Microballoon Wall Thickness Effects on Properties of Syntactic Foams

Abstract

A novel approach for changing the density of syntactic foams, while keeping the microballoon (hollow particles) volume fraction constant, is adopted in this work. This is achieved by selecting microballoons of the same size but with different wall thickness. Five types of microballoons are selected to fabricate syntactic foams. All the types of microballoons have about 40 mm mean particle sizes, but different wall thicknesses. This approach allows to maintain the same volume fractions of constituents and interfacial area while changing the density of syntactic foams. The fabricated syntactic foams are tested for their compressive properties in accordance to the ASTM D 695-96 standard. The results of the experimental investigation show a strong dependence of the compressive properties and the fracture characteristics of syntactic foams on the microballoon wall thickness. Shear cracking followed by cracking under secondary tensile stresses has been observed as the fracture mode. The present approach is found to be more effective than changing the microballoon volume fraction to change the syntactic foam density as it considerably increases the strength to the weight ratio.

Keywords

composites mechanical properties strength syntactic foam microballoon

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References

1. Lawrence, E. , Wulfshon, D. and Pyrz, R. (2001). Microstructural Characterization of Syntactic Foam , Polymers and Polymer Composites, 9(7): 449-457 .

2. Lawrence, E. and Pyrz, R. (2001). Viscoelastic Properties of Polyethylene Syntactic Foam with Polymer Microballoons , Polymers and Polymer Composites, 9(4): 227-237 .

3. Banhart, J. (2001). Manufacture, Characterization and Application of Cellular Metals and Metal Foams , Prog. in Meters Sci., 46: 559-632 .

4. Bardella, L. and Genna, F. (2001). On the Elastic Behavior or Syntactic Foams , Int. J. Solids and Stru., 38: 7235-7260 .

5. Gupta, N. , Karthikeyan, C.S. , Sankaran, S. and Kishore . (1999). Correlation and Processing Methodology to the Physical and Mechanical Properties of Syntactic Foams with and without Fibers , Materials Characterization, 43(4): 271-277 .

6. Karthikeyan, C.S. , Sankaran, S. , Kumar, M.N.J. and Kishore (2001). Processing and Compressive Strengths of Syntactic Foams with and without Fibrous Reinforcement , J. Appl. Poly. Sci., 81: 405-411 .

7. Gupta, N. , Kishore and Sankaran, S. (1999). On the Characterization of Syntactic Foam Core Sandwich Composites for Compressive Properties , J. Reinf. Plast. Compos., 18(14): 1347-1357 .

8. Corigliano, A. , Rizzi, E. and Papa, E. (2000). Experimental Characterization and Numerical Simulations of a Syntactic Foam/Glass-fibre Composite Sandwich , Compos. Sci. Technol., 60: 2169-2180 .

9. Bardella, L. and Genna, F. (2001). Elastic Design of Syntactic Foamed Sandwiches obtained by filling of Three-dimensional Sandwich Fabric Panels , Int. J. Solids Struct., 38: 307-333 .

10.

10. Hodge, A.J. , Kaul, R.K. and Mcmahon, W.M. (2000). Sandwich Composite, Syntactic Foam Core Based Applications for Space Structures . In: Proceedings of 45th International SAMPE Sympositum, May 21-25, 2000, 2293-2300 .

11.

11. D’Almeida, J.R.M. (1999). An Analysis of the Effect of the Diameter or Glass Microspheres on the Mechanical Behavior of Glass Microsphere/Epoxy-resin Composites , Compos. Sci. Technol., 59: 2087-2091 .

12.

12. Kim, H.S. and Khamis, M.A. (2001). Fracture and Impact Behaviors of Hollow Micro-sphere/Epoxy Resin Composites , Composites Part A, 32: 1311-1317 .

13.

13. Gupta, N. , Kishore, Woldesenbet, E. and Sankaran, S. (2001). Studies on Compressive Failure Features in Syntactic Foam Material , J. Mater. Sci., 36(18): 4485-4491 .

14.

14. Kim, H.S. and Oh, H.H. (2000). Manufacturing and Impact Behavior of Syntactic Foam , J. Appl. Polym. Sci., 76: 1324-1328 .

15.

15. Tessier, N.J. (2001). Fire Performance and Mechanical Property Characterization of a Phenolic Matrix Syntactic Foam Core Material for Composite Sandwich Structures , In: Proceedings of 46th International SAMPE Symposium, May 6-10, pp. 2593-2599 .

16.

16. Rizzi, E. , Papa, E. and Corigliano, A. (2000). Mechanical Behavior of a Syntactic Foam: Experiments and Modeling , Int. J. Solids Struct., 37: 5773-5794 .

17.

17. Papanicolaou, G.C. and Bakos, D. (1992). The Influence of the Adhesion Bond between Matrix and Filler on the Tensile Strength of Particulate-filled Polymer , J. Reinf. Plast. Compos., 11: 104-126 .

18.

18. Voros, G. and Pukanszky, B. (1995). Stress Distribution in Particulate Filled Composites and its Effect on Micromechanical Deformation , J. Mater. Sci., 30: 4171-4178 .

19.

19. Liu, Z.H. , Li, J. , Liang, N.G. and Liu, H.Q. (1997). On the Influence Zone and the Prediction of Tensile Strength of Particulate Composites , J. Reinf. Plast. Compos., 16(16): 1997 .

20.

20. Wang, W. and Jasiuk, I. (1998). Effective Elastic Constants of Particulate Composites with Inhomogeneous Interphases , J. Compos. Mater., 32(15): 1391-1524 .

21.

21. Anderson, L.L. and Farris, R.J. (April 1988). A Predictive Model for the Mechanical Behavior of Particulate Composites , Poly. Eng. Sci., 28(8): 522-528 .

22.

22. Vratsanos, L.A. and Farris, R.J. (November 1993). A Predictive Model for the Mechanical Behavior of Particulate Composites. Part I: Model Derivation , Polym. Eng. Sci., 33(22): 1458-1465 .

23.

23. Vratsanos, L.A. and Farris, R.J. (November 1993). A Predictive Model for the Mechanical Behavior of Particulate Composites. Part II: Comparison of model predictions to literature data , Polym. Eng. Sci., 33(22): 1466-1474 .

24.

24. Torquato, S. , Turskett, T.M. and Debenedetti, P.G. (2000). Is Random Close Packing of Spheres Well Defined? Phy. Rev. Let., 84(10): 2064-2067 .

25.

25. Gupta, N. and Woldesenbet, E. (2001). Stress Concentration Factor Approach to Analyze the Deformation and Fracture behavior of Particulate Composites , In: Proceedings of ASC 16th Annual Conference, Blacksburg, VA, Sept. 9-12.

26.

26. Bunn, P. and Mottram, J.T. (1993). Manufacture and Compression Properties of Syntactic Foams , Composites, 24(7): 565-571 .