During thermal cycling, mismatches in the coefficients of thermal expansion and mechanical properties among the constituent layers of solid oxide fuel cell (SOFC) generate interfacial thermal stresses, which may induce crack propagation and delamination, thereby compromising long-term durability and hindering their large-scale commercialization. Corrugated interfaces and an anode functional layer (AFL) are potential structural strategies for improving thermal stress distribution. Therefore, to enhance the structural reliability of SOFC, finite element models of planar and corrugated SOFC with and without an AFL are developed. The thermomechanical responses of the four configurations during the cooling process from 1400 ℃ to 25 ℃ are comparatively investigated. Besides, a pre-crack with an initial length of 0.2 mm is introduced at the electrolyte-anode interface to analyze the propagation behavior using the virtual crack closure technique and the energy release rate (ERR). In addition, a parametric analysis is performed by varying the amplitude of the interface from 0 to 0.1875 mm based on a fixed wavelength.
The results show that the corrugated interface effectively redistributes thermal mismatch stresses and reduces the maximum principal stress at the interface. Compared with the planar configuration, the maximum principal stress along the electrolyte lower surface reduces by 22.65% for the typical corrugated structure. The AFL reduces the peak stress more effectively in the planar configuration, whereas in the corrugated configuration, it mainly alleviates local stress concentrations in the crest and trough regions. Crack propagation analysis further indicates that the corrugated interface markedly suppresses interfacial crack propagation. As the corrugation amplitude increases from 0 to 0.1875 mm, the maximum interfacial stress decreases by up to 36.90%, while the crack propagation length decreases from 3.29 to 0.23 mm. However, increasing the corrugation amplitude also intensifies stress concentrations in the crest and trough regions.
Moreover, the ERR curves of the corrugated SOFC exhibit a characteristic local decrease during the early stage of crack propagation, and this reduction becomes more pronounced with increasing amplitude. This characteristic ERR drop reveals the local weakening effect of the corrugated geometry on the crack-driving force. These results demonstrate that the coordinated design of interfacial morphology and AFL can effectively regulate thermal stress transfer and crack propagation, providing a theoretical basis for the structural optimization and reliability-oriented design of SOFC.