Constitutive parameters identification of thermal barrier coatings using the virtual fields method

Thermal barrier coatings (TBCs) are widely applied in thermal components to protect metallic components. Owing to the complex layered structure of TBCs and difficult preparation of coating, the mechanical characterization of TBCs should be of primary importance. With regard to TBCs, this study deals with the constitutive parameters identification of bi-material. Considering the complex construction and boundary of bi material, the virtual fields method (VFM) was employed in this study. A methodology based on the optimized virtual fields method combined with moiré interferometry was proposed for the constitutive parameters identification of bi-material. The feasibility of this method is verified using simulated deformation fields of a two-layer material subjected to three point bending loading. As an application, the deformation fields of the TBC specimens were measured by moiré interferometry. Then, the mechanical parameters of the coating were identified by the proposed method. The identification results indicate that Young’s modulus of the TBC top coating is 89.91  GPa, and its Poisson’s ratio is 0.23.