Small scale nonlinear analysis of electrostrictive crack problems

摘要

The asymptotic problem of a semi--infinite crack in an electrostrictive ceramic under electric loading is analyzed. A universal relation between the stress intensity factor and the electric field intensity factor under small-scale nonlinear conditions is obtained for a conducting crack as well as for an insulating crack. It is shown that the surfaces of the conducting crack are closed except a small zone near the crack tip, whereas all the surfaces of the insulating crack remain open. Energy release rates due to self similar crack extension as well as due to dissimilar crack extension are also discussed. The energy release rate for the insulating crack does not always have a negative value, in contrast to a linear dielectric theory.