Piezoelectric Damage Fields Analysis And Fracture Criterion For Piezoelectric Materials Based On Damage Extension Force

The fracture of piezoelectric materials is more closely studied as they have been more widely used in engineering. The linear constitutive theory and fracture theory for piezoelectric materials has been developed quite well, but the introduction of damage theory into the fracture mechanics of piezoelectric materials has just appeared.Based on the static anisotropic damage constitutive theory for piezoelectric materials formulated by Yang et al, the mechanical and electric damages around a central crack in a four-point bending piezoelectric beam are analyzed by using the FE iteration method. The influences of the crack length, the mechanical loads and the electric loads on the damage fields around the crack-tip are investigated and some useful conclusions are obtained. The piezoelectric fracture criterion is one of the most important sections of the fracture theory of piezoelectric materials, and it is also the most pop issue concerned by many investigators. Yang et al has established the piezoelectric fracture criteria based on the combinations of mechanical and electrical damage. In the paper, the mechanical and electric damage extension forces, which are conjugated with the mechanical and electric damage, is introduced. And a new fracture criterion of piezoelectric materials is deduced based on the combinations of mechanical and electric damage extension forces. The criterion indicate that the fracture will occur when the combination of damage extension forces reaches its critical value.