Abstract
Eco-Core, a fire resistant core material for sandwich composite structures developed under the US Navy (ONR) program, was used to study its performance as a sandwich beam with glass/vinyl ester face sheet. Performance of Eco-Core was compared with balsa and PVC core sandwich panels. Test specimens were designed to simulate shear, flexural, and edgewise compression loadings. These tests were conducted on Eco-Core as well as balsa and PVC sandwich composite specimens. Failure loads and modes were compared with each other and the analytical prediction. Both Eco-Core and balsa cored sandwich beams had similar failure modes in all three test conditions. In the case of transversely loaded (four-point) beams Eco-Core specimens failed by core shear for span/depth (S/d) ratio less than 4 and the failure mode changed to core tension for S/d >4. This is attributed to weak tensile strength of the core material. An expression for core tension failure load based on beam theory was derived. On the other hand, ductile materials like PVC failed by core indentation. Under edgewise compression, face sheet microbuckling and general buckling are the two potential failure modes for Eco-Core and balsa core sandwich composites. For specimen length/depth ratio L/d <7 the failure is by face sheet microbuckling, for 7 ≤L/d ≤13 the failure is a combination of face sheet microbuckling, debonding and buckling, and for L/d >13 the failure is by general buckling. Predictions from the existing equations agreed well with the experiment for both core materials. For PVC core, wrinkling/shear buckling and general buckling are the potential failure modes. For L/d ≤8.5 the failure is wrinkling and for L/d >8.5 the failure is general buckling.
This is a preview of subscription content, log in via an institution to check access.
Access this chapter
Tax calculation will be finalised at checkout
Purchases are for personal use only
References
Olson K (2003) Keynote Lecture, Proceedings of 6th International Conference on Sandwich Structures, March 31–April 2, Fort Lauderdale, FL
Sorathia U, Perez I (2004) Improving the fire safety of composite materials for naval applications. SAMPE 2004, May 16–20, Long Beach, CA
Shivakumar KN, Argade SD, Sadler RL et al. (2006) Processing and properties of a lightweight fire resistant core material for sandwich structures. J Ad Maters 38(1):32–38
Argade S, Shivakumar K, Sadler R et al. (2004) Mechanical fire resistance properties of a core material. SAMPE, May 16–20, Long Beach Convention Center, Long Beach, CA
Shivakumar KN, Sharpe M, Sorathia U (2005) Modification of eco-core to enhance toughness and fire resistance. SAMPE-2005, Long Beach, CA
Sadler RL, Sharpe MM, Shivakumar KN (2008) Water immersion of eco-core and two other sandwich core materials. SAMPE 2008, May 18–22, Long Beach, CA
Allen HG (1969) Analysis and design of structural sandwich panels. Pergamon, Oxford
Zenkert D (1997) An introduction to sandwich construction. Chameleon, London
Swaminathan G, Shivakumar KN, Sharpe M (2006) Material property characterization of glass and carbon/vinyl ester composites. Compos Sci Technol 66(10):1399–1408
http://www.diabgroup.com/americas/u_products/u_divinycell_h.html
Heath WG (2002) Sandwich construction, Part 2:The optimum design of flat sandwich panels. Aircraft Eng 33:163–176
Gdoutos EE, Daniel IM, Wang KA (2002) Compression facing wrinkling of composite sandwich structures. Mech Mater 35:511–522
Sadler RL, Shivakumar KN, Sharpe MM (2002) Interlaminar fracture properties of split angle-ply composites. SAMPE 2002, Long Beach, CA
Soden PD (1996) Indentation of composite sandwich beams. J Strain Anal 31:353–360
Gdoutos EE, Daniel IM, Wang KA (2002) Indentation failure in composite sandwich structures. Exp Mech 42(4):426–431
Steeves CA, Fleck NA (2004) Collapse mechanisms of sandwich beams with composite faces and a foam core, loaded in three-point bending. Part I:Analytical models and minimum weight design. Int J Mech Sci 46:561–583
Fleck NA, Sridhar I (2002) End compression of sandwich columns. Compos A 33:353–359
Acknowledgment
The authors wish to thank the Office of Naval Research for financial support through grants #N00014-07-1-0465 and #N000140510532. Dr. Yapa Rajapakse was the technical monitor of the grants.
Author information
Authors and Affiliations
Corresponding author
Editor information
Editors and Affiliations
Rights and permissions
Copyright information
© 2009 Springer Science+Business Media B.V.
About this chapter
Cite this chapter
Shivakumar, K., Chen, H. (2009). Structural Performance of Eco-Core Sandwich Panels. In: Daniel, I.M., Gdoutos, E.E., Rajapakse, Y.D.S. (eds) Major Accomplishments in Composite Materials and Sandwich Structures. Springer, Dordrecht. https://doi.org/10.1007/978-90-481-3141-9_15
Download citation
DOI: https://doi.org/10.1007/978-90-481-3141-9_15
Publisher Name: Springer, Dordrecht
Print ISBN: 978-90-481-3140-2
Online ISBN: 978-90-481-3141-9
eBook Packages: Chemistry and Materials ScienceChemistry and Material Science (R0)