Multiscale study on nonlinear mechanical properties of CNT-reinforced CFRTP: Comparison of reinforcing effects of CNT-grafted interphase and CNT-dispersed matrix
Yasutomo UETSUJI, Yusei Fujiwara, Fumiya Araki, Kotomi Onishi, K. Iwata, Yuki Murakami, Chao Luo, Kazuto TANAKA
Abstract
The effect of carbon nanotube (CNT) as a secondary reinforcement material for carbon fiber reinforced thermoplastics (CFRTP), which are used in a wide range of fields such as automobiles and aircrafts, was examined. An asymptotic homogenization theory was adopted for scale coupling, and a hierarchical multiscale finite element analysis (FEA) scheme was constructed. First, single fiber pull-out tests were performed on CF with CNTs grafted on its surface by chemical vapor deposition, and the FEA model of CNT-grafted CF was verified. Next, based on the multiscale FEA, the mechanical properties of the case where the interfacial phase between the CF and the matrix was reinforced by CNTs grafting and the case where CNTs were dispersed in the matrix were systematically compared. As a result, the computation revealed that the CNT-grafted interfacial phase was effective for the transverse fiber and out-of-plane shear properties when the CNT content was 2.0 vol% or less. It also revealed that the CNT-dispersed matrix was effective for the in-plane and out-of-plane shear properties when the CNT content was 3.0 vol% or more, providing an important design guideline for CNT-reinforced CFRTP.