斗栱梁单元模型数值分析——以山西应县木塔为例

Simulation analysis based on Dougong beam element model:A case analysis of Yingxian's Wood Tower in Shanxi

将现代数值模拟技术运用于古建筑研究,构建合理的有限元模型并对斗栱的力学性能进行分析研究,是古建筑保护的一项基本工作。文章以山西应县木塔斗栱构件为实例,运用ANSYS有限元软件构建了能够真实反映斗栱构造特征及结构性能的梁单元有限元模型,对梁单元模型在竖向荷载及水平低周反复荷载作用下的实验过程进行模拟,对比分析了其力学性能、耗能及模拟分析效率。结果表明:梁单元模型可有效地表达斗栱的力学性能,模拟竖向力加载时相应的压缩变形量为11.60 mm,模拟水平低周反复荷载加载时,随着侧向位移的增加模型由弹性状态转变为弹塑性状态,随着竖向荷载的增加需要施加的水平推力增大,与实验结果吻合;梁单元模型可有效地表达斗栱的实际耗散特性,其耗能值与实验结果基本吻合;梁单元模型可提高分析效率,计算分析耗时由7 h减少为30 min。

Applying the modern numerical simulation technology into the study of ancient buildings, and constructing the reasonable FE model to analyze mechanical property of Dou-Gong has become the basic work for the protection of ancient buildings. This research proposed the FE model base beam element to truthfully reflect structural characteristics and properties of Dougong in Yingxian＇s Wood Tower in Shanxi, simulates the experimentation process of the beam element model under the action of vertical loading and horizontal low-cyclic reversed loading, and comparatively analyzes the mechanical properties, energy consumption and simulation analysis efficiency. The models have the following features： The beam element model can express the mechanical property of Dougong effectively, and the amount of compression deformation corresponding to simulating vertical loading is 11.6mm. When simulating cyclic reverse loading, the model translates elastic state into elastic-plastic state with the increase of the lateral displacement, and the horizontal thrust increases with the increase of vertical load, which is in agreement with the result of experiment. The beam element model can express the actual dispersion features of Dougong effectively, whose energy dissipation is basically identical with the experimental result and it can also improve analysis efficiency, and the time of calculation and analysis is reduced from 7 hours to 30 minutes.