<p>In this work, scale influence on crack propagation and on plastic strain distributions in a single FCC crystal is investigated numerically. A novel dynamic continuum crystal plasticity formulation, implemented in the finite element method, is used coupled with a cohesive zone model. A non-conventional fully coupled mixed formulation is proposed where displacements and plastic slips are calculated by balance equations. Geometrically necessary dislocation (GND) effects are introduced through a strain gradient crystal plasticity model. An exploratory study on micro-inertia effects caused by moving micro-defects is also considered. The model introduces three different material sizes: one related to micro-inertia and two others related to GND hardening. When two different GND hardening mechanisms are considered, energetic and dissipative, the current formulation is able to reproduce details of the crack propagation kinematics only obtained before by simulations in the discrete dislocation scale. This work suggests that this was possible because a full dynamic solution is considered. Also, due to micro-inertia, the model is able to capture dislocation starvation for very small scales, which is a novelty for a continuum scale model. Therefore, the present model is able to connect the discrete dislocation scale and the macroscopic scale in the case of crystal fracture.</p>