Residual thermal stresses and warping of the anode-supported planar solid oxide fuel cell (SOFC) were estimated numerically. A 3D finite element (FE) model with viscoelastic constitutive equations was established to c...Residual thermal stresses and warping of the anode-supported planar solid oxide fuel cell (SOFC) were estimated numerically. A 3D finite element (FE) model with viscoelastic constitutive equations was established to calculate the residual stress and warping for the cell. In the fabrication of the cells, some mechanical restriction was employed during the high-temperature treatment followed by a cooling stage in order to prevent the button cell from warping, and then from these specific boundaries and loading conditions, a FE simulation was used to calculate the distribution of the internal stresses in the cell. The results indicate that the concentration of compressive stress appears in the electrolyte layer, and that could cause interfacial micro-cracks or even cohesive failure. Furthermore, from the numerical study, the annealing time (or continuous cooling) is related to the residual stress in the material due to creeping. The compressive stress in the electrolyte layer can be reduced significantly by increasing the cooling time. Therefore, it is possible to optimize the annealing time in order to make the SOFCs flat and have less residual stress, improving the mechanical durability.展开更多
文摘Residual thermal stresses and warping of the anode-supported planar solid oxide fuel cell (SOFC) were estimated numerically. A 3D finite element (FE) model with viscoelastic constitutive equations was established to calculate the residual stress and warping for the cell. In the fabrication of the cells, some mechanical restriction was employed during the high-temperature treatment followed by a cooling stage in order to prevent the button cell from warping, and then from these specific boundaries and loading conditions, a FE simulation was used to calculate the distribution of the internal stresses in the cell. The results indicate that the concentration of compressive stress appears in the electrolyte layer, and that could cause interfacial micro-cracks or even cohesive failure. Furthermore, from the numerical study, the annealing time (or continuous cooling) is related to the residual stress in the material due to creeping. The compressive stress in the electrolyte layer can be reduced significantly by increasing the cooling time. Therefore, it is possible to optimize the annealing time in order to make the SOFCs flat and have less residual stress, improving the mechanical durability.
