摘要
针对新一代大型球面射电望远镜馈源舱索支撑结构存在扭转刚度低的问题,提出增加稳定索系以提高扭转刚度的方法。稳定索系由3根下拉索构成,每根稳定索的上端与馈源舱连接,下端通过导向滑轮与吊重相连。在馈源舱支撑结构因外部扰动发生振动时,稳定索系起到动力吸振作用,有效提高结构的刚度。考虑大跨度悬索自重对悬索形状和张力的影响,建立包含稳定索系在内的馈源舱索支撑结构的系统非线性平衡方程。给出在外部干扰作用下,改型前后结构位移响应的对比,并通过5m试验模型验证该方法的有效性。进而,绘制天线方向图,从增益、第一副瓣电平、交叉极化等方面,对增加稳定索系可能带来的对天线电性能的影响进行定量分析。理论分析与试验结果说明,增加稳定索系的支撑方案可以应用于500m天线工程。
Considering the drawback of weak twisting stiffness of the feed cable-suspended structure for the next generation large spherical radio telescope, a method is proposed to enhance the twisting stiffness of the structure through adding the stable cable system. The stable cable system consists of three tie-down cables. The upper end and the lower end of each stable cable are connected respectively with the feed cabin and a clog through a guiding pulley. While the cable-suspended structure vibrates under some extemal disturbance, the stable cable system acts as a dynamic absorber to enhance the stiffness of the structure effectively. Considering the effect of weight on the shapes and the tensions of the long span cables, the nonlinear equivalent equations of the feed cable-suspended structure including the stable cable system are established. A comparison of the structural displacement responses induced by the external disturbances between the original structure and the improved structure is made. Then, the effectiveness of the proposed method is demonstrated through the experiments of 5 m scaled model. Furthermore, the antenna pattern is drawn, and the quantitative analysis is made to evaluate the effect of the stable cable system on the electromagnetic performance of the antenna in view of the gain, cross polarization, and first minor level. Both the theoretical analysis and the experiments show that the feed cable-suspended structure with stable cable system can be applied to the 500 m antenna project.
出处
《机械工程学报》
EI
CAS
CSCD
北大核心
2009年第3期138-143,共6页
Journal of Mechanical Engineering
基金
国家自然科学基金资助项目(10433020
50475171)
关键词
超大型天线
馈源舱
索支撑结构
刚度
稳定索
模型试验
电磁性能
Super antenna Feed cabin Cable-suspended structure Stiffness Stable cable Model experimentElectromagnetic performance
