含中介轴承内圈局部缺陷的双转子系统的组合共振特性

针对航空发动机双转子系统建立简化的动力学模型,在考虑中介轴承非线性Hertz接触力和径向游隙等非线性因素的情况下,将中介轴承内圈局部缺陷模拟成倒置的等腰梯形凹槽,利用4阶Runge-Kutta法进行数值计算,得到系统的分岔图,并着重分析分岔区域的组合共振特性,结果表明：相较于无故障系统,该系统在分岔图上出现三个新的分岔区域,前两个分岔区域是由内圈故障特征频率与高低压转子的转频形成的组合频率诱发的组合共振引起的,第三个是由内圈故障特征频率诱发共振引起的,在分岔区域内,系统运动的周期性的变化规律表现为从近似单周期运动到概周期运动再到近似单周期运动。

Combination resonance characteristics of a dual-rotor system with a local defect of inter-shaft ,bearing inner ring

A simplified dynamic model of aero-engine with dual-rotor system was established. Considering the non-linear factors such as Hertz contact force and radial clearance of the intermediate bearing, the local defect of the inner ring of the inter-shaft bearing was simulated as an inverted isosceles trapezoidal groove. The Runge-Kutta method of order 4 was used to simulate the fault system and draw the bifurcation diagram. The combination resonance characteristics of the bifurcation region were analyzed emphatically, and the results showed that there were three bifurcation regions in the bifurcation diagram of a dual-rotor system with local defect of inter-shaft bearing. Vibration response analysis showed that the first two bifurcation phenomena were caused by the combined resonance of inner-ring fault, and the last bifurcation phenomenon was caused by the induced resonance of inner-ring fault. In the bifurcation region, the periodicity of system motion would change correspondingly, mainly from approximate single-periodic motion to almost periodic motion and then to approximate single-periodic motion.