Reliability evaluation of thermal barrier coatings for engine combustion chambers based on Monte-Carlo simulation

Due to their outstanding high temperature resistance, thermal barrier coatings are commonly applied in hot section such as aero-engine combustion chambers to protect components from high-temperature airflow. However, its material properties are insecure, the service environment is harsh, and the service life is uncertain. This paper uses a Monte-Carlo simulation-based dependability evaluation method to resolve this uncertainty. To begin with, the failure criteria for thermal barrier coatings were defined, as was the limit state equation. Second, using the Monte-Carlo simulation approach, the failure probability was calculated. Finally, the TBCs' dependability in a thermal gas flow environment was assessed and compared to actual measurement results. The thermal barrier coating in the area where the surface temperature of the combustion chamber is above 1100 °C begins to fail after 4000 h of service under the action of the hot air flow, with a failure rate of more than 60 %. The service life of the thermal barrier coating at surface temperatures of 1000, 1100, and 1197 °C was 6327, 3125, and 1642 h, respectively, based on the time it took to attain 60 % failure probability under the impact of hot air flow. The numerical relative error of the actual failure probability PT of the thermal barrier coating of the combustion chamber obtained by hole detection technology is less than 10 % (except for 3000 h), demonstrating the dependability and applicability of the reliability assessment technique. The reliability of thermal barrier coatings is influenced by temperature and TGO development.