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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.
1

An analysis of induced phenomena caused by rolling motion of nano-particle against work surface :molecular dynamics approach

HU, Cheng-Chin 21 August 2003 (has links)
Abstract This study is to examine the phenomena caused by rolling action of a nano-particle against the work surface. The analysis was done by the molecular dynamics method. The distributed computing scheme was adopted in these simulations to increase the computing efficiency. The study includes the interfacial force between the nano-particle, the work and the roughness of the work surface, and the damage layer thickness of the work surface. It is done by first identifying the main factors, and then to understand how the phenomena is affected by these factors. Finally, the results of these simulations were discussed. The results show that the interactive force most comes from the breaking process between the work surface and the nano-particle. When the nano-particle¡¦s rolling speed is increased, the interactive force is enhanced. But if the speed has reached a high value, the interactive force will be saturated. The interactive force is not significantly affected by temperature. When the adhesive strength between the nano-particle and the work is higher, the interactive force is higher. The roughness of the work surface is affected by the rolling speed of the nano-particle, the temperature, and the adhesive strength between the nano-particle and the work. If the temperature or the interactive force is higher, the roughness of the work surface is higher. If the rolling speed is higher, the roughness of the work surface will increase. But if the rolling speed has reached a high value, the roughness of the work surface will not increase. The damage layer thickness of the work surface is little affected by the rolling speed of the nano-particle or temperature or the adhesive strength between the nano-particle and the work surface.
2

On Ultimate Improvement of Surface Roughness by Polishing Process; effects of work's wavelength

Tsai, Cheng-Min 02 July 2002 (has links)
The effects of work¡¦s surface wavelength on the ultimate surface roughness are considered in this study. Both the experimental and theoretical studies will be done in this study. In the experimental study, the relationships between ultimate surface roughness and various operating parameters will be examined. In the theoretical study, a mathematical model relating the machining rate and various machining parameters are proposed. In the mathematical model, qualitative and quantitative properties of machining rate under various surface geometric condition are obtained by the aid of computer simulation. For the experimental study, a series of experiments will be done to investigate the effects of various factors on the ultimate surface roughness of different work¡¦s surface wavelength.The factors may include the the tool speed, the tool¡¦s surface irregularity, and the particle density of slurry. The comouter simulation indicates that the removal rate is non-linear proportional to tool speed and normal load. Besides, results also showed that the difference of removal rate between peak and valley of surface profile always decreases as the work¡¦s surface wavelength increases. The experimental study confirmed that the relationship between ultimate roughness and wavelength does exist in the specific range of work¡¦s surface wavelength . The model appears to be consistent with currently available experimental data.

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