In this note we investigate the question of higher regularity up to the boundary for quasilinear elliptic systems which origin from the time-discretization of models from infinitesimal elasto-plasticity. Our main focus lies on an elasto-plastic Cosserat model. More specifically we show that the time discretization renders H-regularity of the displacement and H-regularity for the symmetric plast...

In this study, the hydrogen transport phenomenon was numerically evaluated by using hydrogen-enhanced localized plasticity (HELP) mechanisms. Two dominant governing equations, namely, the hydrogen transport model and the elasto-plastic model, were introduced. In addition, the implicitly formulated equations of the governing equations were implemented into ABAQUS UMAT user-defined subroutines. T...

Macroscopically heterogeneous materials, characterised mostly by comparable heterogeneity lengthscale and structural sizes, can no longer be modelled by deterministic approach instead. It is convenient to introduce stochastic approach with uncertain material parameters quantified as random fields and/or random variables. The present contribution is devoted to propagation of these uncertainties ...

There is increasing interest in the use of iterative rather than direct solvers for geotechnical finite element analysis. For large 3D problems iterative solvers offer the only possibility of economical solution on a desktop PC. The major stumbling block with iterative solvers is ensuring fast convergence to a suitably accurate solution. The system of equations is always “preconditioned” to imp...

This paper focuses on the application of a continuum-based method in the Shear Strength Reduction (SSR) analysis of the stability of jointed rock slopes. In order to take into account the jointed nature of the material, the Finite Element Method (FEM) is formulated based on Cosserat theory. Also, it is assumed that failure of the equivalent material can result from failure of the joints, failur...

The paper deals with structural optimization of biomorphic microcellular ceramics invoking an elasto– plasticity with the von Mises yield criterion in the macroscopic model. The return mapping algorithms introduced by Simo and Ortiz in 1985 are applied for the numerical solution of the problem. The latter methods are computationally effective, robust and stable, and have recently become the mos...