抄録
A simplified crack initiation analysis of piezoelectric ceramics under cyclic loading was performed by using the double cantilever beam (DCB) model based on the continuum damage mechanics. A constitutive equation of piezoelectric ceramics and a damage evolution equation that have been proposed by the authors were applied to the DCB model. The crack initiation in the DCB model was dealt within the framework of the continuum damage mechanics ; i.e. damage development in piezoelectric ceramics was described by the evolution equation of a damage variable and the criterion of the crack initiation was based on the value of the damage variable at the crack tip (so-called local approach). The analysis was intended for a crack initiation time under mechanical and electric cyclic-loading. By using the present model, the effect of applied electric field on the crack initiation time was elucidated and variations with process of time in distributions of stress, strain and damage variable in front of the crack tip were predicted. Furthermore, dependence of the crack initiation time on the discretizing size in the numerical analysis was discussed.
