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Friction

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Articles 31 - 60 of 150

Full-Text Articles in Engineering

Influence Of Frictional Or Rotational Kinetic Energy On Wellbore-Fluid/Temperature Profiles During Drilling Operations, Ahmed Q. Al Saedi, Ralph E. Flori, C. Shah Kabir Jun 2019

Influence Of Frictional Or Rotational Kinetic Energy On Wellbore-Fluid/Temperature Profiles During Drilling Operations, Ahmed Q. Al Saedi, Ralph E. Flori, C. Shah Kabir

Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works

Temperature-profile distributions in a wellbore during drilling operations might take different forms when applying the energy balance in the overall system. For steady-state conditions, wherein the wellbore is considered a closed system, adding any source of additional energy to this system can influence the predicted temperature profiles. This study presents a new analytical model to investigate the influence of rotational energy arising from the drillstring operation on the wellbore-temperature behavior.

A significant part of the drilling operation is rotation of the drillstring. Depending on the drilling rig, various equipment provides this kind of energy, such as the rotary table or …


Manufacturing And Testing The Permanent Magnet Linear Motor, Renjie Kang May 2019

Manufacturing And Testing The Permanent Magnet Linear Motor, Renjie Kang

Senior Theses

Controlled mechanical motion is vital in many useful applications in technology. Among them, linear motors have advantages over traditional rotating motors. In this work, we built a permanent magnet linear motor to test and measure its energy efficiency. A maximum 29% total energy efficiency, and 67% energy transfer rate, were detected. In addition, a C-shape support structure was added to the moving part in order to increase the moving accuracy. The tests show that, with the support structure, the fluctuation in the vertical direction decreases significantly, but the friction of the system slightly increases.


Effect Of Water-Based Nanolubricant Containing Nano-Tio2 On Friction And Wear Behaviour Of Chrome Steel At Ambient And Elevated Temperatures, Hui Wu, Fanghui Jia, Jingwei Zhao, Shuiquan Huang, Lianzhou Wang, Sihai Jiao, Han Huang, Zhengyi Jiang Jan 2019

Effect Of Water-Based Nanolubricant Containing Nano-Tio2 On Friction And Wear Behaviour Of Chrome Steel At Ambient And Elevated Temperatures, Hui Wu, Fanghui Jia, Jingwei Zhao, Shuiquan Huang, Lianzhou Wang, Sihai Jiao, Han Huang, Zhengyi Jiang

Faculty of Engineering and Information Sciences - Papers: Part B

A novel experimental method was developed through a ball-on-disk tribometer to study the friction and wear behaviour of a chrome steel at temperatures of 25, 200 and 500 °C. Water-based nanolubricants containing different concentrations of nano-TiO2 from 0.4 to 8.0 wt% were used to investigate their effects on friction-reduction and anti-wear mechanisms, in comparison to the benchmarks under dry and water conditions. The results show that the water-based nanolubricants can significantly reduce coefficient of friction (COF) and improve wear resistance of the chrome steel at both ambient and elevated temperatures. In particular, the use of nanolubricant containing an optimal concentration …


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 …


Design Of A Multidirectional Wear Testing Device For Simulating Wear Of Biocompatible Materials Used In Joint Implants, Carlos A. Rodriguez Betancourth May 2018

Design Of A Multidirectional Wear Testing Device For Simulating Wear Of Biocompatible Materials Used In Joint Implants, Carlos A. Rodriguez Betancourth

Theses and Dissertations

In the present work, a novel multidirectional pin-on-disc wear testing device designated CNC-POD (computer-numerical-control pin-on-disc) capable of replicating the cross-shear motions experienced by a prosthesis in vivo was designed and developed in the UTRGV in order to evaluate the wear resistance of new biomaterials. The CNC-POD consists of six temperature-controlled pin-on-disc stations mounted on a two-axis CNC table (X-Y). Each pin-on-disc station is load-programmable up to 510 Newtons (115 pounds). The CNC table allows the machine to reproduce a wide range of 2D patterns in millimeter scale on the six stations under a specific load. Friction force is measured during …


Manipulation And Automation Of Fbj Short-Axis Fasteners, Shane Forrest Wood Mar 2018

Manipulation And Automation Of Fbj Short-Axis Fasteners, Shane Forrest Wood

Theses and Dissertations

Legislative and market pressures are pushing automakers to achieve new fuel economy requirements in the coming years. To help achieve these goals automakers are reducing the overall weight of the vehicle by increasing the use of high-strength aluminum and advanced high-strength steels, and with this increased use comes the desire to quickly, and securely, join these materials within the vehicle. Friction bit joining is a process that lends itself well to joining these materials. This process uses consumable fasteners that need to be used in an automated production line. The geometry of these fasteners causes two main problems: the bits …


A Constitutive Model For Entangled Polydisperse Linear Flexible Polymers With Entanglement Dynamics And A Configuration Dependent Friction Coefficient. Part I: Model Derivation, David W. Mead, Saman Monjezi, Joontaek Park Jan 2018

A Constitutive Model For Entangled Polydisperse Linear Flexible Polymers With Entanglement Dynamics And A Configuration Dependent Friction Coefficient. Part I: Model Derivation, David W. Mead, Saman Monjezi, Joontaek Park

Chemical and Biochemical Engineering Faculty Research & Creative Works

A new polydisperse "toy" constitutive model is derived and developed from fundamental principles and ideas governing the nonlinear rheology of linear flexible polymers [Mead et al., J. Rheol. 59, 335-363 (2015)]. Specifically, the new model is comprised of four fundamental pieces. First, the model contains a simple differential description of the entanglement dynamics of discrete entanglement pairs. Second, the model contains a differential description of the ij entanglement pair orientation tensor dynamics. Third, following a similar development by Mead and Mishler [J. Non-Newtonian Fluid Mech. 197, 61-79 and 80-90 (2013).], a diluted stretch tube is constructed to describe the relative …


A Constitutive Model For Entangled Polydisperse Linear Flexible Polymers With Entanglement Dynamics And A Configuration Dependent Friction Coefficient. Part Ii. Modeling "Shear Modification" Following Cessation Of Fast Shear Flows, David W. Mead, Saman Monjezi, Joontaek Park Jan 2018

A Constitutive Model For Entangled Polydisperse Linear Flexible Polymers With Entanglement Dynamics And A Configuration Dependent Friction Coefficient. Part Ii. Modeling "Shear Modification" Following Cessation Of Fast Shear Flows, David W. Mead, Saman Monjezi, Joontaek Park

Chemical and Biochemical Engineering Faculty Research & Creative Works

The polydisperse Mead-Park (MP) "toy" molecular constitutive model developed in Paper I [Mead et al., J. Rheol. 62, 121-134 (2017)] as well as our previously published work [e.g., J. Rheol. 59, 335-363 (2015)] is used in the "forward" direction to study model polydisperse melts of entangled linear flexible polymers in severe, fast shear flows. The properties of our new model are elucidated by way of numerical simulation of a representative model polydisperse polymer melt in step shear rate and interrupted shear flow. In particular, we demonstrate how the MP model simulates the individual molecular weight distribution (MWD) component dynamics as …


Design Of Tribologically Enhanced Polymeric Materials For Biomedical Applications, Allen Osaheni Dec 2017

Design Of Tribologically Enhanced Polymeric Materials For Biomedical Applications, Allen Osaheni

Dissertations - ALL

Anytime two surfaces are in normal contact, accompanied by tangential motion, there is potential for deterioration of one or both surfaces. Gradual wear, or the removal of surface material, is typically an undesirable event. Therefore, the need for lubrication arises to minimize the amount of shear stress that develops between opposing surfaces. This reduction in shear stress is characterized by the coefficient of friction (COF). Friction is one of the primary subjects of interest in tribology, the science of the friction and wear of articulating surfaces.

A number of fascinating tribological systems can be found in nature. One example which …


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 …


Grasp Evaluation Method For Applying Static Loads Leading To Beam Failure, Mahyar Abdeetedal, Mehrdad Kermani Ph.D., P.Eng. Sep 2017

Grasp Evaluation Method For Applying Static Loads Leading To Beam Failure, Mahyar Abdeetedal, Mehrdad Kermani Ph.D., P.Eng.

Electrical and Computer Engineering Publications

This paper deals with the problem of purposefully failing or yielding an object by a robotic gripper. We propose a grasp quality measure fabricated for robotic harvesting in which picking a crop from its stem is desired. The proposed metric characterizes a suitable grasp configuration for systematically controlling the failure behavior of an object to break it at the desired location while avoiding damage on other areas. Our approach is based on failure task information and gripper wrench insertion capability. Failure task definition is accomplished using failure theories. Gripper wrench insertion capability is formulated by modeling the friction between the …


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 …


The Effect Of Frictional And Adhesion Forces Attributed To Slurry Particles On The Surface Quality Of Polished Copper, Yi-Koan Hong, Ja-Hyung Han, Tae-Gon Kim, Jin-Goo Park, Ahmed A. Busnaina Dec 2015

The Effect Of Frictional And Adhesion Forces Attributed To Slurry Particles On The Surface Quality Of Polished Copper, Yi-Koan Hong, Ja-Hyung Han, Tae-Gon Kim, Jin-Goo Park, Ahmed A. Busnaina

Ahmed A. Busnaina

The effect of frictional and adhesion forces attributed to slurry particles on the quality of copper surfaces was experimentally investigated during copper chemical mechanical planarization process. The highest frictional force of 9 Kgf and adhesion force of 5.83 nN were observed in a deionized water-based alumina slurry. On the other hand, the smallest frictional force of 4 Kgf and adhesion force of 0.38 nN were measured in an alumina slurry containing citric acid. However, frictional (6 Kgf) and adhesion (1 nN) forces of silica particles in the slurry were not significantly changed regardless of the addition of citric acid. These …


The Effect Of Frictional And Adhesion Forces Attributed To Slurry Particles On The Surface Quality Of Polished Copper, Yi-Koan Hong, Ja-Hyung Han, Tae-Gon Kim, Jin-Goo Park, Ahmed A. Busnaina Dec 2015

The Effect Of Frictional And Adhesion Forces Attributed To Slurry Particles On The Surface Quality Of Polished Copper, Yi-Koan Hong, Ja-Hyung Han, Tae-Gon Kim, Jin-Goo Park, Ahmed A. Busnaina

Ahmed A. Busnaina

The effect of frictional and adhesion forces attributed to slurry particles on the quality of copper surfaces was experimentally investigated during copper chemical mechanical planarization process. The highest frictional force of 9 Kgf and adhesion force of 5.83 nN were observed in a deionized water-based alumina slurry. On the other hand, the smallest frictional force of 4 Kgf and adhesion force of 0.38 nN were measured in an alumina slurry containing citric acid. However, frictional (6 Kgf) and adhesion (1 nN) forces of silica particles in the slurry were not significantly changed regardless of the addition of citric acid. These …


A Comparison Of Nanotribology And Nanoindentation, Steffen Brinckmann, Caroline Fink, Gerhard Dehm Oct 2015

A Comparison Of Nanotribology And Nanoindentation, Steffen Brinckmann, Caroline Fink, Gerhard Dehm

Nanomechanical Testing in Materials Research and Development V

Metal friction and wear is the collective contact and interaction of asperities of micrometer dimension. We use a nanoindenter with tangential force measurement to simulate the behavior in engineering contacts and to fundamentally understand friction and wear.

This presentation investigates the deformation due to a single stroke scratch of a diamond nanoindenter in austenite base. We find that the elastic and plastic equations for static indentation also apply for the dynamic scratching. Additionally, the friction coefficient is found to be normal force dependent and we observe three domains: microstructure dominated friction, plastic plowing dominated wear and wear particle dominated tribology. …


Preliminary Study On The Correlation Between Two-Dimension Surface Texture And Friction, Shih-Huang Chen, Kuan-Lun Hsu, Pei Liu, Hung-Wen Chung Jun 2015

Preliminary Study On The Correlation Between Two-Dimension Surface Texture And Friction, Shih-Huang Chen, Kuan-Lun Hsu, Pei Liu, Hung-Wen Chung

Journal of Marine Science and Technology

The friction of pavement is mainly determined by the microtexture of the surface layer. However, the finer degree of microtexture makes it impossible to observe with naked eye. The object of this study was to develop a High Definition Scan Texture Machine (HDSTM) with 2D Laser CCD to support previous research on the correlation between texture and friction. In addition, this study proposed seven different parameters and sought to find an index for an ideal correlation that could represent the entire pavement texture. By assessing the test results, the Segment of Average Profile Depth (SAPD) was selected as the texture …


Stress Response Of A Rubber Block With Frictional Contact Under Axial Loading, J. Suh, S. Kelly Apr 2015

Stress Response Of A Rubber Block With Frictional Contact Under Axial Loading, J. Suh, S. Kelly

Dr. S. Graham Kelly

Rubber blocks (or springs) are structural components widely used in many applications. Design characteristics of a rubber block under axial loading are an apparent modulus (or compression modulus) and normal and shear stresses on contact surfaces. These are affected by a contact condition of the rubber block in contact with two rigid plates and the shape of the block. The problem of a rubber block bonded to two rigid plates has been solved using various approaches. In contrast, for a rubber block whose one surface is bonded to a rigid plate and the other surface in contact with a frictional …


Analysis Of High Frequency Squeal In A Disc-Brake System Using A Stick-Slip Friction Model, Manish Paliwal, Ajay Mahajan, Peter Filip Apr 2015

Analysis Of High Frequency Squeal In A Disc-Brake System Using A Stick-Slip Friction Model, Manish Paliwal, Ajay Mahajan, Peter Filip

Dr. Ajay Mahajan

This paper presents a two degree of freedom (2-DOF) stick-slip friction model for studying the effect of contact stiffness on the stability of the system. It is shown that the stability is not only a function of non-linear variation in the friction force provide by stick-slip but also depends on the variation in stiffness of contact due to the formation of friction layers on the surface of the rotor and the brake pad. Parametric studies have been presented to show the effect of variation in coefficient of friction and contact stiffness on the system stability.


Sudesh Woodiga, Linda Hanes Apr 2015

Sudesh Woodiga, Linda Hanes

International Alumni

Holder of three degrees from Western Michigan University— bachelor’s, master’s, and doctorate—alumnus Sudesh Woodiga has achieved much success as an aerodynamics engineer at the Ford Motor Company in Dearborn, Mich.


A Constitutive Model For Entangled Polymers Incorporating Binary Entanglement Pair Dynamics And A Configuration Dependent Friction Coefficient, David W. Mead, Nilanjana Banerjee, Joontaek Park Mar 2015

A Constitutive Model For Entangled Polymers Incorporating Binary Entanglement Pair Dynamics And A Configuration Dependent Friction Coefficient, David W. Mead, Nilanjana Banerjee, Joontaek Park

Chemical and Biochemical Engineering Faculty Research & Creative Works

Following recent work [e.g., J. Park et al., J. Rheol. 56, 1057-1082 (2012); T. Yaoita et al., Macromolecules 45, 2773-2782 (2012); and G. Ianniruberto et al., Macromolecules 45, 8058-8066 (2012)], we introduce the idea of a configuration dependent friction coefficient (CDFC) based on the relative orientation of Kuhn bonds of the test and surrounding matrix chains. We incorporate CDFC into the "toy" model of Mead et al. [Macromolecules 31, 7895-7914 (1998)] in a manner akin to Yaoita et al. [Nihon Reoroji Gakkaishi 42, 207-213 (2014)]. Additionally, we incorporate entanglement dynamics (ED) of discrete entanglement pairs into the new Mead-Banerjee-Park (MBP) …


Oxide Scale Characterization Of Ferritic Stainless Steel And Its Deformation And Friction In Hot Rolling, Xiawei Cheng, Zhengyi Jiang, Dongbin Wei, Liang Hao, Jingwei Zhao, Laizhu Jiang Jan 2015

Oxide Scale Characterization Of Ferritic Stainless Steel And Its Deformation And Friction In Hot Rolling, Xiawei Cheng, Zhengyi Jiang, Dongbin Wei, Liang Hao, Jingwei Zhao, Laizhu Jiang

Faculty of Engineering and Information Sciences - Papers: Part A

The oxidation kinetics of ferritic stainless steel 430 was studied in dry and humid air at 1090 °C by Thermo Gravimetric Analysis (TGA). Different atmospheres and heating times were adopted for reheating to obtain different compositions and thickness of the oxide scale. Hot rolling was performed on a 2-high Hille 100 experimental rolling mill at various reductions. Oxide scale thickness and composition were analysed with optical microscopy (OM), scanning electron microscope (SEM) and X-ray diffraction (XRD). The surface profiles were examined by a digital microscope, and the topographic features of the thin oxide scale surface were examined with an atomic …


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 …