Investigation on spatial distribution and evolution features of the running-in attractor based on a new approach

Purpose The purpose of this work is to comprehensively reveal the spatial distribution and evolution features of a running-in attractor. Design/methodology/approach The friction coefficient signals extracted from wear experiments are reconstructed. A projected matrix is obtained based on the reconstructed matrix. Then the approach of three-dimensional (3D) histogram of phase points is proposed, which is used to intuitively characterize the complex properties of the running-in attractor. Findings The space occupied by the running-in attractor gradually contracts, then stabilizes and finally expands; the maximum of phase points number in a certain bin initially decreases, then keeps stable and finally increases rapidly; yet the percentage of bins number storing phase points shows an inverse variation tendency. Consequently, 3D histogram evolves from a nonuniform state to a uniform state then returns back to the nonuniform state, which indicates the evolution rule of "formation, stabilization and disappearance" of the running-in attractor. Originality/value Characterization on the features of the running-in attractor can provide valuable information about friction systems and their dynamic behaviors.