell analysis of structures comprised of multiple patches. The structural patches are C1- or higher-order continuous in the interior, and are joined with C0-continuity. The Kirchhoff–Love shell theory that relies on higher-order continuity of the basis functions is employed in the patch interior as presented in Kiendl et al. [36]. For the treatment of patch boundaries, a method is developed in which strips of fictitious material with unidirectional bending stiffness and zero membrane stiffness are added at patch interfaces. The direction of bending stiffness is chosen to be transverse …

Optimal Design Of Vehicle With Internal Space Frame Structure Subjected To High Impact Load, Jagadeep Thota

UNLV Theses, Dissertations, Professional Papers, and Capstones

Armored military vehicles are heavily used in modern warfare. These vehicles are subjected to lethal attacks from projectiles and land mines. The shocks from these attacks may risk the safety of the occupants and damage the electronic instruments within the vehicle. Extensive research on the analysis and reduction of shocks on civilian vehicles has been performed. Fewer researchers addressed these problems in the case of military vehicles. Space frames are usually used to enhance structural strength of the vehicle while reducing its overall weight. These frames comprise of beams connected together at joints. Recently, space frames were incorporated in military …

Thermal, Magnetic, And Mechanical Stresses And Strains In Copper/Cyanate Ester Cylindrical Coils – Effects Of Variations In Fiber Volume Fraction, Chance Thomas Donahue

Masters Theses

Several problems must be solved in the construction, design, and operation of a nuclear fusion reactor. One of the chief problems in the manufacture of high-powered copper/polymer composite magnets is the difficulty to precisely control the fiber volume fraction. In this thesis, the effect of variations in fiber volume fraction on thermal stresses in copper/cyanate ester composite cylinders is investigated. The cylinder is a composite that uses copper wires that run longitudinally in a cyanate ester resin specifically developed by Composite Technology Development, Inc. This composite cylinder design is commonly used in magnets for nuclear fusion reactors. The application of …

Tk Ripper, Charles Volk, Vincent Priolo, Zachary Mckibbin

Mechanical Engineering

The TK Ripper was designed to pull a rider on a wakeboard up from a deep water start. We believe the force and power required to pull a rider on a wakeboard out of the water provides enough force and power for many other extreme sports.

Edwards Automation Final Project Report, Benjamin (Ben) Johnson, Joel Masters, Matthew (Matt) Stewart

Mechanical Engineering

The body of this work has been created for Edwards Lifesciences in conjunction with senior project requirements. As such, the information produced and contained within is under a non‐disclosure agreement. As per request by sponsor, the body of the work will not be submitted to any outside parties, and the title page will serve as proof of completion.

Strider, Eric Johnson, Alex Trask, Ricardo Garcia

Mechanical Engineering

No abstract provided.

Solar Array Suspension Mechanism Final Design Report For Atk Space, Alex Gould, Randon Kruse, Jeremy Graul, Patrick Barney

Mechanical Engineering

The purpose of this project is to improve the existing Solar Array Suspension Mechanism used by ATK Space for the manufacturing and testing of deployable solar arrays. The current system requires too much time to operate and has too many removable parts that may fall and damage the solar arrays. Through the design and verification process the team successfully constructed a quick connecting suspension mechanism that requires no tools to use and has no removable parts. The final design includes the existing force gauge and large adjustment bars used by ATK Space with the addition of a compression spring adjustment …

Newsletter 41 Issue 1 - Spring 2010 - Nuts And Bolts, Larsen Tractor Museum

Friends of the Larsen Tractor Museum

No abstract provided.

Morphological Evolution Of Single-Crystal Ultrathin Solid Films, Mikhail Khenner

Mikhail Khenner

An introduction to mathematical modeling of ultrathin solid films and the role of such modeling in nanotechnologies: Educational/Research presentation for senior physics majors

Morphological Evolution Of Single-Crystal Ultrathin Solid Films, Mikhail Khenner

Mathematics Faculty Publications

An introduction to mathematical modeling of ultrathin solid films and the role of such modeling in nanotechnologies: Educational/Research presentation for senior physics majors