Numerical Design of Extrusion Process Using Finite Thermo-Elastoviscoplasticity with Damage. Prediction of Chevron Shaped Cracks

2009 ◽  
Vol 424 ◽  
pp. 265-272 ◽  
Author(s):  
Carl Labergère ◽  
Khemais Saanouni ◽  
Philippe Lestriez
Keyword(s):  
Constitutive Equations ◽  
Thermal Effects ◽  
Initial Temperature ◽  
Kinematic Hardening ◽  
Extrusion Process ◽  
Main Process ◽  
Damage Prediction ◽  
User Subroutine ◽  
Micro Cracks ◽  
Fully Coupled

The influence of the initial temperature and its evolution with large plastic deformation on the formation of the fully coupled chevron shaped cracks in extrusion is numerically investigated. Fully coupled thermo-elasto-viscoplastic constitutive equations accounting for thermal effects, mixed and nonlinear isotropic and kinematic hardening, isotropic ductile damage with micro-cracks closure effects are used. These constitutive equations have been implemented in Abaqus/Explicit code thanks to the user subroutine vumat and used to perform various numerical simulations needed to investigate the problem. It has been shown that the proposed methodology is efficient to predict the chevron shaped cracks in extrusion function of the main process parameters including the temperature effect.

Enhanced CDM model accounting of stress triaxiality and Lode angle for ductile damage prediction in metal forming

2020 ◽  
pp. 105678952095804
Author(s):  
Kai Zhang ◽  
Houssem Badreddine ◽  
Naila Hfaiedh ◽  
Khemais Saanouni ◽  
Jianlin Liu
Keyword(s):  
Constitutive Equations ◽  
Damage Model ◽  
Stress Triaxiality ◽  
Ductile Damage ◽  
Irreversible Processes ◽  
State Variables ◽  
Damage Prediction ◽  
Proposed Model ◽  
Lode Angle ◽  
Fully Coupled

This paper deals with the prediction of ductile damage based on CDM approach fully coupled with advanced elastoplastic constitutive equations. This fully coupled damage model is developed based on the total energy equivalence assumption under the thermodynamics of irreversible processes framework with state variables. In this model, the damage evolution is enhanced by accounting for both stress triaxiality and Lode angle. The proposed constitutive equations are implemented into Finite Element (FE) code ABAQUS/Explicit through a user material subroutine (VUMAT). The material parameters are determined by the hybrid experimental-numerical method using various tensile and shear tests. Validation of the proposed model has been done using different tests of two aluminum alloys (Al6061-T6 and Al6014-T4). Through comparisons of numerical simulations with experimental results for different loading paths, the predictive capabilities of the proposed model have been shown. The model is found to be able to capture the initiation as well as propagation of macro-crack in sheet and bulk metals during their forming processes.

scholarly journals Modeling of Thermal Effects in Semiconductor Structures

VLSI Design ◽  
1998 ◽  
Vol 8 (1-4) ◽  
pp. 53-58
Author(s):  
Christopher M. Snowden
Keyword(s):  
Thermal Effects ◽  
Large Scale ◽  
High Electron Mobility Transistors ◽  
Thermal Modelling ◽  
High Electron ◽  
Temperature Model ◽  
Active Devices ◽  
Electron Mobility Transistors ◽  
Fully Coupled ◽  
Scale Surface

A fully coupled electro-thermal hydrodynamic model is described which is suitable for modelling active devices. The model is applied to the non-isothermal simulation of pseudomorphic high electron mobility transistors (pHEMTs). A large-scale surface temperature model is described which allows thermal modelling of semiconductor devices and monolithic circuits. An example of the application of thermal modelling to monolithic circuit characterization is given.

Modelling and numerical simulation of thick sheet double slitting process using continuum damage mechanics

2014 ◽  
Vol 23 (8) ◽  
pp. 1150-1167 ◽  
Author(s):  
Yosr Ghozzi ◽  
Carl Labergere ◽  
Khemais Saanouni ◽  
Anthony Parrico
Keyword(s):  
Numerical Simulation ◽  
Constitutive Equations ◽  
Damage Mechanics ◽  
Continuum Damage Mechanics ◽  
Thick Sheet ◽  
Technological Parameters ◽  
Strongly Coupled ◽  
Mixed Hardening ◽  
Elasto Plasticity ◽  
Fully Coupled

This work concerns the modelling and numerical simulation of specific thick sheet cutting process using advanced constitutive equations accounting for elasto-plasticity with mixed hardening fully coupled with isotropic ductile damage. First, the complex kinematics of the different tools is modelled with specific boundary conditions. Second, the fully and strongly coupled constitutive equations are summarized and the associated numerical aspects are shortly presented. An inverse material identification procedure is used to determine the convenient values of the material parameters. Finally, the double slitting process is numerically simulated and the influence of the main technological parameters studied focusing on the cutting forces.

scholarly journals Damaged behavior under plane stress

2011 ◽  
pp. 341-368
Author(s):  
Thomas Paris ◽  
Khémaïs Saanouni
Keyword(s):  
Plane Stress ◽  
Constitutive Equations ◽  
Stress Condition ◽  
Time Integration ◽  
Reference Case ◽  
Plane Stress Condition ◽  
Integration Schemes ◽  
Hyperbolic Sine ◽  
Time Integration Schemes ◽  
Fully Coupled

This paper deals with the numerical treatment of "advanced" elasto-viscoplasticdamage constitutive equations in the particular case of plane stress. The viscoplastic constitutive equations account for the mixed isotropic and kinematic non linear hardening and are fully coupled with the isotropic ductile damage. The viscous effect is indifferently described by a power function (Norton type) or an hyperbolic sine function. Different time integration schemes are used and compared to each other assuming plane stress condition, widely used when dealing with shell structures as well as to the 3D reference case.

scholarly journals Simulation of Sheet Metal Forming Processes Using a Fully Rheological-Damage Constitutive Model Coupling and a Specific 3D Remeshing Method

Metals ◽  
2018 ◽  
Vol 8 (12) ◽  
pp. 991 ◽  
Author(s):  
Abel Cherouat ◽  
Houman Borouchaki ◽  
Zhang Jie
Keyword(s):  
Finite Element ◽  
Sheet Metal ◽  
Sheet Metal Forming ◽  
Constitutive Equations ◽  
Metal Forming ◽  
Damage Mechanics ◽  
Three Dimensions ◽  
Automatic Process ◽  
Adaptive Remeshing ◽  
Fully Coupled

Automatic process modeling has become an effective tool in reducing the lead-time and the cost for designing forming processes. The numerical modeling process is performed on a fully coupled damage constitutive equations and the advanced 3D adaptive remeshing procedure. Based on continuum damage mechanics, an isotropic damage model coupled with the Johnson–Cook flow law is proposed to satisfy the thermodynamic and damage requirements in metals. The Lemaitre damage potential was chosen to control the damage evolution process and the effective configuration. These fully coupled constitutive equations have been implemented into a Dynamic Explicit finite element code Abaqus using user subroutine. On the other hand, an adaptive remeshing scheme in three dimensions is established to constantly update the deformed mesh to enable tracking of the large plastic deformations. The quantitative effects of coupled ductile damage and adaptive remeshing on the sheet metal forming are studied, and qualitative comparison with some available experimental data are given. As illustrated in the presented examples this overall strategy ensures a robust and efficient remeshing scheme for finite element simulation of sheet metal‐forming processes.

A Thermal Hydrodynamic Lubrication Theory for Hydrostatic Extrusion of Low Strength Materials

1976 ◽  
Vol 98 (2) ◽  
pp. 335-342 ◽  
Author(s):  
R. W. Snidle ◽  
B. Parsons ◽  
D. Dowson
Keyword(s):  
Plastic Deformation ◽  
Theoretical Analysis ◽  
Thermal Effects ◽  
Hydrodynamic Lubrication ◽  
Extrusion Process ◽  
Lubrication Theory ◽  
Lubricant Film ◽  
Hydrostatic Extrusion ◽  
Solid Friction ◽  
Hydrodynamic Lubrication Theory

The paper presents a theoretical analysis of hydrodynamic lubrication in the hydrostatic extrusion process which includes a consideration of thermal effects in the lubricant film arising from the work of plastic deformation. A Newtonian lubricant with an exponential pressure-temperature-viscosity relationship has been assumed and allowance has been made for the effects of redundant deformation of the worked material. The results of the theory are compared with those from previous isothermal and solid friction theories.

Residual Stresses in 3D Sheet Metal Guillotining Using a Coupled Finite Elastoplastic Damage Model

2006 ◽  
Vol 524-525 ◽  
pp. 89-94
Author(s):  
Abel Cherouat ◽  
N. Belamri ◽  
Khemais Saanouni ◽  
P. Autesserre
Keyword(s):  
Numerical Simulation ◽  
Residual Stresses ◽  
Sheet Metal ◽  
Kinematic Hardening ◽  
Damage Model ◽  
Element Model ◽  
Elastoplastic Model ◽  
Dynamic Resolution ◽  
Explicit Dynamic ◽  
Fully Coupled

This work deals with the numerical simulation of 3D guillotining of sheet metal using anisotropic elastoplastic model accounting for non-linear isotropic and kinematic hardening fully coupled with isotropic ductile damage and initial residual stresses. Both theoretical and numerical aspects are presented. A 3D finite element model is developed for the numerical simulation of the study state guillotining process. An explicit dynamic resolution strategy is used to solve the associated initial and boundary value problem. Results from the simulation of the guillotining process are given and the influence of residual stresses is investigated.

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