In this paper, the meshless integral method based on the regularized boundary integral equation [1] has been extended to analyze the large deformation of elastoplastic materials. The updated Lagrangian governing integral equation is obtained from the weak form of elastoplasticity based on Green-Naghdi’s theory over a local sub-domain, and the moving least-squares approximation is used for meshl...

A (microscopic) static elastoplastic field theory of dislocations with moment and force stresses is considered. The relationship between the moment stress and the Nye tensor is used for the dislocation Lagrangian. We discuss the stress field of an infinitely long screw dislocation in a cylinder, a dipole of screw dislocations and a coaxial screw dislocation in a finite cylinder. The stress fiel...

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...

The low Young's modulus of biological particles results in their large deformation against the AFM probe forces; therefore, it is necessary to study the contact mechanics of bioparticles in order to predict their mechanical behaviors. This paper specifically deals with the contact mechanics of DNA nanoparticles with spherical and cylindrical shapes during manipulation. In previous studies, ...

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...

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...