We discuss a new solution algorithm for quasi-static elastoplastic problems with hardening. Such problems are described by a time dependent variational inequality, where the displacement and the plastic strain fields serve as primal variables. After discretization in time, one variational inequality of the second kind is obtained per time step and can be reformulated as each one minimization pr...

Boundary value problems for steady-state flow in elastoplasticity are a topic of mathematical and physical interest. In particular, the underlying PDE may be hyperbolic, and uncertainties surround the choice of physically appropriate stress and velocity boundary conditions. The analysis and numerical simulations of this paper address this issue for a model problem, a system of equations describ...

The plastic zone developed during elastoplastic contact may be effectively modeled as an inclusion in an isotropic half space. This paper proposes a simple but efficient computational method to analyze the stresses caused by near surface inclusions of arbitrary shape. The solution starts by solving a corresponding full space inclusion problem and proceeds to annul the stresses acting normal and...

We present a semi-implicit return mapping algorithm for integrating generic nonsmooth elastoplastic models. The semi-implicit nature of the algorithm stems from ‘‘freezing” the plastic internal variables at their previous state, followed by implicitly integrating the stresses and plastic multiplier. The plastic internal variables are incrementally updated once convergence is achieved (a posteri...

Damage constitutive models based on micromechanical formulation and combination of micromechanical and macromechanical effects are presented to predict progressive damage in aligned and random fiber reinforced composites. To estimate the overall elastoplastic damage responses, an effective yield criterion is derived based on the ensemble-volume averaging process and the first-order effects of e...

The paper is devoted to numerical realization of elastoplastic problems. The main goal is to improve implementation of the related constitutive problems. This can be done if plastic flow rules are defined by subdifferentials of plastic potentials. Then just one plastic multiplier is used even if the plastic potentials are nondifferentiable for unknown stress tensors. Further, the implicit Euler...

The quasi-static problem of elastoplasticity with isotropic hardening is considered, with particular emphasis on its numerical solution by means of a Newton-like method. The smoothness properties necessary for such method can be ensured by Moreau-Yosida’s theorem. After time discretization, the classical formulation of the elastoplastic problem is transformed to a minimization problem. The conv...

in this research a new approach is proposed for elasto-plastic analysis of structures with truss elements. this method covers both perfectly plastic and hardening properties. the proposed technique uses substituting virtual loads instead of modifying the stiffness matrix. to solve this kind of problems, complementary programming is utilized. numerical examples demonstrate that elastoplastic ana...

This paper deals with a variational model applicable to small-deformation structural analysis expressed for linearly elastic-perfectly plastic (von Mises-Hubcr-Hencky) material. The model comprises a unification of the minimum complementary energy principal, the Haar-von Karman principle for deformation elastoplasticity, and (in a sense) the lower bound theorem of Limit Analysis. Thus it corres...