scholarly journals Application of Yield Loci Calculated From Texture Data

1989 ◽  
Vol 11 (1) ◽  
pp. 23-39 ◽  
Author(s):  
P. van Houtte ◽  
K. Mols ◽  
A. van Bael ◽  
E. Aernoudt
Keyword(s):  
Finite Element ◽  
Plastic Anisotropy ◽  
Expansion Method ◽  
Yield Locus ◽  
Stress Space ◽  
Finite Element Calculations ◽  
Plastic Forming ◽  
Yield Loci ◽  
Analytical Expressions ◽  
Series Expansion Method

The concept of the yield locus as a means of representing the plastic anisotropy of a textured material is remembered. It is shown how such yield loci can be used in a very general way, i.e. in full six-dimensional stress space. As an example of how such yield loci can actually be obtained, the series expansion method based on Taylor factors is explained. It is finally shown that these six-dimensional yield loci can be approximated by analytical expressions and under such form brought into finite element calculations of elasto-plastic forming processes.

scholarly journals A hybrid approach for the efficient computation of polycrystalline yield loci with the accuracy of the crystal plasticity finite element method

2022 ◽  
Author(s):  
Abhishek Biswas ◽  
Surya R Kalidindi ◽  
Alexander Hartmaier
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Crystal Plasticity ◽  
Hybrid Method ◽  
Hybrid Approach ◽  
Yield Function ◽  
Yield Locus ◽  
Stress Space ◽  
Crystal Plasticity Finite Element ◽  
Yield Loci

Abstract Direct experimental evaluation of the anisotropic yield locus of a given material, representing the zeros of the material's yield function in the stress space, is arduous. It is much more practical to determine the yield locus by combining limited measurements of yield strengths with predictions from numerical models based on microstructural features such as the orientation distribution function (ODF; also referred to as the crystallographic texture). For the latter, several different strategies exist in the current literature. In this work, we develop and present a new hybrid method that combines the numerical efficiency and simplicity of the classical crystallographic yield locus (CYL) method with the accuracy of the computationally expensive crystal plasticity finite element method (CPFEM). The development of our hybrid approach is presented in two steps. In the first step, we demonstrate for diverse crystallographic textures that the proposed hybrid method is in good agreement with the shape of the predicted yield locus estimated by either CPFEM or experiments, even for pronounced plastic anisotropy. It is shown that the calibration of only two parameters of the CYL method with only two yield stresses for different load cases obtained from either CPFEM simulations or experiments produces a reliable computation of the polycrystal yield loci for diverse crystallographic textures. The accuracy of the hybrid approach is evaluated using the results from the previously established CPFEM method for the computation of the entire yield locus and also experiments. In the second step, the point cloud data of stress tensors on the yield loci predicted by the calibrated CYL method are interpolated within the deviatoric stress space by cubic splines such that a smooth yield function can be constructed. Since the produced yield locus from the hybrid approach is presented as a smooth function, this formulation can potentially be used as an anisotropic yield function for the standard continuum plasticity methods commonly used in finite element analysis.

scholarly journals The Incorporation of Texture-Based Yield Loci Into Elasto-Plastic Finite Element Programs

1995 ◽  
Vol 24 (4) ◽  
pp. 255-272 ◽  
Author(s):  
P. Van Houtte ◽  
A. Van Bael ◽  
J. Winters
Keyword(s):  
Finite Element ◽  
Finite Elements ◽  
Strain Rate ◽  
Crystallographic Texture ◽  
Metal Forming ◽  
Yield Criterion ◽  
Yield Locus ◽  
Stress Space ◽  
Plastic Modulus ◽  
Yield Loci

Elasto-plastic finite elements (FE) methods are nowadays widely used to simulate complex metal forming processes. It is then useful to generate an anisotropic yield criterion from the crystallographic texture and incorporate it into such model. The theory of dual plastic potentials (one in strain rate space and one in stress space) helps to achieve this. There is however a certain danger of losing the convexity of the yield locus during this procedure. Examples of this phenomenon are given and discussed. It is furthermore explained how the yield locus can be used to generate an elasto-plastic modulus for implementation in the FE code. Finally several examples of successful applications of the anisotropic FE code to metal forming problems are given.

The Introduction of Anisotropic Yield Loci Derived from Texture Measurements in Elasto-Plastic Finite Element Calculations

1989 ◽  
pp. 111-114 ◽  
Author(s):  
P. Van Houtte ◽  
A. Van Bael ◽  
E. Aernoudt ◽  
I. Pillinger ◽  
P. Hartley ◽  
...  
Keyword(s):  
Finite Element ◽  
Finite Element Calculations ◽  
Yield Loci

scholarly journals Calculation of Yield Surfaces and Determination of Forming Limit Diagrams of Aluminium Alloys

1993 ◽  
Vol 21 (2-3) ◽  
pp. 93-108 ◽  
Author(s):  
J. J. Fundenberger ◽  
M. J. Philippe ◽  
C. Esling ◽  
P. Lequeu ◽  
B. Chenal
Keyword(s):  
Aluminium Alloys ◽  
Expansion Method ◽  
Strain Ratio ◽  
Orientation Distribution ◽  
Forming Limit ◽  
Deformation Model ◽  
Plastic Strain Ratio ◽  
Yield Loci ◽  
Series Expansion Method

In order to point out the influence of the crystallographic texture on the formability of 2 aluminium alloys, the orientation distribution function (ODF) will be carried out using the series expansion method. Combining the ODF with a Taylor plastic deformation model we are able to calculate the yield loci and to predict the plastic strain ratio which is of high interest in the formability.

An analytical approach for relating hardness and yield strength for materials with high ratio of yield strength to Young modulus

2004 ◽  
Vol 841 ◽  
Author(s):  
Luc J. Vandeperre ◽  
Finn Giuliani ◽  
William J. Clegg
Keyword(s):  
Experimental Data ◽  
Finite Element ◽  
Elastic Modulus ◽  
Flow Stress ◽  
Yield Strength ◽  
Analytical Approach ◽  
Young Modulus ◽  
High Ratio ◽  
Finite Element Calculations ◽  
Analytical Expressions

ABSTRACTFor materials with a high ratio of Y to the elastic modulus, E, experimental data show that the ratio of the hardness to the flow stress decreases from 3 toward 1 as Y / E increases. This behaviour is predicted by finite element calculations but to date analytical expressions have not been able to correctly predict the relation between Y and H nor have they been able to show how the geometry of the indenter is important. Therefore, in this paper the correlation between H and Y for such materials is re-examined using an analytical approach to provide a physical interpretation, which explains the trends observed.

scholarly journals Orthotropic Models of Corrugated Sheets in Finite Element Analysis

2011 ◽  
Vol 2011 ◽  
pp. 1-9 ◽  
Author(s):  
David Wennberg ◽  
Per Wennhage ◽  
Sebastian Stichel
Keyword(s):  
Mechanical Properties ◽  
Finite Element Analysis ◽  
Finite Element ◽  
Finite Elements ◽  
Orthotropic Plate ◽  
Transverse Direction ◽  
Computational Effort ◽  
Element Analysis ◽  
Finite Element Calculations ◽  
Analytical Expressions

To reduce computational effort of finite element (FE) calculations a corrugated sheet is replaced with an orthotropic plate. Analytical expressions for the mechanical properties are studied and compared to finite Element calculations in extension, free vibration, and buckling. Good similarity is shown in the stiffened and transverse direction of the corrugated sheet; however, the orthotropic models do not give an accurate twisting behavior. The stiffened direction of the corrugated sheet best matches the analytical expressions. Keeping in mind the presented limitation, the orthotropic model presented herein can be used to drastically reduce the number of elements needed when modelling corrugated sheet with finite elements.

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