“…Although the extension of the formulation of piezoelectric elasticity to that of thermopiezoelectric elasticity is straightforward, it is not easy to obtain an explicit solution to thermopiezoelectric problems, due to the mathematical complexity. On this subject, recently, several valuable solutions have been presented by some investigators, see, for example, the work of Shang et al [1] for a three-dimensional problem of a penny-shaped crack, Yu and Qin [2], Qin and Mai [3], Yang et al [4], Qin et al [5] for the plane crack problems, and also Shen and Kuang [6], Qin et al [7] for the case of interface cracks. However, it should be noted that the available studies are for the case of impermeable cracks, i.e., cracks are considered as impermeable slits, and thus the electric field inside the cracks is assumed to be zero.…”