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Mechanical Engineering

Friction

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Assessing The Lubrication Performance Of Sunflower Oil Modified With Montmorillonite Clay (Mmt) Nanoparticles For Industrial Applications, Md Mashfiqur Rahman, Md Abu Sayeed Biswas, Laura Peña-Pará, Demófilo Maldonado- Cortés, Javier A. Ortega Feb 2024

Assessing The Lubrication Performance Of Sunflower Oil Modified With Montmorillonite Clay (Mmt) Nanoparticles For Industrial Applications, Md Mashfiqur Rahman, Md Abu Sayeed Biswas, Laura Peña-Pará, Demófilo Maldonado- Cortés, Javier A. Ortega

Mechanical Engineering Faculty Publications and Presentations

Because of the environmental impact and price volatility, there has been a growing concern about using petroleum-based lubricants. This issue has encouraged research into the development of biodegradable lubricants like vegetable oils. This study assessed the tribological behavior of sunflower oil modified with Montmorillonite nanoclay (MMT) as lubricant additives. A block-on-ring tribometer was used to assess the wear and friction characteristics of the nano-lubricants. A custom-made tapping torque tester was used to evaluate the nano-lubricants in a real-world application. It was found that the volumetric wear, Coefficient of Friction, and torque of the system decreased when MMT nanoparticles were added. …


Improving Tribological Properties Of Polydopamine/Polytetrafluoroethylene Coatings Through Incorporating Core-Shell Nanoparticles And Laser Surface Texturing, Firuze Soltani-Kordshuli May 2023

Improving Tribological Properties Of Polydopamine/Polytetrafluoroethylene Coatings Through Incorporating Core-Shell Nanoparticles And Laser Surface Texturing, Firuze Soltani-Kordshuli

Graduate Theses and Dissertations

Polytetrafluoroethylene (PTFE) is a widely used polymer that has unique properties such as chemical and temperature resistance, corrosion resistance, low maintenance cost, and a very low coefficient of friction (COF). These distinctive properties have made PTFE a promising candidate for industrial applications where surfaces are in relative motion. PTFE can be utilized as a thin film solid lubricant to significantly reduce the friction between moving surfaces. However, PTFE coatings have low cohesion and poor adhesion to the substrate resulting in its low wear resistance. This fact limits the application of PTFE coatings in load-bearing situations. To address these limitations, an …


Carbon Nanotori Reinforced Lubricants In Plastic Deformation Processes, Jaime Taha-Tijerina, Juan Manuel Martinez, Daniel Euresti, Patsy Yessenia Arquieta-Guillen Apr 2022

Carbon Nanotori Reinforced Lubricants In Plastic Deformation Processes, Jaime Taha-Tijerina, Juan Manuel Martinez, Daniel Euresti, Patsy Yessenia Arquieta-Guillen

Manufacturing & Industrial Engineering Faculty Publications and Presentations

This research presents the effects of carbon nanotori structures (CNst) dispersed as reinforcement for metal-working and metal-forming lubricants. Synthetic (SL) and deep drawing (DD) nanolubricants were prepared following a two-step method at 0.01 wt.%, 0.05 wt.%, and 0.10 wt.% filler fractions. Slight increases in viscosity (<6%) for nanolubricants were observed as filler fraction was increased through various measured temperatures. Tribological behavior of nanolubricants displayed superb improvements under antiwear and extreme pressure conditions. The load carrying capacity (poz) increased by 16% and 22% at merely 0.01 wt.% CNst reinforcement and up to 73% and 107% at 0.10 wt.% filler fraction for SL and DD nanolubricants, respectively, compared to conventional materials. Additionally, at 0.10 wt.% wear scar evaluations showed a highest benefit of 16% and 24%, for SL and DD nanolubricants, …


Lubrication Performance Of Vegetable Oils Modified With Halloysite Clay Nanotubes (Hnt) As Lubricant Additives, Md Abu Sayeed Biswas Dec 2021

Lubrication Performance Of Vegetable Oils Modified With Halloysite Clay Nanotubes (Hnt) As Lubricant Additives, Md Abu Sayeed Biswas

Theses and Dissertations

Vegetable oil-based nano-lubricants are a great alternative to petroleum-based lubricants because of their less adverse impact on the environment. This work evaluates the tribological performance of sunflower, corn, and peanut oils modified with halloysite clay nanotubes (Al2Si2O2(OH)2nH2O) as lubricant additives at different concentrations. To analyze the tribological performance of the nano-lubricants, a block-on-ring tribometer was used following the ASTM G-077-17 standard procedure. Characterization of HNT was carried out by X-Ray Diffraction (XRD), Scanning Electron Microscopy (SEM), and Thermogravimetric Analysis (TGA). The effect of the HNT on the lubrication performance of the newly developed vegetable oil-based nano-lubricants was evaluated, and the …


Development Of Vegetable Oil-Based Nano-Lubricants Using Montmorillonite Clay (Mmt) Nanoparticles As Lubricant Additives, Md Mashfiqur Rahman Dec 2021

Development Of Vegetable Oil-Based Nano-Lubricants Using Montmorillonite Clay (Mmt) Nanoparticles As Lubricant Additives, Md Mashfiqur Rahman

Theses and Dissertations

Because of the environmental impact and price volatility, there has been a growing concern on the use of petroleum-based lubricants. This issue has stimulated research into the development of biodegradable lubricants like vegetable oils. In this study, the tribological and rheological behavior of sunflower, peanut, and corn oils modified with Montmorillonite nanoclay (MMT) as lubricant additives were evaluated at various concentrations. A custom-made block on ring tribotester was used to evaluate the wear and friction characteristics of the nano-lubricants, following the ASTM G-077-05 standard. The effects of concentration and shear rate on shear viscosity were studied using a parallel plate …


One-Dimensional Lateral Force Anisotropy At The Atomic Scale In Sliding Single Molecules On A Surface, Yuan Zhang, Daniel J. Trainer, Badri Narayanan, Yang Li, Anh T. Ngo, Sushila Khadka, Arnab Neogi, Brandon Fisher, Larry A. Curtiss, Subramanian K.R.S. Sankaranarayanan, Saw Wai Hla Jan 2021

One-Dimensional Lateral Force Anisotropy At The Atomic Scale In Sliding Single Molecules On A Surface, Yuan Zhang, Daniel J. Trainer, Badri Narayanan, Yang Li, Anh T. Ngo, Sushila Khadka, Arnab Neogi, Brandon Fisher, Larry A. Curtiss, Subramanian K.R.S. Sankaranarayanan, Saw Wai Hla

Physics Faculty Publications

Using a q+ atomic force microscopy at low temperature, a sexiphenyl molecule is slid across an atomically flat Ag(111) surface along the direction parallel to its molecular axis and sideways to the axis. Despite identical contact area and underlying surface geometry, the lateral force required to move the molecule in the direction parallel to its molecular axis is found to be about half of that required to move it sideways. The origin of the lateral force anisotropy observed here is traced to the one-dimensional shape of the molecule, which is further confirmed by molecular dynamics simulations. We also demonstrate that …


Adhesion And Deformation Mechanisms Of Polydopamine And Polytetrafluoroethylene: A Multiscale Computational Study, Matthew Brownell Dec 2020

Adhesion And Deformation Mechanisms Of Polydopamine And Polytetrafluoroethylene: A Multiscale Computational Study, Matthew Brownell

Graduate Theses and Dissertations

Polydopamine (PDA) has been shown to bond via covalent bonding, van der Waals forces, and hydrogen bonding and is known to adhere strongly to almost any material. The application of PDA between a substrate and a PTFE surface coating has resulted in low friction and a greatly reduced wear rate. Previous research probing the capabilities and limitations of PDA/PTFE films have studied the wear and mechanical properties of the film, but the overall adhesive and deformation mechanisms remain unclear.

In this research, we investigate the tribological properties of PDA and PTFE molecules and composites from the atomic to the microscale …


Rubber Plunger Surface Texturing For Friction Reduction In Medical Syringes, Haytam Kasem, Harel Shriki, Lihi Ganon, Michael Mizrahi, Kareem Abd-Rbo, Abraham J. Domb Oct 2020

Rubber Plunger Surface Texturing For Friction Reduction In Medical Syringes, Haytam Kasem, Harel Shriki, Lihi Ganon, Michael Mizrahi, Kareem Abd-Rbo, Abraham J. Domb

Friction

Friction is a genuine issue in the use of many medical devices involving rubbery materials such as plungers in medical syringes. This paper presents a new direction for the reduction of friction in medical syringes based on surface texturing of the rubber plunger. The specimens were prepared by casting poly(vinylsiloxane) (PVS) rubber into a pre-fabricated negative template obtained by 3D printing. Friction tests were performed on a home-made test-rig. It was clearly shown that friction resistance can be considerably manipulated when using textured plungers.


Friction And Wear Behaviors Of Mos2-Multi-Walled-Carbon-Nanotube Hybrid Reinforced Polyurethane Composite Coating, Zhaozhu Zhang, Mingming Yang, Junya Yuan, Fang Guo, Xuehu Men Oct 2020

Friction And Wear Behaviors Of Mos2-Multi-Walled-Carbon-Nanotube Hybrid Reinforced Polyurethane Composite Coating, Zhaozhu Zhang, Mingming Yang, Junya Yuan, Fang Guo, Xuehu Men

Friction

MoS2-multi-walled-carbon-nanotube (MWCNT) hybrids containing two-dimensional MoS2 and one-dimensional MWCNTs were synthesized through a one-step hydrothermal reaction. X-ray-diffraction and transmission-electron-microscopy results demonstrated that MoS2 nanosheets were successfully synthesized, and uniformly anchored on the MWCNTs' surfaces. Furthermore, the effects of the MoS2-MWCNT hybrids on the tribological performances of polyurethane composite coatings were investigated using a UMT-2MT tribo-tester. Friction and wear test results revealed that the friction coefficient and wear rate of a 3 wt% MoS2-MWCNT-1 filled polyurethane composite coating were reduced by 25.6% and 65.5%, respectively. The outstanding tribological performance of the MoS2-MWCNT-1 reinforced polyurethane composite coating was attributed to the excellent …


Friction Predication On Pin-To-Plate Interface Of Ptfe Material And Steel, Zhuming Bi, Donald W. Mueller Oct 2020

Friction Predication On Pin-To-Plate Interface Of Ptfe Material And Steel, Zhuming Bi, Donald W. Mueller

Friction

In this paper, the friction behavior at a pin-to-plate interface is investigated. The pin and plate are made of Polytetrafluoroethylene (PTFE) and steel, respectively, and there is a reciprocating motion at the interface. Governing mathematical models for the relations of design variables and frictions are investigated, and a general procedure is proposed to solve the developed models and predict the friction forces at the interface subjected to given test conditions. Novel models have been developed to represent intrigued friction behaviors affected by various factors such as pin geometrics and finishes, lubrication conditions, and reciprocating speed. The test data from experiments …


Water-Based Superlubricity In Vacuum, Chen Xiao, Jinjin Li, Lei Chen, Chenhui Zhang, Ningning Zhou, Tao Qing, Linmao Qian, Jiyang Zhang, Jianbin Luo Oct 2020

Water-Based Superlubricity In Vacuum, Chen Xiao, Jinjin Li, Lei Chen, Chenhui Zhang, Ningning Zhou, Tao Qing, Linmao Qian, Jiyang Zhang, Jianbin Luo

Friction

This study achieved water-based superlubricity with the lubrication of H3PO4 solution in vacuum (highest vacuum degree <10-4 torr) for the first time by performing a pre-running process in air before running in vacuum. The stable water-based superlubricity was sustainable in vacuum (0.02 torr) for 14 h until the test was stopped by the user for non-experimental factor. A further analysis suggested that the superlubricity may be attributed to the phosphoric acid-water network formed in air, which can efficiently lock water molecules in the liquid lubricating film even in vacuum owing to the strong hydrogen bond interaction. Such capability to lock water is strongly affected by the strength of hydrogen bond and environmental conditions. The realization of water-based superlubricity with H3PO4 solution in vacuum can lead to its application in space environment.


Solutions Of The Problem Of Random Vibrations In Hereditary-Deformable Systems Using Impulsive Functions, Inobat Xaldibayeva May 2020

Solutions Of The Problem Of Random Vibrations In Hereditary-Deformable Systems Using Impulsive Functions, Inobat Xaldibayeva

Technical science and innovation

In recent years, probabilistic-statistical methods for studying various problems of mechanics of solid deformable bodies are being applied more than ever.

The principal part of its field of application is the development of a general theory of strength and a hereditarily deformed solid. As known, the theory of random oscillations is increasingly being used in technology.

Current research is aimed to present a numerical-analytical approach for studying the dynamic response of a hereditarily deformable system to unsteady input influences.

It is established that the dynamic reaction of hereditarily deformable systems to an arbitrary form of random perturbations can also be …


Development Of Electromagnetic Friction Dampers For Improving Seismic Performance Of Civil Structures, Mohsen Amjadian Jan 2019

Development Of Electromagnetic Friction Dampers For Improving Seismic Performance Of Civil Structures, Mohsen Amjadian

Dissertations and Theses

Energy dissipation is critical to limiting damage to civil structures subjected to extreme natural events such as earthquakes. Friction is one of the most reliable mechanisms of energy dissipation that has been utilized extensively in friction dampers to improve seismic performance of civil structures. Friction dampers are well-known for having a highly nonlinear hysteretic behavior caused by stick-slip motion at low velocities, a phenomenon that is inherent in friction and increases the acceleration response of the structure under control unfavorably, in spite of the fact that the displacement is generally reduced because of the energy dissipation. This increase in acceleration …


The Effects Of Surface Pace In Baseball, Jason Farlow May 2018

The Effects Of Surface Pace In Baseball, Jason Farlow

Senior Theses

A baseball travels across different surfaces at different paces. The goal of this experiment is to find a percentage difference in speeds the ball will reflect off a given surface. The energy lost on the turf surface was far more significant than on dirt surface as the turf lost an average of 26% of its energy as compared to just 16% of the energy on dirt. In the Northwest conference, teams play on four turf-based infields and five dirt-based infields. The results of this study suggest that kinetic friction forces are more significant in reducing ball rebound speed than in …


Thermal-Fluid Dynamic Model Of Luge Steels, Brandon Stell Dec 2017

Thermal-Fluid Dynamic Model Of Luge Steels, Brandon Stell

Master's Theses

Luge is an Olympic sport in which athletes ride feet-first on sleds down an ice-covered track. Competitors spring from the starting position and accelerate their sled by paddling with spiked gloves against the ice surface. Once the Luger leaves the starting section, their downhill motion is solely propelled by the effects of gravity. Athletes compete, one after the other, for the fastest time. Runs can differ by as little as a thousandth of a second, meaning that every minor sled adjustment, change of line choice, and shift of body position is critical. In the past, the sport of Luge has …


Friction Test Machine, Alec J. Makowski, Megan Hardisty, Brandon L. Killian Jun 2017

Friction Test Machine, Alec J. Makowski, Megan Hardisty, Brandon L. Killian

Mechanical Engineering

Parker Aerospace is interested in collecting empirical data of friction coefficients for skewed roller bearings. A fixture will be designed, constructed and tested to allow a technician to quickly and easily measure the friction torque of a skew roller bearing with varying axial loads, geometries, lubricants, temperatures and rotational speeds in order to improve actuator efficiency.


Computational Modeling Of Transient Processes During Run-In For Tribological Systems, Rob Morien Dec 2016

Computational Modeling Of Transient Processes During Run-In For Tribological Systems, Rob Morien

Theses and Dissertations

Understanding the frictional behavior of machine elements in mutual rolling or sliding contact is important for many engineering applications. When frictional sliding is initiated, the tribological system passes through several stages with each stage possessing its own unique frictional property. The initial transition process preceding stationary sliding is usually called “run-in”. During the run-in time interval, surface topographies of frictional contacts as well as lubricant distribution and surface tribofilms reorganize and adjust through asperity deformation and wear processes before reaching the steady state. This surface stability formed during run-in leads to an improvement in frictional performance during steady state operation, …


Numerical Modeling Of Heat Transfer And Material Flow During Friction Extrusion Process, Hongsheng Zhang Jun 2016

Numerical Modeling Of Heat Transfer And Material Flow During Friction Extrusion Process, Hongsheng Zhang

Theses and Dissertations

Friction extrusion process is a novel manufacturing process that converts low-cost metal precursors (e.g. powders and machining chips) into high-value wires with potential applications in 3D printing of metallic products. However, there is little existing scientific literature involving friction extrusion process until recently. The present work is to study the heat transfer and material flow phenomena during the friction extrusion process on aluminum alloy 6061 through numerical models validated by experimental measurements.

The first part is a study of a simplified process in which flow of a transparent Newtonian fluid in a cylindrical chamber caused by frictional contact with a …


Tribological Testing And Analysis Of Ionic Liquids As Candidate Anti-Wear Additives For Next-Generation Engine Lubricants, William Charles Barnhill May 2016

Tribological Testing And Analysis Of Ionic Liquids As Candidate Anti-Wear Additives For Next-Generation Engine Lubricants, William Charles Barnhill

Masters Theses

In this work, fourteen ionic liquids (ILs) were assayed as potential next-generation engine oil additives. After screening for corrosion, thermal stability and oil solubility, candidate additives were subjected to friction and wear tests in both boundary and mixed regime lubrication. While each IL demonstrated friction and wear reduction compared to base oil without any additives, oil miscible ILs tetraoctylphosphonium bis 2-ethylhexyl phosphate ([P8888][DEHP]) and trioctylammonium bis 2-ethylhexylphosphate ([N888H][DEHP]) were the best performers in bench tests with a XX% and XX% improvement in wear over the base oil respectively. Each of these ILs excellent solubility and superior performance was attributed to …


Friction And Wear Measurements In Automatic Transmission Clutch, Steffen Harm, Dabin Kim, Jean Paulo Mulles, Eric Stavitzski, Hoang Tran Jan 2016

Friction And Wear Measurements In Automatic Transmission Clutch, Steffen Harm, Dabin Kim, Jean Paulo Mulles, Eric Stavitzski, Hoang Tran

Capstone Design Expo Posters

In order to create alternate pathways to increase fuel efficiency, flexible ways to alter and test fluid properties are needed when transmission manufacturers change the operating conditions or components used in automatic transmissions. A prototype was fabricated to satisfy this need by reducing the cost, time of conducting tests while producing accurate results, and also increasing the amount of trials that can be conducted in a laboratory setting. The limitations of developing a new prototype are: safety, weight, ease of use, laboratory size, and establishing accurate results within the amount of time given. This project was approached using the Engineering …


Hybrid Manufacturing Processes For Fusion Welding And Friction Stir Welding Of Aerospace Grade Aluminum Alloys, Megan Alexandra Gegesky Jan 2016

Hybrid Manufacturing Processes For Fusion Welding And Friction Stir Welding Of Aerospace Grade Aluminum Alloys, Megan Alexandra Gegesky

Masters Theses

"Friction stir welding and processing can provide for joints in aerospace grade aluminum alloys that have preferable material properties as compared to fusion welding techniques. Aerospace grade aluminum alloys such as AA2024-T3 and AA7075-T6 are considered non-weldable by traditional fusion welding techniques. Improved mechanical properties over previously used techniques are usually preferable for aerospace applications. Therefore, by combining traditional fusion welding and friction stir processing techniques, it could be plausible to create more difficult geometries in manufactured parts instead of using traditional techniques. While this combination of fusion welding and friction stir processing is not a new technology, its introduction …


The Effects Of Micro-Dimple Texture On The Friction And Thermal Behavior Of A Point Contact, Utsav Kamleshbhai Parmar Jan 2016

The Effects Of Micro-Dimple Texture On The Friction And Thermal Behavior Of A Point Contact, Utsav Kamleshbhai Parmar

Browse all Theses and Dissertations

This study investigates the effects of the micro-dimple texture on the friction and surface temperature performances of a ball-on-disk contact, operating under the speed and load ranges that cover typical gearing applications. Circular shaped micro-dimple arrays with different dimple center distances and dimple depths are implemented on the ball surface to quantify the impacts of these two parameters on the friction coefficient and the maximum ball surface temperature. In addition, the contacts of three surface texture combinations, namely micro-dimpled and polished ball surface versus polished disk surface, polished ball surface versus polished disk surface and ground ball surface versus ground …


High Regression Rate Hybrid Rocket Fuel Grains With Helical Port Structures, Stephen A. Whitmore, Sean D. Walker, Daniel P. Merkley, Mansour Sobbi Jan 2015

High Regression Rate Hybrid Rocket Fuel Grains With Helical Port Structures, Stephen A. Whitmore, Sean D. Walker, Daniel P. Merkley, Mansour Sobbi

Mechanical and Aerospace Engineering Faculty Publications

Results froma development campaign, where modern additive manufacturing methods are used to fabricate hybrid rocket fuel grains with embedded helical ports, are presented. The fuel grains were constructed from acrlyonitrile butadiene styrene using commercially available three-dimensional printer feedstockmaterial.Gaseous oxygen is used as the oxidizer for this test campaign.When compared to cylindrical fuel ports, significant increases in fuel regression rates were observed, and these increases in regression rate diminished with time as the helical fuel port burns to become progressivelymore cylindrical. Comparisons to the helical pipe flow skin friction correlation developed by Mishra and Gupta indicate that increased skin friction only …


On The Nonlinear Tribological Jerk Dynamics At Sliding Interfaces, Divyeshkumar Patel Dec 2014

On The Nonlinear Tribological Jerk Dynamics At Sliding Interfaces, Divyeshkumar Patel

Theses and Dissertations

As the world desires the next industrial revolution, the potential threats that will undermine energy efficient innovations include detrimental frictional effects that exacerbate wear, hasten equipment breakdowns, and worsen heat dissipation. Capturing the inherently nonlinear manifestations of friction fundamentally has been difficult. A fundamental modeling scheme elucidating friction will bolster novel technologies synthesizing wear resistant materials and lubricants needed for sustainable energy efficiency.

Frictional dissipation at dynamical sliding interfaces has been studied for generations. Interfacial sliding frictional effects are prevalent in natural and artificial phenomena such as earthquake, hip and knee joints, and the moving parts of energy-producing and energy-consuming …


Wear Resistant Polydopamine/Ptfe Nanoparticle Composite Coating For Dry Lubrication Applications, Samuel George Beckford Dec 2014

Wear Resistant Polydopamine/Ptfe Nanoparticle Composite Coating For Dry Lubrication Applications, Samuel George Beckford

Graduate Theses and Dissertations

This dissertation presents an investigation into the effect of nanoparticle fillers and a polydopamine adhesive primer on the tribological performance of thin PTFE films. The principal objective of this investigation was to reduce wear in PTFE films, an issue which precludes the use of PTFE films in tribological applications requiring high durability. The friction and wear of the composite films were evaluated using a ball-on-flat configuration in linear reciprocating motion. It was found that the use of a polydopamine adhesive primer reduces the wear of PTFE films more than 600 times. X-ray photoelectron spectroscopy (XPS) results show that a tenacious …


Friction Test Machine, Kyle Raymon Schless, Lynda Beatriz Tesillo, Mustapha Nadri Jun 2014

Friction Test Machine, Kyle Raymon Schless, Lynda Beatriz Tesillo, Mustapha Nadri

Mechanical Engineering

No abstract provided.


Modeling Of Instabilities And Self-Organization At The Frictional Interface, Vahid Mortazavi May 2014

Modeling Of Instabilities And Self-Organization At The Frictional Interface, Vahid Mortazavi

Theses and Dissertations

The field of friction-induced self-organization and its practical importance remains unknown territory to many tribologists. Friction is usually thought of as irreversible dissipation of energy and deterioration; however, under certain conditions, friction can lead to the formation of new structures at the interface, including in-situ tribofilms and various patterns at the interface.

This thesis studies self-organization and instabilities at the frictional interface, including the instability due to the temperature-dependency of the coefficient of friction, the transient process of frictional running-in, frictional Turing systems, the stick-and-slip phenomenon, and, finally, contact angle (CA) hysteresis as an example of solid-liquid friction and dissipation. …


Energy And Thermodynamically Based Approaches For Analysis Of Damage In Contact Problems, Afshin Babaie Aghdam Jan 2014

Energy And Thermodynamically Based Approaches For Analysis Of Damage In Contact Problems, Afshin Babaie Aghdam

LSU Doctoral Dissertations

A novel methodology for analysis of damage in contact problems in presented. Two important categories of contact damage are studied, namely crack nucleation and adhesive wear. The proposed methodology is primarily based on the laws of energy and thermodynamics, and as such offers great advantages by unifying the analysis of damage in a variety of contact configurations. Crack nucleation is the first damage type analyzed. For this purpose, the line-contact fretting configuration is chosen. A thermodynamically-based continuum damage mechanics (CDM) approach is employed. Intense stress gradients in the contact region are found to be highly influential in the crack nucleation …


An Experimental Investigation Characterizing The Tribological Performance Of Natural And Synthetic Biolubricants Composed Of Carboxylic Acids For Energy Conservation And Sustainability, Carlton Jonathan Reeves Dec 2013

An Experimental Investigation Characterizing The Tribological Performance Of Natural And Synthetic Biolubricants Composed Of Carboxylic Acids For Energy Conservation And Sustainability, Carlton Jonathan Reeves

Theses and Dissertations

Over the last several decades the lubrication industry has been striving to bring bio-based lubricants known as biolubricants to prominence. The reasons for the increased environmental initiatives are due to depletion of oil reserves, increases in oil price, stringent government regulations on petroleum-based oils, and most importantly, concerns for protecting the environment. With an estimated, 50% of all lubricants entering the environment and much of these being composed of toxic mineral oils, biolubricants have begun to witness a resurgence. This experimental investigation seeks to develop a new class of ecofriendly biolubricants that are less toxic to the environment, derived from …


Motion And Force Transmission Of A Flexible Instrument Inside A Curved Endoscope, Jitendra P. Khatait Sep 2013

Motion And Force Transmission Of A Flexible Instrument Inside A Curved Endoscope, Jitendra P. Khatait

Jitendra P Khatait

Flexible instruments are increasingly used to perform advanced and complex surgical procedures either manually or robotically. The success of flexible instruments in surgery requires high motion and force fidelity, and controllability of the tip. However, the friction and the limited stiffness of such instruments limit their motion and force transmission. The implementation of flexible instruments in surgery necessitates their characterization, the development of proper tools to understand the effect of various mechanical parameters on their overall performance, and an improvement in motion and force fidelity. Therefore, this thesis describes 2-D and 3-D flexible multibody models of a flexible surgical instrument …