带阻尼结构长叶片振动响应的研究

INVESTIGATION OF VIBRATORY RESPONSE OF LONG BLADE WITH SNUBBER DAMPER

研究了大型汽轮机长叶片的阻尼结构（凸肩或围带）对叶片振动的减振原理及效果．首先引入干摩擦非线性连接元，并进而推导出摩擦力附加刚度及附加阻尼矩阵，建立了有限元动力方程．其次用摩擦阻尼情况下的振型叠加法编制了有限元程序，研究叶片阻尼凸肩（围带）间的正压力与叶片响应的定量关系，找出了规律，在此基础上用８５１叶片作为算例。

This paper deals with the effect of snubber damper on vibration reduction of long blade of large steam turbine. At first, the concept of nonlinear dry friction connecting element is introduced, additional stiffness matrix and damping matrix caused by friction force are developed, and then the finite element dynamic equation is found. Secondly, a finite element computer program is developed via mode superposition considering friction damping, by which the quantitative relation of blades response and normal force acting on snubber dampers is studied, and valuable results are obtained. Finally, an 851 mm long blade is analyzed, and the accurate results show that the dry friction model and the computer program are very efficient for the response analysis.