The translational friction coefficient of a porous cylindrical disk moving in a sheet of fluid which is embedded on both sides in a fluid of different viscosity, is calculated numerically for a wide range of the relevant parameters. These results are used to evaluate the region of validity of certain asymptotic formulae which have been derived previously in the limit of small ratios of the visc...

The idea that snow avalanches might behave as granular flows, and thus be described as Coulomb fluid flows, came up very early in the scientific study of avalanches, but it is not until recently that field evidence has been provided that demonstrates the reliability of this idea. This paper aims to specify the bulk frictional behaviour of snow avalanches by seeking a universal friction law. Sin...

In this research, Forming Limit Diagrams for supertension sheet metals which are using in automobile industry have been obtained. The exerted strains to sheet metals have been measured with four different methods and the errors of each method have also been represented. These methods have been compared with together and the most efficient and economic way of extracting of the exerted strains to...

Forming limit curves (FLC) of deep drawing steel sheets have been determined experimentally and calculated on the base of the material tensile properties following the Hill, Swift, Marciniak-Kuczyński and Sing-Rao methods. Only the FLC modeled from a singly linear forming limit stress curve exhibits good consistence with experimental curve. It was established that a linearized limit stress locu...

Using sedimentation to obtain precisely controlled packings of noncohesive spheres, we find that the volume fraction phiRLP of the loosest mechanically stable packing is in an operational sense well defined by a limit process. This random loose packing volume fraction decreases with decreasing pressure p and increasing interparticle friction coefficient mu. Using x-ray tomography to correct for...

The first stage of the RTM process concerns the preforming of the part. During the preforming of multilayered reinforcements, frictions between the plies occur. An experimental device designed to analyse the ply/ply, ply/tool and yarn/yarn frictions has been set up. Specific contact behaviour for ply/ply friction is directly related to shocks taking place between overhanging yarns of each sampl...

Friction plays an important role in the behavior of flowing granular media. The effective friction coefficient is a description of shear strength in both slow and rapid flows of these materials. In this paper, we study the steady state effective friction coefficient μ in a granular material in two steps. First, we develop a new relationship between the steady state effective friction coefficien...

Fluorinated graphene/ultra high molecular weight polyethylene (FG/UHMWPE) composites were prepared by ultrasonic dispersion and hot pressing. The mechanical propertys and tribological property of pure UHMWPE and FG/UHMWPE composites were investigated by micro hardness tester and high-speed reciprocating friction tester. The wear volume of the sample was measured by the scanning electron microsc...