Multi-objective optimisation of bolt layout for minimising glass seal failure probability in planar SOFC stacks

Solid oxide fuel cell stacks require long-term mechanical integrity of glass seals after thermal ageing, yet quantitative design guidelines for bolted stacks remain limited. This study developed a three-dimensional finite element model of a stack segment, combined with Weibull statistics, response surface methodology, and multi-objective optimisation, to evaluate the reliability of aged G18 glass seals. The effects of bolt layout, pretension load, bolt–edge distance, and washer diameter on the stress distribution and failure probability of the anode- and cathode-side glass seals were investigated. Pretension load was a linear scaling factor for the stress field, whereas bolt–edge distance caused nonlinear changes in the corner layout. The anode-side seal exhibited a higher failure probability than the cathode side. Multi-objective optimisation identified a compromise design comprising a mid-edge bolt layout, a nominal mean contact pressure of 0.272 MPa (170 N per bolt), a 6 mm bolt–edge distance, and a 9 mm washer diameter.