Multi-scale simulations of fracture behavior in CeO₂

Solid oxide fuel cells (SOFCs) are in a complex mechanical-thermal-electrochemical multi-field coupling condition, and traditional calculation methods are difficult to study from different scales concurrently. In this paper, we use a multi-scale method to investigate the mechanical properties of ceria. This multi-scale method cannot only obtain the micro-processes such as pre-phase transformation, phase transformation, and fracture represented by molecular dynamics (MD) calculations, but also acquire the displacement and stress fields by the finite element method (FEM). A center-cracked model is used to study the crack propagation and stress distribution near the crack tip. In the [100] crystal orientation, a stress-induced martensitic phase transformation occurs near the crack tip, while the [111] crystal orientation shows the characteristics of brittle fracture of ceramic materials. The stress-strain relationship calculated by this multi-scale method compares well with the results of MD simulations, which attests to its accuracy.