The finite element simulation was used to characterize the relationship between different crack shapes in the thermal barrier coating ceramic top-coat and the shape and size of bright spots on the coating surface. The results show that when the crack length is less than 1mm

the shape effect of the crack has no obvious effect on the surface temperature distribution and size of coating ceramic top-coat. When the crack length exceeds 1mm

the shape of the bright spot on the surface of the ceramic top-coat gradually follows the shape of the internal delamination crack

and the larger the crack edge effect (the smaller the angle)

the more the shape change of the bright spot on the ceramic top-coat surface above it tends to the shape of the internal delamination crack. Different shape crack size and area have different effects on the maximum temperature of the ceramic top-coat above the crack. With the increase of crack size and area

the maximum temperature of the ceramic top-coat above the three shape cracks increases. When the crack size exceeds 0.5mm

the difference of surface temperature of the three cracks gradually increases

and the increase of surface temperature of cylindrical crack is the most significant. Therefore

the size of the bright spot on the surface of the ceramic top-coat can reflect the actual size of the internal crack

and the relationship between the bright spot size and the internal crack size is not affected by the crack shape

location and other factors.