title: Real internal microstructure based key mechanism analysis on the micro-damage process of short fibre-reinforced composites.
abstract: In this work, the underlying micro-damage mechanisms of randomly oriented short fibre-reinforced composites were revealed based on real internal microstructural characteristics obtained by high-resolution (0.7 μm/pixel) synchrotron radiation X-ray computed tomography (SR-CT). The special 'pore dominant micro-damage processes' were directly observed through SR-CT three-dimensional reconstructed images, which were different from the well-known 'fibre breakage dominant failure mode'. The mechanisms of pore formation and pore evolution were further investigated on the basis of the microstructural parameters extracted from the SR-CT results. On one hand, the pore formation mechanism caused by shear stress concentration was proposed by combining the shear-lag model with the microstructural parameters obtained from the experiment, including the fibre length and orientation angle. On the other hand, the 'fibre-end aggregation-induced pore connection' mode of crack initiation was proposed through a composites model, which considered the parameters of real internal microstructure, including the critical value of the distance between neighbouring fibre ends and the number of neighbouring fibre ends. The study indicated that the shear stress concentration was significant in the region with a large number of neighbouring fibre ends, thus causing pore connection and crack initiation.
authors.affiliation: CAS Key Laboratory of Mechanical Behavior and Design of Materials, Department of Modern Mechanics, University of Science and Technology of China, Hefei 230026, China.
authors.forename: Xiaofang
authors.initials: X
authors.lastname: Hu
authors.affiliation: CAS Key Laboratory of Mechanical Behavior and Design of Materials, Department of Modern Mechanics, University of Science and Technology of China, Hefei 230026, China.
authors.forename: Jian
authors.initials: J
authors.lastname: Fang
authors.affiliation: CAS Key Laboratory of Mechanical Behavior and Design of Materials, Department of Modern Mechanics, University of Science and Technology of China, Hefei 230026, China.
authors.forename: Feng
authors.initials: F
authors.lastname: Xu
authors.affiliation: CAS Key Laboratory of Mechanical Behavior and Design of Materials, Department of Modern Mechanics, University of Science and Technology of China, Hefei 230026, China.
authors.forename: Bo
authors.initials: B
authors.lastname: Dong
authors.affiliation: CAS Key Laboratory of Mechanical Behavior and Design of Materials, Department of Modern Mechanics, University of Science and Technology of China, Hefei 230026, China.
authors.forename: Yu
authors.initials: Y
authors.lastname: Xiao
authors.affiliation: China Academy of Engineering Physics, Mianyang 621900, China.
authors.forename: Luobin
authors.initials: L
authors.lastname: Wang