The Influence Of Different Crack Face Electrical Boundary Conditions On The Nonlinear Behavior Of Ferroelectric Crystal

Based on the time-dependent Ginzburg-Landau equation, this paper investigates the influence of different crack face electrical boundary conditions on the nonlinear electromechanical behaviors of a cracked ferroelectric crystal. Phase field simulations show that the different centered crack face electrical boundary condition has significant influence on the electrical and mechanical responses of the ferroelectric single crystal crystal with a centered crack. In the electrical hysteresis loop, the coercive field for the polarization switching of a crystal with an electrically permeable crack is about50%larger than that for a crystal with an electrically impermeable crack. In the butterfly loop, the remanent strain and the strain variation induced by polarization switching in the single crystal with the permeable crack are larger than those with the impermeable crack; The different macroscopic nonlinear behaviors are attributed to the different polarization switching processes. It is found that the domain switching takes place from the surface of the single crystal with a permeable crack, while it begins from the vicinity of the crack tip when the crack is impermeable. The ferroelectric single crystal with the impermeable crack exhibits strip90°domain switching under the negative electric field, which is consistent with the experimental observation. In the stress-strain curve, we find that the strain of a crystal with a conductive crack is bigger than that for a crystal with an electrically impermeable crack when the initial polarization parallel to the crack face. However, the strain of a crystal with a conductive crack is smaller than that for a crystal with an electrically impermeable crack. when the initial polarization perpendicular to the crack face. In addition, the different edge crack face electrical boundary condition has an obvious effect on the nonlinear behaviors of a ferroelectric crystal with an edge crack under external electric field:the coercive field of crystal with a conductive crack is smaller than that for a crystal with an electrically impermeable crack.