Towards a fracture mechanics for brittle piezoelectric and dielectric materials

A theoretical fracture mechanics for brittle piezoelectric and dielectric m aterials is developed consistent with standard features of elasticity and d ielectricity. The influence of electric field and mechanical loading is con sidered in this approach and a Griffith style energy balance is used to est ablish the relevant energy release rates. Results an given for a finite cra ck in an infinite isotropic dielectric and for steady state cracking in a p iezoelectric strip. In the latter problem, the effect of charge separation in the material and discharge in the crack are considered. Observations of crack behavior in piezoelectrics under combined mechanical and electrical l oad are discussed to assess which features of the theory are useful.