Study of Composite Interface Fracture and Crack Growth Monitoring Using Carbon Nanotubes
- 421 Downloads
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.
KeywordComposites 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.
- 4.Callister Jr., W.D.: Materials science and engineering: an introduction, p. 433. Wiley, New York (2007)Google Scholar
- 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