MIXED FINITE ELEMENT METHOD FOR FRACTURE MODELING OF PIEZO- AND FERROELECTRIC MATERIALS WITH STRAIN GRADIENTS (FLEXOELECTRICITY) [Keynote]
Sergey KozinovGrand Ballroom A
Following the continuous miniaturization of the microelectromechanical systems (MEMS), a size-dependent phenomenon of flexoelectricity starts to play an essential role at the micro- and nanoscale. Direct flexoelectricity is an electromechanical coupling of strain gradients, which are inversely proportional to the length scale, and electric field. Due to the application of strain gradients, the centrosymmetry of the unit cells is broken, allowing a wider choice of dielectrics to be used in applications. In the proposed research, the nonlinear ferroelectric material behavior is further enhanced with strain gradients and applied to fracture problems with naturally occurring gradients of electromechanical fields near the crack tip. Or in another way, it is the incorporation of the remanent strains and polarization into the flexoelectric formulation. Our solution demonstrates the strong influence of the gradients on the ferroelectric domain switching behavior, leading to modified electromechanical fields close to the crack tip compared to the well-known ferroelectric problems.