底框架剪力墙砌体结构数值模拟分析

Numerical analysis of structure of frame and masonry composite structure

底框架剪力墙-上部砌体结构由于底部较柔,上部结构刚度较大,具有一定的耗能能力,在数值模拟时结构建模繁琐.通过对底框架剪力墙-上部砌体结构采用ANSYS有限元软件进行数值模拟分析,分别选用shell63单元和solid65单元模拟砌体结构,两种方法模拟的结构振型相似,自振频率的变化规律和墙体的厚度一致,即厚度小、频率高,厚度大,频率就小,结构受力和变形也和理论值一致;但solid65单元模拟的结构比shell63单元模拟的结构周期偏长,受力增大,塑性分析时,solid65单元不易收敛.通过比较发现,地震谱分析时,用shell63单元模拟能够得到理想的结果,方法简单.

The composite structure of shear-wall bottom and masonry frame is advantageous in energy dissipation with its flexible in the bottom and rigid in the upper body. However, it is difficult to simulate the structure due to the complex numerical algorithm. The ANSYS software was employed to analyze this composite structure. Shell63 element and solid65 element were adopted to model masonry structure respectively. It is found that two results have similar mode shapes; the natural frequencies are changed regularly with the thick of the wall, the frequency is high when the thickness of the wall is small, and it is low when the thickness is big; the stress and deformation of the structure is consistent with the theoretical results as well. The structure simulated with solid65 element has a higher vibration period and greater stress than that with shell63 element. But solid65 element is converged slowly by plastic analysis. By comparative analysis, it is found that shell63 element contributes better results and performs easily using the seismic response spectrum analysis.