Crystal Plasticity Finite Element Simulations of Polycrystalline Aluminium Alloy under Cyclic Loading

2014 ◽  
Vol 891-892 ◽  
pp. 1609-1614 ◽  
Author(s):  
Ling Li ◽  
Lu Ming Shen ◽  
Gwénaëlle Proust
Keyword(s):  
Finite Element ◽  
Cyclic Loading ◽  
Aluminium Alloy ◽  
Crystal Plasticity ◽  
Three Dimensional ◽  
Grain Morphology ◽  
Element Model ◽  
Electron Back Scatter Diffraction ◽  
Plastic Deformation Zone ◽  
Mesh Density

A three-dimensional crystal plasticity (CP) finite element model is developed to reproduce the grain level stress concentration and deformation of polycrystalline aluminium alloy 7075 (AA7075) during fatigue experiments. The grains contained in the model possess the same size and crystallographic orientations obtained from electron back-scatter diffraction experiments. A modified CP constitutive model, which considers the backstress evolution, is employed to describe the mechanical behaviour of AA7075 under cyclic loading. A round-notched specimen from a fatigue test is simulated using the proposed CP model. Convergence studies in terms of mesh density and plastic deformation zone size are carried out to determine the appropriate conditions for the simulation. The simulation results are compared with those obtained using the elasto-plastic model and the CP model without grain morphology. The comparison indicates that with the embedded grain morphology, the proposed model can capture very well the local response induced by the microstructure features, which is vital to the accurate fatigue life prediction of aluminium alloys.

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.

Reliability of SnAgCu Alloys for CMOS Image Sensor QFN Package under Thermal Cycling Loading

2008 ◽  
Vol 594 ◽  
pp. 175-180
Author(s):  
Hsiang Chen Hsu ◽  
Hui Yu Lee ◽  
Wen Lo Shieh
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Three Dimensional ◽  
Region Of Interest ◽  
Element Model ◽  
Cmos Image Sensor ◽  
Image Sensor ◽  
Computational Time ◽  
Mesh Density ◽  
Good Agreement

A three-dimensional finite element model of CMOS image sensor QFN packaging using ANSYS codes is developed to investigate the solder joint reliability under thermal cycle test. The predicted thermal-induced displacements were found to be very good agreement with the Moiré interferometer experimental in-plane deformations. The developed finite element model is then applied to predict fatigue life of Sn4.0Ag0.5Cu, Sn3.5Ag0.5Cu and Sn3.9Ag0.6Cu alloys based on JEDEC standard JESD22-A104. In order to save computational time and produce satisfactory results in the region of interest, an independent more finely meshed so-called submodel scheme based on cut-boundary displacement method is generated. The mesh density for different area ratio of refinery/coarse model was verified and the results were found to be good agreement with previous researches. The modified Coffin-Manson equation and strain energy density based equation are applied to evaluate the reliability of SnAgCu alloys. A series of comprehensive parametric studies were conducted in this paper.

Finite Element Simulation of the Hot Deformation Behavior of AA7075 Using a Coupled Thermo-Mechanical Crystal Plasticity Constitutive Model

2014 ◽  
Vol 553 ◽  
pp. 82-87 ◽  
Author(s):  
Lei Ting Li ◽  
Y.C. Lin ◽  
Ling Li ◽  
Lu Ming Shen
Keyword(s):  
Finite Element ◽  
Temperature Distribution ◽  
Grain Boundaries ◽  
Crystal Plasticity ◽  
Hot Deformation ◽  
Mechanical Response ◽  
Voronoi Tessellation ◽  
Element Model ◽  
Local Deformation ◽  
Electron Back Scatter Diffraction

Three-dimensional crystal plasticity finite element (CPFE) simulations are performed to study the coupled thermo-mechanical response of aluminium alloy 7075 under hot compression loadings. To improve the computational efficiency, a grain-scale representative volume element model with periodic boundary conditions is adopted to represent the macroscopic response. The initial grains are created using Voronoi tessellation method, and the grain orientations are obtained from the electron back-scatter diffraction test. The simulated results indicate that the effects of the grain properties on the local deformation and temperature distribution of the alloy are significant during the hot deformation. The temperature continuity can be found across some grain boundaries while there is a temperature gap at other grain boundaries. The proposed coupled thermo-mechanical CPFE model is able to provide detailed microstructure evolution and temperature distribution in the studied alloy during the hot deformation, which cannot be easily obtained by experiments.

High-cycle fatigue simulation for aluminium alloy using cohesive zone law

2012 ◽  
Vol 227 (4) ◽  
pp. 683-692 ◽  
Author(s):  
Kyungmok Kim
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Aluminium Alloy ◽  
Cohesive Zone ◽  
High Cycle Fatigue ◽  
Three Dimensional ◽  
Element Model ◽  
Fatigue Behaviour ◽  
Cycle Fatigue ◽  
Failure Data

This article describes high-cycle fatigue simulation for 7050-T7451 aluminium alloy using cohesive zone law. A three-dimensional finite element model is developed for fatigue behaviour of aluminium alloy subjected to cyclic bending. A bilinear, cycle-dependent cohesive zone law is implemented with a help of experimental S-N (stress amplitude–number of cycles to failure) data. In the finite element model, a cycle jump strategy is used including stiffness degradation and reduction of fracture energy during cyclic loadings. Additionally, bending experiments are conducted with unnotched specimens and S-N curves are determined. Direct comparison of S-N curves between the simulation and the experiment is performed on bilogarithmic scale. Results show that the proposed method provides a good means of simulating high-cycle fatigue behaviour of aluminium alloys.

Torsional Analysis of a Steel Cord-Rubber Tire Belt Structure

1996 ◽  
Vol 24 (4) ◽  
pp. 339-348 ◽  
Author(s):  
R. M. V. Pidaparti
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Composite Structures ◽  
Three Dimensional ◽  
Element Model ◽  
Torsional Stiffness ◽  
Element Analysis ◽  
Rubber Belt ◽  
Steel Cord ◽  
Torsional Analysis

Abstract A three-dimensional (3D) beam finite element model was developed to investigate the torsional stiffness of a twisted steel-reinforced cord-rubber belt structure. The present 3D beam element takes into account the coupled extension, bending, and twisting deformations characteristic of the complex behavior of cord-rubber composite structures. The extension-twisting coupling due to the twisted nature of the cords was also considered in the finite element model. The results of torsional stiffness obtained from the finite element analysis for twisted cords and the two-ply steel cord-rubber belt structure are compared to the experimental data and other alternate solutions available in the literature. The effects of cord orientation, anisotropy, and rubber core surrounding the twisted cords on the torsional stiffness properties are presented and discussed.

Finite Element Analysis of Nonuniformity of Tires with Imperfections5

2007 ◽  
Vol 35 (3) ◽  
pp. 226-238 ◽  
Author(s):  
K. M. Jeong ◽  
K. W. Kim ◽  
H. G. Beom ◽  
J. U. Park
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Three Dimensional ◽  
Element Model ◽  
Radial Force ◽  
Element Analysis ◽  
The Finite Element Analysis ◽  
Dimensional Finite Element ◽  
Force Variation ◽  
Three Dimensional Finite Element

Abstract The effects of variations in stiffness and geometry on the nonuniformity of tires are investigated by using the finite element analysis. In order to evaluate tire uniformity, a three-dimensional finite element model of the tire with imperfections is developed. This paper considers how imperfections, such as variations in stiffness or geometry and run-out, contribute to detrimental effects on tire nonuniformity. It is found that the radial force variation of a tire with imperfections depends strongly on the geometrical variations of the tire.

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