Applied Mechanics Commons^™

Stochastic Optimal Control In Nonlinear Systems, Celestin Nkundineza

Celestin Nkundineza

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 …

Crack Identification By Multifractal Analysis Of A Dynamic Rotor Response, Grzegorz Litak, Jerzy Sawicki

Jerzy T. Sawicki

Multifractal analysis has been used to diagnose cracked and healthy rotors. Is has been shown that the complexity and regularity criteria of the dynamical systems defined by the multiple scaling of the time series can indicate the damages of the rotating shaft. Relation to the standard power spectrum technique has been also discussed.

Characterization Of Solar Roadways Via Computational And Experimental Investigations, Rajesh Kanna Selvaraju

Electronic Thesis and Dissertation Repository

Efficiency of traditional solar panels is known to be very low and hence necessitates the use of extensive open spaces for producing solar-based electric power. In solar roadways concept, open spaces such as roads, parking lots, bicycle lanes, footpaths are proposed to be utilized. An in-depth quantitative feasibility study for implementing solar roadways in Canada is carried out considering the total available surfaces, solar panel efficiency and effects of fast moving shades. The load carrying capability of commercially available materials for the solar panel top cover is studied in an effort to examine the current as well as near-future implementation …

Wind Turbine Aerodynamics Using Ale–Vms: Validation And The Role Of Weakly Enforced Boundary Conditions, Ming-Chen Hsu, Ido Akkerman, Yuri Bazilevs

Ming-Chen Hsu

In this article we present a validation study involving the full-scale NREL Phase VI two-bladed wind turbine rotor. The ALE–VMS formulation of aerodynamics, based on the Navier–Stokes equations of incompressible flows, is employed in conjunction with weakly enforced essential boundary conditions. We find that the ALE–VMS formulation using linear tetrahedral finite elements is able to reproduce experimental data for the aerodynamic (low-speed shaft) torque and cross-section pressure distribution of the NREL Phase VI rotor. We also find that weak enforcement of essential boundary conditions is critical for obtaining accurate aerodynamics results on relatively coarse boundary layer meshes. The proposed numerical …

Atomistic Investigation Of Scratching-Induced Deformation Twinning In Nanocrystalline Cu, Junjie Zhang, Tao Sun, Yoganda Yan, Dong Shen, Xiaodong Li

Faculty Publications

Deformation twinning is an important deformation mode of nanocrystalline metals. In current study, we investigate the scratching-induced deformation twinning in nanocrystallineCu by means of molecular dynamics simulations. The tribological behavior, the deformation mechanisms, the formation mechanism of deformation twins, and the grain size dependence of the propensity of deformation twinning are elucidated. Simulation results demonstrate that deformation twinning plays an important role in the plastic deformation of nanocrystallineCu under nanoscratching, in addition to dislocation activity and grain boundary-associated mechanism. The nucleation of initial twinning partial dislocations originates from the dissociation of lattice partial dislocations that emit from grain boundary triple …

Static Balancing Of The Cal Poly Wind Turbine Rotor, Derek Simon

Master's Theses

The balancing of a wind turbine rotor is a crucial step affecting the machine’s performance, reliability, and safety, as it directly impacts the dynamic loads on the entire structure.

A rotor can be balanced either statically or dynamically. A method of rotor balancing was developed that achieves both the simplicity of static balancing and the accuracy of dynamic balancing. This method is best suited, but not limited, to hollow composite blades of any size. The method starts by quantifying the mass and center of gravity of each blade. A dynamic calculation is performed to determine the theoretical shaking force on …

Investigation Of Thermomechanical Effects Of Lighting Conditions On Canvas Paintings By Laser Shearography, Morteza Khaleghi, Ivo Dobrev, Philip Klausmeyer, Ellery Harrington, Cosme Furlong

Morteza Khaleghi

Quantitative techniques to characterize thermomechanical effects of light on canvas paintings are necessary in order to better understand the deleterious effects that light has on precious art collections in museum exhibitions. In this paper, we present advances in the development of a customized laser shearography system for temporal characterization of in-plane displacements of canvas paintings when subjected to specific lighting conditions. The shearography system is synchronized with a thermal IR camera and concomitant measurements of derivatives of displacements along two orthogonal shearing directions as well as thermal fields are performed. Due to the nature of the measurements, we have developed …

Ale-Vms And St-Vms Methods For Computer Modeling Of Wind-Turbine Rotor Aerodynamics And Fluid–Structure Interaction, Yuri Bazilevs, Ming-Chen Hsu, Kenji Takizawa, Tayfun E. Tezduyar

Ming-Chen Hsu

We provide an overview of the Arbitrary Lagrangian–Eulerian Variational Multiscale (ALE-VMS) and Space–Time Variational Multiscale (ST-VMS) methods we have developed for computer modeling of wind-turbine rotor aerodynamics and fluid–structure interaction (FSI). The related techniques described include weak enforcement of the essential boundary conditions, Kirchhoff–Love shell modeling of the rotor-blade structure, NURBS-based isogeometric analysis, and full FSI coupling. We present results from application of these methods to computer modeling of NREL 5MW and NREL Phase VI wind-turbine rotors at full scale, including comparison with experimental data.

Numerical Modelling Of Transport In Complex Porous Media: Metal Foams To The Human Lung, Christopher T. Degroot

Electronic Thesis and Dissertation Repository

Transport in porous media has many practical applications in science and engineering. This work focuses on the development of numerical methods for analyzing porous media flows and uses two major applications, metal foams and the human lung, to demonstrate the capabilities of the methods. Both of these systems involve complex pore geometries and typically involve porous domains of complex shape. Such geometric complexities make the characterization of the relevant effective properties of the porous medium as well as the solution of the governing equations in conjugate fluid-porous domains challenging. In porous domains, there are typically too many individual pores to …

Design, Construction, And Evaluation Of An Automated Chicken Coop Door, Kyle Inks

BioResource and Agricultural Engineering

This senior project takes a look into the design, construction, and evaluation of an automated chicken coop door. The idea and need for such a door came from my mother Jan Inks. The parameters for the project include, low production cost, easy installation on existing coops, sleek design, automatically open at a set time in the morning, and automatically close at a set time in the evening.

Biaxial & Twist Testing Of Composite Carbon-Fiber Sandwich Panels For Automotive Racing Vehicles, Erik Eckberg

Materials Engineering

Composite sandwich panels were constructed with 4-ply plain weave carbon-fiber/epoxy face sheets in the 0^o/45^o/0^o/45^o orientation and 1/8^th inch Nomex honeycomb core. The panels were cut into 5-inch square test plates for mechanical testing. All testing was done on a fixture designed and fabricated by Pratt & Miller Engineering and installed on an Instron testing system at Cal Poly. The twist test was performed by supporting diagonal corners of the plate while simultaneously loading the opposite two corners at a crosshead rate of .06 in/min (ASTM 3044-94R11). Out of 10 panels tested, …

Recreational Nordic Sit Ski, Mathew Bissonnette, Johnathon Gorski, Kevin Izumiya

Mechanical Engineering

The purpose of this project was to design, build, and test a recreational Nordic sit ski for use by Disabled Sports Eastern Sierra. The goal was to improve adjustability and reduce weight compared to previous sit ski designs. The project was completed by Cal Poly Mechanical Engineering seniors Mathew Bissonnette, Johnathon Gorski, and Kevin Izumiya. Kinesiology seniors Harpreet Saini and Carl Anderson provided discipline support and disability etiquette training.

The project was sponsored by the National Science Foundation Research to Aid Persons with Disabilities (RAPD) grant. The grant was proposed by and awarded to Dr. Brian Self and Dr. James …

The Hovering Ball Exhibit, Matthew Bauzon, Will Lennox, Michelle Swan

Mechanical Engineering

No abstract provided.

Design Of A Human Powered Helicopter Airframe, Sheen Kao, Daniel Layton, Philip Sobol

Mechanical Engineering

In 1989 Cal Poly’s Da Vinci III was the first human powered helicopter (HPH) to achieve flight; our goal is to research and develop a new airframe for the next generation Da Vinci. This report outlines a brief history of human powered flight and details a method of constructing for the airframe. An optimized airframe geometry was also researched and is explained in detail.

Human Powered Helicopter: Rotor Structure, Joseph Ram, Juan Carlos Olvera

Mechanical Engineering

The following report encompasses the Human Powered Helicopter Rotor Team’s conceptual models and ideas based on research and modeling analysis. The following gives an overview of material researched, concept generation, analyzation, manufacturing, and testing for a rotor structure to be installed in a Human Powered Helicopter.

Aerodynamic Test Platform For Human Powered Vehicle (Hpv), Spencer Wangerin, Spencer Lillywhite, Colburn Davis

Mechanical Engineering

The Aerodynamic Test Platform (ATP) for the Cal Poly HPV Club is a system that was designed by Cal Poly mechanical engineering students to measure aerodynamic characteristics of a human-powered vehicle (HPV). The HPV team desired a system that could quantify the lift, drag, and other aerodynamic qualities of a full scale HPV at various orientations in oncoming airflow. Established methods for determining aerodynamic characteristics include computational fluid dynamics (CFD) and wind tunnel testing of scaled models. The ATP was devised to simulate the test results given by a full-scale wind tunnel without requiring a wind tunnel large enough to …

Supermileage Chassis Dynamometer, Jose Garcia, Steve Janning, Timothy Lui, Kyla Purvis

Mechanical Engineering

This report describes the final design and analysis of a hydraulic chassis dynamometer as a testing tool for California Polytechnic State University, San Luis Obispo Supermileage Vehicle Team (CPSMV). Literature review was conducted to understand the various types of chassis dynamometers on the market as of the year 2011. After rigorous research, it was determined that a hydraulic system was the best system for a chassis dynamometer in terms of functionality, performance, and cost. Critical study of hydraulics, dynamometers, and data acquisition systems (DAQ) was followed by a complete design of a hydraulic system. The chassis dynamometer proposed in this …

California Olive Ranch Hedger, Tyler Enos, Seth Abbott, David Gamba

Mechanical Engineering

The purpose of this project is to evaluate the problems of the current KCI (Kingsburg Cultivator Incorporated) olive tree hedger in use at California Olive Ranch (COR) in Artois, CA, and then correct these problems which should yield a better performing, more efficient, and reliable machine. These problems include: the hydraulic oil temperature getting too high, the saw blades not having enough horsepower, and poor cutting performance due to operator error as well as terrain variations.

Throwing Frame For Athletes With Dissabilities, Andrew Higgins, Stefan Owechko, Gabriel (Gabe) Terrasas, Kevin Crisfield

Mechanical Engineering

Team Zeus’ senior project was to design, build and test a working throwing frame system for Bridge II Sports, a nonprofit organization in North Carolina. The throwing frame is used to allow athletes and individuals with disabilities to throw shot-put, discus, and javelin using a frame to sit against. Team Zeus was specifically tasked to build a frame that is lighter weight and more transportable than products that are currently on the market. This frame also is adjustable to accommodate a wide range of athlete weights, sizes, and abilities. The final result is a 35lb aluminum frame with two different …

Benchmarking Of A Single-Cylinder Engine Toward The Development Of A Direct Fuel-Injection System, Michael J. Nienhuis

Masters Theses

In this study, the performance and efficiency of a single-cylinder gasoline, fourstroke cycle engine was benchmarked in support of the Formula SAE student project. The development of an engine test stand, instrumentation, data acquisition, and test plan is described in detail. Experimental results in the areas of engine performance and efficiency are discussed. Physical test data were used to refine a previous model of a single-cylinder, gasoline, direct-injection engine. Results from this effort are discussed and compared to those obtained in a preliminary study. The current work advances the development of more efficient power-train technologies for application in small displacement …