摘要

A sequence of periodic attractors has been observed in a two-dimensional discontinuous map, which can be considered as a model of impact oscillator. The so-called "transfer number", which is defined as the mean number of transfer from non-impact state to impact state per iteration, is locked onto a lot of rational values to form a curve consisting of many steps. Our numerical investigation confirms that every step is confined by conditions created by the collision between the periodic orbit and the discontinuous boundary of the system. After the last collision the system shows a chaotic motion with intermittent characteristics. Therefore the staircase can be addressed as a "prelude staircase to type V intermittency". The similar phenomenon has also been observed in a model of electric circuit. These results of our study suggest that this kind of staircases is common in two (Or even higher) dimensional discontinuous maps.