Multi-scale numerical simulation of fracture behavior for the gadolinia-doped ceria (GDC) under mechano-electrochemical coupling fields at high temperature

The fracture toughness of gadolinia-doped ceria (GDC) solid oxide fuel cells (SOFCs) electrolyte with a central crack is significantly reduced under the mechano-electrochemical coupling fields at high temperature. In this work, an atom-to-continuum (AtC) multi-scale method combining the finite element method (FEM) and the molecular dynamics (MD) simulation is developed. Firstly, the AtC multi-scale method is validated by investigating the uniaxial tensile stress-strain curves of GDC with a central crack at different temperatures. Then, based on the theory of fracture mechanics, the macrostructure of GDC is transformed into a microscopic intermediate transition model, and a detailed computational procedure for analyzing the fracture toughness of the macrostructure of the GDC is given by the AtC multi-scale method. Finally, the fracture toughness of GDC macrostructure under the mechano-electrochemical coupling fields is studied by the proposed approach. The simulation results show that the fracture toughness of 10GDC and 20GDC under the mechano-electrochemical coupling fields is clearly reduced compared to the uniaxial tensile loading. Among them, the fracture toughness of 10GDC under the mechano-electrochemical coupling fields is decreased by 12.28% and 30.67% at 800 degrees C and 900 degrees C, and the fracture toughness of 20GDC under the mechano-electrochemical coupling fields is decreased by 17.25% and 29.52% at 800 degrees C and 900 degrees C. These findings are critical in predicting the fracture behavior of GDC electrolyte under real working conditions.