scholarly journals Crystal plasticity-based micromechanical finite element modelling of ductile void growth for an aluminium alloy under multiaxial loading conditions

2018 ◽  
Vol 233 (1) ◽  
pp. 52-62
Author(s):  
He-Jie Guo ◽  
Dong-Feng Li
Keyword(s):  
Finite Element ◽  
Single Crystal ◽  
Aluminium Alloy ◽  
Crystal Plasticity ◽  
Void Growth ◽  
Crystallographic Orientation ◽  
Stress Triaxiality ◽  
Void Coalescence ◽  
Stress Strain ◽  
Crystallographic Slip

This work proposes a crystal plasticity-based micromechanical finite element model to account for the inelastic crystallographic slip in an aluminium alloy and its effect on the development of micro-voids. Three-dimensional unit cell with periodic boundary conditions is used to represent the porous single crystal, which is subject to multiaxial external loads with constant stress triaxiality. The effects of stress triaxiality and crystallographic orientation on the ductile failure response for the porous single crystal are then quantified. Through the Taylor–Reuss mean field homogenisation, the stress–strain responses for porous polycrystal under multiaxial stress states are also investigated and compared with the conventional modelling results. The present work indicates that void coalescence strain at single crystal level strongly depends on the crystallographic orientation, particularly when stress triaxiality is low, and the overall stress–strain response of porous polycrystal can be affected by the crystallographic slip-based micro-void growth and polycrystallinity of the material.

Crystal Plasticity Finite-Element Simulation of Single Phase Titanium Alloy with 3D Polycrystalline Models

2014 ◽  
Vol 789 ◽  
pp. 608-615
Author(s):  
Shao Xie ◽  
Bin Tang ◽  
Yi Liu ◽  
Feng Bo Han ◽  
Hong Chao Kou ◽  
...  
Keyword(s):  
Finite Element ◽  
Crystal Plasticity ◽  
Voronoi Tessellation ◽  
Three Dimensional ◽  
Local Stress ◽  
Strain Response ◽  
Stress Strain ◽  
Β Phase ◽  
Crystallographic Slip ◽  
Mesh Density

Based on the rate-dependent crystal plasticity theory, a finite element code which considers crystallographic slip as deformation mechanism of material was developed to investigate the stress–strain response of the β phase of Ti-5553 during uniaxial tension. Three dimensional models with random grain shapes generated by Voronoi tessellation were used for simulations, and two discretization methods were used to disperse the models. Firstly, the parameters of material were identified by fitting simulation stress-strain curves with experimental data. Then the global stress-strain curves were calculated, and effects of mesh type and mesh density were discussed. Results show that mesh type has a relatively significant influence on overall responses, whereas the influence of mesh density is slight. Investigate of local stress-strain response in each grain was also conducted, and obvious inter-granular heterogeneities were observed. Quantitative analysis indicates that the range of stress and strain variations is affected by mesh type.

COMPARATIVE STUDY OF SINGLE CRYSTAL CONSTITUTIVE EQUATIONS FOR CRYSTAL PLASTICITY FINITE ELEMENT ANALYSIS

2008 ◽  
Vol 22 (31n32) ◽  
pp. 5388-5393 ◽  
Author(s):  
MYOUNG GYU LEE ◽  
ROBERT H. WAGONER ◽  
SUNG-JOON KIM
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Single Crystal ◽  
Crystal Plasticity ◽  
Constitutive Equations ◽  
Critical Force ◽  
Stress Strain ◽  
Element Analysis ◽  
Crystal Plasticity Finite Element ◽  
Constitutive Parameters

Two sets of single crystal constitutive equations used for the crystal plasticity finite element analysis are comparatively investigated by simulating simple deformation of oriented single crystals. The first of these consists of conventional constitutive equations, which have been adopted for the prediction of deformation texture and their parameters are generally obtained by back-fitting polycrystalline stress-strain response. The other set uses interactions between moving dislocations on the primary slip system and the corresponding forest dislocations. The idealized Orowan hardening mechanism is adopted for the calculation of the critical force, and constitutive parameters are determined by the geometry of dislocations, thus less fitting procedure is involved. The stress-strain curves of copper single crystal are used to demonstrate how the two models work for the orientation dependent stress-strain responses.

scholarly journals Influence of crystallographic orientation on the void growth at the grain boundaries in bi-crystals

2020 ◽  
Author(s):  
GUADALUPE VADILLO
Keyword(s):  
Grain Boundary ◽  
Representative Volume Element ◽  
Void Growth ◽  
Crystallographic Orientation ◽  
Stress Triaxiality ◽  
Volume Element ◽  
Lattice Rotation ◽  
Lode Parameter ◽  
Representative Volume ◽  
The Impact

Void growth and morphology evolution in fcc bi-crystals are investigated using crystal plasticity fi?nite element method. For that purpose, representative volume element of bi-crystals with a void at the grain boundary are considered in the analysis. Grain boundary is assumed initially perpendicular/coaxial with the straight sides of the cell. Fully periodic boundary conditions are prescribed in the representative volume element and macroscopic stress triaxiality and Lode parameter are kept constant during the whole deformation process. Three di?erent pairs of crystal orientations characterized as hard-hard, soft-soft and soft-hard has been employed for modellingthe mechanical response of the bi-crystal. Simulations are performed to study the implications of triaxiality, Lode parameter and crystallographic orientation on slip mechanism, hardening and hence void evolution. The impact of void presence and its growth on the heterogeneity of lattice rotation and resulting grain fragmentation in neighbouring areas is also analysed and discussed.

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