“…Previous works also provided many analytical solutions as well as proposed the theoretical fundamentals of fracture problems for piezoelectric materials in terms of linear elastic fracture mechanics [10,11] The FEM has applied to model fracture problems in piezoelectric materials. After the first couple of works by Kumar and Singh [12,13], a large number of subsequent contributions in this direction have been made, e.g., see [2,[14][15][16][17][18][19]. Special singular crack-tip elements, crack closure integrals, electro-mechanical J-integral, and so on have been developed for evaluating fracture parameters (e.g., intensity factors, energy release rate) for piezoelectric materials.…”