The objective of the work discussed herein is to develop a nonlinear 3D finite element model to simulate dynamic behavior of polyurea toughened steel plates under impact loading. Experimental and numerical work related to model development are presented. Material properties are incorporated into numerical models to account for strain-rate effects on the dynamic behavior of polyurea and steel. One bare steel plate and four polyurea toughened steel plates were tested under impact loading using a pendulum impact device. Displacement time-history data from experimental work was used to validate the numerical models. Details on material model construction, finite element model development, and model validation are presented and discussed. Results indicate that the developed numerical models can reasonably predict dynamic response of polyurea toughened steel plates under impact loading. 1. Introduction Extreme natural and man-made hazards have always posed threats to civil infrastructure. Typical natural threats include earthquakes and hurricanes and man-made hazards can include malicious events caused by explosions or vehicle collisions. As conventional structures designed primarily based on strength and serviceability criteria can, in some instances, be vulnerable to impulsive and impact loads, it was of interest to examine new structural systems and materials that might better protect important structural components against these loads. This paper summarizes portions of a study that investigated the effectiveness with which an innovative coating material helped improve steel structural component impact resistance. Polyurea is a coating material that has received research interest due to its effective energy absorption properties. Davidson et al. [1] utilized polyurea as a blast load retrofitting material for masonry wall systems in residential or low-rise office structures. Fatt Hoo et al. [2] investigated the performance of polyurea strengthened concrete masonry walls subjected to blast loading. Results suggested that polyurea coated concrete masonry walls could improve blast resistance and reduce fragmentation. Also, Porter et al. [3] indicated that polyurea can be used to increase blast resistance of timber-framed structures. Nevertheless, the performance of various substrate materials coated with polyurea, from brittle materials like the aforementioned concrete and masonry to more ductile materials like steel, may vary widely because of the inherent different material behavior between brittle and ductile materials, and, as a result, approaches for
References
[1]
J. S. Davidson, J. R. Porter, R. J. Dinan, M. I. Hammons, and J. D. Connell, “Explosive testing of polymer retrofit masonry walls,” Journal of Performance of Constructed Facilities, vol. 18, no. 2, pp. 100–106, 2004.
[2]
M. S. Fatt Hoo, X. Quyang, and R. J. Dinan, “Blast response of walls retrofitted with elastomer coatings,” in Proceedings of the 8th International Conference on Structures Under Shock and Impact, pp. 129–138, WIT Press, Crete, Greece, 2004.
[3]
J. R. Porter, R. J. Dinan, M. I. Hammons, and K. J. Knox, “Polymer coatings increase blast resistance of existing and temporary structures,” The AMPTIAC Quarterly, vol. 6, pp. 47–52, 2002.
[4]
M. A. Meyers, Dynamic Behaviour of Materials, John Wiley & Sons, Hoboken, NJ, USA, 1994.
[5]
G. R. Johnson and W. H. Cook, “A constitutive model and data for metals subjected to large strains, high strain rates, and high temperatures,” in Proceedings for the Army Science Conference, Orlando, Fla, USA, 1983.
[6]
T. B？rvik, M. Langseth, O. S. Hopperstad, and K. A. Malo, “Ballistic penetration of steel plates,” International Journal of Impact Engineering, vol. 22, no. 9-10, pp. 855–886, 1999.
[7]
T. Borvik, O. S. Hopperstad, T. Berstad, and M. Langseth, “Perforation of 12？mm thick steel plates by 20？mm diameter projectiles with flat, hemispherical and conical noses, part II: numerical simulations,” International Journal of Impact Engineering, vol. 27, no. 1, pp. 37–64, 2001.
[8]
T. B？rvik, A. H. Clausen, M. Eriksson, T. Berstad, O. Sture Hopperstad, and M. Langseth, “Experimental and numerical study on the perforation of AA6005-T6 panels,” International Journal of Impact Engineering, vol. 32, no. 1–4, pp. 35–64, 2006.
[9]
N. K. Gupta, M. A. Iqbal, and G. S. Sekhon, “Experimental and numerical studies on the behavior of thin aluminum plates subjected to impact by blunt- and hemispherical-nosed projectiles,” International Journal of Impact Engineering, vol. 32, no. 12, pp. 1921–1944, 2006.
[10]
I. M. Ward and D. W. Hadley, An Introduction to the Mechanical Properties of Solid Polymers, John Wiley & Sons, New York, NY, USA, 1993.
[11]
J. Yi, M. C. Boyce, G. F. Lee, and E. Balizer, “Large deformation rate-dependent stress-strain behavior of polyurea and polyurethanes,” Polymer, vol. 47, no. 1, pp. 319–329, 2006.
[12]
J. Shim and D. Mohr, “Using split Hopkinson pressure bars to perform large strain compression tests on polyurea at low, intermediate and high strain rates,” International Journal of Impact Engineering, vol. 36, no. 9, pp. 1116–1127, 2009.
[13]
C. M. Roland, J. N. Twigg, Y. Vu, and P. H. Mott, “High strain rate mechanical behavior of polyurea,” Polymer, vol. 48, no. 2, pp. 574–578, 2007.
G. R. Johnson and W. H. Cook, “Fracture characteristics of three metals subjected to various strains, strain rates, temperatures and pressures,” Engineering Fracture Mechanics, vol. 21, no. 1, pp. 31–48, 1985.
[16]
D. L. Littlefield, C. E. Anderson Jr., Y. Partom, and S. J. Bless, “The penetration of steel targets finite in radial extent,” International Journal of Impact Engineering, vol. 19, no. 1, pp. 49–62, 1997.
[17]
H. Kurtaran, M. Buyuk, and A. Eskandarian, “Design automation of a laminated armor for best impact performance using approximate optimization method,” International Journal of Impact Engineering, vol. 29, no. 1-10, pp. 397–406, 2003.
[18]
D. Fuentes, D. Littlefield, J. T. Oden, and S. Prudhomme, “Extensions of goal-oriented error estimation methods to simulations of highly-nonlinear response of shock-loaded elastomer-reinforced structures,” Computer Methods in Applied Mechanics and Engineering, vol. 195, no. 37-40, pp. 4659–4680, 2006.
[19]
LSTC, LS-DYNA Keyword User’s Manual, Livermore, Calif, USA, 2007.
[20]
C.-C. Chen, A study of blast effects on polyurea coated steel components [Doctoral Dissertation], The Pennsylvania State University, State College, Pa, USA, 2009.
