Densification Behavior of Metal Powder Under Uniaxial Cold Compaction

2010 ◽  
Author(s):  
Mostafa Darroudi ◽  
Hojat Ghassemi ◽  
Mahmoud Akbari Baseri
Keyword(s):  
Finite Element ◽  
Metal Powder ◽  
Volume Fraction ◽  
Compaction Pressure ◽  
Solid Volume Fraction ◽  
Powder Compaction ◽  
Wall Friction ◽  
Isotropic Hardening ◽  
Spherical Powder ◽  
Von Mises

Metal powder compaction is a quite important process in Powder Metallurgy (PM) industry and it is widely applied in the manufacturing of key components in different fields. During metal powder compaction, the solid volume fraction changes and many mechanical characteristics become different. The Finite Element simulation provides a flexible and efficient approach for the researches of this process and its complicated mechanical behaviors. In this paper, several 2D finite element spherical powder compaction models are generated. Different particle arrangements are build up and different friction coefficients are set to the inter-particle contacts and die wall contact for a certain arrangement. The Von Mises yield surface with isotropic hardening plasticity model is applied in the simulation and the displacement controlled load is used to compress the structure up to 25% of die height. Results show that the die wall friction increases compaction pressure but inter-particle friction has negligible effect.

Finite Element Simulation of Tensile Behaviors in the Elastic Region for PP/Nano-TiO2 Composites

2010 ◽  
Vol 150-151 ◽  
pp. 1819-1823
Author(s):  
Yu Jiao Wu ◽  
Ming Rui Gao ◽  
Yu Ling Chen ◽  
Juan Li ◽  
Shao Lin Ju
Keyword(s):  
Finite Element ◽  
Stress Field ◽  
Volume Fraction ◽  
Local Stress ◽  
Von Mises Stress ◽  
Analysis Model ◽  
Nano Tio2 ◽  
Two Phase ◽  
Element Analysis ◽  
Von Mises

Polypropylene(PP)/nano-TiO2 composites were prepared by the melt intercalation molding. Based on the assumption of continuum mechanics model for materials, a finite element analysis model for the composites was constructed using ANSYS 11.0 software. In the stage of deformation (pre-yield regime) the response mechanism of the stress and the strain for composites was investigated, and the von mises stress field of PP/nano-TiO2 composites has also been simulated. It was found that the simulation results are Consistent with the testing results at low volume strain level. The results simulated using the 2D model are accurate with the experimental results. If the volume fraction of particles is less, other particles have little influence on the local stress field of a certain particle, no obvious overlap or cross of the stress field could be found between two neighboring particles. While applying different loads, the stress jumps to maximum stress value in the interaction region of the two phase firstly, and then it occurs that the particles debond with the matrix.

scholarly journals Development of a continuum plasticity model for the commercial finite element code ABAQUS

2011 ◽  
Vol 2 (2) ◽  
pp. 275-283
Author(s):  
M. Safaei ◽  
W. De Waele
Keyword(s):  
Finite Element ◽  
Yield Surface ◽  
Euler Method ◽  
Integration Scheme ◽  
Isotropic Hardening ◽  
Implicit Integration ◽  
Backward Euler ◽  
User Material Subroutine ◽  
Von Mises ◽  
Future Work

The present work relates to the development of computational material models for sheet metalforming simulations. In this specific study, an implicit scheme with consistent Jacobian is used forintegration of large deformation formulation and plane stress elements. As a privilege to the explicitscheme, the implicit integration scheme is unconditionally stable. The backward Euler method is used toupdate trial stress values lying outside the yield surface by correcting them back to the yield surface atevery time increment. In this study, the implicit integration of isotropic hardening with the von Mises yieldcriterion is discussed in detail. In future work it will be implemented into the commercial finite element codeABAQUS by means of a user material subroutine.

scholarly journals MHD darcy-forchheimer nanofluid flow and entropy optimization in an odd-shaped enclosure filled with a (MWCNT-Fe3O4/water) using galerkin finite element analysis

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Wael Al-Kouz ◽  
Abderrahmane Aissa ◽  
Aimad Koulali ◽  
Wasim Jamshed ◽  
Hazim Moria ◽  
...  
Keyword(s):  
Finite Element ◽  
Rayleigh Number ◽  
Volume Fraction ◽  
Solid Volume Fraction ◽  
Darcy Number ◽  
Heated Wall ◽  
Entropy Generation Rate ◽  
Hybrid Nanofluid ◽  
Galerkin Finite Element ◽  
The Impact

AbstractMHD nanoliquid convective flow in an odd-shaped cavity filled with a multi-walled carbon nanotube-iron (II, III) oxide (MWCNT-Fe3O4) hybrid nanofluid is reported. The side walls are adiabatic, and the internal and external borders of the cavity are isothermally kept at high and low temperatures of Th and Tc, respectively. The governing equations obtained with the Boussinesq approximation are solved using Galerkin Finite Element Method (GFEM). Impact of Darcy number (Da), Hartmann number (Ha), Rayleigh number (Ra), solid volume fraction (ϕ), and Heated-wall length effect are presented. Outputs are illustrated in forms of streamlines, isotherms, and Nusselt number. The impact of multiple parameters namely Rayleigh number, Darcy number, on entropy generation rate was analyzed and discussed in post-processing under laminar and turbulent flow regimes.

Gravity granular flows of slightly frictional particles down an inclined bumpy chute

1996 ◽  
Vol 316 ◽  
pp. 197-221 ◽  
Author(s):  
J. Cao ◽  
G. Ahmadi ◽  
M. Massoudi
Keyword(s):  
Volume Fraction ◽  
Solid Volume Fraction ◽  
Wall Friction ◽  
Surface Boundary ◽  
Mean Velocity ◽  
Energy Profiles ◽  
Inclination Angles ◽  
Gravity Driven ◽  
Boundary Roughness ◽  
Good Agreement

Gravity-driven granular flow of slightly frictional particles down an inclined, bumpy chute is studied. A modified kinetic model which includes the frictional energy loss effects is used, and the boundary conditions for a bumpy wall with small friction are derived by ensuring the balance of momentum and energy. At the free surface, the condition of vanishing of the solid volume fraction is used. The mean velocity, the fluctuation kinetic energy and the solid volume fraction profiles are evaluated. It is shown that steady granular gravity flow down a bumpy frictional chute could be achieved at arbitrary inclination angles. The computational results also show that the slip velocity may vary considerably depending on the granular layer height, the surface boundary roughness, the friction coefficient and the inclination angles. The model predictions are compared with the existing experimental and simulation data, and good agreement is observed. In particular, the model can well predicate the features of the variation of solid volume fraction and fluctuation energy profiles for different particle–wall friction coefficients and wall roughnesses.

Finite Element Implementation of a Thermoviscoplastic Model for Ratcheting

2004 ◽  
Author(s):  
Rashid K. Abu Al-Rub ◽  
George Z. Voyiadjis
Keyword(s):  
Finite Element ◽  
Strain Rate ◽  
Yield Criterion ◽  
Isotropic Hardening ◽  
Strain Rate Effects ◽  
Finite Element Implementation ◽  
Rate Dependent ◽  
Proposed Model ◽  
Integration Algorithms ◽  
Von Mises

A thermoviscoplastic constitutive model is proposed to simulate the uniaxial/multiaxial ratcheting of cyclically stable materials and its finite element implementation is also achieved. The kinematic and isotropic hardening rules used in the proposed model are similar to that developed by Voyiadjis and Abu Al-Rub [1], except for the coupling with temperature and strain-rate effects. The proposed constitutive equations include thermo-elasto-viscoplasticity, a dynamic yield criterion of a von Mises type, the associated flow rules, non-linear strain hardening, strain-rate hardening, and temperature softening. In the finite element implementation of the proposed model new implicit stress integration algorithms are proposed. The proposed unified integration algorithms are extensions of the classical rate-independent radial return scheme to the rate-dependent problems. A new expression of consistent tangent modulus is also derived for rate- and temperature-dependent inelasticity. The proposed model is verified by simulating the uniaxial ratcheting of a metallic material.

Study of Material Modeling Strategies for Deformability Analysis of Rectangular Cups

2012 ◽  
Vol 498 ◽  
pp. 243-248
Author(s):  
Hirpa G. Lemu ◽  
T. Trzepieciński
Keyword(s):  
Finite Element ◽  
Metal Forming ◽  
Yield Criterion ◽  
Material Modeling ◽  
Isotropic Hardening ◽  
Friction Anisotropy ◽  
Element Analysis ◽  
Forming Simulation ◽  
The Finite Element Analysis ◽  
Von Mises

A comparative study of different material modeling strategies in deformability analysis of rectangular cups is presented in this paper. The article focuses on application of dynamic explicit and static implicit approaches in Finite Element Methods (FEM) for metal forming simulation where different material models and contact conditions with friction are involved. The simulated results are verified using results from experimental study of the deformation on the same material. Further, a comparison between a quadratic Hill anisotropic yield criterion and von Mises yield criterion with isotropic hardening has been studied. The results confirm that the dynamic explicit method is more efficient in simulating sheet metal forming processes. The study shows also that the finite element analysis undoubtedly gives good approximate numerical results to real processes when the material and friction anisotropy are considered.

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