摘要
FAST望远镜的AB转轴机构相当于具有两个水平正交轴的万向节,用于调整馈源舱内设备的指向角。其外环(A环)曲梁跨度大,承载重,且要求轻质和高刚度。基于弯扭耦合的曲梁理论建立了A环结构的基本微分方程,给出了结构变形挠度与结构参数之间的关系。以结构总重量作为结构优化总目标,以不同倾角下曲梁跨中最大扰度及最大扰度差作为主要约束条件,应用信赖域法对实腹式箱梁和桁架式梁两种结构方案进行了优化计算,并对两种结构方案进行了比较。初步的优化结果表明桁架式梁结构方案具有更轻的结构重量。
The AB positioner of FAST telescope functions as a gimbal with two horizontal orthogonal rotation axes to tune the pointing angle of equipment in a focus cabin. Its outer ring （Ring A） is a large-span curve beam, demanded light weight and high stiffness under heavy loads. Based on the coupled bending and torsion theory of a curve beam, the differential equations are deduced to find analytical solutions directly, which link beam deflections with structural parameters. The objective function is built to minimize the total structural weight under the main restrains of the maximal deflection on the mid-span and the maximal deflection difference caused by the different rotation angles. The trust-region algorithm is successfully employed to search the global function minimum. Two structural concepts, namely a thin-wall box girder and a truss girder, are applied respectively and compared in the optimization. The preliminary computation shows the truss girder concept has lighter optimal structural weight.
出处
《工程力学》
EI
CSCD
北大核心
2013年第9期95-102,共8页
Engineering Mechanics
基金
国家自然科学基金项目(10973023)
关键词
FAST望远镜
曲梁
结构优化
信赖域法
桁架式梁
FAST telescope
curve beam
structural optimization
trust-region algorithm
truss girder
