机载天线阵面系统的随机振动响应与疲劳分析

Random Vibration Response and Fatigue Life Analysis of the Airborne Antenna Array System

基于随机振动频域理论和“3σ法则”,研究机载天线阵面系统在宽窄随机载荷谱作用下的约束模态和振动应力分布,进一步分析阵面系统的疲劳损伤和薄弱区域。研究结果表明:单一方向激励不仅能激起结构在该方向的部分模态,同时能够激起结构其他方向的模态。阵面系统中天线单元和框架、支撑板采用不同性能的铝合金材料,需要综合应力水平和材料参数,从疲劳角度评估结构强度。在随机载荷作用下,低应力水平的框架、支撑板疲劳损伤较大,天线阵面系统的寿命取决于框架与支撑板。

Based on random vibration frequency domain theory and“3σ”principle,this paper studies the constrained mode and vibration stress distribution of airborne antenna array system under wide and narrow random load spectrum.The fatigue damage and weak area of array system are further analyzed.The results show that single direction excitation can not only excite partial modes of the structure in this direction but also excite other modes of the structure.Aluminum alloy materials with different properties are used in antenna unit,frame and support plate of array system.The structural strength is evaluated from the perspective of fatigue by combining stress level and material parameters.Under random load,the fatigue damage of the frame and support plate is large at low stress level,and the frame and support plate determines the life of antenna array system.