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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
51

Analysis of Heat Generation and Temperature in High Speed, High Temperature Bearing Balls

Ringger, Hans R. 01 April 1973 (has links)
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.
52

A survey of cylindrical bearing practice of the United States

Yates, Chapin Winston January 1940 (has links)
A complete summary of this thesis would be too lengthy due to the amount of material covered, so only the most important points will be brought out. (a) The journal bearing is one of the most important elements of machinery. (b) An outline of the fundamentals of oiling and grooving bearings has been given. The bearing metals and the lubricants in use today and the functions of the lubricating engineer have been discussed. (c) Present day journal bearing practices have been described for the following types of equipment: automobile engines, aircraft engines, Diesel engines, steam turbines, electric motors, and generators, rolling mills, railroad cars and engines, heavy duty equipment, line shafting, gyroscopes, ships and steam engines. (d) The basic theory of the perfectly lubricated journal bearing is understood, but exact mathematical solution of the phenomena occurring within the bearing is as yet impossible. (e) By coordinating mathematical investigation and experimental evidence, a fairly good analysis can be made of journal bearing behavior. (f) Needs rational method of designing bearings is a good example of well coordinated mathematical investigation and experimental results. This method of analysis gives the designer a fairly accurate indication of the performance of a journal bearing to be expected. (g) Because of the limitations of theory a large number of manufacturers do extensive research and experimental work in conjunction with their products, to aid in the development of the Journal bearings used. (h) Those interested in further study on this subject are advised to study references 79 and 80 in addition to those already mentioned. Reference 79 is a survey of bearing practice undertaken in 1934 by H.A.S. Howarth. This survey is a valuable adjunct to this thesis, yet is too long to repeat here. Reference 80 is another article by Howarth summarizing the important formulas and charts that had been offered by bearing analysts during the years prior to 1935. / Master of Science
53

Frequency Response Based Repetitive Control for Periodic Coefficient Systems Motivated by Cam Followers

Yau, Henry January 2017 (has links)
Cam follower systems are generally designed to operate at a fixed speed or a range of fixed speeds. However manufacturing defects, wear, or a change of design goals may require altering the camshaft speed to produce a follower trajectory which is not possible using a fixed speed. The follower trajectory may also be optimized for some performance criteria such as minimizing vibration and wear. Like most real world systems, the differential equations governing a cam follower system are nonlinear. A common approach for controlling a nonlinear system is to first linearize the system about a nominal operating point, then apply linear control laws. In many cases, such as the cam follower system, one can create a trajectory and numerically solve the nonlinear system for the inputs required to follow it. Linearizing about this solution creates a linear time varying system whose states are deviations from the desired solution. The speed trajectory in the cam follower system is periodic, which results in a linear system with periodic coefficients. Repetitive control creates control systems that aim to converge to zero tracking error following a periodic command, or aim to completely cancel the effects of a periodic disturbance. Using the inverse of the steady state frequency response as a compensator has been shown to be very effective for linear time invariant systems. That idea is applied here to linear time periodic systems. The periodic state matrices lend themselves well to frequency domain representations, which can be used to construct a matrix form of the steady state frequency response. The first law studied in this work analyzes a moving window implementation which monitors the output errors and previous commands to create an update to the change in the command for the current time step using the inverse of the steady state frequency response matrix. Asymptotic convergence conditions for zero tracking error are derived. When the number of samples in one period is not an integer number, the moving window method is not feasible without interpolation. Therefore a second method based on the projection algorithm from adaptive control is developed and analyzed. In linear constant coefficient systems, one generally needs to incorporate a frequency cutoff filter to robustify to high frequency model error. The additional intricacies of designing a cutoff filter for periodic systems is considered, aiming to handle the fact that for periodic coefficient systems, addressing error components below the intended cutoff can excite harmonics above the cutoff. The control laws developed in this work are applicable to any nonlinear system which may be linearized about a periodic trajectory. Development of these control laws is motivated by improving the performance of a cam follower system. Additional improvements in cam follower behavior can be done through parameter optimization. This includes optimizing a nonlinear follower spring such that it provides just sufficient force to maintain contact while reducing the load on the cam.
54

Zinc pot bearing material wear rate as a function of contact pressure and velocity

Snider, James M. January 2002 (has links)
Thesis (M.S.)--West Virginia University, 2002. / Title from document title page. Document formatted into pages; contains x, 80 p. : ill. (some col.). Includes abstract. Includes bibliographical references (p. 69-70).
55

Compliant mechanisms to perform bearing and spring functions in high precision applications /

Cannon, Jesse R., January 2004 (has links) (PDF)
Thesis (M.S.)--Brigham Young University. Dept. of Mechanical Engineering, 2004. / Includes bibliographical references (p. 83-85).
56

Influence of microstructure in rolling contact fatigue of bearing steels with inclusions

Alley, Erick Shaw. January 2009 (has links)
Thesis (M. S.)--Mechanical Engineering, Georgia Institute of Technology, 2009. / Committee Chair: Neu, Richard; Committee Member: Damm, E. Buddy; Committee Member: Gall, Ken; Committee Member: Gokhale, Arun; Committee Member: McDowell, David; Committee Member: Zhou, Min
57

Development of lead-free PTFE based sliding bearing materials /

Khoddamzadeh, Alireza. January 1900 (has links)
Thesis (M.App.Sc.) - Carleton University, 2007. / Includes bibliographical references (p. 132-139). Also available in electronic format on the Internet.
58

Friction of a lubricated journal bearing.

Bickell, William A. January 1923 (has links)
No description available.
59

A CADAM interface for the computer-aided selection of Timken tapered roller bearings

Ciabattoni, Dino January 1987 (has links)
This thesis presents an interactive computer-graphics geometry interface that simplifies the tapered roller bearing selection procedure. An applications program has been developed that links the CADAM data base to SELECT-A-NALYSIS (SAN), Timken's bearing selection and analysis program. The independent modular format of the SAN preprocessor eliminates the ambiguity and difficulty associated with conventional bearing selection routines. Interactive-graphic menu selection allows program logic to be followed while design geometry is selected from a CADAM model. In addition to the discussion of the program development and structure, step-by-step instructions for an example problem are provided. Complete program listings are also supplied to facilitate future additions and modifications to the preprocessor. / M.S.
60

An experimental study of fretting corrosion at a bearing/cartridge interface

Frantz, Robert Dean January 1983 (has links)
A device has been built to study fretting corrosion phenomena at a bearing/cartridge interface. The research is a continuation of a larger study funded by the Naval Research Laboratory. Its main objective is to determine the important parameters influencing fretting and fretting corrosion in rolling element bearings. The new device is capable of varying load from zero to 200 N (45 lbf), amplitude of vibration from zero to 500 µm (0.0197 in.), and frequency from 2.5 to 100 Hz for axial relative motion. Five sets of bearings and cartridges can be tested simultaneously at the same amplitude and frequency of vibration. Using this device with 52100 hardened steel bearings mounted in SAE 1020 steel cartridges, five analyses were carried out to investigate how load, frequency, amplitude, and presence of a grease influence the extent of fretting corrosion at the interface. / M.S.

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