Mechanical stability

Abstract

This article summarizes the approach to assessing the mechanical stability of solid oxide fuel cell (SOFC) ceramic materials and cell structures. The sources of stress are reviewed and their potential relaxation by creep is discussed together with the approach that is taken to calculate the complex stress distributions that arise in a working SOFCs. The alternative approaches to failure of brittle ceramics based on critical stress (strength) and fracture mechanics are described and illustrated using examples of stability of thin layers and probability of delayed fracture of an electrolyte. The critical stress approach is then illustrated in a more complicated example of a repeat‐unit channel in an anode‐supported SOFCs. The methodology illustrates how the cumulative probability of failure of the unit can be estimated as it passes through manufacture, initial commissioning, and representative duty cycles.