发动机管路系统传递特性分析方法

Analysis Method of Transmission Characteristics of Engine Pipeline System

为克服发动机试车时管路系统无测点、无法评价振动响应的缺陷,提出了基于传递率函数和功率谱密度传递率的测试信号进行传递特性分析、预估发动机管路系统上任意未知测点的响应特性的方法。以某型发动机管路振动分析为例,首先,获取发动机管路系统结构动力特性的精确描述。通过模态试验的测试数据,对管路结构的有限元模型进行模型修正,进而得到有限元对结构动力学特性的精确仿真;然后,实现从发动机机匣到管路的振动传递。基于热试车试验,通过传递率函数分析机匣上测点振动响应之间的关系,建立机匣到管路的振动传递描述;最后,实现管路任意位置的响应预估。通过机匣上测点到管路任意点的功率谱密度传递率与试车稳态时测点的功率谱密度分析,预估管路任意位置的响应。此外,利用了两条不同的传递路径分析,得到了相近的预估结果,验证了本方法的有效性。

In order to overcome the defects that the pipeline system has no measurement points and cannot evaluate the vibration response during the engine test run,a test signal based on the transfer rate function and the power spectral density transfer rate is proposed to analyze the transfer characteristics and predict any unknown measurement points on the engine pipeline system.The method of response characteristics.Taking a certain type of engine pipeline vibration analysis as an example,firstly,obtain an accurate description of the dynamic characteristics of the engine pipeline system structure.Through the test data of the modal test,the finite element model of the pipeline structure is modified to obtain an accurate simulation of the dynamic characteristics of the structure by the finite element;then,the vibration transmission from the engine casing to the pipeline is realized.Based on the hot commissioning test,the relationship between the vibration responses of the measuring points on the casing is analyzed through the transfer rate function,and the description of the vibration transmission from the casing to the pipeline is established.Finally,the response prediction of any position of the pipeline is realized.Through the analysis of the power spectral density transfer rate from the measuring point on the casing to any point of the pipeline and the power spectral density of the measuring point in the steady state of the test run,the response at any position of the pipeline is estimated.In addition,two different transmission path analyses were used,and similar estimated results were obtained,which verified the effectiveness of this method.