Analytical solutions for the low-velocity impact damage of composite sandwich panels are found by considering systems of discrete masses, springs and constant-force dashpots. Equivalent spring and dashpot forces for the sandwich panel are derived from the static load-indentation response and adjusted with dynamic material properties of the facesheet and core. Predictions of the maximum impact force are about 15% higher than experimental values, which is the same order of accuracy that is obtained from the static load-indentation analysis. Damage initiation due to tensile failure by hemispherical-nose shape projectiles and shear failure by blunt projectiles are examined. Predicted tensile and shear failure loads are about 20% higher than experimental results.
1. Williamson, J. E. and Lagace, P. A. 1993. “Response Mechanism in the Impact of Graphite/Epoxy Honeycomb Sandwich Panels,” in the Proceeding of the 8th ASC Technical Conference, Cleveland, OH:287-297.
2.
2. Ferris, R. and Sankar, B. V. 1997. “Static Indentation and Low Velocity Impact Tests on Sandwich Plates,” in the Proceedings of the 1997 ASME International Mechanical Engineering Congress and Exposition, Dallas; 55:485-490.
3.
3. Herup, E. J. and Palazotto, A. N.1997. “Low-Velocity Impact Damage Initiation in Graphite/Epoxy/Nomex Honeycomb-Sandwich Plates,”Composites Science and Technology; 57:1581-1598.
4.
4. Wen, H. W., Reddy, T. Y., Reid, S. R. and Soden, P. D.1998. “Indentation, Penetration and Perforation of Composite Laminates and Sandwich Panels under Quasi-Static and Projectile Loading,”Key Engineering Materials; 141-143:501-552.
5.
5. Abrate S.1997. “Localized Impact on Sandwich Structures with Laminated Facings.”Appl. Mech. Rev.50(2):69-82.
6.
6. Yang, S. H. and Sun, C. T. 1982. “Indentation Law for Composite Laminates,” in Composite Materials: Testing and Design (Sixth Conference), ASTM STP 787, I. M. Daniel (ed.):425-449.
7.
7. Olsson, R. and McManus, H. L. 1995. “Simplified Theory for Contact Indentation of Sandwich Panels,” in the Proceedings of the 36th AIAA/ASME/ASCE/AHS/ASC Structures, Structural Dynamics and Materials Conference, New Orleans, LA:1812-1820.
8.
8. Turk, M. H. and Hoo Fatt, M. S.1999. “Localized Damage Response of Composite Sandwich Plates,”Composites Part B: Engineering; 30:157-165.
9.
9. Ericsson, A. and Sankar, B. V. 1992. “Contact Stiffness of Sandwich Plates and Application to Low Velocity Impact Problems,” in the Proceedings of Sandwich Construction 2, EMAS, UK; 1:139-159.
10.
10. Thomsen, O. T.1995. “Theoretical and Experimental Investigation of Local Bending Effects in Sandwich Plates,”Composite Structures; 30:85-101.
11.
11. Gibson, L. J. and Ashby, M. F.1997. Cellular Solids Structures and Properties, Second Ed., Cambridge University Press.
12.
12. Dobyns, A. L.1981. “The Analysis of Simply-Supported Orthotropic Plates Subjected to Static and Dynamic Loads,”AIAA Journal; 19(5):642-650.
13.
13. Plantema, F. J.1966. Sandwich Construction, John Wiley & Sons, NY.
14.
14. Vinson, J. R.1999. The Behavior of Sandwich Structures of Isotropic and Composite Materials, Technomic Publishing Company.
16. Sierakowski, R. L.1997. “Strain Rate Effects in Composites,”ASME Applied Mechanics Review; 50(12) Part 1:741-761.
17.
17. Al-Hassani, S. T. S and Kaddour, A. S.1998. “Strain Rate Effects on GRP, KRP, and CFRP Composite Laminates,”Key Engineering Materials; 141-143:427-452.
18.
18. Nemes, J. A., Eskandari, H. and Rakitch, L.1998. “Effect of Laminate Parameters on Penetration of Graphite/Epoxy Composites,”International Journal of Impact Engineering; 21(1-2):97-112.
19.
19. Goldsmith, W. and Sackman, J. L.1991. “An Experimental Study of Energy Absorption in Impact on Sandwich Plates,”International Journal of Impact Engineering; 12(2):241-262.
20.
20. Gellhorn, E. V. and Reif, G. 1992. “Think Dynamic—Dynamic Test Data for the Design of Dynamically Loaded Structures,” in the Proceedings of Sandwich Construction 2, EMAS. UK; 1:541-557.
21.
21. Goldsmith, W., Dharan, C. K. H. and Chang, H.1995. “Quasi-Static and Ballistic Perforation of Carbon Fiber Laminates,”Int. J. Solids Structures; 32(1):89-103.
22.
22. Cantwell, W. J. and Morton, J.1990. “Impact Perforation of Carbon Fibre Reinforced Plastics,”Composites Science and Technology; 39:119-141.
23.
23. Harding, J., Li, Y. L., Saka, K. and Taylor, M. E. C. 1989. “Characterization of the Impact Strength of Woven Carbon Fibre/Epoxy Laminates,” in the Proceeding of the International Conference on Mechanical Properties of Materials at High Rates of Strain, Oxford:403-410.
24.
24. Harding, J. and Welsh, L. M.1983. “A Tensile Testing Technique for Fiber-Reinforced Composites at Impact Rates of Strain,”Journal of Material Science; 18:1810-1826.
25.
25. Harding, J.1989. “Impact Damage in Composite Materials,”Science & Engineering of Composite Materials; 1(2):41-68.
