星载索网反射面天线的预张力设计

星载索网反射面天线是由张拉索、膜以及支撑梁单元构成的组合结构,具有高度几何非线性,天线内部索、膜单元的张力不易控制.针对索、膜-桁架反射面天线结构中,索、膜张力确定的非线性问题,文中提出了一种张力设计的2步法:第1步,仅考虑索、膜结构,根据各向同性应力假设,推导了膜结构的平衡矩阵和平衡方程,在此基础上,建立以索、膜张力为设计变量,以索、膜张力均匀性为目标的优化模型,为避免索松弛和膜褶皱,引入相应张力约束;第2步,考虑梁结构的弹性变形对索膜张力和天线均方根误差的影响,采用逆迭代法对索膜张力予以修正.某6m天线的算例表明,该方法可在一定程度上有效控制索膜张力的分布,快速得到一组平衡的索膜预张力.

Pretension Design for Cable-truss Spaceborne Reflector Antenna

Cable-truss spaceborne reflector antenna is a typical cable-membrane-beam structure which has the characteristic of highly nonlinear. There is a certain difficulty to determine the internal tensile force. This paper presents a two-step force-finding method for cable-membrane-beam antenna structures. In the first step, only the cable network and reflector membrane are considered. The equilibrium matrix of membrane is deduced by using isotropic stress assumption. On this basis, an optimization model, in which the pretensions of cable and membrane is treated as design variables, the mean square of cable and membrane pretensions as the objective is established to seek the initial equilibrium state. To avoid the appearance of slack cables and/or compressive areas on the membrane as well, constraints of cable and membrane pretensions are introduced. In the second step, an inverse iteration method is adopted to compensate the affection of the beam deformations on the tensions obtained in the first step. The pretension design results of a 6 m antenna structure show that the proposed method can effectively control the pretension distribution and rapidly obtain a set of equilibrium tensions.