航空发动机燃油弯管结构参数对固有频率的影响规律研究

Study on the Influence of Structural Parameters of Fuel Bend Pipe on Natural Frequency of Aircraft Engine

摘要:

探明航空燃油弯管振动模态特性，需要对航空发动机燃油弯管结构参数对固有频率的影响规律进行研究。首先，通过模拟实验，对简单固支管路的模态进行分析；其次，采用力锤法进行试验，验证模拟数据的准确型；然后，对不同外部结构参数的燃油弯管进行有限元建模，并分析各阶模态振型和固有频率变化情况。最后，基于动力学原理，对固有频率随结构参数变化的原因进行解释。结果表明：弯管的第 1 阶振型为一弯变形，最大变形量为 96.63 mm，主要振动方向为 Z 方向；第 2 阶为二弯变形，最大变形量为 78.20 mm，主要振动方向为Y 方向。半径、跨度、弯曲半径是影响弯管管路固有频率主要的结构参数。

Abstract:

In order to investigate the vibration modal characteristics of aviation fuel bend pipes, This article studies the influence of structural parameters of fuel bend pipes on the natural frequency of aircraft engines. Firstly, the modal analysis of a simple fixed support pipeline was conducted through simulation experiments. Secondly, the force hammer method is used for testing to verify the accuracy of the simulated data. Next, finite element modeling was conducted on fuel bend pipes with different external assembly parameters, and the changes in modal shapes and natural frequencies of each order were analyzed. Finally, based on the principles of dynamics, the reasons for the variation of natural frequency with assembly parameters were explained. The research results indicate that the first mode of vibration of the bent pipe is a bending deformation, with a maximum deformation of 96.63 mm, and the main vibration direction is in the Z direction; The second stage is the second bending deformation, with a maximum deformation of 78.20 mm, and the main vibration direction is in the Y direction. Radius, span, and bending radius are the main structural parameters that affect the natural frequency of bent pipes. The natural frequency is positively correlated with the radius of the pipeline and the bending radius. As the radius and bending radius increase, the stiffness of the pipeline also increases; The natural frequency is negatively correlated with the span of the pipeline, as an increase in span leads to an increase in pipeline mass and a decrease in pipeline stiffness.