Scattering Of SH Waves By Mode-Ⅲ Crack In An Orthorhombic Piezoelectric Material And Bi-materials Consisting Of It, Elastic And Piezomagnetic Materials

Piezoelectric materials and piezoelectric-piezomagnetic composites are two classes of functional media. They have been widely used as electroacoustic and magnetoelectric devices, such as sensors, filters, transducers, resonators, delay lines, etc. The applications of these devices related to the elastic wave propagation. Therefore reliability analysis and nondestructive evaluation of piezoelectric and magnetoelectric devices demand a better understanding of dynamic fracture behaviors of piezoelectric and piezoelectric-piezomagnetic materials.This dissertation investigates the scattering of SH waves caused by a mode-III crack in an orthorhombic piezoelectric material, an orthorhombic piezoelectric-elastic bi-material and an orthorhombic piezoelectric-piezomagnetic bi-material. The Fourier transform and singular integral equation method are used solve the problems considered. Numerical results are given to shown the effects of material properties, combination forms and incident wave frequency on the dynamic stress intensity factor(DSIF). The main conclusions include that:(1) For the mode-III crack in orthorhombic media The peak values of DSIF corresponding to PMN-PT and KNbO3 are lager than those corresponding to KTP and KTA. The changes of elastic constant55 c and piezoelectric constant15 e have significant effects, but the change of permittivity can be neglected.(2) The peak values of DSIF at the crack left tip decrease with increasing the incident angle, while the peak values of DSIF at the crack right tip increase.(3) For the orthorhombic piezoelectric-piezomagnetic bi-material, the change of piezomagnetic constant 15 h has no effect on the DSIF almost.