A ®nite element model for investigating damage evolution in brittle matrix composites was developed. This modeling is based on an axisymmetric unit cell composed of a ®ber and its surrounding matrix. The unit cell was discretized into linearly elastic elements for the ®ber and the matrix and cohesive elements which allow cracking in the matrix, ®ber-matrix interface, and ®ber. The cohesive elem...

This paper is concerned with the convective instabilities associated with the boundary-layer flow due to a rotating disk. Shear-thinning fluids that adhere to the power-law relationship are considered. The neutral curves are computed using a sixth-order system of linear stability equations which include the effects of streamline curvature, Coriolis force and the non-Newtonian viscosity model. A...

This study uses a torsional split-Hopkinson bar to investigate the shear response and fracture characteristics of unweldable Al-Sc alloy during mechanical testing at shear strain rates of 800 s , 1500 s , 2200 s 1 and 2800 s 1 and temperatures of 150 C, 25 C and 300 C. The experimental results show that both the shear strain rate and the temperature have a significant effect on the shear proper...

a mathematical analysis has been carried out for the axial flow of a bingham plastic fluid, in the concentric cylinder viscometer which consists of a cylindrical sample holder (the cup) and a cylindrical spindle (the bob) coaxial with the cup. the fluid to be tested flows through the annular gap of the cup and the bob system, sheared by the rotation of the inner cylinder, while the outer cylind...

This paper examines two-dimensional vortex motion in a shear-flow with nonuniform vorticity. Typically, a vortex travels to an extremum in the background vorticity distribution. In general, the rate of this migration increases with the magnitude of the background vorticity gradient; however, a retrograde vortex, which rotates against the local shear, moves orders of magnitude faster than a prog...

The role of hemodynamics on platelet thrombus formation was studied in venules and arterioles of the rat mesentery. Thrombus formation was induced by the fluorescent dye/light method for examination of the following factors: 1) the effect of wall shear rate on thrombus initiation, 2) the effect of wall shear rate on the growth of thrombi, and 3) the relation between platelet thrombus initiation...

The thermomechanical problem involving simple shearing of a finite slab made of an isotropic and viscoplastic material is studied with the objective of finding the e&t of the strain hardening parameter, strain-rate hardening parameters, thermal softening coeflicient and thermal conductivity on the initiation and growth of adiabatic shear bands. The body is placed in a hard loading device, i.e. ...

We explore the use of Large Amplitude Oscillatory Shear (LAOS) deformation to probe the dynamics of shear-banding in soft entangled materials, primarily wormlike micellar solutions which are prone to breakage and disentanglement under strong deformations. The state of stress in these complex fluids is described by a class of viscoelastic constitutive models which capture the key linear and nonl...

On the basis of a hydrodynamical model analogous to that in critical fluids, we investigate the influences of shear flow upon the electrostatic contribution to the viscosity of binary electrolyte solutions in the Debye-Hückel approximation. Within the linear-response theory, we reproduce the classical limiting law that the excess viscosity is proportional to the square root of the concentration...