裂纹拉杆转子连接界面非线性建模与多参数演变规律研究

Nonlinear modeling of the connection interface of a rod-fastened rotor with cracked rodand its multi-parameter evolution

针对含拉杆裂纹的转子非线性振动现象,基于Paris裂纹扩展规律,建立了裂纹拉杆刚度模型;以界面接触刚度表征拉杆预紧作用,建立了轮盘接触刚度模型;采用Capone短轴承模型,完成了含拉杆裂纹的转子连接界面非线性动力学建模。通过系统Poincare截面分析发现,在转速与偏心多因素影响下得到的e-n分岔集中,系统在倍周期分岔与拟周期分岔之间交替变化;在裂纹扩展与转速的η-n分岔集中,解的分岔点分布不连续;不同转速下,位移随裂纹扩展的分岔轨迹比较复杂,拉杆裂纹的存在会加速或减缓分岔点的出现。结果表明:拉杆裂纹对转子稳定性作用机理受系统参数集的影响。研究结论对拉杆转子的参数设计与故障识别有一定意义。

The nonlinear vibration phenomenon of a circumferential rod-fastened rotor with cracked rod is of nonlinear property.The stiffness model of the cracked rod was established based on the supposition of Paris crack propagation and the model of the disk interface contact stiffness was also established,by which the preloading effect of the rod was characterized.On this basis,a nonlinear dynamics model of the connection interface of the rotor with cracked rod was completed by refering to the Capone short bearing model.The solution was analysed by virtue of the Poincare section surface method.It is found that the system alternates between the periodic doubling bifurcation and the quasi-periodic bifurcation in the e-n bifurcation set obtained under the influence of the factors of rotational speed and eccentricity.The solution distribution of bifurcation points on theη-n bifurcation set obtained under the influence of crack propagation and rotational speed is discontinuous.At different rotational speed,the bifurcation trajectory of displacement along with the crack propagation is rather complicated,and the presence of rod crack will accelerate or decelerate the occurrence of the bifurcation point.The results show that the mechanism of the effect of rod crack on rotor stability is affected by the system parameter set.The conclusion has certain significance for parameter design and fault identification of rod-fastened rotors.