Failure mechanisms and their finite element modeling of air plasma spray thermal barrier coatings: A review

In order to study thermal barrier coatings reliability and durability understanding their failure mechanisms is crucial. These coatings are used in high temperature and extreme heat gradients working conditions. In this paper an overview of failure mechanisms of air plasma spray thermal barrier coatings under various thermal and mechanical loading has been carried out. Since the costs of experimental tests with real working conditions of these coatings are very high and there are many limitations for these methods in terms of their performance conditions, these methods cannot provide the actual conditions for TBC to reflect well. Hence, the finite element methods play an important role in study of these issues and it is expected for these methods to be able to determine the TBC failure patterns under real conditions. In this paper the applicability of new finite element methods to simulate the failure mechanisms of thermal barrier coatings under thermal and mechanical loads has been discussed. Some of these methods are virtual crack closure technique, extended finite element method and cohesive zone model. Meanwhile, a comparison between these finite element methods in terms of advantages and limitations have been made.