A phenomenological macroscopic plasticity model is developed for steels that exhibit strain-induced austenite-to-martensite transformation. The model makes use of a stress-state dependent transformation kinetics law that accounts for both the effects of the stress triaxiality and the Lode angle on the rate of transformation. The macroscopic strain hardening is due to nonlinear kinematic hardeni...

A new constitutive model is introduced which is formulated in the framework of classical theory of plasticity. In the model the total strains are calculated using a stress-dependent stiffness, different for both virgin loading and un-/reloading. The plastic strains are calculated by introducing a multi-surface yield criterion. Hardening is assumed to be isotropic depending on both the plastic s...

We propose a modification of the hydrodynamic model of the dynamics in ultrarelativistic nuclear collisions. A modification of the energymomentum tensor at the initial stage describes the lack of isotropization of the pressure. Subsequently, the pressure is relaxing towards the equilibrium isotropic form in the local comoving frame. Within the Bjorken scaling solution a bound is found on the de...

Miniaturization of electronics to the nanoscale brings new challenges. Because of their small size and immense information and power processing capacity, large temperature gradients exist across nanoelectronics and power electronics solder joints. In this paper, a fully coupled thermomechanical-diffusion model is introduced to study the thermomigration induced strength degradation. A nonlinear ...

This study is aimed at evaluation of the deformation behavior of Shirasu soil (volcanic sandy soil) for reclamation and embankment construction, using elastoplastic constitutive equation based on the subloading surface model with the rotational hardening. Test results for isotropic consolidation and monotonic/cyclic loading-unloading compression with several lateral stresses under the drained c...

The dynamic plastic buckling of a homogeneous and isotropic thin thermoviscoplastic cylindrical shell loaded radially is studied analytically by analyzing the stability of its stressed/deformed configuration under superimposed infinitesimal perturbations. The wave number of the perturbation that maximizes its initial growth rate is assumed to determine the buckling mode. Cubic algebraic equatio...

A number of robust, and computationally efficient, algorithms are presented for the development of an overall strategy to estimate the material parameters characterizing a class of complex viscoplastic material models (i.e., rate dependent plastic flow, nonlinear kinematic hardening, thermal/static recovery, isotropic and anisotropic, etc.). The entire procedure is automated through the integra...

This note deals with two-mechanism models (= 2M models). 2M models (or, generally, multimechanism models) are a useful tool for modelling of complex material behavior. They have been studied and applied for the last twenty years. This note is focused on the modelling of 2M models in continuum-mechanical framework mainly in the case of plastic behaviour. In particular, some classes of 2M models ...

The quasi-static viscoplastic resp. elastoplastic evolution problem with isotropic or kinematic hardening is considered with emphasis on optimal convergence and adapted mesh-refining in the spatial discretization. Within one time-step of an implicit time-discretization, the finite element method leads to a minimisation problem for non-smooth convex functions on discrete subspaces. For piecewise...