基于分段纤维模型的网壳结构极限承载力分析

针对采用有限元通用梁单元模拟杆件无法准确计算网壳结构塑性变形的发展情况,提出采用分段纤维模型模拟结构杆件以准确计算网壳结构的极限承载力。通过参数化分析,同时考虑计算效率与精度,确定了截面纤维与杆件积分段的合理划分数量。分别采用分段纤维模型与有限元软件通用梁单元模拟杆件计算网壳结构的极限承载力。计算结果表明,采用分段纤维模型可计算塑性变形的分布位置与发展程度,且可模拟杆件失稳,采用有限元软件通用梁单元建立计算模型将高估网壳结构的极限承载力。

ULTIMATE BEARING CAPACITY ANALYSIS OF LATTICEDSHELL STRUCTURE BASED ON SUBSECTION FIBER MODEL

Development of plastic deformation of latticed shells cannot be calculated accurately if members of the structure are simulated by general beam element of finite element program.Subsection fiber model is proposed to simulate the structural members to obtain an accurate ultimate bearing capacity of the latticed shell.Considering both of the efficiency and accuracy,the appropriate division numbers of section fibers and integration segments of the member are determined by parameter analysis method.Both the subsection fiber model and the general beam element of finite element program are used to calculate the ultimate bearing capacity of the structure.Numerical results indicate that the distribution and development of the plastic deformation of the structural members can be calculated accurately when the structural members are simulated by subsection fiber model.The ultimate bearing capacity of the structure will be overestimated if the structural members are simulated by general beam element of finite element program.