基于多尺度模型的单层网壳非线性屈曲分析

为同时模拟细观节点的局部变形和宏观结构的整体稳定性，通过对全梁一致单元模型的屈曲分析得出力学响应集中的重点区域，对该区域进行精细化建模，采用壳单元离散，宏观结构采用梁单元离散。建立了基于多点约束法的多尺度模型，并对多尺度模型及全梁单元模型进行了模态分析、考虑初始缺陷的双重非线性屈曲分析。对比结果可知：基于多点约束法的多尺度模型不会改变结构的频率、周期等固有特性，但因刚度分布的改变会导致振型变化；多尺度模型的稳定临界荷载相比一致单元模型有不同程度的降低。研究表明：多尺度模型能较为精准地模拟出细观节点的受力和变形，更贴近于实际工程的同时，在宏观层面的分析上也不失可信度。

Nonlinear buckling analysis of single-layer reticulated shell based on multi-scale model

In order to simulate the local deformation of the mesoscopic node and the overall stability of the macro structure at the same time, this paper obtains the key area of the mechanical response concentration through the buckling analysis of the whole beam uniform element model. The region is refined modeled, and the shell element is used to discrete the macro structure. A multi-scale model based on multi-point constraint method is established, and modal analysis and double nonlinear buckling analysis considering initial defects are carried out for the multi-scale model and the whole beam element model. The comparison results show. The multi-scale model based on multi-point constraint method does not change the inherent characteristics of the structure such as frequency and period, but the change of stiffness distribution will lead to the change of vibration mode. The stability critical load of the multi-scale model is reduced to varying degrees compared with that of the uniform element model. The results show that the multi-scale model can accurately simulate the stress and deformation of micro-joints, which is closer to the actual engineering and is reliable in the analysis of macro level.