Feb. 19, 2022

Nanoscale fracture mechanism in CFRPs is still debated owing to the considerable difficulty in determining the three-dimensional mechanism of fracture using conventional techniques such as optical and/or electron mi- croscopy relying on side-surface- and fracture-surface-based observation. In this study, microscopic damages such as fiber/matrix debonding and microcracks under mixed-mode (mode I + II) loading are characterized in situ using nondestructive nanoscopic synchrotron radiation X-ray computed tomography (nanoscopic SR X-CT).

It is clearly shown that crack formation proceeds in three steps: (i) initiation at the carbon fiber/epoxy matrix interface, (ii) propagation into the epoxy, and (iii) formation of microcracks (hackles) in the resin matrix, and the resulting microstructures of cracks at the nanoscale are largely affected by the local fiber geometrical distribu- tions.

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Reference 1

Nanoscale in situ observation of damage formation in carbon fiber/epoxy composites under mixed-mode loading using synchrotron radiation X-ray computed tomography
Masao Kimura, Toshiki Watanabe, Sota Oshima, Yasuo Takeichi, Yasuhiro Niwa, Yuji Seryo, Masaki Hojo
Composites Science and Technology, 230, p.109332 (2022)
https://dx.doi.org/10.1016/j.compscitech.2022.109332

Reference 2

Development of spectromicroscopes for multiscale observation of heterogeneity in materials at photon factory, IMSS, KEK
Yasuhiro Niwa, Yasuo Takeichi, Toshiki Watanabe, Masao Kimura
AIP Conference Proceedings, 2054, p.050003 (2019)
https://aip.scitation.org/doi/abs/10.1063/1.5084621

Reference 3

Finding Degradation Trigger Sites of Structural Materials for Airplanes Using X-Ray Microscopy
Masao Kimura, Yasuo Takeichi, Toshiki Watanabe, Yasuhiro Niwa, Ken'ichi Kimijima
The Chemical Record, 7, p.1462 (2019)
https://onlinelibrary.wiley.com/doi/abs/10.1002/tcr.201800203