Energy Release Rate for Piezoelectric Body

Abstract

Crack Energy Density (CED), that is, the parameter that enables a unified description of crack behavior without any restriction on constitutive equation and its applicability had been shown for ordinary materials was extended to piezoelectric body in the previous paper. Taking into consideration this new knowledge about CED, in this paper, the energy release rate for piezoelectric body is discussed and the fundamental matters such as the relations of energy release rate with CED, its derivatives and J integral are elicited. A crack is modeled by a notch with a sufficiently small root radius and a sharp crack is treated as the limit when root radius approaches zero. Energy release rate is derived through two different procedures and it is shown that energy release rate is equal to the electric enthalpy area density, that is, the difference between mechanical CED and complementary electrical CED. Moreover, how mechanical and electrical contributions of energy release rate are given is also discussed.