A phenomenological constitutive relation using the conventional J2-fiow isotropic hardening yield function as well as a threshold shear stress based yield function that governs a 'directionally preferred plastic component' of shear strain, developed by the authors in an earlier work, is used for the simulation of the shear band formation. The constitutive relation which is expressed as an expli...

In recent years, the studies on the enhancement of the prediction capability of the sheet metal forming simulations have increased remarkably. Among the used models in the finite element simulations, the yield criteria and hardening models have a great importance for the prediction of the formability and springback. The required model parameters are determined by using the several test results,...

The paper is devoted to the numerical solution of an elastoplastic constitutive initial value problem containing the Mohr-Coulomb yield criterion, a nonassociative plastic flow rule, and a nonlinear isotropic hardening. The constitutive problem is discretized by the implicit Euler method. Instead of the conventional Koiter formulations, we define the plastic flow rule using the subdifferential ...

The mechanical behavior of a metallic sandwich sheet material composed of two flat face sheets and two bi-directionally corrugated core layers is analyzed in detail. The manufacturing of the sandwich material is simulated to obtain a detailed unit cell model which accounts for the non-uniform thickness distribution and residual stresses associated with the stamping of the core layers. Virtual e...

The common engineering practice is the selection of certain physical factors such as geometry, loading, boundary conditions, and material properties. In reality these data are more or less uncertain. In many engineering problems this uncertainty should be taken into consideration. Fuzzy set theory allows to determine randomness model response to the external loading. Two methods extension princ...

Abstract In this paper a selected type of elasto-viscoplastic constitutive equations is considered. The viscoplastic model which was proposed by Marquis generalized allowing multiple terms describing the isotropic and kinematic hardening. Furthermore, presented formulation enables one to use an arbitrary equivalent plastic strain function describe hardening behavior. What more, backstress evolu...

Abstract Ground movements induced by deep excavations may cause damages on neighboring existing buildings. Finite element simulations generally give acceptable estimates of the horizontal displacements retaining wall, but results are less satisfactory for vertical ground surface behind structure. A possible explanation is that most constitutive models describe volumetric strains in a simplified...

Rocket engine thrust chambers withstand very high temperatures and thermal gradients during service that induce multiple damaging phenomena such as plasticity, low-cycle-fatigue (LCF) creep. Numerical models can be used the design of these mechanical components in order to simulate main processes, accounting for complex material behavior due non-linear hardening viscoplasticity. This work repre...

Abstract The description of the cyclic mobility observed prior to liquefaction in geomaterials requires sophisticated constitutive formulation describe plastic deformation induced during loading with small stress amplitude inside yield surface. This requirement is realized subloading surface model , which enclosing a purely elastic domain not assumed, while assumed other elastoplasticity models...

Flatness is an important quality parameter of heavy plates and it generally achieved through cyclic elastoplastic deformation the plate in a hot roller leveller following rolling cooling processes. To investigate optimize levelling (straightening) process, Finite Element (FE) simulations are widely used. Generally, flow curves with isotropic hardening used for simulations. However, material mig...