On the opening of a class of fatigue cracks due to thermo-mechanical fatigue testing of thermal barrier coatings

► Numerical simulations of cracks observed in thermo-mechanical testing of TBCs. ► Cracks initiate in the TGO, grow into the bond coat kink to grow parallel to the TGO. ► Surfaces of the crack obtain a permanent separation after continued cycling. ► FEA with inelastic properties of bond coat and TGO, and TGO oxidation. ► Permanent crack separation due to structural ratcheting in the vicinity of the crack.