On the calculation of energy release rate for viscoelastic cracked laminates

The energy release rate (ERR) of crack growth as the energy change at the same time t between the two states of the structure is redefined, one is with crack length a under the loading σ(t), the other is the state with crack length a+Δa under the same loading condition. Thus the defined energy release rate corresponds to the released energy when a crack grows from a to a+Δa in an infinitesimal time. It is found that under a given loading history, the ERR is a function of time, and its maximum value should correspond with the critical state for delamination to propagate. Following William's work, the explicit expressions of ERR for DCB experimental configurations to measure the interfacial fracture toughness have been obtained through the classical beam assumption. Contributed by WANG Biao Foundation items: the National Natural Science Foundation of China (50232030, 10172030); the Natural Science Foundation of Heilongjiang Province. Biography: LIU Yu-lan (1962-), Doctor E-mail: myliu51@hotmail.com