单层空间网格结构抗连续倒塌的多尺度有限元模型分析

采用多尺度有限元模型对单层空间网格结构进行抗连续倒塌分析,综合了不同类型单元在有限元分析中的优点,有利于提高计算精度,合理确定不同类型单元之间的连接是确保其计算精度的关键.以两个单层空间网格结构的典型子结构拟静力试验结果作为校验,探讨了多尺度有限元模型在空间网格结构抗连续倒塌分析中的应用,提出了基于位移一致原则的不同尺度单元之间连接关系建立方法.以此为基础,完成了Kiewitt与Geodesic单层球面网壳的抗连续倒塌分析.研究结果表明:采用所提出的位移一致原则,连接界面与微观响应区域保持适当距离,可以得到结构计算的最优近似解;多尺度有限元模型在节约计算资源的基础上能够得到正确、合理的计算结果,采用刚性节点假定能够进一步减少模型的单元数量;多尺度有限元模型分析能够更为细致地显示局部应力分布,寻求网格结构失效的起始位置.此外,由多尺度有限元模型所建立的空心球节点,能较好地模拟结构的实际受力工况.

Multi-scale finite element analysis for anti-progressive collapse of single-layer spatial grid structures

The advantages of different types of elements are synthesized in the multi-scale finite element analysis, which can improve the calculation accuracy of the engineering structures. The connection between different types of elements is a key issue that determines the accuracy of the simulation. Based on the quasi-static test of two typical substructures of single-layer spatial grid structures, the multi-scale finite element analysis method was thoroughly discussed in anti-progressive collapse analysis of spatial grid structures. The connection with the principle displacement of identical displacement between different scale elements was established and verified through experiment. Then, this method was employed in the anti-collapse analysis of the Kiewitt and Geodesic domes. The study results show that the optimal approximate solution of the simulation can be obtained by using the principle of identical displacement, when the distance between the connection interface and the micro critical area is appropriate. The multi-scale model can obtain the correct and reasonable calculation results with reduced computational resources. The rigid body assumption for joints can further reduce the number of elements. The detail local stress distribution obtained through multi-scale numerical analysis can facilitate the analysis to identify the initial failure position. Additionally, due to the real modeled hollow spherical joints in the multi-scale model, the simulation is more close to the actual situation and results in more accurate structural response.