关键词: 转子-轴承系统, 裂纹, 非线性特性, 分岔, 混沌

Abstract: A dynamic model was set up for a cracked two-span rotor-bearing system to investigate the influences of crack and its angular orientation on nonlinear dynamic characteristics of the system. The periodical, quasi-periodical and chaotic motions were found in the system response which will enter into chaos by a doubling-period or intermittent bifurcation route and leave chaos by a doubling-period inverse bifurcation route. Such frequency multiples as 1/3, 1/2, 2/3, 1 and 2 were found within the sub-critical speed range, but the peak values of double or higher frequencies obviously decrease within the super-critical speed range. The influence of cracking angle β on the dynamic behavior of a cracked rotor is important insomuch as the quasi-periodical, periodical and/or chaotic motions in system response will occur along with different cracking angles in the vicinity of the area where ω=3ω0/2. It therefore requires more attention to pay when a fault diagnosis is doing for a multi-span rotor system running at a super-critical speed.