转子非线性扭转振动成因研究
Nonlinear Torsional Vibration Research of a Rotor System

目前研究转子扭转振动的非线性现象，多数采用直接假设存在立方非线性，并未对其存在的原因进行解释。针对此问题，从几何变形的角度出发，推导出转子扭转振动中产生刚度渐软的duffing非线性现象的原因。首先，在未考虑非线性影响的情况下用ANSYS进行了模态求解；其次，在考虑非线性项时，建立多自由度的数学模型，采用模态截断的方法和多尺度法分析了系统的主共振；最后，通过数值仿真与扫频试验结果的定量对比，证明了转子扭转振动中存在刚度渐软的立方非线性理论的正确性。
Most of researcher assume that there exist cubic nonlinear term directly when investigate the non-linear phenomena of torsional vibration of rotor. However, they do not explore the reason why emerge non-linear phenomena. In this paper, softing duffing non-linear terms is gotten in torsional vibration of rotor with geometry deformation. Then modal analysis are carried out by use of ANSYS software without considering the influence of nonlinear terms. A multi-degree of freedom nonlinear modal are proposed, and principal resonance is obtained taking advantage of mode truncation technique and the method of multiple scales. Finally, through the quantitative analysis between numerical simulation and frequency sweep test of torsional vibration, the results indicate the accuracy of softing duffing nonlinear phenomena in a rotor torsional system.