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Structural Performance of Eco-Core Sandwich Panels

  • Kunigal Shivakumar
  • Huanchun Chen

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.

Keywords

Failure Load Sandwich Panel Face Sheet Sandwich Beam Core Sandwich 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

Notes

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.

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Copyright information

© Springer Science+Business Media B.V. 2009

Authors and Affiliations

  1. 1.Center for Composite Materials Research, Department of Mechanical and Chemical EngineeringNorth Carolina A&T State UniversityGreensboroUSA

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