双跨裂纹转子-轴承系统非线性动态响应与混沌

建立了具有非线性油膜力的双跨裂纹弹性转子 轴承系统模型,研究了裂纹存在和裂纹角对系统非线性动力学特性的影响,发现此系统响应存在着周期、拟周期和混沌运动等复杂的运动形式,进入混沌的道路是倍周期分岔或阵发性分岔,离开混沌的道路为倍周期倒分岔·在亚临界转速区系统响应中出现了1/3倍频,1/2倍频,2/3倍频,1倍频,2倍频等频率成分,但是在超临界转速区,2倍频及以上频率的峰值明显减小·裂纹角β对裂纹转子的动力学行为有着重要影响,在ω=3ω0/2区域附近系统响应会随着裂纹角的不同,出现拟周期、周期和混沌等复杂的运动,因而对以超临界转速运行的多跨转子系统进行故障诊断时需加以注意·

Nonlinear Response and Chaos of Two-Span Rotor-Bearing System with Crack Fault

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.