A mathematical model was constructed for the mechanical interactions between two contact fibers, based on which numerical simulations were performed and the results are in good accordance with the experiments. The settling fiber begins to slide at earlier time and the entire interaction duration diminishes as the initial position of the contact point, the initial orientation of fiber and the fiber specific weight increase or the solvent viscosity decreases. Both the slipping start-up time and the departing time delay as the fiber aspect ratio increases, however, the effect caused by reducing the diameter is more significant than that caused by increasing the length. Finally, a synthetic parameter which can uniquely describe the start-up time and the finishing time of the sliding motion of the fibers was derived. (C) 2003 Kluwer Academic Publishers.