Variational bounds and integral relations method in problems of stability

The aim of this work is to analyze the steady-shear rheological behavior and the absolute viscosity of epoxy matrix reinforced with graphene nanoplatelets (xGnP) before cure. Three different grades of xGnP (grades C, M and H) were dispersed homogenously at different weight percentages (wt%) into the epoxy matrix, ranging from 0.5 to 5 wt%. It is found that nanocomposite fluids with xGnP-C exhibit a Newtonian behavior at shear rate in the range 0.1–100 s−1, conversely, nanocomposite fluids with xGnP of grade M and H exhibit a shear-thinning behavior with the increase of nanoplatelet loading. Results from this analysis indicate how the steady shear rheological properties of the nano-reinforced polymer fluids depend on the geometrical characteristics of the graphene nanoplatelets.

Steady-shear rheological properties of graphene-reinforced epoxy resin for manufacturing of aerospace composite films

This survey is devoted to some typical problems modeling technological processes of treatment of materials, rolling of a rigid body on a lubricated surface, the behavior of layers of the Earth’s crust for continuous loading, and dynamical interaction of elements of viscoplastic constructions.

Hydrodynamical and computational aspects and stability problems for viscoplastic flows

The equations describing the flow of a viscoplastic fluid on a rotating disk are derived and are solved by perturbation technique and numerical computation respectively for 2 cases. This makes it possible to calculate the thickness distribution of film. Two kinds of distribution of thickness have been found. For the viscoplastic fluid for which both viscosity and yield stress are independent of radial coordinate r, the thickness h decreases with increasing r. For a Bingham fluid for which both viscosity and yield stress are function of time and r, the thickness h increases with increasing r.

/pdf/flow-of-a-viscoplastic-fluid-on-a-rotating-disk-4h1j9ykkl2.pdf

Flow of a viscoplastic fluid on a rotating disk

The flow problem given in the title has been considered for a modified Maxwell fluid. The resulting spin line equation is solved both numerically and analytically. It has been found that the results obtained by the above two methods are in agreement. This confirms the accuracy of the perturbation method which we adopted.

范椿

Papers

Flow of a viscoplastic fluid on a rotating disk

The steady isothermal spinning of viscoelastic fluids