TC4 alloy is widely used in the high temperature environment. This paper proposed an ununified viscoplastic constitutive model according to uniaxial creep experiment and tensile of alloy. The inelastic strain rate was decomposed into two parts: plastic rate. calculated by multiaxial ductility exhaustion damage law, get from yield function containing kinematic hardening effect. implicit stress i...

A constitutive model is developed within the framework of Perzyna’s viscoplasticity for predicting the stress-strain-time behaviour of soft porous rocks. The model is based on the hyperelasticity and multisurface viscoplasticity with hardening. A time-stepping algorithm is presented for integrating the creep sensitive law. An example of application to one-dimensional consolidation is presented....

Semi-solid materials undergo strain localization and shear band formation as a result of granular nature of semi-solid deformation. In the present study, to analyze the shear localization, a unified viscoplastic constitutive model was developed for the homogeneous flow. Then, a linearized analysis of the stability performed by examining the necessary condition for the perturbation growth. For t...

In this study, we present a model based on the “second-order” nonlinear homogenization method for estimating the macroscopic response and the evolution of microstructure in two-dimensional viscoplastic porous media. The estimates of the new model are compared with unit cell finite element calculations and the earlier “variational” nonlinear homogenization method. The three methods are compared ...

A nonlocal constitutive formulation for a porous ductile material is investigated, in which delocalizadon relates to the damage mechanism. An elastic-viscoplastic material model is used, with delocalization incorporated in terms of an integral condition on the rate of increase of the void volume fraction. Two model problems are analysed to study the effect of including this material length, one...

For the first time, a Newton method is proposed for the unregularized viscoplastic fluid flow problem. It leads to a superlinear convergence for Herschel-Bulkley fluids when 0 < n < 1, where n is the power law index. Performances are enhanced by using the inexact variant of the Newton method and, for solving the Jacobian system, by using an efficient preconditioner based on the regularized prob...