【作者】 黄莉榕；

【导师】 尹晓春；

【作者基本信息】 南京理工大学 ， 固体力学， 2010， 硕士

【摘要】 波导是传播无线电波的导体,雷达中的波导是在雷达中传播射频信号的一种高频馈线。馈线系统将大功率电磁波脉冲由发射机传输到天线,然后又把微弱的反射信号从天线传回到接收机,它是由波导及一系列高频器件、组件所形成的系统。因此,研究馈线系统的疲劳特性对雷达的使用性能和使用寿命具有重要意义。本文以某一型号雷达的馈线系统作为研究对象,在理论分析和实验研究的基础上,借助有限元技术,开展馈线系统疲劳特性分析,研究馈线系统是否满足疲劳要求。基于馈线系统所处环境的特殊性,对组成馈线系统的各种波导进行了静强度有限元分析校核,并且通过实验验证了静强度分析校核的正确性。同时,在数值仿真和实验过程中,指出了波导结构中易发生塑性变形的危险区域。针对数值计算结果表明的波导结构的部分易发生塑性变形的区域,对波导进行了结构优化分析,并且对比分析了优化模型在七种不同工况下的计算结果,研究发现,优化后的关键区域的应力减小了50%以上。然后,对优化后的馈线结构进行了瞬态动力学分析,并根据冲击试验条件,对冲击试验过程进行了仿真。最后,利用对优化后的馈线结构进行了谱分析。在谱分析的基础之上,利用基于高斯分布和Miner线性疲劳累积定律的三区间法,对馈线结构进行了随机振动疲劳分析,分析结果表明,优化后的馈线结构满足疲劳要求。本文所研究的对象虽然仅是针对一种型号雷达的馈线系统,但所形成的数值分析和实验方法可以移植到其它型号雷达的馈线系统的疲劳特性分析中,从而可对提高我国雷达馈线系统的整体性能起到积极的推动作用。更多还原

【Abstract】 Waveguide is the conductor of radio waves transmission. It is a kind of high-frequency feeder spreads the radio frequency signal in radar. The feeder system is consisted of waveguides and a series of high-frequency devices and other components. It transmits the high-power electromagnetic pulse from the transmitter to the antenna, and then spread the weak reflected signal from the antenna back to the receiver. Therefore, it is significant to study the fatigue property of the feeder system for the performance and the service life of radar.Based on theoretical and experimental analysis, the present paper develops an analysis of the fatigue property of a typical feeder system. The static strength is simulated for the various waveguides under their working conditions by means of finite element method. The static strength of numerical simulations is verified then by the experiments. The local area where plastic deformation occurred with high probability is also presented for the waveguides. To eliminate the plastic deformation area of the waveguide structures that the numerical results showed, the structure optimization of the waveguide is made. The comparison between the optimized modal and the previous modal under seven different loading conditions shows that the stress of the key parts gets a reduction over 50 percent.Then, the transient dynamic analysis of the optimized feeder structure is conducted by the numerical simulations under the impact test condition, and the spectral analysis of the optimized feeder structure is made. On the numerical results of the spectral analysis, the random vibration fatigue analysis of the feeder structure is obtained by means of the three interval method base on Gaussian distribution and Miner linear fatigue accumulation law. The results show that the optimized feeder structure meets the requirements of fatigue life.Although the object of our research is in only one type of the feeder system in radar, the numerical analysis and experimental methods also can be suitable for the other feeder system in almost any other type of radar. It can play an active role in promoting the improvement of the overall performance of the feeder system.更多还原