TRANSIENT THERMOELASTIC FRACTURE OF BRITTLE SUBSTRATES BONDED TO BRITTLE FILMS

The effects of transient thermal loads on the propagation of cracks in brittle substrate caused by the residual tension in a brittle film ar e studied using a finite element approach. Based on the assumption tha t cracks in homogeneous brittle solids seek a trajectory for which K-I I = 0, the results show how the crack trajectory change from transient growth to steady state depends upon the film thickness, the ratio of the elastic moduli of the film and substrate, the race of application of the thermal load and time.