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Abstract

A new test specimen, denoted "Tilted Sandwich Debond" (TSD) specimen, for characterization of debond failure of foam core sandwich structure is experimentally examined. The bottom face of a sandwich is attached to an incline, and debond progression is examined under vertical load application to the partially debonded top face. The purpose of the test is to achieve face/core debonding as opposed to crack deflection into the core (kinking). For a sandwich consisting of glass/vinylester face sheets and PVC foam core, a critical angle of the incline, 0 = Oc was identified. When 0 < Oc, it was found that an existing debond kinked into the core. The desired face/core debond failure occurred when 0 > Oc. It was observed that 0C decreases with increasing crack length. The fracture toughness for debonding, expressed as the critical strain energy release rate, Gc, increased with increasing magnitude of the shear component.

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References

1. D. Zenkert, "Damage Tolerance of Foam Core Sandwich Constructions," Ph.D thesis, The Royal Institute of Technology, Stockholm. Sweden. 1987.

2. L. A. Carlsson , L. S. Sendlein and S. L. Merry , "Characterization of Face Sheet/Core Shear Fracture of Composite Sandwich Beams," J. Compos. Mater., Vol. 25. 1991, pp. 101-116.

3. M. L. Williams , "The Stress Around a Fault or Crack in Dissimilar Media." Bull. Seismol. Soc. Am., Vol. 49, 1959, pp. 199-204.

4. A. H. England , "A Crack Between Dissimilar Media," J Appl. Mech., Vol. 32,1965, pp. 400-402.

5. J. R. Rice . "Elastic Fracture Mechanics Concepts for Interface Cracks," J. Appl. Mech., Vol. 55. 1988, pp. 98-103.

6. S. Prasad and L. A. Carlsson , "Debonding and Crack Kinking in Foam Core Sandwich Beams-II: Experimental Investigation," Eng. Fracture Mech., Vol. 47, 1994, pp. 825-841.

7. J. W. Hutchinson , M. E. Mear and J. R. Rice , "Crack Paralleling an Interface Between Dissimilar Materials," J. Appl. Mech., Vol. 54, 1987, pp. 828-832.

8. N. A. Fleck , J. W. Hutchinson and Z. Suo , "Crack Path Selection in a Brittle Adhesive Layer," Int. J Solids Struct., Vol. 27, 1991, pp. 1683-1701.

9. M. He and J. W. Hutchinson , "Kinking of a Crack Out of an Interface," J Appl. Mech., Vol.56, 1989, pp. 270-278.

10.

10. S. Prasad and L. A. Carlsson , "Debonding and Crack Kinking in Foam Sandwich Beam-I: Analysis of Fracture Specimens," Eng. Fracture Mech., Vol. 47, 1994, pp. 813-824.

11.

11. W. J. Cantwell and P. Davies , "A Study of Skin-Core Adhesion in Glass Fiber Reinforced Sandwich Materials," Appl. Compos. Mater., Vol. 3, 1996, pp. 407-420.

12.

12. W. J. Cantwell , R. Scudamore , P. Davies and J.-B. Ferrer , "New Test Methods for Characterizing Skin-Core Debonding in Composite Sandwich Structures," Proc. ICMM-1J Conf, Australia, July 1997.

13.

13. A. T. Echtermeyer and D. McGeorge , "Fracture Toughness of Core-Skin Interfaces of Sandwich Materials," Proc. from 4th Int'l Conf on Sandwich Construction (Vol. 2), Royal Institute of Technology, Stockholm, Sweden, June 9-11, 1998.

14.

14. J. L. Grenestedt, personal communication, Royal Institute of Technology, Stockholm, Sweden, 1996.

15.

15. L. A. Carlsson and R. B. Pipes , "Experimental Characterization of Advanced Composite Materials," Technomic Publishing Co., Inc., Lancaster, PA, 1997.

16.

16. H. L. Ewalds and R. J. H. Wanhill , "Fracture Mechanics," Edward Arnold, London, 1989.

17.

17. K. M. Liechti and Y. S. Chai , "Asymmetric Shielding in Interfacial Fracture Under In-Plane Shear," J. Appl. Mech., Vol. 59, June 1992, 295-304.

18.

18. M. Stibe , "Fracture Toughness of Divinycell H100, H130 and H200," Barracuda Technologies AB, Sweden, 1991.

The Tilted Sandwich Debond (TSD) Specimen for Face/Core Interface Fracture Characterization

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