TY - JOUR
T1 - Evolution of fibre deflection leading to kink-band formation in unidirectional glass fibre/epoxy composite under axial compression
AU - Wang, Ying
AU - Emerson, Monica J.
AU - Conradsen, Knut
AU - Dahl, Anders B.
AU - Dahl, Vedrana A.
AU - Maire, Eric
AU - Withers, Philip J.
N1 - Publisher Copyright:
© 2021 The Author(s)
PY - 2021/9/8
Y1 - 2021/9/8
N2 - We present the first experimental observation and quantification of the evolution of the three-dimensional (3D) deflection of fibres leading up to kink-band formation in notched unidirectional glass fibre-epoxy composites. This has been achieved by in situ synchrotron X-ray computed tomography (CT) quantified by advanced image analysis. The 3D trajectories of individual fibres were extracted to monitor the change in fibre profiles with increasing compressive load. Initially the fibre trajectory varies significantly from fibre to fibre, the waviness of which cannot be represented by a simple idealised profile. However, the change in the fibre shapes during axial compression is similar for all fibres, as the fibres deflect towards the final kinking direction. The precursor to kink-band nucleation has been identified as a local tilting of fibres in the region where the kink bands ultimately form, defining a micro-buckle band. Even at 99.9% of the failure load this micro-buckle band is much narrower (~150 μm (~12 fibre diameters) wide), and the angle of inclination of the band much shallower (~8°), compared to the final 300–400 μm (25–33 fibre diameters) wide, and 25–30° inclined, kink band. It is notable that kink-band boundaries are delineated by fibre fractures, many of which exhibit wedge-shaped multiple fractures.
AB - We present the first experimental observation and quantification of the evolution of the three-dimensional (3D) deflection of fibres leading up to kink-band formation in notched unidirectional glass fibre-epoxy composites. This has been achieved by in situ synchrotron X-ray computed tomography (CT) quantified by advanced image analysis. The 3D trajectories of individual fibres were extracted to monitor the change in fibre profiles with increasing compressive load. Initially the fibre trajectory varies significantly from fibre to fibre, the waviness of which cannot be represented by a simple idealised profile. However, the change in the fibre shapes during axial compression is similar for all fibres, as the fibres deflect towards the final kinking direction. The precursor to kink-band nucleation has been identified as a local tilting of fibres in the region where the kink bands ultimately form, defining a micro-buckle band. Even at 99.9% of the failure load this micro-buckle band is much narrower (~150 μm (~12 fibre diameters) wide), and the angle of inclination of the band much shallower (~8°), compared to the final 300–400 μm (25–33 fibre diameters) wide, and 25–30° inclined, kink band. It is notable that kink-band boundaries are delineated by fibre fractures, many of which exhibit wedge-shaped multiple fractures.
KW - A. Polymer-matrix composites (PMCs)
KW - B. Mechanical properties
KW - C. Deformation
KW - D. X-ray computed tomography
KW - Fibre micro-buckling
UR - https://www.scopus.com/pages/publications/85110068887
U2 - 10.1016/j.compscitech.2021.108929
DO - 10.1016/j.compscitech.2021.108929
M3 - 文章
AN - SCOPUS:85110068887
SN - 0266-3538
VL - 213
JO - Composites Science and Technology
JF - Composites Science and Technology
M1 - 108929
ER -