挤压油膜阻尼器-滑动轴承-转子系统非线性动力特性的数值分析及实验研究

 采用非线性模型,研究挤压油膜阻尼器 -滑动轴承 -转子系统的运动稳定性和分岔特性。利用有限元离散变分不等原理和基于线性规划余原理的迭代方法,求解自由边值条件下的油膜力。采用模态综合技术中的缩减系统线性自由度的方法,并提出基于 Newmark法的预估 -校正 -局部迭代的方法,求解系统响应。采用 Poincaré映射法,将周期解的确定转化为 Poincaré截面上不动点的确定,然后分析不动点的稳定性。最后通过实验转子,从实验与数值计算进行对比分析,验证了挤压油膜阻尼器的减振特性及其提高系统运动稳定性的特性,同时也说明了上述方法可以有效地分析这类系统的局部非线性动力特性。

NUMERICAL AND EXPERIMENTAL STUDY ON NONLINEAR DYNAMIC BEHAVIOR OF THE FLUID FILM BEARING-ROTOR SYSTEM WITH SQUEEZE FILM DAMPER

The stability and bifurcation of the fluid film bearing-rotor system with a squeeze film damper are studied using a nonlinear model. The oil film forces under free boundary conditions are solved by finite element discrete variational inequalities and iterative method based on complementary principle in linear programming. The mode synthesis technique is adopted to reduce the linear degree of freedom and the Newmark method combined with predictor-corrector algorithm is presented to analyze the response of the reduced system. For determining the periodic solution, the Poincaré mapping is used to discretize the continuous flow, then the fixed point on Poincaré section and its stability are determined equivalent to the periodic solution and its stability respectively. Finally, the system is investigated experimentally by a rotor under the theoretic guidance. The results show that the squeeze film damper is very effective in preventing sub-synchronous and non-synchronous dynamic response, and the stability of the system can be improved greatly. It is also testified that nonlinear dynamical properties can be analyzed efficiently by the above theory and method.