Experimental Mechanics

, Volume 19, Issue 1, pp 9–16 | Cite as

Wave propagation in transversely impacted composite laminates

An experimental investigation was conducted of wave-propagation characteristics, transient strains and residual properties of composite laminates under high-velocity impact
  • I. M. Daniel
  • T. Liber
  • R. H. LaBedz
Article

Abstract

An experimental investigation was conducted to determine wave-propagation characteristics, transient-strain distributions and residual properties for unidirectional and angle-ply boron/epoxy and graphite/epoxy laminates impacted with silicon-rubber projectiles at velocities up to 250 ms−1 (820 ft/s). Tests were conducted at normal and 45-deg oblique impact. Strain signals obtained from surface and embedded strain gages were recorded and analyzed to determine the types of waves, propagation velocities, peak strains, strain rates and attenuation characteristics. The predominant wave is a flexural on propagating at different velocities in different directions. The flexural wave velocity is higher in the higher-modulus direction. In general, measured wave velocities were higher than theoretically predicted. The amplitude of the in-plane wave is less than ten percent of that of the flexural wave. Peak strains and strain rates in the transverse to the (outer) fiber direction are much higher than those in the direction of the fibers. Strain rates up to 640 s−1 were measured. Under oblique 45-deg impact, the flexural wave is still the predominant one. Peak strains under this oblique impact range between 36 and 56 percent of those under normal impact of the same velocity. Residual elastic properties and strength were measured around the point of impact. The most significant result was a reduction in the transverse strength of the unidirectional laminates. The dynamics of impact were also studied with high-speed photography. The projectile is completely flattened within 50–70 μs and the total contact time is of the order of 300 μs.

Keywords

Wave Velocity Composite Laminate Peak Strain Normal Impact Residual Property 

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References

  1. 1.
    Sun, C.T. andSierakowski, R.L., “Recent Advances in Developing FOD Resistant Composite Materials,”Shock and Vibration Digest,7 (2),69–76 (Feb.1975).Google Scholar
  2. 2.
    Moon, F.C., “A Critical Survey of Wave Propagation and Impact in Composite Materials,” NASA-Lewis Res. Ctr,NASA CR-121226 (May 1973).Google Scholar
  3. 3.
    Ross, C.A. andSierakowski, R.L., “Elastic Waves in Fiber-Reinforced Composites,”Shock and Vibration Digest,7 (1),96–107 (Jan.1975).Google Scholar
  4. 4.
    Musgrave, M.J.P., “On the Propagation of Elastic Waves in Aeolotropic Media,”Proc. Roy. Soc., London, A,226,339 (1954).MATHMathSciNetGoogle Scholar
  5. 5.
    Synge, J.L., “Elastic Waves in Anisotropic Media,”J. Math. and Phys.,35,323 (1957).MATHMathSciNetGoogle Scholar
  6. 6.
    Buchwald, V.T., “Elastic Waves in Anisotropic Media,”Proc. Roy. Soc. London, A,253,563 (1959).MATHMathSciNetGoogle Scholar
  7. 7.
    Moon, F.C., “Theoretical Analysis of Impact in Composite Plates,” NASA-Lewis Res. Ctr,NASA CR-121110 (1972).Google Scholar
  8. 8.
    Moon, F.C., “Stress Wave Calculations in Composite Plates Using the Fast Fourier Transform,”Computers and Structures,3,1195–1204 (1973).CrossRefGoogle Scholar
  9. 9.
    Dally, J.W., Link, J.A. and Prabhakaran, R., “A Photoelastic Study of Stress Waves in Fiber Reinforced Composites,” Proc. 12th Midwestern Mech. Conf., 937–949 (1971).Google Scholar
  10. 10.
    Tauchert, T.R. andMoon, F.C., “Propagation of Stress Waves in Fiber-Reinforced Compasite Rods,”AIAA J.,9 (8),1492–1498 (1971).Google Scholar
  11. 11.
    Tauchert, T.R. andGuzelsu, A.N., “An Experimental Study of Dispersion of Stress Waves in a Fiber-Reinforced Composite,”J. Appl. Mech.,39,98–102 (1972).Google Scholar
  12. 12.
    Arseneaux, P.J., “An Experimental Investigation of Stress Waves in Rods of a Fiber-Reinforced Composite,” Brown Univ. Tech. Report No. 21, U.S. Army Res. Office, Contract No. DA-31-124-ARO(D)-358.Google Scholar
  13. 13.
    Rowlands, R.E., Daniel, I.M. andPrabhakaran, R., “Wave Motion in Anisotropic Media by Dynamic Photomechanics,”Experimental Mechanics,14 (11),433–439 (Nov.1974).CrossRefGoogle Scholar
  14. 14.
    Daniel, I.M. and Liber, T., “Wave Propagation in Fiber Composite Laminates,” NASA CR-135086 (Jul. 1976).Google Scholar

Copyright information

© Society for Experimental Mechanics, Inc. 1979

Authors and Affiliations

  • I. M. Daniel
    • 1
  • T. Liber
    • 1
  • R. H. LaBedz
    • 1
  1. 1.Mechanics of Materials DivisionIIT Research InstituteChicago

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