Investigation of different discrete modeling strategies to mimic microstructural aspects that influence the fracture energy of refractory materials

Abstract

The mismatch between the coefficient of thermal expansion of the constituents within refractory ceramics could advantageously be used to tune the fracturing behavior by inducing numerous microcracks within the microstructure. The Wedge Splitting Test (WST) is thus commonly used to characterize such different fracturing behaviors. The present study aims to model the different fracture behaviors of refractory ceramics by proposing a Discrete Element Method (DEM) approach to reproduce fracture energy variation and crack branching during WSTs.Two model ceramics are used as references: a highly brittle pure Magnesia and a quasi-brittle Magnesia Hercynite. By using the proposed DEM approach for local strength randomization, a wide range of fracture behaviors is simulated and compared to the reference materials. Moreover, the crack branching obtained from these simulations was qualitatively compared to the experimental observations by Digital Image Correlation (DIC). Finally, a discrete/continuous hybrid model (DEM/FVM) was proposed to optimize the WST simulations.

Keywords

• Refractory ceramics
• Discrete element method (DEM) modeling
• Finite volume model (FVM)
• Fracture mechanics
• Quasi-brittle mechanical behavior
• Wedge splitting test