Stress investigation on interacting defects in piezoelectric materials

• Main Author: Zhang, Hongxia
• Other Authors: Xiao Zhongmin
• Format: Theses and Dissertations
• Published: 2008
• Subjects: DRNTU::Engineering::Mechanical engineering::Mechanics and dynamics
• Online Access: https://hdl.handle.net/10356/5287
• Institution: Nanyang Technological University

Dislocation emission mechanisms for micro crack initiation are proposed, at the tips of a semi-infinite rigid conducting line for plane case and a finite rigid conducting line for plane and antiplane cases in a piezoelectric medium. The crack is simulated by distributed piezoelectric screw/edge dislocations for antiplane/plane cases. By evaluating mechanical strain energy release rates, connections are obtained between critical rigid line extension forces and critical crack extension forces in the same solid. Two critical crack lengths are observed. Furthermore, the electroelastic interactions are investigated of a screw/edge dislocation and collinear interfacial rigid conducting/dielectric lines in a piezoelectric bimaterial, by using complex variable methods and Stroh formalism. The solutions of the field variables and all kinds of singularities at rigid line tips are obtained. Rigid line extension forces and the image force on the dislocation are calculated. Numerical examples are performed to analyze some important parameters on rigid line extension forces and image forces.