基于向量式有限元的大跨度钢结构施工力学分析方法

针对大跨度钢结构施工容易产生刚体位移等强烈非线性过程的特点,采用向量式有限元分析方法进行施工过程模拟.基于向量式有限元的基本理论,引入张拉索单元,通过控制张拉索单元的原长,实现大跨度预应力钢结构张拉全过程模拟;引入千斤顶单元,实现大跨度钢结构的脱架模拟.在此基础上,利用MATLAB语言编制了基于向量式有限元理论的施工过程分析程序,并通过悬臂梁拼装、索桁架张拉成形以及大跨度张弦桁架的张拉施工过程模拟分析,与传统分析方法进行比较,验证理论推导和自编程序的正确性与有效性.结果表明,采用基于向量式有限元的施工力学分析方法能够准确模拟结构拼装、预应力张拉成形和结构脱架等施工过程.

Construction Mechanics Analysis of Long-span Steel Structure Based on Vector Form Intrinsic Finite Element Method

Since the long-span steel structure is prone to perform nonlinearity such as yielding rigid body motion under construction loading, construction process analysis was conducted by the Vector Form Intrinsic Finite Element method (VFIFE). Based on the basic theory of the VFIFE, the tensioning cable element was introduced to simulate the tensioning process by adjusting the length of the cable element. In addition, the jack element was used for the unloading analysis of the long-span steel structure. Moreover, the VFIFE based program was developed by the MATLAB, and compared with the conventional method by means of three FE models such as the assembly of cantilever beam, the tension forming of cable truss, and the tensioning construction of long-span truss string structure. To this end, the VFIFE theory and program were verified and validated. The result showed that the assembly, tension forming, and unloading of the long-span steel structures could be reasonably simulated by the VFIFE.