上海65m射电望远镜地震响应分析

Analysis of seismic response to Shanghai 65 m radio telescope

为掌握上海65 m射电望远镜结构抗震性能,首先依据其建设场地条件,在Ⅶ度抗震设防烈度下,运用时程分析法对初步设计方案中天线结构的安全性能进行分析;随后分别给出结构在多遇地震、多遇地震与静力组合以及罕遇地震作用下的关键力学响应指标.结果表明:在多遇地震与静力组合工况下,发现了结构的薄弱环节——背架以及俯仰结构有若干杆件进入塑性;在罕遇地震作用下,3条地震动中人工合成地震动对结构影响最大,并且在3条地震动作用下,结构均未发生失稳倒塌.后对初步设计方案进行了局部改进,选取最不利工况模型(俯仰角为5°的计算模型)进行Ⅷ度抗震设防烈度下的多遇地震响应分析,结果表明所有杆件应力均满足设计要求.

To master the aseismic ability of Shanghai 65m radio telescope structure,according to the information of site conditions,the safety properties of antenna structure in the initial design was analyzed under activities of frequent and rare earthquake by using time-history method when aseismic fortification intensity is Ⅶ.Subsequently mechanical responsive targets which are crucial to the structure under activities of frequent earthquake,frequent earthquake combined with static unitized load mode and infrequent earthquake were given.The results show that the weaknesses of the structure（plastic deform appears in some bars） are found under activities of frequent earthquake combined with static unitized load mode.Under activities of infrequent earthquake,artificial ground motion produces the most intensive effect on the structure.To every kind of different pitching angle model the antenna structure does not break down under the activities of 3 kinds of infrequent earthquake.After some modifications to the initial design,and choosing the most disadvantageous model（its pitching angle is 5°）,the analysis results under activities of frequent earthquake show that all targets of all bars meet the corresponding requirements of specifications when aseismic fortification intensity is Ⅷ.