Modelling thermal fatigue of alumina brick via cyclic compression and 3D pore topology analysis

In this study, fatigue damage progression in alumina refractories was investigated under mechanical cyclic compression, employed as a surrogate for thermal fatigue. The decrease in Young’s modulus with the number of cycles confirmed progressive damage accumulation. Three-dimensional pore configurations visualized by X-ray CT revealed the expansion of open pores accompanied by the absorption of adjacent closed pores, indicating crack growth. One-dimensional persistent homology was applied to quantify local pore configurations, introducing the H-value as a structural parameter representing pore distribution. Fatigue damage was modeled as the product of a static structural component, defined as a function of the H-value, and a dynamic damage amplification factor expressed by a Weibull cumulative distribution function linked to dissipated energy. This model describes fatigue damage as the gradual evolution of pore structure associated with energy dissipation and enables fatigue life prediction based on critical damage thresholds. The findings provide a fundamental basis for the design and operation of refractory structures with improved fatigue resistance.