不同储料工况粮仓动力特性及相互作用分析

Dynamic Property and Interaction Analysis of the Granary Considering Loading Conditions

为研究不同储料工况下立筒群仓的动力特性及各单仓个体之间的动力相互作用,以河南省郑州市某工程用粮食群仓为研究对象,进行了空仓和满仓2种储料工况下的结构模态分析。该粮仓尺寸较大,由3行5列共15个单仓个体组成,平面外轮廓24.0 m×40.0 m,总高34.5 m。为获得较全面的分析结果,对粮仓前7阶自振频率和振型进行了分析研究,结果表明:空仓工况频率值大于满仓工况频率值,空仓是满仓的几乎2倍,说明粮食散粒体对粮仓所提供的质量效应远远大于其提供的刚度效应。粮仓前3阶振型为结构整体变形,而且受储料的影响不明显,各单仓个体的动力反应大小基本相同,可以忽略单仓个体之间的动力相互作用;粮仓后4阶振型为结构局部变形,满仓工况较空仓工况结构振型的平面形状和立面形状更复杂,各单仓个体因所处位置不同受约束程度不同所以动力反应大小不同,而且参与动力相互作用的单仓个体数目也较空仓工况多,说明储料的存在对4阶及以上振型影响显著。

In order to study dynamic property and interactions among the individuals of group silos,the grain warehouse of a project in Zheng- zhou,Henan province was taken as the object of study,and modal analysis was carried out by FEM method. The granary had 15 individuals with 3 rows and 5 columns ,so it was large with 24.0 meters wide ,40.0 meters long and 34.5 meters high. For obtaining good and comprehensive results, the first seven modes （frequencies and mode shapes） were analyzed. The results showed that：Frequencies of empty silos were bigger than full silos, and there was almost 1 times difference. It was stated that material mass had bigger effect on structural frequencies than its stiffness. The first three mode shapes were mainly the overall deformation, and the dynamic responses were almost the same for each individual, evidently, they were little influenced by materials ,and the dynamic interactions could be ignored. Later four mode shapes were mainly the individual local deformation, and they were more complex for full silos than empty silos. Further,the dynamic response for each individual was different due to its location. In addition,interactional individuals were more for full silos than empty silos. It was illustrated from the above that the fourth mode shapes and above were largely influenced by materials.