Considering unilateral interfacial crack in thermal barrier coating(TBC)

virtual crack closure technique(VCCT) was used to calculate strain energy release rate of the structure under thermal loading

and unilateral interfacial crack propagation behavior was studied according to the results.During calculation

the stable temperature field was obtained by the given temperature boundary conditions

and taken as the thermal loading in the structure.The temperature-dependent material parameters were adopted.The results show that

in the given conditions

the total energy release rate is greater than interfacial fracture toughness during crack initiation stage

indicating that once the unilateral interfacial crack appears

the unstable propagation will occur subsequently under thermal loading.When the crack extends close to the free end

the total energy release rate decreases rapidly and drops below the interface fracture toughness

leading to stop of crack propagation.The analysis shows that

for the structure of TBC with unilateral interface crack under high thermal loading

the ceramic coat won't flake-off completely.