Characterization of Damage Modes in Impacted Thermoset and Thermoplastic Composites

Abstract

Composite materials remain extremely vulnerable to out-of-plane impact loads, which may lead to severe losses in strength and stiffness. Impact induced damage is often a complex mixture of transverse cracks, delaminations and fiber failures. An ex perimental investigation was undertaken to quantify damage tolerance and resistance in composite materials impacted using the drop-weight method. Tests were conducted on laminates of several different carbon-fiber composite systems such as epoxies, modified epoxies, and amorphous and semicrystalline thermoplastics. In this paper, impacted com posite specimens have been examined using destructive and nondestructive techniques to establish the characteristic damage states. Specifically, optical microscopy, ultrasonic and scanning electron microscopy techniques have been used to identify impact induced damage mechanisms. Damage propagation during post impact compression was also stud ied.

Get full access to this article

View all access options for this article.

References

Srinivasan, K. , W.C. Jackson and J.A. Hinkley. 1991. NASA TM 102755.

Srinivasan, K. , W.C. Jackson and J.A. Hinkley. 1991. Proceedings of the 36th International SAMPE Syniposium/Exhibition, pp. 850-862.

Williams, J.G. 1984. NASA TM 85756.

Smith, B.T. , J.S. Heyman , A.M. Buoncristiani , E.D. Blodgett , J.G. Miller and S.M. Freeman. 1989. Materials Evaluation, 47(12):1408-1416.

Russell, A.J. and K.N. Street. 1987. Toughened Composites, ASTM STP 937, N. J. Johnston , ed. , Philadelphia, PA: ASTM, pp 275-294.

Dost, E.F. , L.B. Ilcewicz and J.H. Gosse. 1988 Proceedings of the American Society for Composites, 3rd Technical Conference, pp. 354-363.