水轮发电机组整机系统随机振动的直接谱分析

为了解决水轮机随机振动分析问题，采用了多级模态综合技术建立水轮机包括转动部件和固定部件在内的整机系统模型。由于轴承油膜刚度、阻尼，运动方程系数矩阵具有非对称特性。将系统所受随机激励分解为确定性分布矢量和一个随机过程标量的乘积，在位形空间对运动方程解耦，将直接谱分析方法推广到非对称系统，直接得到整机系统随机响应谱密度函数矩阵的每个元素，从而方便地计算随机响应的均方值，为水轮发电机组随机振动分析提供有效可行的方法。

Direct spectrum analysis for random vibration on whole hydroelectric generator system

A multiple modal synthesis method was adopted to obtain governing equation for a whole hydroelectric generator system including rotary and fixed components. On account of unsymmetric coefficient matrices of oil film stiffness and damping in bearing, the matrices in governing equation were unsymmetric. The random excitation was reduced to a determined vector describing a load distribution on the system and a scalar random process. The direct spectrum analysis method was extended to unsymmetric system after the governing equation was decoupled in configuration space. Every element of response power spectrum density function matrix can be obtained directly and the mean square values can also be calculated conveniently. The examples show that the approach is practical on random vibration analysis for engineering.