非惯性系下旋转柔性叶片的动力学分析

Dynamic analysis of rotating flexible blades in a non-inertial coordinate system

旋转柔性叶片是汽轮机关键零部件,针对叶片振动损伤问题,考虑经历大范围运动的柔性叶片刚性运动与弹性变形运动之间的相互耦合,应用哈密顿原理建立了旋转柔性叶片非线性动力学控制方程.考虑旋转离心惯性力的影响以及轴向变形与横向变形之间的耦合,基于假设模态法对方程进行离散,研究了不同转速下梁端部位移的响应.研究结果表明,刚性旋转运动对柔性叶片端部位移的响应具有明显的影响,并且由于离心力的存在,出现了动力刚化现象,文中所用方法及数值仿真结果可用于研究旋转柔性叶片的振动失效问题.

Rotating flexible blades are key components in steam turbines. To analyze vibrational failure of rotating blades due to the coupling of elastic deformation and rotating rigid motion under large-scale motion, non-linear dynamical control equations were derived based on the Hamilton principle. Displacement responses of blade tips were studied and simulated numerically based on the assumed mode method, considering the influence of rotating centrifugal inertial force and the coupling of axial deformation and transverse deformation. Results showed that rigid rotational motion has significant influence on displacement responses of blade tips, and the phenomenon of dynamic stiffening results from the existence of centrifugal inertial force. Results given in this paper can be used in the study of vibrational failure of rotating flexible blades.