In this study, the bending behaviors for a carbon fiber-reinforced plastic (CFRP) cable with a twisted structure were evaluated based on a compression bending test. This test was selected because under three-point and four-point bending, fractures under the indenters make evaluation of the bending properties difficult. Accordingly, the compression bending of a CFRP cable with different lay angles was successfully evaluated. The results showed that the bending strengths obtained by the compression test exceeded those obtained from three- and four-point bending tests by 8% and 1%, respectively, owing to the prevention of the fracture under the indenter. The bending stiffness did not depend on lay angle of the cables, but the compression bending strength increased with an increase of the lay angle. These results were in good agreement with the theoretical relationships between the bending stiffness, bending strength, and lay angle. Thus, the validity of evaluating the bending behaviors of CFRP cables based on compression bending was demonstrated. Moreover, it was found that the bending behaviors of the CFRP cables were related to the lay angle and lay length.

Al2017 is widely used as a rivet material in the aerospace industry. However, the application of Al2017 rivets on carbon fiber reinforced plastics (CFRPs) poses a challenge owing to the significant natural potential difference causing galvanic corrosion. We tested poly-vinyl chloride lining film and three inhibitors, 1,2,4 triazole (124T), 3 amino 1,2,3 triazole (3AT), and 1,2,3 benzotriazole (BTA) to investigate their potential to inhibit galvanic corrosion on Al2017 CFRP joints when subjected to a 5 wt% NaCl water solution under fastening conditions. Our findings demonstrated that the lining film was effective in preventing corrosion; however, BTA showed a stronger prevention effect than those of 124T and 3AT in terms of corrosion current levels. Although Al2017 with anodized coating showed pit corrosion in assembled form with CFRP, triazole group inhibitor was found to be effective in inhibiting pit formation.

Two extensions were developed for the modified compliance method in JIS K7086 double cantilever beam (DCB) test to accommodate recent high-rigidity CFRP bonded with tough adhesive. First, shear bending in the short crack condition was considered for the approximation of polynomial in the estimation of energy release rate. Second, sample thickness was set as a variable to maintain a crack length-to-crack opening ratio of 0.4, which is specified in the current JIS K7086 standard with a fixed sample thickness of 3 mm. In the case of the DCB, test was conducted on the T800S/3900-2B (TORAY) unidirectional CFRP specimen bonded with AF555 (3M) tough epoxy adhesive, the extended methods showed a stable energy release rate in the short crack conditions. Conversely, the current method specified in JIS K7086 showed a decreasing value as the crack length increased. In contrast, both methods showed identical energy release rates when compared to the present JIS K7086 standard for the general-use Araldite 2015 （Huntsman） adhesive.

The thermal conductivity of the Carbon Fiber Reinforced Plastic (CFRP) can be locally controlled by regulating the carbon fiber orientation by passing them through a thin nozzle. To manufacture heat-conductive components, a novel method is proposed to print CFRP with photo-/thermo-curing resin and pitch-based short carbon fibers using 3D printing. Subsequently, CFRP with unidirectionally oriented fibers were successfully fabricated using the developed method. In addition, a thermal conductivity meter for high thermal conductivity CFRP thin sheets was fabricated, and the thermal conductivity of unidirectionally fiber-oriented, 3D-printed CFRP specimens with a fiber content of 25 and 30 vol% were measured. The anisotropy of the thermal conductivity of the CFRP samples were confirmed, and the thermal conductivity increased with increasing fiber content. At 30 vol% fiber content, the fiber-directional thermal conductivity was 14.9 W/m･K, which is equivalent to that of stainless steel. The cross-sectional observation of the samples showed that voids were formed during fabrication. These voids may have obstructed the heat transfer pathways, and thus, CFRPs with a considerably higher thermal conductivity were fabricated by reducing the void ratio.