OS-V: 1200 Bar Impact

Taylor TestAn elastic-plastic cylindrical bar impacts a rigid planar target with a high velocity (120-266 m/s). Verify the deformation results with the real test results.

You will be are interested in the deformed geometry of the bar after the impact.


Figure 1. FE Model

Cylindrical bar: length L=16mm, radius R=4mm

Benchmark Model

The finite element model, as shown in Figure 1 is meshed with first order CHEXA elements (32 elements along its length and 8 elements along its radius). The bar to target contact is frictionless. The appropriate boundary conditions are applied on the symmetry planes of the quarter model. The cylindrical bar is imparted 3 different velocities of 120.170 and 266 m/s.

Material

Bar (Elastic-Plastic Stainless Steel) Material Properties
Young's modulus
2.10E+05 N/mm2
Poisson's ratio
0.3
Density
7.85E-09 ton/mm3
Johnson & Cook Plasticity Parameters
A
350
B
1000
n
0.65
C
0.07
m
1

Results

The dimensions of the deformed bar differ from the real test values by less than 5%.
Table 1. Results of Bar Impact Test Case
Impact Velocity Length/Radius Reference Value OptiStruct Results
Absolute Value Error %
120 m/s Length 15.3 15.1 -1.30
Forward Radius - 4.433 -
Mid-Length Radius - 4.050 -
176 m/s Length 14.6 14.320 -1.90
Forward Radius 4.8 4.753 -1.04
Mid-Length Radius 4.1 4.128 +0.68
266 m/s Length 13.3 12.980 -2.40
Forward Radius 5.5 5.362 -2.50
Mid-Length Radius 4.2 4.335 +3.21


Figure 2. Deformed Shapes of the Bar

Model Files

The model files used in this problem include:

<install_directory>/hwsolvers/demos/optistruct/verification
  • /Bar1.fem
  • /Bar2.fem
  • /Bar3.fem
1 Calleja P., Terras C., Dormeval R., Ansarf J.-P. (CEA): “Taylor's test on aluminum, copper and stainless steel”, Physics Journal, colloquium C5, supplement to no. 8, Vol. 46, August 1985, pp. C5-91 to C5-99