Other Mechanical Engineering Commons^™

Predicting Vehicle Dynamics For Roadside Safety Using Multibody Systems Simulations, Brett D. Schlueter

Department of Mechanical and Materials Engineering: Dissertations, Theses, and Student Research

Accurate means for predicting vehicle dynamics is required in the design and testing of roadside safety hardware. Past research has used finite element (FE) modeling to this end, but multibody systems (MBS) modeling may provide a more efficient way to solve these problems. MBS modeling using Adams/Car was investigated by first compiling an introduction to the program, then performing basic vehicle dynamics simulations using a supplied model. Next, a model of a 2270 kg pickup was created and validated against physical test data involving impact with a speed bump. Finally, pickup trajectories in 4H:1V and 6H:1V V-ditches were predicted for …

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 …

Maximal Force Characteristics Of The Ca2+-Powered Actuator Of Vorticella Convallaria, Sangjin Ryu, Matthew J. Lang, Paul Matsudaira

Department of Mechanical and Materials Engineering: Faculty Publications

The millisecond stalk contraction of the sessile ciliate Vorticella convallaria is powered by energy from Ca²⁺ binding to generate contractile forces of ~10 nN. Its contractile organelle, the spasmoneme, generates higher contractile force under increased stall resistances. By applying viscous drag force to contracting V. convallaria in a microfluidic channel, we observed that the mechanical force and work of the spasmoneme depended on the stalk length, i.e., the maximum tension (150–350 nN) and work linearly depended on the stalk length (~2.5 nN and ~30 fJ per 1 mm of the stalk). This stalk-length dependency suggests that motor units of …

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 …

Shear-Horizontal Vibration Modes Of An Oblate Elliptical Cylinder And Energy Trapping In Contoured Acoustic Wave Resonators, Huijing He, Jiashi Yang, John A. Kosinski

Department of Mechanical and Materials Engineering: Faculty Publications

We study shear-horizontal free vibrations of an elastic cylinder with an oblate elliptical cross section and a traction-free surface. Exact vibration modes and frequencies are obtained. The results show the existence of thickness-shear and thickness-twist modes. The energy-trapping behavior of these modes is examined. Trapped modes are found wherein the vibration energy is largely confined to the central portion of the cross section and little vibration energy is found at the edges. It is also shown that face-shear modes are not allowed in such a cylinder. The results are useful for the understanding of the energy trapping phenomenon in contoured …

Order-Disorder Transition Of Aragonite Nanoparticles In Nacre, Zaiwang Huang, Xiaodong Li

Faculty Publications

Understanding nacre’s bottom-up biomineralization mechanism, particularly, how individual aragonite platelets are formed, has long remained elusive due to its crystallographic peculiarity and structural complexity. Here we report that crystallographic order-disorder transition can be triggered within individual aragonite platelets in pristine nacre by means of heat treatment and/or inelastic deformation, offering a unique opportunity to discriminate mysterious aragonite nanoparticles in transmission electron microscopy. Our findings unambiguously uncover why aragonite nanoparticles in pristine nacre have long been inaccessible under TEM observation, which is attributed to the monocrystal-polycrystal duality of the aragonite platelet. The underlying physical mechanism for why an individual aragonite platelet …

Nonlinear Mechanical Behavior Of The Human Common, External And Internal Carotid Arteries In Vivo, Alexey Kamenskiy, Yuris A. Dzenis, Jason N. Mactaggart, Thomas G. Lynch, Syed A. Jaffar Kazmi, Iraklis I. Pipinos

Department of Mechanical and Materials Engineering: Faculty Publications

Introduction—The mechanical environment and properties of the carotid artery play an important role in the formation and progression of atherosclerosis in the carotid bifurcation. The purpose of this work was to measure and compare the range and variation of circumferential stress and tangent elastic moduli in the human common (CCA), external (ECA) and internal (ICA) carotid arteries over the cardiac cycle in vivo.

Methods—Measurements were performed in the surgically exposed proximal cervical CCA, distal ECA and distal ICA of normotensive patients (n = 16) undergoing carotid endarterectomy. All measurements were completed in vivo over the cardiac cycle …

Design And Implementation Of The Kinect Controlled Electro-Mechanical Skeleton (K.C.E.M.S), Jason Richard Ekelmann

Doctoral Dissertations and Master's Theses

Mimicking real-time human motion with a low cost solution has been an extremely difficult task in the past but with the release of the Microsoft Kinect motion capture system, this problem has been simplified. This thesis discusses the feasibility and design behind a simple robotic skeleton that utilizes the Kinect to mimic human movements in near real-time. The goal of this project is to construct a 1/3-scale model of a robotically enhanced skeleton and demonstrate the abilities of the Kinect as a tool for human movement mimicry. The resulting robot was able to mimic many human movements but was mechanically …

Scalability Study Of Explicit Finite Element Method On Shared And Distributed Memory Architectures, Leonardo Orea-Amador, Jack F. Chessa Ph.D.

COURI Symposium Abstracts, Summer 2012

Parallel architectures in computer systems are powerful tools for processing enormous amounts of information. The results of this research will illustrate their optimal usage by evaluating the scalability of the code Abaqus in the cases of domain decomposition and loop parallelization architectures. The scalability was analyzed using concomitant variation having the DoF (Degrees of Freedom) and CPU (Central Processing Unit) numbers as the variables. Abaqus jobs with less than 100,000 DoF showed similar scalability than that of jobs with more than 500,000. These results contradict the original hypothesis which proposed that small jobs would show poor scalability and vice versa. …

Development Of A Pyrotechnic Shock Simulation Apparatus For Spacecraft Applications, Joseph Binder, Matthew Mccarty, Chris Rasmussen

Aerospace Engineering

This report details the research, design, construction, and testing of a pyrotechnic shock simulation apparatus for spacecraft applications. The apparatus was developed to be used in the Space Environments Lab at California Polytechnic State University. It will be used for testing spacecraft components with dimensions up to 24”x12”x12” as well as CubeSats. Additionally, it may be used as an instructional or demonstrational tool in the Aerospace Department’s space environments course. The apparatus functions by way of mechanical impact of an approximately 20 lb stainless steel swinging hammer. Tests were performed to verify the simulator’s functionality. Suggestions for improvement and further …

Pier Portal, Andrew Belis, Andrew (Andy) Crafts, Jeremy Depangher, Aaron Hein, Michael Machado, Aaron Poulos

Computer Engineering

This project constitutes the design, build, and test of a camera system that runs on a track along the length of a pier piling at the Cal Poly pier in Avila Beach. The goal of the camera system is to observe the abundant sea life active on the surface of the piling underwater and in the tidal zone. The camera system will stream live video to the internet, record HD video, and be controllable remotely. The track is mounted to the piling with brackets and extends from the sea floor to a few feet above the pier deck. The camera, …

Robotic Fingerspelling Hand For Deaf-Blind Communication, Brian Fang, Colby Dixon, Trevor Wong

Mechanical Engineering

Robotic fingerspelling hand for the deaf-blind. The hand forms the shapes of the American Manual Alphabet with 11 servos. The project was sponsored by The Smith-Kettlewell Eye Reaserch Institute.

Mini Pump, Stephen Scruggs, Britta Berg-Johansen, Kyle Kriete

Mechanical Engineering

No abstract provided.

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 …

Main Reduction Gear Debris Identification And Removal Device, Gordon Cline, Alex Tittiger, Michael O'Brien

Mechanical Engineering

This report details the development of a tool to remove objects and debris from a large gearbox found on ships of the United States Navy, specifically to be used by NAVSEA. The tool is to be used in situations where an object or contaminant cannot easily be removed or found without completely disassembling the gearbox. This will be done using a boom arm, a cable, a gripper and a borescope. This combination will allow for a large amount of mobility and versatility when searching for the object or contaminant, which is necessary for use in different gearboxes. The process we …

Design Of A Releasable Snowboard Binding, Rex Crossen, Brian Kruse, Timothy Scott

Mechanical Engineering

A releasable snowboard binding will be proposed to our sponsor. This binding will allow the user to release and engage on demand for aerial tricks, comfort, and increased safety. The releasable snowboard binding we will come up with will be revolutionary within the snowboard industry and make current bindings old and inferior.

Human Powered Generation - Seesaw: A Dc House Project, William Varsh, Jeffrey Healy

Electrical Engineering

This project is a proof of concept work, where playground equipment is implemented for power generation. In using a seesaw design, this project was able to show how a simple mechanical motion could be transformed in electrical power. A seesaw power generator was designed and constructed to demonstrate its feasibility. Results show that with some modification and improvement to the current design, the seesaw me indeed provide a viable method to produce electricity.

Three-Dimensional Geometry Of The Human Carotid Artery, Alexey Kamenskiy, Jason N. Mactaggart, Iraklis I. Pipinos, Jai Bikhchandani, Yuris A. Dzenis

Department of Mechanical and Materials Engineering: Faculty Publications

Accurate characterization of carotid artery geometry is vital to our understanding of the pathogenesis of atherosclerosis. Three-dimensional computer reconstructions based on medical imaging are now ubiquitous; however, mean carotid artery geometry has not yet been comprehensively characterized. The goal of this work was to build and study such geometry based on data from 16 male patients with severe carotid artery disease. Results of computerized tomography angiography were used to analyze the cross-sectional images implementing a semiautomated segmentation algorithm. Extracted data were used to reconstruct the mean three-dimensional geometry and to determine average values and variability of bifurcation and planarity angles, …

Innovative Cargo Rack Solutions, Travis Mccart, Brian Blummer, Whit Ratcliff

Mechanical Engineering

This report describes the process of designing, building, and testing a lowering mechanism for a roof-mounted SUV cargo box. It provides a detailed problem description and a specific list of requirements that our design must comply with. Existing products and concepts are presented which meet one or more of our design requirements. Six design concepts are discussed and down-selected to three for further development. A final design has been chosen and described in detail. A team management plan is included to specify member responsibilities and a schedule details major deadlines and goals. Manufacturing processes and testing procedures are described in …