开闭裂纹挠性转子动特性研究

Dynamic Behavior of a Flexible Rotor with Transverse Crack

采用裂纹深度修正的非线性开闭裂纹模型 ,研究涡动影响下挠性裂纹转子的动力学行为。数值仿真表明 :裂纹深度与非线性响应之间有比较确定的关系。随着裂纹深度增加 ,裂纹转子会在 m/ n倍临界转速附近出现次谐波分叉现象和拟周期运动 ;在亚临界转速范围内 ,系统在 2 / 3倍临界转速处可通过倍周期分叉途径进入混沌状态 ;在超临界转速范围内 ,1、2倍临界转速的不稳定区不断扩大 ,非线性因素抑制作用使系统产生周期跳变、倍分叉和混沌等非线性力学行为 ;阻尼对系统响应有很大影响。

A nonlinear crack modal, modified by the crack depth, is used to study a cracked rotor with the influences of whirl speed. Numerical simulations show that there is a clear relation between the caused phenomena and the crack depth. As the crack depth increases, there are period 2 and quasi period motions in the vicinity of the rotating speed ratio m/n. Under critical speed, periodic vibrations turn to chaotic motions in the route of doubling bifurcation when the rotating speed ratio is close to 2/3. The unstable region at the speed ratio near 1 and 2 becomes wide. For the limitation of nonlinear factors, there are many nonlinear phenomena, such as period catastrophe, period doubling bifurcation and chaos. Damping coefficient has a large influences on the system response.