This study describes a general liquefaction flow instability criterion for elastoplastic soils based on the concept of loss of uniqueness. We apply the criterion to the general case of axisymmetric loading and invoke the concepts of effective stresses and loss of controllability to arrive at a general criterion for the onset of liquefaction flow. The criterion is used in conjunction with an ela...

For control applications involving small displacements and velocities, friction modeling and compensation can be very important. In particular, the modeling of presliding displacement (motion prior to fully developed slip) can play a pivotal role. In this paper, it is shown that existing single-state friction models exhibit a nonphysical drift phenomenon which results from modeling presliding a...

In recent years, cohesive zone models (CZMs) have been developed and widely used in numerical simulations to account for crack initiation and propagation in different materials and structures. This study is focused on the modeling of the elastoplastic damageable behaviour of ductile materials. The damage is associated with a cohesive behaviour of the interface between the purely elastoplastic s...

Abstract-The elastoplastic constitutive analysis which utilizes the model of multiplicative decomposition of the defo~ation gradient into its elastic and plastic parts has been mainly developed and applied to elastically isotropic materials, which remain isotropic during the process of plastic deformation. This paper extends the application of the model to materials that change their elastic pr...

We explain an interface for the implementation of rate-independent elastoplasticity which separates the pointwise evaluation of the elastoplastic material law and the global solution of the momentum balance equation. The elastoplastic problem is discretized in time by diagonally implicit Runge-Kutta methods and every time step is solved with a Newton iteration. For the discretization in space t...

Friction originates at the area of real contact which depends on (changing) surface topography. Observing and measuring multi-asperity interfaces is difficult, making it challenging to quantitatively study interplay between frictional force In this paper, we systematically manipulate topography use a fluorescence microscopy-based visualization technique reveal interplay. We demonstrate good agr...

Thermodynamic and kinetic approaches for sublimation inside elastoplastic material under tensile stress are developed for large strains. Various conceptual problems related to irreversible plastic deformation are addressed for a spherical bubble. They include definitions of the thermodynamic driving forces and activation energies, nontraditional concepts of a critical nucleus, path dependence o...

A fItrite element scheme (together with a conjugate gradient algorithmj is demonstrated to be a very effective method for analyzing general elastoplastic torsion of prismatic bars posed as quadratic programming problems. Solutions for bars with elliptical and Sokolovsky’s oval cross-sections are presented. The solutions for the elliptical bars agree with the existing elastic and limit plastic s...

In this paper we study the wedge disclination within the elastoplastic defect theory. Using the stress function method we found exact analytical solutions for all characteristic fields of a straight wedge disclination in a cylinder. The elastic stress, elastic strain, elastic bend-twist, displacement and rotation have no singularities at the disclination line. We found a modified stress functio...