Compilation method of a load-enhanced accelerated mission test spectrum for turbine blades based on creep-fatigue damage equivalent

Accelerated testing of aero-engine key components reduces testing costs by enhancing the load conditions, with damage equivalence as the core principle. In this study, a compilation method of the load-enhanced accelerated test spectrum for turbine blades under creep-fatigue damage conditions was proposed. The modified rain-flow counting method was employed to classify and count the comprehensive mission spectrum. By analyzing the thermo-mechanical loads on the blades and establishing the creep-fatigue life prediction method based on the Larson-Miller parameter, life assessments were conducted for full-scale blades under various operating conditions. Using the relative Miner’s rule, the enhanced peak load for the accelerated spectrum was derived based on fatigue damage equivalence, while the dwell time was determined based on creep damage equivalence. The designed accelerated spectrum reduces cycle duration by 93.3% compared to the original spectrum, while improving the acceleration efficiency by 42.9% relative to the method based on the main operating condition. Under the applicable conditions, the proposed approach achieves significant acceleration effects while maintaining creep–fatigue damage consistency with the original spectrum, thereby effectively shortening the turbine blade development process and demonstrating substantial engineering application value.