Reverse piezo-resistivity of 3D printed continuous carbon fiber/PA6 composites in a low stress range

Abstract

The 3D printing of carbon fiber reinforced thermoplastics (CFRTPs) is crucial in many fields such as aerospace engineering and electrical motorbikes. Structural health monitoring of 3D printed CFRTPs is important for its practical application. CFRTPs are monitored using the electrical resistance change method, but this method has not been applied to 3D printed CFRTPs. In this study, we used the electrical resistance change method to monitor CFRTPs. The electrical properties were measured in terms of fiber orientation and electrode distance. In addition, a cyclic test was performed to reveal the change in the electrical resistance. Our results reveal that the volume resistance along the 90° orientation has a larger standard deviation than those for the other specimens. The change in resistance exhibited reverse piezo-resistivity at the low stress range in the cyclic tests. The reverse piezo-resistivity occurred due to fiber waviness, which is generated during the 3D printing process.

Keywords:

• additive manufacturing
• carbon fiber reinforced thermoplastic
• structural health monitoring
• electrical resistance change method
• self-sensing

Acknowledgements

The synchrotron radiation experiments were performed at the BL46XU of SPring-8 with the approval of the Japan Synchrotron Radiation Research Institute (JASRI) (Proposal No. 2018B1842).

Disclosure statement

No potential conflict of interest was reported by the authors.