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为研究单层网壳结构的失效机理,以3个单层球壳缩尺模型为例,通过对节点构形度进行分析研究提出,节点构形度的对数标准差ST(lg(q))可作为衡量单层球壳结构整体刚度均匀性的判定参数。通过与试验结果对比可知,节点构形度的对数标准差ST(lg(q))与结构的倒塌破坏特征及极限状态时输入的峰值加速度密切相关。对跨度为40 m,矢跨比分别为1/3、1/5、1/7的4种杆件截面的凯威特K6型单层球壳结构进行了参数分析(包括节点构形度分析、静力稳定分析和地震作用下的动力时程分析)。研究结果表明,K6型单层球壳结构在杆件质量相近的条件下,节点构形度的对数标准差ST(lg(q))越小,结构的稳定承载力和极限状态时输入的峰值加速度越高,且地震作用下结构的延性越好,强度破坏特征越明显。通过统计分析建立了适用于跨度为40 m的K6型单层球壳结构刚度均匀性判定准则,即当节点构形度的对数标准差ST(lg(q))不大于0.4时,结构整体刚度均匀,相应的结构稳定承载能力和极限状态时输入的APG相对较高,且地震作用下的延性较大。
In order to study the failure mechanism of single-layer reticulated shell structure, taking 3 single-layer spherical shell shell scale model as an example, by analyzing and researching the node shape, the logarithmic standard deviation ST (lg (q) ) Can be used as a parameter to judge the overall stiffness uniformity of single-layer spherical shell structure. Compared with the experimental results, we can see that the logarithmic standard deviation ST (lg (q)) of the node shape is closely related to the collapse characteristics of the structure and the peak acceleration input in the limit state. The parameters of the Kweit K6 single-layer spherical shell with four kinds of cross-sections of 40 m span and span ratio of 1/3, 1/5 and 1/7 were analyzed (including the analysis of the node configuration , Static stability analysis and dynamic time history analysis under earthquake action). The results show that the smaller the logarithmic standard deviation ST (lg (q)) is, the lower the stability of bearing capacity and the limit state of K6 single-layer spherical shell are. The higher the peak acceleration, the better the ductility of the structure under earthquake and the more obvious the damage characteristics. Through the statistical analysis, the criteria for determining the stiffness uniformity of single-layer spherical shell K6 which is suitable for a span of 40 m are established. That is, when the logarithmic standard deviation ST (lg (q)) of the node configuration is not more than 0.4, The stiffness is uniform, the APG input is relatively high and the ductility is large under the earthquake.