Self-Healing of Interfacial Debonding in Fiber-Reinforced Polymers and Effect of Microstructure on Strength Recovery

K. Sanada*, 1, N. Itaya1, y. Shindo2
1 Department of Mechanical Systems Engineering, Toyama Prefectural University, Kurokawa 5180, Imizu, Toyama 939-0398, Japan
2 Department of Materials Processing, Graduate School of Engineering, Tohoku University, Aoba-yama 6-6-02, Sendai 980-8579, Japan

© 2008 Sanada et al.

open-access license: This is an open access article distributed under the terms of the Creative Commons Attribution 4.0 International Public License (CC-BY 4.0), a copy of which is available at: ( This license permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

* Address correspondence to this author at the Department of Mechanical System Engineering, Toyama Prefectural University, Kurokawa 5180, Imizu, Toyama 939-0398, Japan; Tel: +81-766-56-7500; Fax: +81-766-56-6131; E-mail:


This study focuses on the optimizing the microstructure to improve the efficiency for healing interfacial debonding in fiber-reinforced polymers (FRPs). Healing is accomplished by incorporating a microcapsulated healing agent and catalytic chemical trigger within a coating layer on the surface of the fiber strands. Self-healing is demonstrated on flat tensile specimens of unidirectional FRPs. The effects of microcapsule diameter and concentration, and number of filaments in the fiber strand on tensile strength of virgin and healed specimens are discussed. Microstructure of the fracture surfaces of specimens was also examined by a scanning electron microscope. Additionally, finite element analyses were performed to predict the microcapsule-matrix debonding process during uniaxial tensile loading.