Engineering Commons^™

Wear Analysis Of Cu-Al Coating On Ti-6al-4v Under Fretting, Karl N. Murray

Theses and Dissertations

The effects of changes in the coefficient of friction (CoF) between the contacting surfaces on the fretting wear characteristics of Cu-Al coating on Ti-6Al-4V were investigated. This Cu-Al coating is part of a system that is applied to titanium turbine blades to reduce fretting at the interface. In the application, there is a solid lubricant that is added on top of the coating as an assembly aid and to help reduce the friction while the lubricant remains within the contact. Previous studies have researched the characteristics of the coating without the additional lubricant. In this study, liquid motor oil was …

Spatial Admittance Selection Conditions For Frictionless Force-Guided Assembly Of Polyhedral Parts In Single Principal Contact, Shuguang Huang, Joseph M. Schimmels

Mechanical Engineering Faculty Research and Publications

By judiciously selecting the admittance of a manipulator, the forces of contact that occur during assembly can be used to guide the parts to proper positioning. This paper identifies conditions for selecting the appropriate spatial admittance to achieve reliable force-guided assembly of polyhedral parts for cases in which a single feature (vertex, edge, or face) of one part contacts a single feature of the other, i.e., all single principal contact cases. These conditions ensure that the motion that results from frictionless contact always instantaneously reduces part misalignment. We show that, for bounded misalignments, if an admittance satisfies the misalignment-reducing conditions …

Modelling Solids Friction Factor For Dense-Phase Pneumatic Conveying Of Powders, Peter W. Wypych, David B. Hastie

Faculty of Engineering - Papers (Archive)

This paper presents results from an investigation into power-function modelling of solids friction factor for the dilute-phase and fluidised dense-phase (FDP) conveying of powders. Three different diameters/lengths of pipeline were used to generate a wide range of steady-state data and also explore important scale-up issues. The effect of pressure tapping locations on the data and derived models was also investigated. Different sets of power-function model solutions were used for comparison purposes and also to check scale-up stability and accuracy. Comparisons with predictions from recent models developed by other researchers are included. It is concluded that certain forms of the power …

Friction And Adhesion In Rigid Surface Indentation Of Nitrile Rubber, Stephen Jerrams

Articles

When a rigid body in the form of a plane strain indentor is forced into an elastomer, the asperities on the surface of the indentor are filled by the softer material. As depth of ingress increases, the rubber displaced into the indentor asperities exhibits stick-slip behaviour. The rubber adheres to the rigid body and if the depth of ingress is held at a maximum, the level of adhesion remains constant despite short-term load relaxation occurring in the rubber.

This text describes the influence of a range of factors on indentation forces and adhesion in rigid indentation of hydrogenated nitrile rubbers. …

Analysis Of Computational Methods For The Treatment Of Material Interfaces, Minh C. Nguyen

Theses and Dissertations

Rocket sled tests at the Air Force Research Laboratory's Holloman High Speed Test Track frequently approach velocities where gouging development becomes the limiting factor to achieving higher operating velocities. Direct observation of the gouging process is not possible so computational modeling is necessary to study the phenomenon. Since gouging development is dependent on the impact surface conditions, the method used to model material interfaces directly affects the accuracy of the solution. Three methods are available in the hydrocode CTH to handle material interfaces: 1) materials are joined at the interface, 2) a frictionless slide line is inserted, and 3) a …

Friction In The Roll Bite Under Various Hot Rolling Conditions, Weihua Sun, A. K. Tieu, Hongchun Li, Zhengyi Jiang, Guodong Wang, Xianghua Liu

Faculty of Engineering - Papers (Archive)

In this paper, the effect of hot rolling parameters on the friction coefficient was studied by inverse calculation on the experimental roll loads where the hot rolling experiments were carried out at

7.5-45.0% reductions, 0.12-0.72m/s speeds and temperature of 850-1025°C. Dry rolling, water, oil/water mixture emulsion and pure oil were used as lubricants in the experiments. In carrying out the calculation, a flow stress model for the present test material was first obtained experimentally. Hot rolling parameters, including reduction, roll speed, work piece entry temperature and lubrication conditions, were investigated to determine their effect on friction coefficient and mill loads. …

Friction And Asperity Contact In Strip Rolling, A. K. Tieu, Zhengyi Jiang, Cheng Lu, Prabuono B. Kosasih

Faculty of Engineering - Papers (Archive)

This paper reviews different aspects of friction and asperity contacts in strip rolling. The mixed film lubrication model considers the effect of asperity flattening and the lubrication within the working zone. The oil concentration of the emulsion at entry and throughout the roll bite is considered together with the thermal effects of the contacts. The actual area of contact due to asperity deformation can be determined from a 3-wavelength FEM model. The deformation of a randomly generated surface of the hot strip with oxide scale can also be modeled by an FEM method. The friction variation in the roll bite …

3d Finite Element Analysis Of Surface Roughness And Friction In Hot Strip Rolling, Zhengyi Jiang, A. K. Tieu

Faculty of Engineering - Papers (Archive)

Surface roughness of oxide scale and strip in hot strip rolling has a significant influence on the friction and lubrication conditions. In this paper, the authors present the measured surface roughness of oxide scale and strip by Atomic Force Microscope (AFM) and Surface Profilometer respectively for hot rolled strip on a Hille 100 experimental rolling mill. Based on the friction coefficient determined through a sensor roll on the rolling mill, a 3D rigid visco-plastic finite element simulation was carried out, and the relationship between the surface roughness and friction coefficient was investigated. Results show that the lubrication in hot strip …

Admittance Selection For Force-Guided Assembly Of Polygonal Parts Despite Friction, Shuguang Huang, Joseph M. Schimmels

Mechanical Engineering Faculty Research and Publications

An important issue in the development of force guidance assembly strategies is the specification of an appropriate admittance control law. This paper identifies conditions to be satisfied when selecting the appropriate admittance to achieve force-guided assembly of polygonal parts for multipoint contact with friction. These conditions restrict the admittance behavior for each of the various one-point and two-point contact cases and ensure that the motion that results from contact reduces part misalignment for each case. We show that, for bounded friction and part misalignments, if the identified conditions are satisfied for a finite number of contact configurations and friction coefficients, …

Velocity Effects On The Wear, Friction And Tribochemistry Of Aluminum Mmc Sliding Against Phenolic Brake Pad

A.S. Md Abdul Haseeb

Two aluminum metal matrix composites (MMC) reinforced with 13 vol.% of SiC or B4C particles were made by stir casting followed by hot extrusion. Effects of sliding velocity on the wear, friction and tribochemistry of the worn surfaces of both composites sliding against a commercial phenolic brake pad have been investigated under dry condition. The wear tests were carried out using a pin-on-disc type apparatus at two linear sliding speeds: 1.62 and 4.17 m s-1 under a constant contact pressure of 0.75 MPa for a sliding distance of 5832 m. The coefficient of friction was recorded and wear rate of …

Velocity Effects On The Wear, Friction And Tribochemistry Of Aluminum Mmc Sliding Against Phenolic Brake Pad

A.S. Md Abdul Haseeb

Two aluminum metal matrix composites (MMC) reinforced with 13 vol.% of SiC or B4C particles were made by stir casting followed by hot extrusion. Effects of sliding velocity on the wear, friction and tribochemistry of the worn surfaces of both composites sliding against a commercial phenolic brake pad have been investigated under dry condition. The wear tests were carried out using a pin-on-disc type apparatus at two linear sliding speeds: 1.62 and 4.17 m s-1 under a constant contact pressure of 0.75 MPa for a sliding distance of 5832 m. The coefficient of friction was recorded and wear rate of …

Effect Of Fullerene Containing Lubricants On Wear Resistance Of Machine Components In Boundary Lubrication, Andriy Titov

Dissertations

Fullerenes, a new form of carbon nanomaterials, possess unique physical and mechanical properties that make their use as additives to liquid lubricants potentially beneficial. The goal of this study was to investigate the effect of fullerene containing lubricants on wear resistance of steel-bronze couples operating under boundary lubrication conditions. A mathematical model of deformed asperity contact was built to calculate real contact area and real contact pressure. Computer controlled wear friction testing methodology and equipment were designed, developed and implemented for obtaining reliable and objective experimental data. In addition, optical and scanning electron microscopy and standard surface texture analysis were …

Admittance Selection For Planar Force-Guided Assembly For Single-Point Contact With Friction, Shuguang Huang, Joseph M. Schimmels

Mechanical Engineering Faculty Research and Publications

This paper identifies procedures for selecting the appropriate admittance to achieve reliable planar force-guided assembly for single-point frictional contact cases. A set of conditions that are imposed on the admittance matrix is presented. These conditions ensure that the motion that results from contact reduces part misalignment. We show that, for bounded misalignments, if an admittance satisfies the misalignment-reduction conditions at a finite number of contact configurations and a given coefficient of friction /spl mu//sub M/) then the admittance will also ensure that the conditions are satisfied at all intermediate configurations for all coefficients less than /spl mu//sub M/.

On Friction And Surface Cracking During Sliding Of Ice On Ice, Maurine Montagnat, Erland M. Schulson

Dartmouth Scholarship

As a complement to earlier measurements on the friction of both granular fresh-water ice and S2 columnar salt-water ice, new experiments were performed on the friction of S2 columnar fresh-water ice sliding against itself at low velocities (5 × 10−7 to 5 × 10−1 m s−1) and at −10°C, using the same double-shear device as was used earlier. The results showed that under a given set of experimental conditions the kinetic coefficient of friction of S2 fresh-water ice compares favorably with that of the other two variants.The experiments also revealed friction-induced surface cracks and recrystallized grains.These deformation features are explained, …

Fretting Wear Of Metallic Multilayer Films

A.S. Md Abdul Haseeb

Fretting wear behaviour of electrodeposited Cu/Ni multilayer films with 10 and 5 nm thick sublayers has been investigated against a hardened steel ball as the counter body and compared with that of the constituents, Cu and Ni. The wear tests were carried out by using a ball-on-flat geometry at a translation frequency of 8 Hz and slip amplitude of 100 μm. Friction force was recorded on line during the tests. At the end of the tests, the wear scars were examined by laser surface profilometry, scanning electron microscopy and energy dispersive X-ray microanalysis. It has been observed that the frictional …

Design And Fabrication Of A Micro-Bearing Assembly To Study Rotor Friction, Daniel W. Brown

Journal of the Microelectronic Engineering Conference

The objective of this investigation was to design and fabricate a metrology tool for measuring the wear in micro-bearings. The critical component of the tool was a silicon test bed consisting of a bearing shaft and a set of microchannels to direct an air stream onto the fins of a micro-rotor assembled onto the bearing shaft. By driving the micro-rotor pneumatically, surface interactions between the bearing and the rotor can be studied over time. The silicon test bed mates to a custom aluminum chuck which has provisions for sealing the test bed and supplying air pressure from an external source. …

Turbine Blade Surface Roughness Effects On Shear Drag And Heat Transfer, Jess W. Drab

Theses and Dissertations

This work used scaled samples of actual turbine blade surfaces to characterize correlations between turbine surface roughness, friction coefficient, and convective heat transfer rate-parameters which affect an engine's efficiency and the blade's lifespan. For erosion/deposits, friction coefficients up to 250 times higher and convective heat transfer coefficients of up to 150 times higher were found when compared to a flat plate baseline. Other roughness types (pitting and fuel deposits) yielded less dramatic results. These results did not follow existing friction coefficient-to-heat transfer coefficient correlations, such as the Reynolds analogy. While these analytical and empirical correlations hold for flat plates, they …

Static Friction And Surface Roughness Studies Of Surface Micromachined Electrostatic Micromotors Using An Atomic Force/Friction Force Microscope, Sriram Sundararajan, Bharat Bhushan

Sriram Sundararajan

A technique to measure the static friction forces (stiction) encountered in surface micromachined micromotors using a commercial atomic force microscope (AFM)/friction force microscope has been developed and is described. An AFM tip is pushed against a rotor arm of the micromotor so as to generate lateral deflection (torsion) of the tip, which is measured by the AFM. The maximum value of the lateral deflection obtained prior to rotor movement (rotation) is a measure of the static friction force of the micromotors. This technique was employed to study the effect of humidity and rest time on the static friction force of …

Effect Of Mechanical Factors On Tribological Properties Of Palm Oil Methyl Ester Blended Lubricant

A.S. Md Abdul Haseeb

The effects of mechanical factors viz. applied load and temperature on the tribological performance of 5% palm oil methyl ester (POME) blended lubricant were studied using a steel-cast iron pair. Wear and frictional measurements were made using a stationary steel ball and a reciprocating cast iron plate in a modified universal wear and friction testing machine. The test conditions were contact pressure, 400 MPa; mean contact velocity, 0.34 m/s; reciprocating stroke, 80 mm; loads, 100-1100 N (fixed temperature); and temperature, 40-140°C (fixed load). Wear scar surfaces were investigated using scanning electron microscopy (SEM) to understand the wear mechanisms involved. Analysis …

Topography-Induced Contributions To Friction Forces Measured Using An Atomic Force/Friction Force Microscope, Sriram Sundararajan, Bharat Bhushan

Sriram Sundararajan

Most friction studies using an atomic force/friction force microscope, while concentrating on material-induced effects, often present users with conflicting and confusing interpretations of the topography-induced friction forces. It has been generally reported that topography-induced contributions are independent of scanning direction and can be removed by subtracting friction data from forward and backward scans. In this article, we present friction studies on samples with well-defined topography variations and find that the above-given statement is not generally true. At surface locations involving significant changes in topography, the topography-induced contributions to friction forces are found to be different between forward and backward scanning …

Utilizing Gis Technology To Improve Indot Pavement Friction Data Management And Distribution, Karen Zhu

JTRP Technical Reports

Pavement friction condition provides an important parameter in selecting highway rehabilitation and maintenance projects. The Research Division of Indiana Department of Transportation has been conducting annual pavement friction testing on the Indiana highway network. Due to the large amount of data accumulated, an efficient system is in demand for data management. In this project, we developed a computer program that constitutes an integrated system for friction data management and distribution. In the developed system, database technology was utilized for data storage and organization; networking technology was utilized for real-time data distribution; geographic information systems (GIS) technology as well as computer …

Neurocontroller Alternatives For "Fuzzy" Ball-And-Beam Systems With Nonuniform Nonlinear Friction, Danil V. Prokhorov, Donald C. Wunsch, Paul H. Eaton

Electrical and Computer Engineering Faculty Research & Creative Works

The ball-and-beam problem is a benchmark for testing control algorithms. Zadeh proposed (1994) a twist to the problem, which, he suggested, would require a fuzzy logic controller. This experiment uses a beam, partially covered with a sticky substance, increasing the difficulty of predicting the ball's motion. We complicated this problem even more by not using any information concerning the ball's velocity. Although it is common to use the first differences of the ball's consecutive positions as a measure of velocity and explicit input to the controller, we preferred to exploit recurrent neural networks, inputting only consecutive positions instead. We have …

Effect Of Inhibitor On Electrochemical Behavior Of 1cr18 Stainless Steel In Acidic Solution Under Friction, Jinping Xiong

Journal of Electrochemistry

The electrochemical behavior of 1Cr18 stainless steel had been studied using a reciprocating triboelectrochemical equipment under friction in 0.2 mol/L H2SO4 solution with and without addition of thiourea, the frictionized surface of 1Cr18 stainless steel had been examined by the SEM, XPS and IR. The results showed that the loss rate of 1Cr18 stainless steel in the solution could be reduced by addition of thiourea. The adsorption of thiourea on the surface of 1Cr18 stainless steel prohibited the oxidization of Cr3+ to form Cr() and formation of passive film consisting of CrO42- or/and Cr(), and make the passive range to …

Computer Control Of Machines With Friction For Precise Motion, Simon Webb, Zheng Li, Christopher David Cook

Faculty of Engineering - Papers (Archive)

We study the problem of precise control of machines with static and Coulomb friction. An experimental X-Y testbed built for testing various control methods is described and initial experimental results are presented. A simple pole placement controller is designed for computer control of the X-Y testbed based on a generalised sampled-data hold. Robustness and stability of the controller are analysed. Simulation suggests that this controller is able to achieve precise position control even when parameters of both the dynamics of the machine and the characteristics of friction are unknown

Stay-In-Place Deck Panels - Horizontal Shear Strength Of Bridge Deck Panels - Part 2, Phani Kumar Nukala, J. A. Ramirez, Robert H. Lee, Menashi D. Cohen

JTRP Technical Reports

One of the most economic methods of bridge deck construction consists of prestressed concrete deck panels used in stay-in-place forms in conjunction with the cast-in-place concrete topping instead of the traditional monolithic roadway deck slabs. The performance of this type of deck as a composite unit is only possible if the horizontal shear stress resulting from bending of the deck if effectively transferred across the interface of the two elements. It is assumed that horizontal shear stresses are transmitted across the interface due to bond between the precast panel and cast-in-place concrete acting in conjunction with the horizontal shear connectors …

Frictional Performance Of Pavements And Estimates Of Accident Probability [Dec. 1980], James L. Burchett, Rolands L. Rizenbergs

Kentucky Transportation Center Research Report

Objectives of this study were to evaluate standard and experimental surfaces throughout Kentucky in terms of skid resistance and effects of traffic, and to provide criteria for judging suitability of these surfaces to satisfy requirements for skid resistance and economics. The effects of traffic were quantified by regression analysis and scatter of data. Criteria included an estimate of accident risks, effects of speed on skid resistance, and seasonal variations in skid resistance.

Pavements on low volume roads (less than 1,000 vehicles per day) maintained adequate skid resistances. Open-graded friction courses, with the possible exception of sections using phosphate slag aggregate, …

Analysis Of Heat Generation And Temperature In High Speed, High Temperature Bearing Balls, Hans R. Ringger

Theses and Dissertations

This thesis reports an investigation of the generation of heat on, and the prediction of temperature of high-speed, dry-film lubricated, stainless steel bearing balls.

Skid Resistance Of Pavements [Sept. 1972], Rolands L. Rizenbergs, James L. Burchett, Cass T. Napier

Kentucky Transportation Center Research Report

Standard pavement types and experimental surfaces on roads throughout Kentucky were evaluated in terms of skid resistance and effects of traffic, wear, and polishing. Friction-vs-speed gradients and the relationships between locked-wheel and incipient friction were determined. Asphaltic concrete pavements on high-speed, four-lane roads were found to be significantly more skid resistant than on two-lane highways and somewhat more skid resistant than concrete surfaces (especially those containing calcareous gravel aggregates). Sand-asphalt surfaces containing significant proportions of limestone sands showed inadequate level of friction for the traffic sustained. Several experimental sand asphalts without limestone sands exhibited greater skid resistance; Kentucky rock asphalt …

Florida Skid Correlation Study Of 1967 – Skid Testing With Automobiles, Rolands L. Rizenbergs

Kentucky Transportation Center Research Report

The inclusion of automobiles in the Florida skid correlation study was promoted by the recognition of the following needs: 1) to compare stopping-distance measurements obtained with different instrumentation, 2) to suggest a standard method of stopping-distance testing, 3) to relate skid-resistance measurements of trailer-type testers with stopping distances of automobiles, and 4) to explore other skid-resistance measurements techniques using an automobile.

The vehicles were all full-size automobiles. Each vehicle was instrumented to measure a distance from a predetermined pressure in the brake hydraulic system to where the vehicle came to rest. Stopping distance in most of the automobiles was read …

A Study Of Frictional Drag Force Reduction On A Flat Plate By The Injection Of A Dilute Solution Of Guar Gum Into The Boundary Layer, Neil Henry Clay

Theses and Dissertations

The study of frictional drag force reduction has been the subject of much research for many years. One of the significant developments in the field of frictional drag force reduction has been the discovery of the effectiveness of dilute polymer solutions in reducing drag. By using dilute high-polymer solutions frictional drag forces in pipe flow have been reduced by as much as 70 per cent.