15 research outputs found
Normal heat conductivity in two-dimensional scalar lattices
The paper revisits recent counterintuitive results on divergence of heat
conduction coefficient in two-dimensional lattices. It was reported that in
certain lattices with on-site potential, for which one-dimensional chain has
convergent conductivity, for the 2D case it turns out to diverge. We
demonstrate that this conclusion is an artifact caused by insufficient size of
the simulated system. To overcome computational restrictions, a ribbon of
relatively small width is simulated instead of the square specimen. It is
further demonstrated that the heat conduction coefficient in the "long"
direction of the ribbon ceases to depend on the width, as the latter achieves
only 10 to 20 interparticle distances. So, one can consider the dynamics of
much longer systems, than in the traditional setting, and still can gain a
reliable information regarding the 2D lattice. It turns out that for all
considered models, for which the conductivity is convergent in the 1D case, it
is indeed convergent in the 2D case. In the same time, however, the length of
the system, necessary to reveal the convergence in the 2D case, may be much
bigger than in its 1D counterpart.Comment: 6 pages, 6 figure
The Evolution of Static Friction for Elastic-Plastic Spherical Contact in Pre-sliding
The evolution of static friction and tangential stiffness in presliding of an elastic-plastic sphere in contact with a rigid flat, under full stick contact condition, is analyzed. Empirical dimensionless equations are developed for these parameters
Modelling the criticality of silicon nitride surface imperfections under rolling and sliding contact
Ceramic rolling elements of hybrid bearings may initially include surface imperfections. In order to provide reliable operation of a bearing, the criticality of such imperfections under rolling contact fatigue is examined by defining them as Star features: intersecting semi-elliptical surface cracks. Parametric study is conducted using Finite Element Method and discussed with help of previously published experimental observations. The effects of the Star feature morphology and configuration, contact pressure and crack face friction are investigated in terms of stress intensity factors. Possible crack propagation scenarios are explained in the present study