Prediction of Free Surface Roughening by 2D and 3D Model Considering Material Inhomogeneity

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.

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Inhomogeneous 3D Finite Element Model for Prediction of Free Surface Roughening

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.418-420.1040 ◽

2011 ◽

Vol 418-420 ◽

pp. 1040-1043 ◽

Cited By ~ 4

Author(s):

Tsuyoshi Furushima ◽

Tetsuro Masuda ◽

Kenichi Manabe ◽

Sergei Alexandrov

Keyword(s):

Surface Roughness ◽

Finite Element ◽

Free Surface ◽

Experimental Result ◽

Surface Roughening ◽

Sensitivity Index ◽

Fe Model ◽

K Value ◽

3D Finite Element ◽

Material Inhomogeneity

In this study, we evaluated the characteristics of 3D finite element (FE) model considering material inhomogeneity for prediction of free surface roughening. Free surface roughening behavior can be observed by this model. The variation in material inhomogeneity parameter value has a strong correlation with the rate of increase in the surface roughness. macroscopic strength coefficient K value does absolutely not affect the rate of increasing surface roughness. Strain hardening sensitivity index n value slightly affects the free surface roughening behavior. The true stress – true strain curve of the inhomogeneous FE model is in good agreement with those of the homogeneous FE model and the experimental result. As a result, the characteristics evaluation of suggested model considering material inhomogeneity is conducted.

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

CIRP Annals ◽

10.1016/j.cirp.2021.04.035 ◽

2021 ◽

Author(s):

T. Furushima ◽

M. Yamane

Keyword(s):

Free Surface ◽

Metal Forming ◽

Material Constant ◽

Strain Ratio ◽

Surface Roughening

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Surface roughening with plastic deformation of sintered metals. (1st Report, Development of free surface roughness in upsetting of sintered aluminium.)

TRANSACTIONS OF THE JAPAN SOCIETY OF MECHANICAL ENGINEERS Series C ◽

10.1299/kikaic.56.228 ◽

1990 ◽

Vol 56 (521) ◽

pp. 228-234

Author(s):

Norio TAKAKURA ◽

Katsuhiko YAMAGUCHI ◽

Masayoshi FUKUDA

Keyword(s):

Surface Roughness ◽

Plastic Deformation ◽

Free Surface ◽

Surface Roughening

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NUMERICAL SOLUTIONS OF 2D AND 3D SLAMMING PROBLEMS

The International Journal of Maritime Engineering ◽

10.5750/ijme.v153ia2.851 ◽

2021 ◽

Vol 153 (A2) ◽

Author(s):

Q Yang ◽

W Qiu

Keyword(s):

Free Surface ◽

Numerical Solutions ◽

Stokes Equations ◽

Type Equation ◽

The Body ◽

Navier Stokes ◽

Time Step ◽

Navier Stokes Equations ◽

Highly Nonlinear ◽

2D And 3D

Slamming forces on 2D and 3D bodies have been computed based on a CIP method. The highly nonlinear water entry problem governed by the Navier-Stokes equations was solved by a CIP based finite difference method on a fixed Cartesian grid. In the computation, a compact upwind scheme was employed for the advection calculations and a pressure-based algorithm was applied to treat the multiple phases. The free surface and the body boundaries were captured using density functions. For the pressure calculation, a Poisson-type equation was solved at each time step by the conjugate gradient iterative method. Validation studies were carried out for 2D wedges with various deadrise angles ranging from 0 to 60 degrees at constant vertical velocity. In the cases of wedges with small deadrise angles, the compressibility of air between the bottom of the wedge and the free surface was modelled. Studies were also extended to 3D bodies, such as a sphere, a cylinder and a catamaran, entering calm water. Computed pressures, free surface elevations and hydrodynamic forces were compared with experimental data and the numerical solutions by other methods.

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Dam-Break Flows: Comparison between Flow-3D, MIKE 3 FM, and Analytical Solutions with Experimental Data

Applied Sciences ◽

10.3390/app8122456 ◽

2018 ◽

Vol 8 (12) ◽

pp. 2456 ◽

Cited By ~ 5

Author(s):

Hui Hu ◽

Jianfeng Zhang ◽

Tao Li

Keyword(s):

Experimental Data ◽

Free Surface ◽

Analytical Solution ◽

Water Depth ◽

3D Model ◽

Real Life ◽

Surface Profile ◽

Dam Break ◽

Computational Time ◽

Free Surface Profile

The objective of this study was to evaluate the applicability of a flow model with different numbers of spatial dimensions in a hydraulic features solution, with parameters such a free surface profile, water depth variations, and averaged velocity evolution in a dam-break under dry and wet bed conditions with different tailwater depths. Two similar three-dimensional (3D) hydrodynamic models (Flow-3D and MIKE 3 FM) were studied in a dam-break simulation by performing a comparison with published experimental data and the one-dimensional (1D) analytical solution. The results indicate that the Flow-3D model better captures the free surface profile of wavefronts for dry and wet beds than other methods. The MIKE 3 FM model also replicated the free surface profiles well, but it underestimated them during the initial stage under wet-bed conditions. However, it provided a better approach to the measurements over time. Measured and simulated water depth variations and velocity variations demonstrate that both of the 3D models predict the dam-break flow with a reasonable estimation and a root mean square error (RMSE) lower than 0.04, while the MIKE 3 FM had a small memory footprint and the computational time of this model was 24 times faster than that of the Flow-3D. Therefore, the MIKE 3 FM model is recommended for computations involving real-life dam-break problems in large domains, leaving the Flow-3D model for fine calculations in which knowledge of the 3D flow structure is required. The 1D analytical solution was only effective for the dam-break wave propagations along the initially dry bed, and its applicability was fairly limited.

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