Effects of electric field on nanocrack propagation

The present work is concerned with the application of Atomistic Field Theory (AFT) in modeling and simulation of dynamic nanocrack propagation under electrical and mechanical loadings. AFT enables us to express an atomic scale local property of a multi-element crystalline (which has more than one kind of atoms in the unit cell) system in terms of the distortions of lattice cells and the rearrangement of atoms within the lattice cell, thereby making AFT suitable to fully reproduce both atomic-scale and continuum level phenomena. Atomistic Field Theory and its corresponding finite element (FE) implementation are briefly introduced. Taking both efficiency and accuracy into account, we adopt a cluster-based summation rule for atomic force calculations in the FE formulations. Single crystal MgO under electrical/mechanical loading is modeled and simulated. Numerical results show that electric fields can serve as a tool to shield the crack initiation and propagation in the ionic crystal materials, thereby offering new perspectives on fracture mechanics at nano scale.