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.

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 23.5mm, the die radius is 25mm, the die shoulder radius is 4mm, width of the tool is 50mm, length of sheet is 120mm, sheet thickness is 1mm and the width of the sheet is 30mm. The punch stroke is 28.5mm. 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 master surface and the sheet as slave and for the contacts between the die and the sheet die is considered as master and sheet as slave.

The material properties are:

E: 70.5 kN/mm²
$υ$: 0.342
$σ$ ₀ (Initial yield stress): 194 N/mm²
Hollomon hardening: $σ$ =K x $ε$ 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

Model Files

The model files used in this problem include:

<install_directory>/hwsolvers/demos/optistruct/verification

/contb3f0.fem
/contb3fc.fem

Reference

NAFEMS Ltd, The Standard NAFEMS BENCHMARKS TNSB Rev. 3, NAFEMS Ltd, Scottish Enterprise Technology Park, Whitworth Building, East Kilbride, Glasgow, United Kingdom, 1990.