Mechanical Engineering Commons^™

Experimental And Numerical Investigation Of The Mechanism Of Blast Wave Transmission Through A Surrogate Head, Yi Hua, Praveen Akula, Linxia Gu, Jeff Berg, Carl A. Nelson

Mechanical & Materials Engineering Faculty Publications

This work is to develop an experiment-validated numerical model to elucidate the wave transmission mechanisms through a surrogate head under blast loading. Repeated shock tube tests were conducted on a surrogate head, i.e., water-filled polycarbonate shell. Surface strain on the skull simulant and pressure inside the brain simulant were recorded at multiple locations. A numerical model was developed to capture the shock wave propagation within the shock tube and the fluid-structure interaction between the shock wave and the surrogate head. The obtained numerical results were compared with the experimental measurements. The experiment-validated numerical model was then used to further ...

Six Degree-Of-Freedom, Musculotendon Joint Stiffness: Examples With The Knee, Joshua G. A. Cashaback

Open Access Dissertations and Theses

Increased muscle stiffness helps prevent excessive movement that can lead to ligament and soft-tissue damage. There is empirical evidence suggesting that muscles are important in preventing injuries caused by excessive translational movements. Very little is known, however, on how our muscles provide translational stiffness. This thesis uses complementary theoretical (Chapters 2 and 3) and experimental (Chapter 4) techniques to address how muscles provide translational joint stiffness.

In Chapters 2 and 3, we used an elastic energy approach to successfully derive equations that quantify muscular contributions to joint stiffness. From the equations, we were able to determine how the geometric orientation ...

Synthetic Jet Micropump, Sherif Abdou

Open Access Dissertations and Theses

The production of a novel micropump based on the synthetic jet principle is investigated both numerically and experimentally. The proposed micropump consists of a synthetic jet actuator driven by a vibrating diaphragm issuing into an inverted T- shaped channel structure forming the inlet/outlet channels of the pump.

The software package Ansys is used to perform numerical investigations of the operation of the proposed micropump. Simulations were performed to study the effect of changing the inlet/outlet channel dimensions as well as the operating frequency, amplitude and duty cycle of the excitation signal. Inlet/outlet channel widths ranging from 200 ...

Synthetic Jet Actuator For Active Flow Control, Sherif Abdou

Open Access Dissertations and Theses

This thesis investigates the characteristics of a long aspect ratio synthetic jet actuator and its application for the active control of the vibrations of the downstream cylinder in a tandem cylinder arrangement.

A long aspect ratio synthetic jet is produced through an axial slit along part of the length of a cylinder. The jet is excited acoustically by a pair of loudspeakers mounted at the cylinder terminations. The study compares between the performance of two different slits with aspect ratios of 273 and 773. The comparison is based on the spanwise distribution of the mean jet velocity and phase between ...

Simulating Scwr Thermal-Hydraulics With The Modified Cobra-Tf Subchannel Code, Dinusha Wikumpiya Lokuliyana

Open Access Dissertations and Theses

Among the six GEN-IV reactor concepts recommended by the Gen-IV International Forum, supercritical water-cooled reactors (SCWR) have gained significant interests due to its economic advantage, technology and experience continuity. In the last few years, extensive R&D activities have been launched covering the various aspects of SCWR development, especially in thermal-hydraulic analysis. In Canada, most R&D projects are led by AECL or NRCan.

SCWR design and development require the modification of simulation codes used for design and safety demonstration of subcritical water-cooled reactors. This study modifies the subchannel code COBRA-TF, applicable to only subcritical water-cooled reactors, to a new ...

Flow Accelerated Corrosion In Single And Dual S-Shape Bends Under Single And Two Phase Annular Flow Conditions, Hazem Mohamed Mohamed Ahmed Mazhar

Open Access Dissertations and Theses

Flow Accelerated Corrosion (FAC) is defined as a flow enhanced mass transfer phenomenon that results in pipe wall thinning of the piping system and results in abrupt failure in some cases. FAC is controlled by the transport of corrosion species from the wall to the bulk fluid and is determined by the local distribution of the mass transfer coefficient. The overall objective of this research is to investigate the mass transfer in pipe bends arranged in single and dual S- shape configurations under single and annular two phase flow conditions. A novel wall dissolving mass transfer technique was developed to ...

Nano-Multilayered Self-Adaptive Hard Pvd Coatings For Dry High Performance Machining, Li Ning

Open Access Dissertations and Theses

In this research~ quaternary nitride nano-multilayered coatings of the form TiAICrN/MexN were comprehensively characterized. Based on this research principles which can be applied for guiding coating design were developed using the concept of self-adaptability.

Comprehensive studies were performed on the following aspects: the tlibological properties of the coatings at elevated temperatures, tool life, and cutting forces, tribo-oxide formation, wear mechanisms and wear progression, chip characteristics and the mechanisms of chip formation. The techniques applied for comprehensive characterization of the coatings were mainly Scanning Electron MicroscopelEnergy Dispersive Spectrometer (SEMIEDS) and X-ray Photoelectron Spectroscopy (XPS).

The concept of self-adaptability as applied ...

Characterizing Phantom Arteries With Multi-Channel Laser Ultrasonics And Photo-Acoustics, Jami L. Johnson, Kasper Van Wijk, Michelle Sabick

Mechanical and Biomedical Engineering Faculty Publications and Presentations

Multi-channel photo-acoustic and laser ultrasonic waves are used to sense the characteristics of proxies for healthy and diseased vessels. The acquisition system is non-contacting and non-invasive with a pulsed laser source and a laser vibrometer detector. As the wave signatures of our targets are typically low in amplitude, we exploit multi-channel acquisition and processing techniques. These are commonly used in seismology to improve the signal-to-noise ratio of data. We identify vessel proxies with a diameter on the order of 1 mm, at a depth of 18 mm. Variations in scattered and photo-acoustic signatures are related to differences in vessel wall ...

Monitoring In-Service Performance Of Fibre-Reinforced Foamed Urethane Sleepers/Bearers In Railway Urban Turnout Systems, Sakdirat Kaewunruen

Sakdirat Kaewunruen

Special track systems used to divert a train to other directions or other tracks are generally called \'railway turnout\'. A traditional turnout system consists of steel rails, switches, crossings, steel plates, fasteners, screw spikes, timber bearers, ballast and formation. The wheel rail contact over the crossing transfer zone has a dip-like shape and can often cause detrimental impact loads on the railway track and its components. The large impact also emits disturbing noises (either impact or ground-borne noise) to railway neighbors. In a brown-field railway track where an existing aged infrastructure requires renewal or maintenance, some physical constraints and construction ...

Wooden Bikes Present Capstone Challenge For Engineering Students, Jenni Hodges

News Releases

Four Cedarville seniors are building and testing wooden bicycles for a capstone engineering project. Team leader Jake Miller said the project offers a unique opportunity for students to connect their interests in engineering, woodworking and cycling.

High-Resolution, Real-Time Three-Dimensional Shape Measurement On Graphics Processing Unit, Nikolaus L. Karpinsky, Morgan D. Hoke, Vincent Chen, Song Zhang

Mechanical Engineering Publications and Papers

A three-dimensional (3-D) shape measurement system that can simultaneously achieve 3-D shape acquisition, reconstruction, and display at 30 frames per second (fps) with 480,000 measurement points per frame is presented. The entire processing pipeline was realized on a graphics processing unit (GPU) without the need of substantial central processing unit (CPU) power, making it achievable on a portable device, namely a laptop computer. Furthermore, the system is extremely inexpensive compared with similar state-of-art systems, making it possible to be accessed by the general public. Specifically, advanced GPU techniques such as multipass rendering and offscreen rendering were used in conjunction ...

The Penn Haptic Texture Toolkit For Modeling, Rendering, And Evaluating Haptic Virtual Textures, Heather Culbertson, Juan Jose Lopez Delgado, Katherine J. Kuchenbecker

Departmental Papers (MEAM)

The Penn Haptic Texture Toolkit (HaTT) is a collection of 100 haptic texture and friction models, the recorded data from which the models were made, images of the textures, and the code and methods necessary to render these textures using an impedance-type haptic device such as a SensAble Phantom Omni. This toolkit was developed to provide haptics researchers with a method by which to compare and validate their texture modeling and rendering methods. The included rendering code has the additional benefit of allowing others, both researchers and designers, to incorporate our textures into their virtual environments, which will lead to ...

Hvac Chapter 1, Dr Alireza Zolfaghari

Dr Alireza Zolfaghari

No abstract provided.

Non-Oxidative And Oxidative Torrefaction Characterization And, Wei-Hsin Chen

Wei-Hsin Chen

No abstract provided.

Using “Expert Employees” To Identify Duties And Tasks For Cadd Technicians In North Central Idaho: Lessons Learned From A Modified Dacum Process, Raymond A. Dixon Ph.D., Linda S. Stricklin Ph.D.

Online Journal for Workforce Education and Development

Objective: We conducted a job analysis to identify the competency profile of an entry level CADD technician in North central Idaho. Background: In 2011, the Clearwater Economic Development Association and NIMA collaborated with Lewis-Clark State College and the University of Idaho in a project to strengthen the capacity of Career and Technology Education (CTE) teachers to teach computer aided drafting and designing (CADD). An application to the National Science Foundation, Advanced Technology Education (NSF ATE) program was made and funding began July of 2011. Method: A modified DACUM was used. A total of seven expert workers from six companies ...

Absolute Three-Dimensional Shape Measurement Using Coded Fringe Patterns Without Phase Unwrapping Or Projector Calibration, William F. Lohry, Vincent Chen, Song Zhang

Mechanical Engineering Publications and Papers

This paper presents a novel stereo-phase-based absolute three-dimensional (3D) shape measurement that requires neither phase unwrapping nor projector calibration. This proposed method can be divided into two steps: (1) obtain a coarse disparity map from the quality map; and (2) refine the disparity map using wrapped phase. Fringe patterns are modified to encode the quality map for efficient and accurate stereo matching. Experiments demonstrated that the proposed method could achieve high-quality 3D measurement even with extremely low-quality fringe patterns.

Three-Dimensional Shape Measurement With Dual Reference Phase Maps, Junfei Dai, Chen Gong, Song Zhang

Mechanical Engineering Publications and Papers

Single reference-phase-based methods have been extensively utilized in digital fringe projection systems, yet they might not provide the maximum sensitivity given a hardware system configuration. This paper presents an innovative method to improve the measurement quality by utilizing two orthogonal phase maps. Specifically, two reference phase maps generated from horizontal and vertical (i.e., orthogonal) fringe patterns projected are combined into a vector reference phase map through a linear combination for depth extraction. The experiments have been conducted to verify the superiority of the proposed method over a conventional single reference-phase-based approach.

Citations Of Articles Authored By Wojciech M. Budzianowski, Wojciech M. Budzianowski

Wojciech Budzianowski

No abstract provided.

Experimental Convective Heat Transfer In Entrance Portion Of Rib Roughened Channels, Gidley E. Dorlus

Mechanical Engineering Master's Theses

Leading edge cooling of turbine blades is essential in the advancement of the turbine industry. There are many different methods of blade cooling, from jet impingement to film cooling to convective cooling. The present experimental investigation presented delves into the use of convective cooling along with rib-roughened walls using the steady state liquid crystal technique. There were four test sections used for this investigation, using ribs at a 45° angle on the side wall and a 90° angle on the nose portion of the test section, both relative to the incoming flow. Within each test section, 2 or 3 different ...

Exploration Of Hot Switching Damage And Damage Mechanisms In Mems Switch Contacts, Ryan Patrick Hennessy

Mechanical Engineering Dissertations

Ohmic contact, or contact-­type, Microelectromechanical Systems (MEMS) switches employ two separable metal electrodes as a contact. In the switch environment, the switch contact may experience either of two switching modes. Cold switching refers to the application of an electrical signal across the switch only when the contact is fully closed. On the other hand, hot switching refers to the application of a signal while the switch is being opened and closed. Compared to cold switching, hot switching leads to shorter contact lifetimes.

This work explores the effect of multi-­domain coupling on the behavior of an electrical contact, what ...