Damage Analysis of Thermal Barrier Coatings Subjected to a High-Velocity Impingement of a Solid Sphere

Abstract

A delamination of thermal barrier coatings (TBC) applied to turbine blades in gas turbine could be caused by a high-velocity impingement of various foreign objects. It is important to accurately predict the size of interfacial crack for safety operation of gas turbine. In this study, in order to establish a practical equation for prediction of the length of interfacial crack, a high velocity impingement test and a finite element analysis (FEA) based on a cohesive model were conducted. As the result, the length of interfacial crack is linearly increased with the impact velocity. In addition, it was confirmed that it was accurately estimated by the FEA. The equation for prediction of the length of interfacial crack was formulated based on these results and the energy conservation before and after impingement. Finally, the applicability of the equation was demonstrated in a wide range of impact velocity through a comparison with the experimental results.

Damage Evaluation of Thermal Barrier Coatings Subjected to a High-Velocity Impingement of a Solid Sphere under Room and High Temperature Conditions

“…12) Using this system, the damage mechanism of TBCs and metallic substrates caused by FOD has been investigated. 13,14) In this study, to clarify the damage mechanism of TBCs caused by FOD under a high-temperature environment, a new high-velocity impingement testing system (H-SPITS) wherein a solid sphere can be impinged at environmental temperatures up to 900°C is developed. The influences of temperature and impingement velocity on the deformation and damage behaviors of TBCs are investigated through a high-velocity impingement test conducted at RT and 900°C.…”