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URN etd-0905112-112610
Author Shao-Heng Chang
Author's Email Address No Public.
Statistics This thesis had been viewed 5333 times. Download 708 times.
Department Mechanical and Electro-Mechanical Engineering
Year 2011
Semester 2
Degree Ph.D.
Type of Document
Language zh-TW.Big5 Chinese
Title Modeling of nano-particle motion: subjected to press of two moving bodies
Date of Defense 2012-07-13
Page Count 66
Keyword
  • adhesive strength
  • steady-state motion
  • molecular dynamics simulations
  • Abstract This dissertation aims to establish a mathematical model to predict the steady-state (stationary) motion of
    a nano-particle that is suppressed between two parallel moving objects. The main purpose of this study
    intends to find an appropriate means to reduce surface damage caused by moving nano-paricle. This study
    will show that, via the molecular dynamics (MD) analysis, the surface will result in different sizes of
    damaged layer and surface roughness when a nano-particle moves in a distinct way on it. Therefore, it has
    a significant value in the applications of high precision polishing and surface cleaning to identify the
    dominant factors in affecting the motion of nano-particle.
    The proposed model is to find the steady-state motion by meeting the conditions of force and torque
    balances on a moving nano-particle. Several hypotheses are suggested to derive the interaction force
    occurred at the interface between particle and each object. The hypothesis starts from the energy point of
    view. It is claimed that the potential and kinetic energies of object atoms will increase when nano-particle
    moves relative to the object. Because of the relative motion, some of the object atoms will be pushed or
    driven away, depending on the manner of motion. The increment of potential or kinetic energies is
    assumed to be proportional to the number of pushed or driven atoms. The increase of energy is supplied
    from the works done by the normal stress and shear stress at the interface of particle. The interaction at
    the front end of particle is very different from that at the rear end when particle rolls on object surface.
    There is a pushing action at the front end while a pulling action occurs at the rear end. The magnitudes of
    both actions are dominated and proportional to the adhesive strength between particle and object.
    The computer simulations show that the particle motion is mainly affected by the relative adhesive
    strength among particle and two objects. If the adhesive strength between particle and one object increase,
    the particle will increase the sliding speed relative to another object. On the other hand, if the adhesive
    strength between particle and one object is close to that of another object, the particle tends to have
    significant rolling motion relative to two objects. The suppressed loading between particle and objects has
    little effect on the qualitative trend of particle motion. The validity of proposed model is evaluated by the
    molecular dynamics simulation. It indicates that the predicted behaviors of proposed model are consistent
    with that from the analysis of molecular dynamics simulations.
    Advisory Committee
  • KUANG-HUA FUH - chair
  • Jung-Shu Wu - co-chair
  • Y.T. Sheen - co-chair
  • C.T. Pan - co-chair
  • Y.T.Su - advisor
  • Files
  • etd-0905112-112610.pdf
  • Indicate in-campus at 1 year and off-campus access at 2 year.
    Date of Submission 2012-09-05

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