Integrated Engine-Cycle and Structural Modelling for Reusable Liquid Rocket Engines

Kurzfassung

Designing reusable liquid rocket engines requires early-stage methods that consistently link engine-cycle modelling with structural durability assessment. Engine cycle simulations provide essential performance insight, yet their direct implications for the fatigue life of critical components across the full operational envelope remain insufficiently quantified. Consequently, methods are needed that are efficient to apply while maintaining the accuracy required to resolve the mechanisms that drive failure. This study presents an integrated modelling framework that couples gas-generator cycle analysis with thermo-mechanical fatigue assessment of a regeneratively cooled combustion chamber in the ~1 MN thrust class. The cycle is modelled in EcosimPro-ESPSS to obtain transient boundary conditions, which are subsequently applied in an ANSYS-based finite-element model and further evaluated using a previously developed post-processing damage evolution fatigue method. This combined approach enables time-efficient and precise evaluation by incorporating temperature-dependent material data and a cycle-driven damage formulation to estimate fatigue evolution throughout a representative operating sequence. The results demonstrate how transient thermo-mechanical loading governs damage accumulation and provide a basis for assessing reusability margins and potential operational-envelope adaptations at early design stages.