空间抛物面状通讯天线振动模态浓缩现象分析

应用摄动理论分析了空间大型抛物面状通讯天线振动模态发生“浓缩”现象的机理．这类天线属于对质量缺陷很敏感的周期对称性结构，这种结构具有高密度（近频）模态，当近频模态发生联合使结构内部振动发生“浓缩”现象时，强烈的振动被“浓缩”到天线结构中某一小区域．研究结果表明，具有大量弱联子结构的天线当其肋架质量存在缺陷后容易激起模态“浓缩”现象．以８肋架天线为计算机模拟计算模型验证了分析结果的正确性．对影响天线结构模态“浓缩”现象的结构参数也作了分析讨论．

Analysis of vibratory mode confinement of space paraboloid communication antenna structure

The poisibility of confinement of vibratory modes in space paraboloid communication antennas was investigated by perturbation methods. These antennas belong to a class of cyclic symmetry structures that have been shown to be sensitive to mass disorder,and these structures have high modal densities (nearly equal frequencies). When the confinement phenomenon occurred, the modal amplitude of a global mode became confined to a local region of the structure. The results of the study indicated that mode confinement was most likely to occur in antennas consisting of a large number of weakly coupled substructures. The analytical and numerical results of the example of 8 rib antenna were compared in details and excellent argreement was found. Effects of the parameters on the mode confinement were also discussed in this paper.