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Journal of Nanomaterials
Volume 2011, Article ID 746029, 9 pages
Research Article

Fracture Toughness of Carbon Nanotube-Reinforced Metal- and Ceramic-Matrix Composites

1AML, Department of Engineering Mechanics, Tsinghua University, Beijing 100084, China
2Department of Mechanical Engineering, The Ohio State University, Columbus, OH 43210, USA
3Department of Civil and Environmental Engineering and Department of Mechanical Engineering, Northwestern University, Evanston, IL 60208, USA

Received 15 July 2010; Accepted 1 November 2010

Academic Editor: Teng Li

Copyright © 2011 Y. L. Chen et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


Hierarchical analysis of the fracture toughness enhancement of carbon nanotube- (CNT-) reinforced hard matrix composites is carried out on the basis of shear-lag theory and facture mechanics. It is found that stronger CNT/matrix interfaces cannot definitely lead to the better fracture toughness of these composites, and the optimal interfacial chemical bond density is that making the failure mode just in the transition from CNT pull-out to CNT break. For hard matrix composites, the fracture toughness of composites with weak interfaces can be improved effectively by increasing the CNT length. However, for soft matrix composite, the fracture toughness improvement due to the reinforcing CNTs quickly becomes saturated with an increase in CNT length. The proposed theoretical model is also applicable to short fiber-reinforced composites.