面向工程设计的热障涂层寿命预测方法

Methodology of life prediction for thermal barrier coatings in engineering design

针对带热障涂层涡轮叶片的工程设计需求,发展了一种热障涂层寿命预测方法。根据热障涂层系统的受载特征,建立了能够高效求解涂层各层关键力学行为的降维力学模型。通过热障涂层模拟件在经历高温长时氧化、热疲劳载荷后的剥落抗力测试,获取了涂层界面损伤的演化规律。在此基础上,对涂层总损伤进行解耦,建立了氧化-力学耦合损伤模型,提升了涂层损伤与剥落寿命的预测精度。基于上述理论模型,开发了可与现有构件设计流程相集成的热障涂层损伤分析与寿命预测软件工具,并进行了涡轮叶片算例验证。结果表明:上述方法对于热障涂层整个损伤演化过程的预测误差在±10%以内。

A methodology of life prediction for thermal barrier coatings was developed to meet the engineering design requirement of turbine blades with coatings.According to the loading feature of thermal barrier coatings,a simplified mechanical model was adopted to calculate the critical behavior of each layer efficiently.The interfacial damage evolution generated in the coatings was measured by the spalling-resistance tests on the simulated specimens with thermal barrier coatings after undergoing hightemperature long-term oxidation and thermal fatigue.On this basis,the total damage in the coatings was decomposed and a damage model considering the coupling of oxidatively induced and mechanically induced damages was proposed to improve the prediction accuracy of damage and spallation life.Lastly,based on the theoretical models,a software tool for damage analysis and life prediction of thermal barrier coatings,which can be integrated in the existing design process of components,was developed and verified by the instance of turbine blade.The results showed that the above-mentioned method predicted the evolution of damage generated in thermal barrier coatings with an error of±10%.