The Experts below are selected from a list of 4233 Experts worldwide ranked by ideXlab platform

Hitoshi Washizu - One of the best experts on this subject based on the ideXlab platform.

  • coarse grained model for spring friction study of micron scale iron by smoothed particle hydrodynamics
    EPL, 2018
    Co-Authors: Le Van Sang, Akihiko Yano, Shuji Fujii, Natsuko Sugimura, Hitoshi Washizu
    Abstract:

    The paper presents the construction of a coarse-grained model to investigate dry sliding friction of the body-centered-cubic Fe micron-scale system by smoothed particle hydrodynamics simulations and examines influences of the spring force on the characters of friction. The atoms Fe system is coarse-grained into the two different simple-cubic particle systems, one of 432000 and the other of 16000 particles. From the detection of Stick-Slip Motion, friction coefficient, dependence of friction coefficient on isotropy or anisotropy of the spring force and externally applied normal load, we find that the coarse-grained model is a reasonable modeling process for the study of the friction of the Fe system, and the anisotropic behavior presents better friction of the system than the isotropic one.

  • Coarse-grained model for spring friction study of micron-scale iron by smoothed particle hydrodynamics
    'IOP Publishing', 2018
    Co-Authors: Le Van Sang, Akihiko Yano, Shuji Fujii, Natsuko Sugimura, Hitoshi Washizu
    Abstract:

    The paper presents the construction of a coarse-grained model to investigate dry sliding friction of the body-centered-cubic Fe micron-scale system by smoothed particle hydrodynamics simulations and examines influences of the spring force on the characters of friction. The $N_{atom} =864\times 10^{12}$ atoms Fe system is coarse-grained into the two different simple-cubic particle systems, one of 432000 and the other of 16000 particles. From the detection of Stick-Slip Motion, friction coefficient, dependence of friction coefficient on isotropy or anisotropy of the spring force and externally applied normal load, we find that the coarse-grained model is a reasonable modeling process for the study of the friction of the Fe system, and the anisotropic behavior presents better friction of the system than the isotropic one

Laurent Limat - One of the best experts on this subject based on the ideXlab platform.

  • Advancing liquid contact line on visco-elastic gel substrates: Stick-Slip vs. continuous Motions
    Soft Matter, 2012
    Co-Authors: Tadashi Kajiya, Adrian Daerr, Francois Lequeux, Tetsuharu Narita, Laurent Royon, Laurent Limat
    Abstract:

    We studied the dynamics of water sessile droplets advancing on hydrophobic and visco-elastic poly(styrene-butadiene-styrene)(SBS)–paraffin gel substrates at various inflation rates. During the advancing process, the droplet contact line exhibits three different regimes of Motions. When the contact line advances at a high velocity, it moves continuously with a constant contact angle. As the contact line slows down, it starts a Stick-Slip Motion: the contact line is pinned at a certain position and then suddenly Slips forward. With further decrease of the velocity, the contact line stops the Stick-Slip Motion and continuously advances again. The observed threshold values for the transitions of the contact line Motions (continuous–Stick-Slip–continuous) indicate that the rheology of the gel drastically affects the dynamics of liquid on its surface. We suggest that on visco-elastic gels, the moving contact line exhibits both aspects of wetting on elastic solids and wetting on viscous liquids depending on the characteristic frequency of the gel surface deformation. At an intermediate regime, the Stick-Slip Motion of the contact line appears. We also propose a simple geometrical model in the Stick-Slip regime which allows us to relate the jumps of the droplet radius to the jumps of the apparent contact angle

  • moving contact lines of a colloidal suspension in the presence of drying
    Langmuir, 2006
    Co-Authors: Emmanuelle Rio, Adrian Daerr, Francois Lequeux, Laurent Limat
    Abstract:

    This article presents the first experimental study of an advancing contact line for a colloidal suspension. A competition between the hydrodynamic flow due to the drop velocity and the drying is exhibited: drying accounts for particle agglomeration that pins the contact line whereas the liquid flow dilutes the agglomerated particles and allows the contact line to advance continuously. The dilution dominates at low concentration and high velocity, but at high concentration and low velocity, the contact line can be pinned by the particle agglomeration, which leads to a Stick-Slip Motion of the contact line. The calculation of the critical speed splitting both regimes gives an order of magnitude comparable to that of experiments. Moreover, a model of agglomeration gives an estimation of both the size of the wrinkles formed during Stick-Slip and the force exerted by the wrinkle on the contact line.

Paul J Winberry - One of the best experts on this subject based on the ideXlab platform.

  • basal mechanics of ice streams insights from the Stick Slip Motion of whillans ice stream west antarctica
    Journal of Geophysical Research, 2009
    Co-Authors: Paul J Winberry, Sridhar Anandakrishnan, Richard B Alley, Robert Bindschadler, Matt A King
    Abstract:

    The downstream portion of Whillans Ice Stream, West Antarctica, moves primarily by Stick-Slip Motion. The observation of Stick-Slip Motion suggests that the bed is governed by velocity-weakening physics and that the basal physics is more unstable than suggested by laboratory studies. The Stick-Slip cycle of Whillaňs Ice Plain exhibits substantial variability in both the duration of Sticky periods and in Slip magnitude. To understand this variability, we modeled the forces acting on the ice stream during the Stick phase of the Stick-Slip cycle. The ocean tides introduce changes in the rate at which stress is applied to the ice plain. Increased loading rates promote earlier failure and vice versa. Results show that the bed of Whillans Ice Stream strengthens over time (healing) during the quiescent intervals in the Stick-Slip cycle, with the bed weakening during Slip events. The time-dependent strengthening of the ice plain bed following termination of Slip events indicates that the strength of the bed may vary by up to 0.35 kPa during the course of a single day. Copyright 2009 by the American Geophysical Union.

Yongsheng Leng - One of the best experts on this subject based on the ideXlab platform.

  • Stick Slip friction and energy dissipation in boundary lubrication
    Physical Review Letters, 2011
    Co-Authors: Yajie Lei, Yongsheng Leng
    Abstract:

    Shearing of a simple nonpolar film, right after the liquid-to-solid phase transition under nanometer confinement, is studied by using a liquid-vapor molecular dynamics simulation method. We find that, in contrast with the shear melting and recrystallization behavior of the solidlike phase during the Stick-Slip Motion, interlayer Slips within the film and wall Slips at the wall-film interface are often observed. The ordered solidified film is well maintained during the Slip. Through the time variations of the frictional force and potential energy change within the film, we find that both the friction dissipation during the Slip and the potential energy decay after the Slip in the solidified film take a fairly large portion of the total energy dissipation.

Chunli Bai - One of the best experts on this subject based on the ideXlab platform.

  • friction coefficients derived from apparent height variations in contact mode atomic force microscopy images
    Langmuir, 1999
    Co-Authors: Chen Wang, Guangyi Shang, Zhang Lin, And Jingjiao Guan, Chunli Bai
    Abstract:

    Self-organized monolayer domains of liquid crystal (LC) on mica surface were investigated by contact mode atomic force microscopy (AFM) and friction force microscopy (FFM). By analyzing contributions of friction to the apparent height in AFM height images, we calculated the friction forces and the relevant friction coefficients. It is observed that the difference between the magnitude of the friction force on LC monolayers and mica was proportional to the normal load. The friction coefficients of the LC monolayers and bare mica were obtained as 0.076 and 0.094, respectively. In addition, frictional asymmetry of LC monolayers was observed in our study, which was attributed to the molecular tilt, and a possible explanation was proposed in terms of the Stick−Slip Motion of the tip apex on the molecular scale.