Syntactic foams are hollow particle filled composites that have recently emerged as attractive materials for use in advanced structural applications. The present study focuses on the effect of radius ratio and volume fraction of microballoons on the ultrasonic properties of syntactic foam composites. Twenty-four different types of syntactic foams, with different radius ratios and volume fractions, are used in this study. Foam slabs are fabricated by varying the volume fraction of microballoons from 10 to 60% for each type of microballoon. The pulse echo method is used for the ultrasonic imaging of these materials, and determines their ultrasonic attenuation behavior. Coefficient of attenuation, ultrasonic velocities, and modulus are observed to depend upon the radius ratio as well as the volume fraction of microballoon of the composites. A major finding in this research is the discovery of a non-destructive method to determine the dynamic modulus of particulate composites.
Shutov, F.A. (1991). Syntactic Polymeric Foams, Handbook of Polymeric Foams and Foam Technology, pp. 355-374, Hanser Publishers, New York.
2.
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.
3.
Gupta, N. and Woldesenbet, E. (2004). Experimental Investigation on the Effect of Cenosphere Radius Ratio on the Flatwise Compressive Properties of Syntactic Foams, Composites Part A: Applied Science and Manufacturing, 35(1): 103-111.
4.
Gupta, N. and Woldesenbet, E. (2003). Hygrothermal Studies on Syntactic Foams and Compressive Strength Determination, Composite Structures, 61(4): 311-320.
5.
Karthikeyan, C.S. and Kishore, S.S. (2001). Effect of Absorption in Aqueous and Hygrothermal Media on the Compressive Properties of Glass Fiber Reinforced Syntactic Foam, J. Reinf. Plast. Comp., 20(11): 982-993.
6.
Mix, P. (1987). Introduction to Non Destructive Testing-A Training Guide, John Wiley & Sons, New York.
7.
Krautkramer, H. and Krautkramer, J. (1969). Ultrasonic Testing of Materials, Springer Verlag, New York.
8.
Anson, L.W. and Chivers, R.C. (1993). Ultrasonic Velocity in Suspensions of Solids in Solids - A Comparison of Theory and Experiment, J. Phys. D. , 26(10): 1566-1575.
9.
Ying, C.F. and Truell, R. (September 1956). Scattering of a Plane Longitudinal Wave by a Spherical Obstacle in an Isotropically Elastic Solid, Journal of Applied Physics, 27(9): 1086-1097.
10.
Sabina, F.J. and Willis, J.R. (1988). A Simple Self-consistent Analysis of Wave Propagation in Particulate Composites, Wave Motion, 10(2): 127-142.
11.
Datta, S.K. (1977). A Self-Consistent Approach to Multiple Scattering by Elastic Ellipsoidal Inclusions, Journal of Applied Mechanics, 44(3): 657-662.
12.
Kanuan, S.K., Levin, V.M. and Sabina, F.J. (2004). Propagation of Elastic Waves in Composites with Random Set of Spherical Inclusions (Effective Medium Approach), Wave Motion, 40(1): 69-88.
13.
Watermann, P.C. and Truell, R. (1961). Multiple Scattering of Waves, Journal of Mathematical Physics, 2: 512-537.
14.
Lax, M. (1952). Multiple Scattering of Waves. II. The Effective Field in Dense Systems, Physical Review, 85(4): 621-629.
15.
Szabu, T.L. and Wu, J. (2000). A Model for Longitudinal and Shear Wave Propagation in Viscoelastic Media, The Journal of the Acoustical Society of America, 107(5): 2437-2446.
16.
Kim, J.Y. (2004). On the Generalized Self-consistent Model for the Elastic Wave Propagation in Composite Materials, Int. J. Solids Structures, 41(16-17): 4349-4360.
17.
Kinra, V.K. and Ker, E.L. (1983). An Experimental Investigation of Pass Bands and Stop Bands in Two Periodic Particulate Composites, International Journal of Solids and Structures, 19(5): 393-410.
18.
Kinra, V.K. , Petraitis, M.S. and Datta, S.K. (1980). Ultrasonic Wave Propagation in a Random Particulate Composite, International Journal of Solids and Structures, 16(4): 301-312.
19.
Kinra, V.K. , Day, N.A., Maslov, K., Henderson, B.K. and Diderich, G. (1998). The Transmission of a Longitudinal Wave through a Layer of Spherical Inclusions with a Random or Periodic Arrangement, J. Mech. Phys. Solids, 46(1): 153-165.
20.
Kinra, V.K. and Anand, A. (1982). Wave Propagation in a Random Particulate Composite at Long and Short Wavelengths, Int. J. Solids Structures, 18(5): 367-380.
21.
Kinra, V.K. , Ker, E. and Datta, S.K. (1982). Influence of Particle Resonance on Wave Propagation in a Random Particulate Composite, Mechanics Research Communications, 9(2): 109-114.
22.
Beltzer, A.I. , Bert, C.W. and Striz, A.G. (1983). On Wave Propagation in Random Particulate Composite, Int. J. Solids Structures , 19(9): 785-791.
23.
Layman, C., Sanjeeva Murthy, N., Yang, R.B. and Wu, J. (March 2006). The Interaction of Ultrasound with Particulate Composites, J. Acoust. Soc. Am., 119(3): 1449-1456.
24.
ASTM C 271-94. Standard Test Method for Density of Sandwich Core Materials, ASTM International, PA, USA.
25.
ASTM E664-93. Standard Practice for the Measurement of the Apparent Attenuation of Longitudinal Ultrasonic Waves by Immersion Method, ASTM International, PA.
26.
ASTM E494-95. Standard Practice for Measuring Velocity in Materials, ASTM International, PA, USA.
27.
Gupta, N., Priya, S., Islam, R. and Ricci, W. (2006). Characterization of Mechanical and Electrical Properties of Epoxy-Glass Microballoon Syntactic Composites, Ferroelectrics, 345(June): 1-12.
28.
Krishnamurthy, S., Matikas, T.E., Karur, P. and Miracle, D.B. (1995). Ultrasonic Evaluation of the Processing of Fiber-reinforced Metal-Matrix Composites, Composite Science and Technology, 54(2): 161-168.
29.
Markham, M.F. (1957). Measurement of Elastic Constants by the Ultrasonic Pulse Method, British Journal of Applied Physics, 8(S6): S56-S63.
30.
Rose, J.L. (1999). Ultrasonic Waves in Solid Media, Cambridge University Press, UK.
31.
Bardella, L. and Genna, F. (2005). Some Remarks on the Micromechanical Modeling of Glass/Epoxy Syntactic Foams, In: Proceedings of 20th Annual Technical Conference of the American Society for Composites, Philadelphia, PA, USA, #101.
