Characterisation of fracture evolution of a single cemented brittle grain using in-situ X-ray computed tomography

In this paper, the diametrical fragmentation of a single brittle glass bead cemented by ductile epoxy resin is studied using in-situ X-ray computed tomography, focusing on the fractures within the grain that underpin its crushability. Key quantities of interest include the evolution of fracture regions, paths and orientations, as well as the evolution of fracture statistics within the grain. The complex nature of the fracture process is revealed by qualitative and quantitative analysis based on both continuous X-ray radiography and discrete tomography. A series of image processing techniques are used and developed to obtain the statistical details of fragment volume, surface area, morphological geometry, fracture spatial locality and fracture preferential orientations. The single cemented grain failure consists of an initial splitting fracture process creating large and irregular glass fragments, followed by a further rapid propagation of multiple fractures through the cleavage fragments in the form of severe comminution that tends to generate smaller and more regular fragments. Despite the whole fragmentation process shows a shifting trend of the overall median anisotropy of fragments and a decreasing trend of conversion rate between fracture energy and input energy, it still maintains a constant fragment surface area power law distribution and appears to remain scale-invariant over time. The central region of the glass bead is markedly more susceptible to fracture with a constant preferred fracture orientation along the loading direction, indicating that the tensile-activated fracture is the dominant fracture mechanism during diametrical fragmentation.

Automated summary

This paper investigates the diametrical fragmentation of a single brittle glass bead cemented by ductile epoxy resin using in-situ X-ray computed tomography, focusing on the fractures within the grain. The study reveals the complex nature of the fracture process and the dominant fracture mechanism during the fragmentation process.