Non-homogeneous Strain Fields Research Articles

Effects of nonlocal damage in porous plastic solids

A nonlocal constitutive formulation for a porous ductile material is investigated, in which delocalization relates to the damage mechanism. An elastic-viscoplastic material model is used, with delocalization incorporated in terms of an integral condition on the rate of increase of the void volume fraction. Two model problems are analysed to study the effect of including this material length, one relates to localization of plastic flow in shear bands, while the other considers a metal matrix composite. Both model problems involve final failure in strongly nonhomogeneous strain fields, and it is shown that the inherent mesh sensitivity of the numerical failure predictions can be removed by using the nonlocal material model considered here.

Dislocation motion by double-kink migration in a bent crystal Velocity measurements in silicon

Abstract The motion of the side arms of a dislocation half-loop in a non-homogeneous strain field is considered in terms of the double-kink mechanism. It is shown that the side arm moves as a unit and remains parallel to the Peierls valleys. This leads to an association of the measured velocity in cantilever bending with the stress at the midpoint of the side arm.

The moiré method for measuring large-plane nonhomogeneous deformations

Moire-fringe equations have been developed for directly determining the components of Green's and Cauchy's deformation tensors from measurements of fringe pitch and angle. The equations, which were previously verified for large-plane homogeneous deformations, are used to determine the deformation-tensor components for nonhomogeneous strain fields. The results are compared to theoretical values. Specifically, the deformations investigated are pure bending of a rectangular block, and extension of a tapered plane specimen.