Applied Composite Materials

, Volume 17, Issue 4, pp 347–362 | Cite as

Study of Composite Interface Fracture and Crack Growth Monitoring Using Carbon Nanotubes

  • Mollie A. Bily
  • Young W. KwonEmail author
  • Randall D. Pollak


Interface fracture of woven fabric composite layers was studied using Mode II fracture testing. Both carbon fiber and E-glass fiber composites were used with a vinyl ester resin. First, the single-step cured (i.e., co-cured) composite interface strength was compared to that of the two-step cured interface as used in the scarf joint technique. The results showed that the two-step cured interface was as strong as the co-cured interface. Carbon nanotubes were then applied to the composite interface using two-step curing, and then followed by Mode II fracture testing. The results indicated a significant improvement of the interface fracture toughness due to the dispersed carbon nanotube layer for both carbon fiber and E-glass fiber composites. The carbon nanotube layer was then evaluated as a means to monitor crack growth along the interface. Because carbon nanotubes have very high electrical conductivity, the electrical resistance was measured through the interface as a crack grew, thus disrupting the carbon nanotube network and increasing the resistance. The results showed a linear relationship between crack length and interface resistance for the carbon fiber composites, and allowed initial detection of failure in the E-glass fiber composites. This study demonstrated that the application of carbon nanotubes along a critical composite interface not only improves fracture properties but can also be used to detect and monitor interfacial damage.


Composites interface Fracture strength Carbon nanotubes Crack monitoring 



This project was supported in part by the Air Force Office of Scientific Research and the Naval Surface Warfare Center Carderock Division. The authors gratefully thank Professor Sarath Menon of the Naval Postgraduate School for assistance in imaging CNT samples.


  1. 1.
    Mouritz, A.P., Gellert, E., Burchill, P., Challis, K.: Review of advanced composite structures for naval ships and submarines. Compos. Struct. 53, 21–41 (2001)CrossRefGoogle Scholar
  2. 2.
    Faulkner, S.D., Kwon, Y.W., Bartlett, S., Rasmussen, E.A.: Study of composite joint strength with carbon nanotube reinforcement. J. Mater. Sci. 44(11), 2858–2864 (2009)CrossRefADSGoogle Scholar
  3. 3.
    Saito, R., Dresselhaus, M.S.: Physical properties of carbon nanotubes, pp. 11–12. Imperial College, London (1998)CrossRefGoogle Scholar
  4. 4.
    Callister Jr., W.D.: Materials science and engineering: an introduction, p. 433. Wiley, New York (2007)Google Scholar
  5. 5.
    Harris, P.J.F.: Carbon nanotube composites. Int. Mater. Rev. 49, 31 (2004)CrossRefGoogle Scholar
  6. 6.
    Weber, I., Schwartz, P.: Monitoring bending fatigue in carbon-fibre/epoxy composite strands: a comparison between mechanical and resistance techniques. Compos. Sci. Technol. 61, 849–853 (2001)CrossRefGoogle Scholar
  7. 7.
    Kang, I., Schulz, M.J., Kim, J.H., Shanov, V., Shi, D.: A carbon nanotube strain sensor for structural health monitoring. Smart Mater. Struct. 15, 737–748 (2006)CrossRefADSGoogle Scholar
  8. 8.
    Dharap, P., Li, Z., Nagarajaiah, S., Barrera, E.V.: Nanotube film based on single-wall carbon nanotubes for strain sensing. Nanotechnology 15, 379–382 (2004)CrossRefADSGoogle Scholar
  9. 9.
    Nofar, M., Hoa, S.V., Pugh, M.D.: Failure detection and monitoring in polymer matrix composites subjected to static and dynamic loads using carbon nanotube networks. Compos. Sci. Technol. 69(10), 1–22 (2009)CrossRefGoogle Scholar
  10. 10.
    Thostenson, E.T., Chou, T.W.: Carbon nanotube networks: sensing of distributed strain and damage for life prediction and self healing. Adv. Mater. 18, 2837–2841 (2006)CrossRefGoogle Scholar
  11. 11.
    Zhang, W., Sakalkar, V., Koratkar, N.: In situ health monitoring and repair in composites using carbon nanotube additives. Appl. Phys. Lett. 91, 133102 (2007)CrossRefADSGoogle Scholar
  12. 12.
    Tsu-Wei, C., Thosetenson, E.T.: Carbon nanotube/vinyl ester nanocomposites for in situ sensing. University of Maryland University College, Adelphia, MD. Office of Naval Research Solid Mechanics Program Review Meeting: Marine Composites and Sandwich Structures, pp. 42–49. September 17–29, 2008.Google Scholar
  13. 13.
    Kwon, Y.W., Slaff, R., Bartlett, S., Greene, T.: Enhancement of composite scarf joint interface strength through carbon nanotube reinforcement. J. Mater. Sci. 43(20), 6695–6703 (2008)CrossRefADSGoogle Scholar
  14. 14.
    Todo, M., Nakamura, T., Takahashi, K.: Effects of moisture absorption on the dynamic interlaminar fracture toughness of carbon/epoxy composites. J. Compos. Mater. 34, 630–648 (2000)CrossRefGoogle Scholar

Copyright information

© © US Government 2009

Authors and Affiliations

  • Mollie A. Bily
    • 1
  • Young W. Kwon
    • 1
    Email author
  • Randall D. Pollak
    • 1
  1. 1.Department of Mechanical and Astronautical EngineeringNaval Postgraduate SchoolMontereyUSA

Personalised recommendations