Modeling of the Grain Shape Effect on the Elastic-Inelastic Behavior of Polycrystals With Self-Consistent Scheme

2009 ◽  
Vol 132 (1) ◽  
Author(s):  
A. Abdul-Latif ◽  
M. Radi
Keyword(s):  
Grain Shape ◽  
Spherical Inclusion ◽  
Shape Effect ◽  
Inelastic Behavior ◽  
Consistent Model ◽  
Self Consistent ◽  
Eshelby’S Tensor ◽  
Anisotropic Elastic ◽  
Nonlinear Elastic ◽  
Interaction Law

Based on a well established nonincremental interaction law for fully anisotropic elastic-inelastic behavior of polycrystals, tangent formulation-based and simplified interaction laws of softened nature are derived to describe the nonlinear elastic-inelastic behavior of fcc polycrystals. Using the Eshelby’s tensor, the developed approach considers that the inclusion (grain) form is ellipsoidal. It has been clearly demonstrated by Abdul-Latif et al. (2002, “Elastic-Inelastic Self-Consistent Model for Polycrystals,” ASME J. Appl. Mech., 69, pp. 309–316) for spherical inclusion that the tangent formulation-based model requires more calculation time, and is incapable to describe correctly the multiaxial elastic-inelastic behavior of polycrystals in comparison with the simplified model. Hence, the simplified nonincremental interaction is studied considering the grain shape effect. A parametric study is conducted showing principally the influence of the some important parameters (the grain shape (α) and the new viscous parameter γ) and the effect of their interaction on the hardening evolution of polycrystals. Quantitatively, it is recognized that the model describes suitably the grain shape effect together with the new viscous parameter γ on the strain-stress behavior of aluminum and Waspaloy under tensile test.

scholarly journals The Rules for the Lattice Rotation Accompanying Slip as Derived From a Self-Consistent Model

1999 ◽  
Vol 31 (4) ◽  
pp. 217-230 ◽  
Author(s):  
R. A. Lebensohn ◽  
T. Leffers
Keyword(s):  
Solid Mechanics ◽  
Grain Shape ◽  
Rolling Plane ◽  
Lattice Rotation ◽  
Consistent Model ◽  
Plane Strain Deformation ◽  
Self Consistent ◽  
The One ◽  
Equiaxed Grains ◽  
Very High

The rules for the lattice rotation during rolling (plane strain) deformation of fcc polycrystals are studied with a viscoplastic self-consistent model. Very high values of the ratesensitivity exponent are used in order to establish Sachs-type conditions with large local deviations from the macroscopic strain. The lattice rotation depends on the grain shape. For equiaxed grains the lattice rotation follows the MA rule, which is the one normally used in solid mechanics. For elongated and flat grains the lattice rotation follows a different rule, the PSA rule. In the standard version the model performs a transition from MA to PSA with increasing strain. There is avery clear difference between the textures resulting from the two different rules. MA leads to a copper-type texture, and PSA leads to a brass-type texture.

Grain Shape Effect and the Viscoplastic Parameter on the Evolution of Isotropic and Kinematic Hardening of Metallic Materials under Cyclic Loading

2019 ◽  
Vol 820 ◽  
pp. 48-59
Author(s):  
Abdelhamid Kerkour-El Miad ◽  
A. Kerour-El Miad ◽  
Redouane Kouddane
Keyword(s):  
Grain Shape ◽  
Kinematic Hardening ◽  
Inelastic Strain ◽  
System Level ◽  
Elastic Behavior ◽  
Isotropic Hardening ◽  
Shape Effect ◽  
Metallic Materials ◽  
Crystallographic Slip ◽  
Self Consistent

The main objective of this work is to study the grain shape effect (aspect ratio α = a / b) and the viscoplastic parameter γ on the evolution of the kinematic and isotropic hardening of FCC type metallic materials, under uniaxial cyclic Tension-Compression ‘‘TC’ and to interpret these results. These parameters of shape and viscoplastic were developed and introduced by Abdul-Latif and Radi, indeed in this study we use their model. Expressed within the framework of a self-consistent approach, the rate-dependent inelastic strain is examined at the crystallographic slip system level describing a constitutive model for FCC metallic polycrystals, whereas the elastic strain is determined at the granular level. Based on the Eshelby’s tensor, the elastic behavior is assumed to be compressible. For a polycrystalline structure, the grains deform plastically by crystallographic slip located at the most favorably oriented systems supporting a high resolved shear stress . The approach considers that the inclusion (grain) form is ellipsoidal of half axes defining by a, b and c such as a ≠b= c. Several numerical tests are carried out highlighting the role of shape and viscoplastic parameter on the evolution of kinematic and isotropic hardening. A general comparison between the and effect on the overall hardening of the polycrystal shows that this work hardening is more sensitive to the parameter (for given ) compared to (for given). Keywords: Grain shape effect, Ellipsoidal inclusion, Viscoplastic parameter effect, Kinematic and isotropic hardening, Uniaxial cyclic ‘‘TC‘‘, Self-consistent model.

Elastic Property Estimation in Polycrystalline Films with Crystallographic Texture and Grain Shape

1995 ◽  
Vol 403 ◽  
Author(s):  
B. C. Hendrix ◽  
L. G. Yu ◽  
K. W. Xu ◽  
J. W. He
Keyword(s):  
Thin Films ◽  
Elastic Constants ◽  
Crystallographic Texture ◽  
Grain Shape ◽  
Elastic Anisotropy ◽  
Polycrystalline Films ◽  
Property Estimation ◽  
Bulge Testing ◽  
Consistent Model ◽  
Self Consistent

AbstractAlthough methods of measuring the elastic properties of thin films have made great advances with the use of bulge testing of membranes, deflection of micromachined beams, and nanoindentation, most results are still being compared to either isotropic or single crystal elastic constants, neither of which are, in general, appropriate for textured polycrystalline films. This paper uses recent results of a self-consistent model (after Krbner and Kneer) which calculates the elastic anisotropy arising from crystallographic texture and which has been extended to predict the anisotropy resulting from grain shape. These results are compared to the various Voigt, Reuss, and Hill approximations that are appropriate for different crystallographic textures. The accuracies of the different models are evaluated in terms of their ability to predict the biaxial modulus and indentation compliance that are most commonly measured in thin films.

Application of Principal Component Analysis (PCA) for the Choice of Parameters of a Micromechanical Model

2019 ◽  
Vol 820 ◽  
pp. 75-84
Author(s):  
Aissa Kerkour-El Miad ◽  
A. Kerour-El Miad
Keyword(s):  
Principal Component Analysis ◽  
Micromechanical Model ◽  
Principal Component ◽  
Component Analysis ◽  
Elastic Behavior ◽  
Phase Lag ◽  
Consistent Model ◽  
Self Consistent ◽  
Sinusoidal Waveform ◽  
Interaction Law

The main objective of this work is to apply the Principal Component Analysis (PCA) to the key parameters of a micromechanical model, namely the shape parameter of inclusion (grain) (ratio =a/b) and γ viscoplastic parameter in view of a better simulation. In this work, the sensitivity of the model to parameters and γ is evaluated on the stabilized global stress during cyclic Tension-Compression (TC) loadings and out-of-phase Tension–Torsion, with a sinusoidal waveform and a phase lag of 90 between the two sinusoidal signals TT90 loadings. Indeed several values ​​of and γ are pulled thanks to these loading, we use later the PCA in order to choose the couple (, γ) adequate to launch our simulation. The model used is expressed as part of the self-consistent approach and time-dependent plasticity. Based on the Eshelby tensor, this model considers that the elastic behavior is compressible. For a polycrystalline structure, the grains are deformed by crystallographic sliding located in the most favorably oriented systems and which support a strong constrained stress . Keywords: PCA, grain shape , viscoplastic parameter γ, Self-consistent model, Non-incremental interaction law, Elasto-inelastic. TC and TT90 loading

Modeling of Grain Shape Effect on Multiaxial Plasticity of Metallic Polycrystals

2013 ◽  
Vol 135 (2) ◽  
Author(s):  
A. Abdul-Latif
Keyword(s):  
Grain Shape ◽  
Inelastic Strain ◽  
Cyclic Behavior ◽  
Loading Path ◽  
Model Parameters ◽  
Shape Effect ◽  
Inelastic Behavior ◽  
Aspect Ratios ◽  
Ellipsoidal Shape ◽  
Aluminum Alloy 2024

A simplified nonincremental interaction law is used describing the nonlinear elastic-inelastic behavior of FCC polycrystals proposed recently (Abdul-Latif and Radi, 2010, “Modeling of the Grain Shape Effect on the Elastic-Inelastic Behavior of Polycrystals with Self-Consistent Scheme,” ASME J. Eng. Mater. Technol., 132(1), p. 011008). In this scheme, the elastic strain defined at the granular level based on the Eshelby's tensor is assumed to be isotropic, uniform and compressible. Hence, the approach considers that the inclusion (grain) has an ellipsoidal shape of half axes defining by a, b and c such as a ≠ b = c. The granular heterogeneous inelastic strain is locally determined using the slip theory. Both elastic and inelastic granular strains depend on the granular aspect ratio (α = a/b). An aggregate of grains of ellipsoidal shape is supposed to be randomly distributed with a distribution of aspect ratios having a log-normal statistical function. The effect of this distribution on the mechanical behavior is investigated. A host of cyclic inelastic behavior of polycrystalline metals is predicted under uniaxial and multiaxial loading paths. Using the aluminum alloy 2024, an original complex cyclic loading path type is proposed and carried out experimentally. After the model parameters calibration, the elastic-inelastic cyclic behavior of this alloy is quantitatively described by the model. As a conclusion, the model can successfully describe the elasto-inelastic at the overall and local levels.

THEORY AND SELF-CONSISTENT MODEL OF DUST-DRIVEN WINDS

2002 ◽  
Vol 5 ◽  
pp. 65-65
Author(s):  
S. Liberatore ◽  
J.-P.J. Lafon ◽  
N. Berruyer
Keyword(s):  
Consistent Model ◽  
Self Consistent

scholarly journals Stellar Flares: Observations and Theory

1989 ◽  
Vol 104 (2) ◽  
pp. 49-52
Author(s):  
Suzanne L. Hawley
Keyword(s):  
Scaling Law ◽  
Dynamic Scaling ◽  
X Ray ◽  
Temperature Distributions ◽  
Photometric And Spectroscopic Observations ◽  
Stellar Flares ◽  
Consistent Model ◽  
Self Consistent ◽  
Flare Model ◽  
Large Flare

AbstractPhotometric and spectroscopic observations of a very large flare on AD Leo are presented. A self consistent model of a flare corona, transition region and chromosphere is developed; in particular the chromospheric temperature distributions resulting from X-ray and EUV irradiation by coronae of various temperatures are determined. The predicted line fluxes in Hγ are compared to the observed line fluxes to find the coronal temperature as a function of time during the flare. This run of temperature with time is then compared with the predictions of an independent theoretical flare model based on a dynamic scaling law (see paper by Fisher and Hawley, these proceedings).

scholarly journals A Self‐Consistent Model for Sorption and Transport in Polyimide‐Derived Carbon Molecular Sieve Gas Separation Membranes

2020 ◽  
Vol 132 (46) ◽  
pp. 20523-20527
Author(s):  
Oishi Sanyal ◽  
Samuel S. Hays ◽  
Nicholas E. León ◽  
Yoseph A. Guta ◽  
Arun K. Itta ◽  
...  
Keyword(s):  
Gas Separation ◽  
Molecular Sieve ◽  
Carbon Molecular Sieve ◽  
Separation Membranes ◽  
Gas Separation Membranes ◽  
Consistent Model ◽  
Self Consistent
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