Gear’s normal contact stiffness played an important role in the mechanical equipment. In this paper, the M-B fractal model is modified and the contact surface coefficient is put forward to set up the fractal model, considering the influence of friction, which could be used to calculate accurately the involute arc cylindrical gears’ normal contact stiffness based on the fractal theory and Hertz ...

The obscrved semidiurnal wind in the troposphere at five niid-latmit,ude stations shows a, phase lead over the wind dcduccd from frictionlcss theory, and a smaller amplitude, espccially near the earth’s surface, than the theoretical value. By making use of the obscrved fact that the tidal pressure-dependent (frictionless) wind changes much less rapidly with height than does the observed wiiid i...

We consider a widely used higher order glacier flow model with a variety of parameterizations of wall slip, including Coulomb friction, regularized Coulomb friction laws and a power law. Mathematically, the Coulomb friction problem is found to be analogous to a classical friction problem in elasticity theory. We specifically analyze the case in which slip is possible everywhere at the boundary,...

The oil film behavior of a series of fifteen lubricating oils was tested in a single cylinder spark ignition engine. The oil film thickness between the piston and cylinder liner of this engine was observed using the Laser Induced Fluorescence (LIF) technique. The data was examined for correlations between physical properties of the oil and characteristics of the oil film. The region of the oil ...

A baseline theory is developed in this paper for the design of oil-lubricated centrally pivoted plane-pad thrust bearings. By focusing on the hydrodynamics generated by the viscosity-temperature effects of the lubricating oil, a mathematical model is derived with a single dimensionless parameter Wth. The nominal value of Wth is 0.1 for typical pad bearings in current industrial practice. The th...

In the analysis of orthogonal cutting process using FE simulations, predictions are greatly influenced by two major factors; a) flow stress characteristics of work material at cutting regimes and b) friction characteristics mainly at the chip-tool interface. The influence of work material flow stress upon FE simulations may be less or even none when there is a constitutive model for work materi...

We have applied both the master equation method and harmonic transition state theory to interpret the velocity-dependent friction behavior observed in atomic friction experiments. To understand the discrepancy between attempt frequencies measured in atomic force microscopy experiments and those estimated by theoretical models, both thermal noise and instrumental noise are introduced into the mo...

The failure reasons of reciprocating sealing in OPI-1800AWS fracturing pump are analyzed by scanning electron microscope technology (SEMT). The lubrication mechanism of plunger seal friction pair is analyzed by hydrodynamic lubrication theory. During its discharge and suction stroke, the reciprocating sealing friction pair meets the conditions of hydrodynamic lubrication, a certain thickness of...

We have examined the influence of rotation on the potential energy and the transport coefficients of the collective motion (friction and mass coefficients). For axially symmetric deformation of nucleus 224 T h we found that at excitations corresponding to temperatures T ≥ 1 M eV the shell correction to the liquid drop energy practically does not depend on the angular rotation. The friction and ...

The interlayer sliding potential of multilayered hexagonal boron nitride (h-BN) and graphene is investigated using density-functional theory including many-body van der Waals (vdW) interactions. We find that interlayer sliding constraints can be employed to tune the contribution of electrostatic interactions and dispersive forces to the sliding energy profile, ultimately leading to different sl...