A finite element assessment of influential factors in evaluating interfacial fracture toughness of thermal barrier coating

It was previously reported that the adhesion strength of thermal sprayed yttria-stabilized zirconia coatings, as measured by the modified tensile test, decreased with increased coating thickness. Results from this method include the effects of both residual stress introduced during the spraying process and the adhesive glue used for the specimen preparation. This work quantified these effects by means of finite element analysis. The model also considered friction factors for interfacial crack closure induced by compressive residual stress in the coatings. It is concluded that friction factors affect interfacial fracture toughness slightly, but the most significant effect is caused by a change in the crack propagation path in the case of the thinnest coatings. •Interfacial fracture toughness of thermal barrier coating is focused.•The results obtained by the modified tensile test are parametrically studied.•The most influential factor on the test results is the crack propagation path.