Showing papers in "International Journal of Plasticity in 1989"

TL;DR: In this paper, the cyclic constitutive equations developed and used at ONERA and LMT-Cachan are presented in detail in terms of a hierarchy of various models, including the Ohno-Kachi time-independent plasticity theory, two unified viscoplastic models by Walker and by Krempl and Yao, the new developments of the endochronic theory by Watanabe and Atluri.

TL;DR: In this article, a yield function that describes the behavior of orthortropic sheets, metals exhibiting planar anisotropy and subjected to plane stress conditions is proposed, which is shown to give a reasonable approximation to plastic potentials calculated with the Taylor/Bishop and Hill theory of polycrystalline plasticity for plane stress states.

TL;DR: In this paper, a set of internal variable type constitutive equations which model large elastic-viscoplastic deformations of metals at high temperatures is formulated, and the values for the materials parameters appearing in these functions are determined.

TL;DR: In this article, a theoretical approach to the problem of transformation plasticity in steels is proposed, in the case where the Magee mechanism is negligible and the phases are ideal-plastic.

TL;DR: In this paper, the model for the plastic behavior of steels during phase transformations was extended to include strain-hardening effects (isotropic or kinematic hardening) and an expression for the transformation plastic strain rate was obtained by modifying the treatment of Part I in a suitable manner.

TL;DR: In this paper, a mathematical formulation for modeling the evolution of deformation induced crystallographic texture in steady state bulk forming processes is presented, which treats the material response of the polycrystalline aggregate as a statistical function of the response of individual grains.

TL;DR: In this article, a general approach to the problem of determination of elastoplastic properties of metallic polycrystals at finite transformations is presented. But the authors focus on the case of granular media for which the elastic tangent moduli may be considered piecewise constant.

TL;DR: In this paper, a fully implicit, Euler backward time-integration procedure for a set of internal variable constitutive equations for isothermal, isotropic elasto-viscoplasticity with isothermal hardening is presented.

TL;DR: In this paper, the effect of yield surface shape on sheet forming limits based on the Marciniak and Kuczynski approach is studied, and a diagram called "yield surface shape hardening diagram (YSSHD)" is proposed in order to describe the impact of yield surfaces shapes on forming limit diagrams more precisely.

TL;DR: In this paper, a model capable of simulating the load-deformation-temperature behavior of materials with shape memory is described, which considers the thermo-mechanical properties of these materials as the result of an activated process.

TL;DR: In this paper, the analytical properties of the constitutive equations in plasticity with a nonassociated flow rule are investigated under the assumption of small deformations and the tangent stiffness tensor is assessed.

TL;DR: In this paper, the main features of the behavior of stainless steels are taken into account in the unified model developed and used at ONERA. And the capabilities of the model are then checked against the example of type 316 L stainless steel at 600°C.

TL;DR: In this article, the effect of the plastic spin on the behavior of initially anisotropic materials is demonstrated by obtaining in closed analytical form the stress-strain response of orthotropic and transversely isotropic materials subjected to various kinds of homogeneous large inelastic deformations, at different rates and temperatures.

TL;DR: In this article, the effects of texture on the deformation behavior of glassy polymers were investigated using a physically-based constitutive model of Boyce, Parks, and Argon describing the rate, temperature, and pressure dependent inelastic deformation of initially isotropic polymers.

TL;DR: In this article, the authors characterize the deformations which leave these elements unchanged and find that these "defect-preserving" deformations strictly include the elastic deformations, and that if one admits such deformations in variational principles determining equilibria of the lattice, then the crystal is necessarily weak, in some sense.

TL;DR: In this article, the possibilities of intersection of yield and bounding surfaces are examined for a somewhat general framework of two-surface plasticity theory for workhardening materials, and a general inequality is established for avoiding intersection.

TL;DR: In this article, a plasticity model involving nonassociative flow rule in the hierarchical modeling approach is considered with respect to response of cohesionless materials, and five different schemes including associative response, and four others to represent the non-aggregative response are analyzed from the viewpoints of accuracy and computer time.

TL;DR: In this article, anisotropic von Mises and Drucker-Prager criterion is proposed for describing the macroscopic states of stress which result in failure of brittle and ductile materials.

TL;DR: In this paper, a necessary and sufficient condition for shear banding in two-dimensional space is derived for finite elastoplastic deformation of compressible materials, and the criterion for the initiation of shear bands, a geometric instability, is that the governing field equations become hyperbolic.

TL;DR: In this paper, a modified form of the Chaboche theory and the Bodner-Partom theory are examined qualitatively by predicting the uniaxial stress-strain behavior of INCONEL 718 at 1200°F.

TL;DR: In this paper, the plastic behavior of metals after cyclic prestraining is systematically and experimentally investigated in a state of plane stress that consists of axial and torsional stress (strain) components.

TL;DR: In this paper, the constitutive formulation of Perzyna for viscoplastic deformation combined with the theory of thermally activated motion of dislocations is used to model plastic deformation of 1100-0 aluminum.

TL;DR: In this article, the conditions imposed on the rate-type constitutive equations by the existence of the instantaneous elastic response are investigated, and the results showed that if the shear and bulk moduli depend on both stress and strain, but only through their separate invariants, then they depend on the first invariants only, and if the bulk modulus must satisfy a partial differential equation, then these moduli must be chosen among the solutions of an over determined system of equations.

TL;DR: In this paper, a general method is presented to calculate solid angles, in N dimensional spaces, associated with a given cone of vectors, applied to a study of the shape of a facetted crystal yield surface.

TL;DR: In this article, a simple method for the analysis of the elastic-plastic bending of plates of arbitrary shape is developed based upon the concept of contour lines of equal deflection on the surface of the plate, and uses Ilyushin's theory for small plastic deformations.

TL;DR: In this paper, an early version of the viscoplastic constitutive equation proposed by Bodner and Partom, which was formulated with one scalar state variable, was adopted to model the experimental results of 2618-T61 aluminum.

TL;DR: In this article, the sensitivity of strain histories to several rate-dependent and rateindependent constitutive models were studied, using a finite difference technique, and the differences in strain profiles were found to increase dramatically from small to large dynamic plastic deformation.