An Integrated Creep Damage Analysis Method of Turbine Blades Based on the Service History

The creep fracture life of turbine blades is a limitation of the whole engine life because of its high operating temperature. Thus, developing an analysis approach of creep damage based on complex service history is of significant importance for the safe operation and economic overhaul. Within this content, an integrated creep damage analysis method is constructed, which can be used to calculate the accumulation of creep damage in real time once obtaining the service history. This approach first gets some critical parameters such as rotor speed and turbine forward temperature of the turbine blades through thermodynamic performance model of the engine. Then the stress and temperature states of the turbine blade is obtained by the thermal-fluid-solid coupling analysis. Based on the numerical results, a train of surrogate models from engine operating state to the detail load states including temperature, thermal stress and centrifugal stress are established. The classical Rabotnov-Kachanov creep model is selected to calculate the creep damage accumulation. This integrated damage analysis method has been carried out by a turbofan engine’s turbine blades. The results show that this method works well and quickly when faced with a large number of flight record data with only once numerical simulation under the typical service state. The blades damage accumulation changes reasonably as flight profile. The proposed method decreases the time cost by the developed surrogate models when flight profile changes, which has the potential to be used to monitor individual engine life and to extend to study the other damage types of turbine blades under different flight loads.