机载甚低频拖曳天线非线性振动分析

The analysis of vibration of trailing antenna on an aircraft

拖曳天线力学特征和控制是对飞机对潜通信系统进一步深入论证需要解决的关键问题之一,其中振动分析是其动力学特征研究的一个重要部分。本文通过对其运动状态及其受力进行分析,建立了机载甚低频拖曳天线动力学模型。针对模型复杂的非线性和耦合性,在考虑机载甚低频拖曳天线旋转平衡时构型的基础上,采用Galerkin法研究求解了甚低频天线末端锥袋的非线性振动。研究表明:在一阶模态截断下,利用多尺度摄动方法,当ω1:ω2:ω3近似等于2:2:1、1:1:2、1:1:1时,机载甚低频拖曳天线发生内共振;在特定的飞行状态下,其水平面面内的两个振动会发生内共振,而垂直方向则不会,因此不会对机载甚低频拖曳天线的垂直度产生显著的影响。

The dynamic character and control of trailing antenna on an aircraft is one of most important problems which need to be investigated,and the analysis of the vibration of the trailing antenna is the important part.The mathematics model of the trailing antenna is established.For the complicated nonlinear and strongly coupled dynamic model,the dynamic model is discretized to obtain numerical solution by Galenkin method based on the steady state of the trailing antenna on an aircraft.Results obtained reveal that resonance conditions are ω1 :ω2 :ω3≈2:2:1,ω1 :ω2 :ω3≈1:1:2 and ω1 :ω2 :ω3≈1:1:1.Above results indicate that the vibrations of the horizontal plane are in internal resonance and the perpendicular one which the swing of is small is not in internal resonance.So the influence of vibration to the verticality is little.