Simulation of plastic anisotropy in metal forming (original) (raw)

Concepts for including plastic anisotropy in metal forming simulations

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.

Concepts for integrating plastic anisotropy into metal forming simulations

Advanced Engineering …, 2002

overview anisotropy Adv Engin Mater 2002

Anisotropy Modeling

Forming simulation of aluminum sheets using an anisotropic yield function coupled with crystal plasticity theory

2010

This paper describes the application of a coupled crystal plasticity based microstructural model with an anisotropic yield criterion to compute a 3D yield surface of a textured aluminum sheet (continuous cast AA5754 aluminum sheet). Both the in-plane and out-of-plane deformation characteristics of the sheet material have been generated from the measured initial texture and the uniaxial tensile curve along the rolling direction of the sheet by employing a rate-dependent crystal plasticity model. It is shown that the stress-strain curves and R-value distribution in all orientations of the sheet surface can be modeled accurately by crystal plasticity if a ''finite element per grain" unit cell model is used that accounts for nonuniform deformation as well as grain interactions. In particular, the polycrystal calculation using the Bassani and Wu (1991) single crystal hardening law and experimental electron backscatter data as input has been shown to be accurate enough to substitute experimental data by crystal plasticity data for calibration of macroscopic yield functions. The macroscopic anisotropic yield criterion CPB06ex2 (Plunkett et al., 2008) has been calibrated using the results of the polycrystal calculations and the experimental data from mechanical tests. The coupled model is validated by comparing its predictions with the anisotropy in the experimental yield stress ratio and strain ratios at 15% tensile deformation. The biaxial section of the 3D yield surface calculated directly by crystal plasticity model and that predicted by the phenomenological model calibrated with experimental and crystal plasticity data are also compared. The good agreement shows the strength of the approach. Although in this paper, the Plunkett et al. (2008) yield function is used, the proposed methodology is general and can be applied to any yield function. The results presented here represent a robust demonstration of implementing microscale crystal plasticity simulation with measured texture data and hardening laws in macroscale yield criterion simulations in an accurate manner.

Class 2013 RWTH Aachen and MPI Düsseldorf: Microstructure Mechanics Crystal Mechanics

Introduction of a texture component crystal plasticity finite element method for anisotropy simulations

Advanced Engineering …, 2001

This article reviews continuum-based variational formulations for describing the elastic-plastic deformation of anisotropic heterogeneous crystalline matter. These approaches, commonly referred to as crystal plasticity finite-element models, are important both for basic microstructure-based mechanical predictions as well as for engineering design and performance simulations involving anisotropic media. Besides the discussion of the constitutive laws, kinematics, homogenization schemes and multiscale approaches behind these methods, we also present some examples, including, in particular, comparisons of the predictions with experiments. The applications stem from such diverse fields as orientation stability, microbeam bending, single-crystal and bicrystal deformation, nanoindentation, recrystallization, multiphase steel (TRIP) deformation, and damage prediction for the microscopic and mesoscopic scales and multiscale predictions of rolling textures, cup drawing, Lankfort (r) values and stamping simulations for the macroscopic scale.

Multiscale modelling of the plastic anisotropy and deformation texture of polycrystalline materials

European Journal of Mechanics - A/Solids, 2006

A hierarchical multilevel method is presented for the plastic deformation of polycrystalline materials with texture-induced anisotropy. It is intended as a constitutive material model for finite element codes for the simulation of metal forming processes or for the prediction of forming limits. It consists of macroscopic models of which the parameters are to be identified using the results of two-level (meso/macro) or three-level (micro/meso/macro) models. A few such two-level models are presented, ranging from the full-constraints Taylor model to the crystal-plasticity finite element models, including the grain interaction models GIA, LAMEL and ALAMEL. Validation efforts based on experimental cold rolling textures obtained for steel and aluminium alloys are shortly discussed. An assessment is also given of the assumptions of the LAMEL and ALAMEL models concerning stress and strain rate heterogeneity at grain boundaries, based on the results of a crystal plasticity finite element study. Finally a recent three-level model which also looks at the microscopic level (dislocation substructure) is discussed.

Study of Material Anisotropy in Metal Forming Using Finite Element Methods

The chapter discusses the numerical investigation of anisotropic properties of sheet metal forming using finite element method (FEM) in ABAQUS, a computer-aided engineering tool that deals with the most influent parameters in a forming process such as simulating sheet metal forming. Stamping of rectangular parts was simulated by the static and explicit approach in the presence of contact conditions with friction. The experimental and numerical results of rectangular cup drawing are presented. The aim of experimental study is to analyze the material behavior under deformation and further use the results to verify numerical simulation results taking into consideration friction and material anisotropy. Implicit and explicit nonlinear analyses were carried out using ABAQUS/Standard and ABAQUS/Explicit. Frictional properties of the deep drawing quality steel sheet were determined by using the pinon-disc tribometer. A comparison of quadratic Hill anisotropic yield criterion and von Mises yield criterion with isotropic hardening has been done. It is found that plastic anisotropy in ductile sheet metal has influence on deformation behavior of the material. The study indicates that FEM analysis undoubtedly guarantees the most approximate numerical results to real process when material and friction anisotropy are taken into consideration.

Simulation of plastic anisotropy in metal forming (original) (raw)

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