We present a dynamical model of DNA mechanical unzipping under the action of a force. The model includes the motion of a fork in a sequence-dependent landscape, the trap(s) acting on the bead(s) and the polymeric components of the molecular construction (unzipped single strands of DNA and linkers). Different setups are considered to test the model, and the outcome of the simulations is compared to simpler dynamical models existing in the literature where polymers are assumed to be at equilibrium.