航空发动机外部管路的振动响应分析

Vibration Response Analysis of Aeroengine External Pipelines

针对航空发动机外部管路的动力学设计需求,采用基于试车实测数据的振动响应求解方法,对典型管路的振动响应特性进行了计算分析。研究结果表明:在风扇机匣位置的管路主要承受转子不平衡和风扇气动激励,表现为典型的简谐激励特征,可采用谐响应分析方法求解其振动响应。低阶振型对管路的动态特性起决定作用,振动能量输入导管结构后,响应输出方向可能发生变化。在燃烧室及尾喷口位置的管路主要承受来自于燃烧室火焰脉动和气动噪声激励,表现为典型的随机激励特征,可采用动力学谱密度方法求解其振动响应,得到功率谱密度响应曲线及具有一定置信度的位移分布和应力分布。

In order to satisfy dynamic design requirements of aeroengine external pipelines, the computational analysis of vibration response charactmistics of some typical pipelines were conducted based on vibration response solving method of real test data. The results show that the primary external loads for the pipelines installed on the fan casing and high pressure compressor casing are sorts of harmonic excitation ; the harmonic solving method is raised to obtain the dynamic response ; the dynamic property of the pipelines are defined by low level vibration mode;the direction of the response may be changed when the vibrational energy is imported to the structure of the pipelines. While the primary external loads for the pipelines installed on the combustion casing and outlet are sorts of random excitation. The power spectral analysis is used to predict the random dynamical response, to get the power spectral density response curve and the displacement and stress distribution with a certain degree of confidence.