Finite element analysis of four fracture mechanism in the thermal barrier coating

Chen, Yuhui and Yang, xiaoxiang and Zhong, Shuncong (2014) Finite element analysis of four fracture mechanism in the thermal barrier coating. Advanced Materials Research, 933. pp. 187-191. ISSN 1022-6680

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Abstract

With the development of high temperature protective material, thermal barrier coatings are used in the field of aircraft and industrial steam turbine. They have characteristics of complex structure and long-term work in high temperature environment, etc. Because of multilayer material physical properties mismatch, oxidation, interface roughness, creep stress and so on, the coatings system is easy to produce cracks, expand and link near the interface of coating during thermal cycling. By establishing I, II, III, IV four numerical models of crack fracture mechanisms, assuming that the thickness of oxidation layer is constant, considering the influence of interface roughness and material properties mismatch in the process of thermal cycling, it gets the results of residual stress field near the crack and the influence of the interface. Compared to the presence of defects, four kinds of crack failure mechanisms are analyzed. Energy release rate is calculated by the virtual crack closure method, which can conclude the cracks of I, IV tip stress concentration phenomena are obvious, crack II is easy to expand, due to the temperature load, crack III does not appear stress concentration phenomenon at the tip.