This paper presents a summary of the new semi-analytical integration method presented in [10] for von Mises elastoplasticity model with combined linear isotropic-kinematic hardening within a small deformation range. Solutions for the case of constant strain rate and constant stress rate assumptions are also presented. Furthemore, it is shown how the general solution reduces to the particular ca...

In this paper the effect of different hardening models in simulating the U-bending process for AA5754-O and DP-Steel, taking a benchmark of NUMISHEET 93 2-D draw bending, has been discussed. The hardening models considered in simulations are: isotropic hardening, pure (linear) kinematic hardening and combined (nonlinear kinematic) hardening. The influence of hardening models on predicting sprin...

Based on experimental results, a dislocation material model describing the dynamic strain aging effect at different temperatures is presented. One and two stage loading tests were performed in order to investigate the influence of the loading direction as well as the temperature influence due to the hardening mechanism. Bergström’s theory of work hardening was used as a basis for the model deve...

The goal of this research is to study the anisotropic material behavior during forming processes, represented by both complex yield loci and kinematic-isotropic hardening models. A first part of this paper describes the main concepts of the ‘Stress-strain interpolation’ model that has been implemented in the non-linear finite element code Lagamine. This model consists of a local description of ...

Structural design analyses are conducted with the aim of verifying the exclusion of ratchetting. To this end it is important to make a clear distinction between the shakedown range and the ratchetting range. The performed experiment comprised a hollow tension specimen which was subjected to alternating axial forces, superimposed with constant moments. First, a series of uniaxial tests has been ...

We study axisymmetric thermomechanical deformations of a thick target being penetrated by a fast-moving rigid cylindrical rod with a hemispherical nose, and presume that target deformations appear steady to an observer situated at the penetrator nose tip. Both isotropic and kinematic hardening of the target material are considered. It is found that kinematic hardening increases the normal stres...

The question of ‘generalization’ to finite strains of the constitutive relations of infinitesimal strain theory of elasticity, and classical elasto-plasticity with isotropic and kinematic hardening, is critically examined. Simple generalizations, which lead to physically plausible material behaviour, are presented. The current controversies surrounding (i) the choice of stress-rate in the above...

The boundary value problem representing one time step of the primal formulation of elastoplasticity with positive hardening leads to a variational inequality of the second kind with some non-differentiable functional. This paper establishes an adaptive finite element algorithm for the solution of this variational inequality that yields the energy reduction and, up to higher order terms, the R−l...

We prove the wellposedness, with respect to the maximum norm, of stress-strain laws of nonlinear kinematic hardening type, in particular of the Chaboche model.