Experimental study and numerical modeling of the damage evolution of thermal barrier coating systems under tension

This study investigated the damage evolution (i.e., formation of vertical cracks, transformation of vertical cracks to interfacial crack and delamination) of thermal barrier coating systems under tension by using experimental and numerical methods. Experimental results revealed that the first transverse crack that was perpendicular to the load direction occurred when the strain of the top coat reached 0.5%. The full-scale strain of the top coat layer obtained by using the Digital Image Correlation technique indicated that surface cracks formed due to the coalescence of micro-cracks. Moreover, the results of the finite element method demonstrated that the vertical cracks initiated from the coating surface and extended through the thickness of the coatings. The density of the surface cracks was used as a damage evolution indicator such that numerical simulation could predict the cracking behaviour under tension loading. The results were consistent with those of the experimental study.