Influence of residual surface stress on the fracture of nanoscale piezoelectric materials with conducting cracks

In this paper, we analyze the stress and electric field intensity factors affected by residual surface stress for conducting cracks in piezoelectric nanomaterials. The problem is reduced to a system of non-linear singular integral equations, whose solution is determined by iteration technique. Numerical results indicate that the residual surface stress can significantly alter the crack tip fields at nanometer length scales. Due to the residual surface stress, the electric field can produce stress around crack tip. This suggests a strong electromechanical coupling crack tip field for nanoscale piezoelectric materials. Such a finding is considerably different from the classical fracture mechanics results. A transit electric field to stress load ratio is identified, for which influences of residual surface stresses vanish. The research is useful for the applications of nanoscale piezoelectric devices.