FAST圈梁支承结构性能理论与实验研究

PERFORMANCE RESEARCH OF FAST RING BEAM BY THEORETICAL AND EXPERIMENTAL

圈梁结构是500 m口径球面射电望远镜(FAST)反射面的主支承结构。承载反射面单元的柔性索网通过150个牵索耳板与圈梁结构相连。建设和观测过程中,基于结构可靠性考虑以及反射面精度要求,主支承结构的刚度必须得到保证。研究发现,如此巨大尺度的结构,温度荷载对圈梁结构的刚度起控制作用。通过科学合理地温度应力释放、结构刚度调整,以及采用预留变形空间的方法,利用有限元模拟并进行实验验证,研究基准面时圈梁刚性变形,为观测时变位抛物面提供输入调整依据。

The ring beam is the main supporting structure of the Five-hundred-meter Aperture Spherical radio Telescope（FAST） reflector. The flexible cable net structure bearing reflector units are connected with a ring beam structure by 150 ear-plate joints. During construction and observation, we tried to ensure the stiffness of the main support structure by the base of the theory of structural reliability and the requirement of reflector accuracy. Since the temperature load plays a controlling role for such a large-scale structure, we used the finite element simulation software and tested reflector precision to find the rules of structure stiffness, by releasing temperature stress, adjusting the stiffness of the structure and reserving deformation space, and then made the parameters to be a real time parabolic so as to adjust the deformation observation.