OBJECTIVES

• Half-symmetric models of monolithic Aluminum (AI5083) and ceramic tiles supported by AI5083.
• Create computational models of experimental data.
• Sharp projectiles nose causes greater damage in the ceramic than a flat projectile nose.
• JH-2 is the best model to show damage, as there is a gradual softening as damage accumulates [1]

APPROACH

• Computational modeling of Depth of Penetration (DOP) experiments in AutoDyn
• AutoDyn is a finite element analyzer
• Impacts by a .30 cal AMP2 (Standard velocity 850 m/s) projectile are modeled using Smoothed-particle hydrodynamics (SPH) elements in AutoDyn
• SPH is a mesh free numerical solver that can be used for nonlinear problems like impact and solid penetration that experience large deformations and strains [2]
• SPH is preferable in DOP studies over Eulerian and Lagrangian methods which both have limitations with their meshes [2]
• SPH does not delete nodes and therefore does not create discontinuities in the failure model
• Data will be compared to the experimental results from ARL-TR-2219, 2000
• SPH particle size used is 0.2 mm assuming dust smaller than 0.2 mm can be ignored.
• Simulations are occurring in an infinite well with stationary boundary conditions applied to the edges.
• DOP is calculated: DOP = L - Lnp
-Where L is the length of entire target, ceramic and AI5083
-Lnp is the length of the target left unpenetrated when the velocity and kinetic energy of the projectile core have reached zero
- Measured from nose of the project core or where ceramic is embedded in the backing which ever has penetrated deeper

SETUP

DOP SIMULATIONS ON MONOLITHIC AI5083

• Simulation results do not show the same trend as the ARL data at higher velocities [3]
• Softening of the material as they fail is believed to be the cause of the discrepancy

DOP CERAMIC TILE SUPPORTED BY AI5083

• The ARL Measured no DOP [3]
-DOP was measured only when ceramic was totally defeated [3]
• Measuring from the embedded provided a 10% error in the measurement of DOP from experimental to computational.
• Is more accurate as a way of modeling the damage that occurred.

SUMMARY

• The projectile deforms as it is defeated in the ceramic tile while no deformation is seen in the monolithic AI5083.
• The ceramic tile supported by the AI5083 improves upon the DOP of monolithic AI5083
• Future work will include:
-Modeling in LS-DYNA to make use of parallel processing for larger models
•• Validating the computational model with experimental results.
•• Improving the performance of the ceramic
•• Modeling with different ceramics and different projectiles

REFERENCES

[1] Lamberts, A.P.T.M.J. "Numerical Simulation of Ballistic Impacts on Ceramic Material." Eindhoven University of Technology, 22 Aug. 2007. Web. 16 Apr. 2014.
[2] Quan, Xiangyang, and Naury Birnbaum. "SPH Simulation of the Ballistic Perforation of GFRP." 18th International Symposium and Exhibition on Ballistics. Tx, San Antonio. 15 Nov. 1999.
[3] Moynihan, Thomas J., Shun-Chin Chou, and Audrey L. Mihalcin. Application of the Depth-of-Penetration Test Methodology to Characterize Ceramics for Personnel Protection. Rep. Aberdeen Proving Ground, MD: Army Research Laboratory, April 2000. Print.

ACKNOWLEDGEMENTS

This work is supported by the Office of Naval Research through the Composite Materials Research program and University of Delaware Center for Composite Materials.