Engineering Commons^™

Anisotropic Thermal Property Measurement Of Carbon-Fiber/Epoxy Composite Materials, Tian Tian

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

This work originated from a need for understanding heat transfer in carbon-fiber/epoxy natural-gas tanks undergoing rapid heating during refilling. The dissertation is focused on the determination of the anisotropic thermal properties of carbon-fiber/epoxy composite materials for in-plane and through-thickness directions. An effective anisotropic parameter estimation system consisting of the 3ω experimental technique and an anisotropic two-dimensional heat transfer model is developed.

In the present work, the 3ω method, an experimental technique that has been well established to evaluate the thermal properties of isotropic materials, especially thin film materials, is extended to treat the thermal properties of bulk anisotropic …

Design, Analysis, And Testing Of In Vivo Surgical Robots, Tyler David Wortman

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

Advances in technology have shaped the history of surgical procedures. Recent developments have allowed surgical procedures to become less invasive than traditional open procedures. The transition to Minimally Invasive Surgery (MIS) has resulted in decreased recovery times, improved cosmetic results, and reduced costs. For these reasons, there is interest in further reducing the invasiveness of surgical procedures by accessing the abdominal cavity through a single incision, such as with Laparoendoscopic Single-Site (LESS) surgery. Added complexities, such as unintuitive controls and limited dexterity, prevent the widespread adoption of LESS for complex surgical procedures. Multi-functional in vivo surgical robots have been designed …

Feasibility Analysis And Concept Development Of A Crash Cushion Diaphragm Structure For High-Speed Race Tracks, Curt Lee Meyer

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

A new diaphragm and dual guide rail system was designed for use in a crash cushion for high-speed race tracks. These structural components were designed to provide sufficient lateral support to redirect impacting vehicles and compress the energy-absorbing elements of the crash cushion. The primary design criteria stated that the diaphragm/guide rail system should be capable of withstanding a 100-kip lateral impact load. The guide rail was to be configured in order to not require replacement after a design impact event. Initial design and modeling resulted in two candidates for guide rail sections which were evaluated during physical testing. The …

Articulated Mechanism Design And Kinematics For Natural Orifice Translumenal Endoscopic Surgery Robot, Wei Jian Chin

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

Natural Orifice Translumenal Endoscopic Surgery (NOTES) is a fairly recent surgical approach that eliminates the need for external incisions on the patient. NOTES takes the minimally invasive surgery paradigm a step further by using a natural orifice as the pathway to transport surgical tools to the surgical site and completely eliminating the need for even the smallest incision on the skin. Although the concept of NOTES has been in existence for the past decade, technological deficiencies prevent it from being widely accepted in human surgeries. A novel multifunctional robot for NOTES has been developed to overcome these limitations and make …

Six Degree Of Freedom Miniature In Vivo Robot For Laparoendoscopic Single-Site Surgery, Ryan L. Mccormick

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

The shift in surgery from open procedures to minimally invasive surgery (MIS) techniques have provided benefits of decreased recovery time, improved cosmetic results, and reduced costs. As advances in MIS move to minimize the number of external incisions, such as with Laparoendoscopic Single-Site (LESS) surgery, additional complexities are introduced. These complexities, including unintuitive controls, reduced dexterity, and limited workspace, hinder these methods from more widespread implementation in more complicated surgical procedures.

Through the use of a miniature in vivo robotic surgical platform designed for LESS surgery, these complexities can be mitigated, allowing for wider adoption of MIS by placing the …

Robotic Manipulator With Multiple Instruments For Natural Orifice Translumenal Endoscopic Surgery, Chi Min Seow

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

This thesis presents a novel robotic manipulator with multiple instruments for use in Natural Orifice Translumenal Endoscopic Surgery (NOTES). NOTES is a newly emerging surgical technique that eliminates external incisions on patients’ skin. As a result, better cosmetics, shorter recovery time, and reduced risk of external infection can be achieved.

Research has been ongoing in academia and industry to make this surgical procedure more feasible in human surgeries. Although several robotic platforms have been developed, none of them has the required capability to provide surgeons with the most appropriate tool in a safe and timely matter during surgery. This robotic …

Simulation And Control System Of A Railroad Track Power Harvesting Device, Kyle J. Phillips

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

With the vastness of existing railroad infrastructure, there exist numerous road crossings which are lacking warning light systems and/or crossing gates due to their remoteness from existing electrical infrastructure. Along with lacking warning light systems, these areas also tend to lack distributed sensor networks used for railroad track health monitoring applications. With the power consumption required by these systems being minimal, extending electrical infrastructure into these areas would not be an economical use of resources. This motivated the development of an energy harvesting solution for remote railroad deployment.

This thesis describes a computer simulation created to validate experimental on-track results …

Energy Harvesting Systems Design For Railroad Safety, Abolfazl Pourghodrat

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

Railroad grade crossings are locations of significant interest for prevention of collisions, injuries and fatalities. Another area of concern is derailments resulting from mechanically deficient track structures. Many of these incidents occur in remote areas due to the lack of electrical infrastructure to power automated warning systems and/or track health monitoring sensor networks.

Providing electrical infrastructure to railroad crossings in remote areas is often not economical, and other alternative sources of electricity such as solar and wind energy are not reliable or robust. This motivated development of devices for in situ energy harvesting.

Initially, an improved mechanical energy harvesting device …

Fracture Analyses Of Aging Aircraft Structures And Human Aorta, Ananth Ram Mahanth Kasavajhala

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

Understanding the behavior of fracture due to preliminary flaws in materials is essential to escalate the life and reliability of a structure. The present work is focused on investigating the influence of various structural parameters on the pre-crack growth stress state, initiation and propagation of flaws in two distinct fields of engineering that is, aging aircraft structural repair (aerospace) and the human aortic dissection (life sciences). Three dimensional finite element methodologies, coupled with linear elastic fracture mechanics (LEFM) formulation was utilized in both the cases.

A model of pre-cracked Al 7075 T6 plate was used to analyze pre- and post- …

Mechanical Properties Of Pecvd Boron Carbide, Dhairyashil Aher

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

To the best of our knowledge, the mechanical properties of PECVD boron carbide (BC) grown using ortho-carborane as a source molecule have never been investigated before. Therefore, this thesis is an attempt to apply the bulge test and the nanoindentation technique for the mechanical characterization of PECVD BC thin films. Mechanical properties such as the Young’s modulus, hardness and residual stress were investigated. The bulge test system using an interferometry technique to measure the deflection of membrane has been designed. Commercially available LPCVD SiN_x membrane windows were used as a substrate to deposit BC films for the bulge test. …

Gas Embolic Factors In Cardiovascular Health, Eric L. Cutler

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

Gas emboli are a clinical issue often encountered in the space exploration, marine construction, and medical fields. Individuals involved with these disciplines will often have asympomatic gas emboli circulating throughout their bodies on a regular basis. A study into the impact of chronic asymptomatic gas emboli on the risk of atherosclerosis in humans is thus presented. This research utilized a custom built cardiovascular flow simulator and accompanying data acquisition system to experimentally determine the influence of gas emboli under varied circumstances on the mean wall shear stress of a tube in-vitro. A directly inverse relationship between gas embolus presence in …

Design And Analysis Of Blast Induced Traumatic Brain Injury Mechanism Using A Surrogate Headform: Instrumentation And Outcomes, Eyitejumade A. Sogbesan

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

Brain injury cases in military personnel exposed to improvised explosive devices (IED) in combat have been on the rise. In Iraq and Afghanistan improved helmets and body armor are not enough protection against blast wave threats. The United States military are sponsoring researchers and scientists around the globe to find the associations between pressure waves and traumatic brain injury (TBI).

Lack of accurate data and blast wave exposure information in returning soldiers has slowed the innovation needed to effectively diagnose TBI and other related brain injury as a result of pressure waves. More detailed data will be required to gain …