Finite element analysis of the three-dimensional crack and defects in piezoelectric materials under the electro-mechanical coupling field

This paper presents three-dimensional planar crack and non-planar defects analysis of piezoelectric materials by the finite element method (FEM). Based on practical engineering, a series of reasonable three-dimensional defects models are established. Different from the usual two-dimensional plane as a three-dimensional defect form, the present paper takes into account the different causes, concrete position, and various shapes of typically three-dimensional non-planar defects in practical engineering. By changing the geometric size of the defect and the electro-mechanical boundary conditions, the effects of three-dimensional defect geometry and different electro-mechanical coupling boundary conditions on the distribution of stress, electric field strength, and electric displacement around the defect are investigated. The calculation results show that the electro-mechanical parameters are strongly affected by the geometry of defect and boundary conditions. Furthermore, the distribution of electro-mechanical parameters in the detailed position of the different three-dimensional defect model is also studied, which can accurately assess the location where the defect is prone to fracture. It is concluded that this paper can be used as a reference of three-dimensional defects and the service life of piezoelectric materials in practical engineering structures.