飞机机载线槽结构对电磁防护性能的影响研究

Research on the influence of aircraft airborne trunking structure on electromagnetic protection performance

针对雷击环境下,飞机机载平台内的线束易受到连接设备及外部辐射源的复杂电磁干扰问题,考虑线槽不同结构对线槽防护性能的影响,基于三同轴法,结合Van Helvoort形状系数,推导出线槽转移阻抗从低频到高频状态下的理论表达式。进而建立含不同高宽比线槽防护仿真模型,研究不同形状、尺寸的线槽防护性能。最后建立复合材料机身内线槽的雷击电磁防护仿真模型,分析机身不同位置、不同形状线槽的防护作用,进一步验证了不同结构线槽防护性能的差异性。结果表明:高宽比每增加1/2,线槽屏蔽效能约增加5 dB,且有效保护区域逐渐扩大;随着与机身蒙皮间距增大,机身内部线缆感应电流线性减小;线槽密封性与防护性能成正比。

In response to the complex electromagnetic interference problem of connecting equipment and external radiation sources in the wiring harness of aircraft airborne platforms under lightning strike environment,considering the impact of different structures of the wiring duct on the protective performance of the wiring duct,based on the three axis method and combined with the Van Helvoort shape coefficient,a theoretical expression for the transfer impedance of the wiring duct from low frequency to high frequency state is derived.Furthermore,a simulation model for the protection of wire ducts with different aspect ratios is established to study the protection performance of wire ducts with different shapes and sizes.Finally,a lightning electromagnetic protection simulation model was established for the internal trunking of the composite material fuselage,analyzing the protective effects of different positions and shapes of trunking on the fuselage,and further verifying the differences in the protective performance of different structural trunking.The results show that for every 1/2 increase in aspect ratio,the shielding effectiveness of the trunking increases by about 5 dB,and the effective protection area gradually expands.As the distance between the body and the skin increases,the induced current of the cables inside the body decreases linearly.The sealing performance of the trunking is directly proportional to its protective performance.