Research On Fracture Behavior Of Holes With Edge Cracks In Piezoelectric /Magnetoelectroelastic Materials

At present, with the rapid development of the science and technology, the changing direction of the smart materials is focus on the intelligence and function. Smart structures and devices are widely used in high-tech fields such as aerospace, information technology,new materials technology, etc, and show its great advantages. However, due to the inherent brittle weakness of smart materials, it is easy to produces defects in manufacturing and processing such as cracks, holes, inclusions, and dislocations, etc,which can lead to failure of these materials. As we know, holes are commonly existing in structures. Due to stress concentration phenomenon around the holes, cracks are emanating from holes easily, which results in failure of these materials. Therefore, it is significant to study the cracked-hole problems in smart materials.Complex function method is one of the effective methods to study fracture mechanics. By constructing a new conformal mapping and using the Stroh-type formalism and Cauchy integral, the anti-plane problems of isotropic piezoelectroelastic solids containing a regular triangle hole with smooth vertices which emanates an edge crack and four cracks originating from an elliptical hole were studied. Under the assumption that the surfaces of the crack and hole were electrically permeable and electrically impermeable, respectively, the expressions of the field intensity factors, the energy release rates and mechanical strain energy release rates near the crack tip were obtained. Furthermore, the impacts of electrically permeable and electrically impermeable boundary conditions on the crack growth were discussed.The study on an edge crack emanating from a regular triangle hole with smooth vertices or four cracks originating from an elliptical hole in piezoelectric materials was extended to the magneto-electro-elastic materials when the solid was subjected to remotely uniform anti-plane shear loading and in-plane electric and magnetic loading,under the magneto-electrically permeable and impermeable boundaries. The expressions of the field intensity factors, the energy release rates and mechanical strain energy release rates near the crack tip were obtained under the magneto-electrically permeable and impermeable boundaries. The numerical examples were conducted to show that the influences of the geometrical parameters of crack, applied mechanical load, electric displacement and magnetic load on the crack growth under different electric boundary conditions.