# OS-V: 0250 3D Sheet Metal Forming

Contacts Benchmark 3 For quasi-static analysis using elastic plastic material, geometric non-linearity and nonlinear boundary conditions.

OptiStruct FE results examine the forming angle and angle after the punch is released. OptiStruct also examines the contact features of the rigid and deformable bodies and sliding contact around the circular surfaces.

## Model Files

Before you begin, copy the file(s) used in this problem to your working directory.

## Benchmark Model

Hexa8 elements are used to create the half model of the sheet and Quad4 elements are used to model the punch and the die. The punch radius is 23.5 mm, the die radius is 25 mm, the die shoulder radius is 4 mm, width of the tool is 50 mm, length of sheet is 120 mm, sheet thickness is 1 mm and the width of the sheet is 30 mm. The punch stroke is 28.5 mm. The bottom surface is fixed. Two different contact properties are used, one with coefficient of friction 0.0 and the second with coefficient of friction 0.1342. For the contacts between the punch and the sheet, punch is considered as main surface and the sheet as secondary and for the contacts between the die and the sheet die is considered as main and sheet as secondary.

The material properties are:
Material Properties
Value
E
70.5 kN/mm2
$\upsilon$
0.342
$\sigma$ 0 (Initial yield stress)
194 N/mm2
Hollomon hardening
$\sigma$ =K x $\text{ε}$ n
K = 550.4 N/mm2
n = 0.223

## Nonlinear Static Analysis Results

Characteristic angles during process.
Frictional Coefficient=0 NAFEMS OptiStruct Results Normalized
Forming angle 21.88 20.50 1.067317
Angle after release 48.38 45.53 1.062596
Frictional Coefficient=0.1348 NAFEMS OptiStruct Results Normalized
Forming angle 21.84 22.437 0.973392
Angle after release 54.45 43.22 1.259833

## Reference

NAFEMS R0094 - Advanced finite element contact benchmarks, Konter 2006