Oxidation Failure With Its Reliability Analysis Of TBCs In Consideration Of Interface Morphology

Thermal barrier coatings(TBCs)have been applied in heat insulation protection field such as high temperature components of aero-engine due to its merit for protective base,alleviate thermal shock load,improve engine efficiency and prolong the service time,etc.However,the service environment of TBCs is appalling,and the geometrical morphology and microstructure of TBCs are extremely complicated which makes it difficult to predict the failure of the coating,that caused a great threat to the safety of the coating in the aircraft engine.Therefore,exploring the coating failure mechanism and reliability analysis,will not only be conducive to the healthy development of Aerospace,but also can provide important guidance for the application and optimization of thermal barrier coatings.The study found that the effect of interface morphology on the oxidative cracking of the coating was very significant.So,in this study,we use the Monte Carlo method to evaluate the oxide failure reliability of TBCs in consideration of the interface morphology as spherical and sine surface.The main research content as follows:Firstly,the merit and demerit of common reliability calculation method were analyzed.The calculation principle and steps of First-order Second-moment Method and Monte Carlo method were introduced in detail,and then to analyze the merit and demerit of two methods by choosing the different functions and different distributions of the random parameters.Secondly,the reliability assessment for oxidation failure of TBCs within spherical interface is performed.The performance function for oxide failure of TBCs was obtained according to the energy release rate criterion.The Monte Carlo method was used to calculate the failure probability of TBCs under different conditions.Then,the relationship between the failure probability and parameters was investigated,and the sensitivity factor of each parameter was obtained.The critical parameters in effecting the coating failure were obtained by comparing the sensitivity factors.Thirdly,the reliability assessment for oxidation failure of TBCs within sine interface was performed.The stress of the interface is the key factors to interface failure,to investigate this,the stress field in cooling stage of coatings were analyzed by using finite element software ABAQUS.The performance function for oxide failure of TBCs was established according to the energy release rate criterion.The Monte Carlo method was used to calculate the failure probability of TBCs under different conditions.Then,the relationship between the failure probability and parameters was investigated,and the sensitivity factor of each parameter was obtained.The dominant parameters in effecting the coating failure were obtained by comparing the sensitivity factors.In general,this article is on the perspective of probability and statistics,and the reliability assessment of oxide failure of TBCs was performed by MATLAB software which is based on Monte Carlo method.