Anisotropy and Formability (original) (raw)

International journal of …, 2010

This paper presents synthetically the most recent models for description of the anisotropic plastic behavior. The first section gives an overview of the classical models. Further, the discussion is focused on the anisotropic formulations developed on the basis of the theories of linear transformations and tensor representations, respectively. Those models are applied to different types of materials: body centered, faced centered and hexagonalclose packed metals. A brief review of the experimental methods used for characterizing and modeling the anisotropic plastic behavior of metallic sheets and tubes under biaxial loading is presented together with the models and methods developed for predicting and establishing the limit strains. The capabilities of some commercial programs specially designed for the computation of forming limit curves (FLC) are also analyzed.

Simulation of plastic anisotropy in metal forming

REVIEWS culation of the final mechanical properties of the formed sample. Further related essential applications are in the fields of optimizing tool designs, predicting pressing forces, and simulating the final surface appearance of the part. The latter aspect involves both, macroscopic (e.g., wrinkling) as well as microstructural (e.g., ridging, orange peel) mechanisms for changes in surface quality during forming.

Modelling of anisotropic behaviour and forming limits of sheet metals

2015

In the last decades, numerical simulation has gradually extended its applicability in the field of sheet metal forming. Constitutive modelling and formability are two domains closely related to the development of numerical simulation tools. This paper is focused, on the one hand, on the presentation of new phenomenological yield criteria developed in the last decade, which are able to describe the anisotropic response of sheet metals, and, on the other hand, on new models and experiments to predict/determine the forming limit curves.

Concepts for including plastic anisotropy in metal forming simulations

Concepts for integrating plastic anisotropy into metal forming simulations

Advanced Engineering …, 2002

Evolution of anisotropy of sheet metals during plastic deformation

International Journal Sustainable Construction & Design, 2013

Sheet metals generally exhibit a considerable anisotropy due to their crystallographic texture. The mechanical anisotropic characteristics of the sheet metal have a great influence on the shape of the specimen after the deformation. Therefore many successful phenomenological models have been proposed for use in Finite Ele-ment (FE) codes to simulate the anisotropic behavior of a material. The anisotropy is mainly described on the basis of the initial Lankford coefficients and/or yield stresses along the orthotropic (rolling and transverse) and diagonal axes of the sheet metals. The different yield functions make use of different combinations of these constant parameters to represent a 3-dimensional surface (in case of plane stress) determining the transition between elastic and plastic deformation. Generally, the evolution of anisotropy is not considered in the formulation of a constitutive model. Therefore we studied the effects of plastic work on the evolution of anisotropic beh...

Finite element modelling of anisotropic elastic–viscoplastic behaviour of metals

Finite Elements in Analysis and Design, 1999

An implementation of the uni"ed theory of visco-plasticity of Bodner in a three-dimensional "nite element program for the analysis of anisotropic inelastic behaviour of selected metals is presented in this paper. A derivation of an e!ective hardening parameter for the anisotropic (directional) deformation state is also given in this paper using some basic assumptions introduced by Bodner. The e!ect of the imposed strain rate on the level of the stress}strain curve is also investigated. A comparison of the results of the present "nite element model with some published theoretical and experimental results for pure titanium and 2024-T4 aluminium alloy is also made.

On linear transformations of stress tensors for the description of plastic anisotropy

International Journal of Plasticity, 2007

The derivation of anisotropic yield functions based on the approach of linear transformations of a stress tensor is investigated for general and plane stress states. The number of coefficients available for the description of plastic anisotropy is discussed. A few specific yield functions are given to illustrate the concept. Among these examples, a plane stress formulation is described in more detail, namely,

IMPORTANCE OF ANISOTROPIC COEFFICIENTS FOR MATERIAL CONSTITUTIVE MODELS IN FORMING AND CRUSHING SIMULATIONS

Transstellar Journal , 2019

The unique material properties of aluminium material have gained more attention in automotive and aerospace industries owing to its lightweight and high strength, without compensating the safety and performance. In order to develop efficient Finite Element models of tubular elements which undergone prior forming processes, a constitutive material model should be utilized for aluminum alloy sheet to account for plastic anisotropy. The principal aim of the present article is to describe the significance of material anisotropy, and to determine various coefficients for material constitutive models in forming and crushing simulations. The uniaxial tensile tests have been performed to calculate yielding strength, ultimate tensile strength, strain hardening exponent, and anisotropy factor according to ASTM-E517 standard. As a result, the current paper highlighted the significance of utilizing constitutive material model which considers anisotropy, so as to obtain the accurate crashworthiness parameters of energy absorbing tubular structures during numerical simulations.

Anisotropy and Formability (original) (raw)

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