空间钢框架结构的二阶渐进弹塑性分析

给出了空间钢框架结构几何非线性有限元列式，可以直接考虑单元的轴向扭转屈曲效应；在此基础上采用塑性流动理论并应用Orbison屈服面方程，得到了空间钢框架塑性铰分析的弹塑性刚度矩阵，用以对空间钢框架结构进行二阶弹塑性分析并可以考虑单元内塑性的发展和内力的重分布；在单元内部采用截面内力跟踪技术以考虑单元内部形成塑性铰的情况．给出的几个算例，说明该方法计算效率高，精度可靠，可以用于大型空间钢框架结构的高等结构分析。

Second-order analysis for space-framed structures with a gradually elastic-plastic numeric model

Based on the flow theory and Orbisons yield surface, an efficient model of gradual plastic-hinge for space-framed structure analysis is presented in the light of lumped plastic assumption and the corresponding elastio-plastic stiffness matrix is derived. The model can accurately depict the effects of inner gradual plastic-hinge and the internal forces redistribution. The elastic and inelastic analysis can be implemented by using the same model with the condensa- tion technique to eliminate the internal freedoms. Theoretically, the model is accurate and shows its advantage in structural advanced analysis. Its validity is verified by several numerical examples.