虚拟激励法在叶轮随机振动分析中的应用

叶轮在运转过程中受到各种随机气动载荷的作用。分析时可以采用时域方法，用单向耦合方式求解结构的位移及应力响应，但整个多载荷步瞬态分析十分耗时。本文基于频域分析，采用虚拟激励法求解随机气动载荷作用下叶轮结构的响应问题，同时利用ANSYS谐响应分析模块及 APDL 命令流，实现了多维多点虚拟激励法在离心式压缩机叶轮的工程应用，得到叶轮结构的响应谱特征，继而求得响应的均值、方差、各阶谱矩等，为求解叶轮的超越概率以及可靠度指标等打下了基础。

Application of Pseudo-Excitation Method in Random Vibration Analysis of Impellers

Impellers are loaded in the operation process under the action of various random aerodynamic forces. Time domain-based methods can be used in displacement and stress analyses with one-way coupling strategy. However, the entire multiple load steps for transient analysis are extremely time-consuming. In this paper, the pseudo-excitation method based on frequency domain analysis is adopted to solve the random response problems of the impeller under the action of aerodynamic load. The multi-dimensional, multiple point virtual excitation is applied to the impeller through harmonic response analysis provided by ANSYS and the ANSYS APDL commands to obtain the response spectrum characteristics of the impeller structure. The mean value, variance and orders of moment etc. of the response spectrum are then determined, which lays a foundation for solving the probability and reliability index of the impeller.