New strain-ratio-independent material constant of free surface roughening for polycrystal sheets in metal forming

CIRP Annals ◽  
2021 ◽  
Author(s):  
T. Furushima ◽  
M. Yamane
Keyword(s):  
Free Surface ◽  
Metal Forming ◽  
Material Constant ◽  
Strain Ratio ◽  
Surface Roughening

Prediction of Surface Roughening and Necking Behavior for Metal Foils by Inhomogeneous FE Material Modeling

2013 ◽  
Vol 554-557 ◽  
pp. 169-173 ◽  
Author(s):  
Tsuyoshi Furushima ◽  
Hitomi Tsunezaki ◽  
Tomoko Nakayama ◽  
Kenichi Manabe ◽  
Sergei Alexandrov
Keyword(s):  
Free Surface ◽  
Metal Forming ◽  
Fe Analysis ◽  
Confocal Laser ◽  
Surface Roughening ◽  
Fe Model ◽  
Metal Foil ◽  
Material Inhomogeneity ◽  
Metal Foils ◽  
Axial Tensile

Micro metal forming with metal foils is one of the promising approaches to fabricate micro parts. In this study, a finite element (FE) model for metal foil considering material inhomogeneity due to different flow stresses for each crystal grain to predict free surface roughening and necking behavior is suggested. Material used is pure copper C1020-O, pure aluminum 1N30-O and pure titanium TR270C-O with thickness of 0.05mm. Material inhomogeniety parameter of variation in α value is determined by parameter fitting between uni-axial tensile test and FE analysis considering material inhomogeneity under uni-axial tensile state. Standard deviation σsd of variation in α value of 0.28 for C1020-O is obtained by parameter fitting process. In addition, free surface roughening behavior is observed by FE analysis considering material inhomogeneity and confocal laser microsope. As a result, the increase in surface roughness with uni-axial tensile deformation can be observed for both FE analysis and experiment. In addition, it is considered that the generation of concave parts in free surface roughening is due to grains with low flow stress by quantitative measurement of FE analysis and confocal laser microscope. Surface roughening behavior of FE analysis considering material inhomogeneity is in good agreement with that of experimental results. Thus, the validation of FE model considering material inhomogeniety for metal foils can be verified. Furthermore, the effect of material properties for metal foils such as grain size, material inhomogeneity parameters and strain hardening sensitivity on necking behavior is investigated. As a results, it is found that the ratio of surface roughening to thickness strongly affects necking behavior for metal foil. In particular, in case of large n-value, the concave part generated by surface roughening during plastic deformation would cause the onset of necking for metal foils. Therefore, it is found that the factor of surface roughening is very strong in micro metal forming with metal foils.

Eulerian FEA With Volume of Solid (VOS) Application in Metal Forming

2010 ◽  
Author(s):  
K. S. Al-Athel ◽  
M. S. Gadala
Keyword(s):  
Finite Element ◽  
Free Surface ◽  
Process Improvement ◽  
Metal Forming ◽  
Material Flow ◽  
Solid Mechanics ◽  
Uniform Mesh ◽  
Element Formulation ◽  
Volume Of Fluid Method ◽  
Whole Process

The adaptation of the volume of fluid method (VOF) to solid mechanics (VOS) is presented in this work with the focus on metal forming applications. The method is discussed for a general non-uniform mesh with Eulerian finite element formulation. The implementation of the VOS method in metal forming applications is presented by focusing on topics such as the contact between the tool and the workpiece, tracking of the free surface of the material flow and the connectivity of the free surface during the whole process. Improvement on the connectivity of the free surface and the representation of curves is achieved by considering the mechanics of different metal forming processes. Different applications are simulated and discussed to highlight the capability of the VOS method.

scholarly journals Fracture and surface roughening behaviors in micro metal forming

2018 ◽  
Vol 15 ◽  
pp. 1481-1486 ◽  
Author(s):  
Tsuyoshi Furushima ◽  
Hitomi Tsunezaki ◽  
Yutaro Hirose
Keyword(s):  
Metal Forming ◽  
Surface Roughening

GS0402 Free Surface Roughening Behavior of Sheet Metals Under Compressive Strain

2016 ◽  
Vol 2016.22 (0) ◽  
pp. _GS0402-1_-_GS0402-2_
Author(s):  
Tsuyoshi FURUSHIMA ◽  
Kohei AOTO ◽  
Ken-ichi MANABE ◽  
Sergei ALEXANDROV
Keyword(s):  
Free Surface ◽  
Compressive Strain ◽  
Surface Roughening ◽  
Sheet Metals

Weak Formulations with Upwind Shift for Calculation of Free Surface Corrections and Simulation of Steady-State Forming Problems

2014 ◽  
Vol 611-612 ◽  
pp. 1311-1318
Author(s):  
Lionel Fourment ◽  
Ugo Ripert
Keyword(s):  
Free Surface ◽  
Steady State ◽  
Metal Forming ◽  
Wire Drawing ◽  
Computational Time ◽  
Steady Regime ◽  
Order Of Magnitude ◽  
Material Forming ◽  
Dramatic Shift ◽  
Simulation Time

For many material forming processes steady-state formulations allows reducing numerical simulation time by an order of magnitude with respect to more conventional approaches. In the presented approach, the steady regime is iteratively computed by a free surface algorithm that alternates computations of the metal forming flow over a known geometry and known contact surfaces, with computations of domain corrections to satisfy free and contact surface conditions. Several weak formulations of the second problem equations are investigated to get a robust algorithm suitable for parallel computations with unstructured meshes. Analytical problems show the necessity to introduce an upwind shift within these weak formulations. Contact inequations enforces this necessity by requiring a more dramatic shift. A robust and accurate algorithm is so obtained, which is successfully applied to 3D complex metal forming processes like rolling. In the wire drawing application, computational time is reduced by more than fifteen with respect to the incremental calculation of the steady-state.

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