薄壁圆管截面空间梁系塑性及弹塑性矩阵

目前应用广泛的空间网壳结构，大多数均由高频焊接薄壁圆钢管作为基本结构单元，为了精确对该类结构进行弹塑性分析，必须获得材料的弹塑性本构关系。通过推导理想弹塑性材料，任意应力状态的塑性矩阵和弹塑性矩阵，并结合薄壁圆管截面空间梁系中微梁元的特殊应力状态，得出该类结构进入塑性状态后的本构关系。为空间网壳结构的弹塑性地震响应及抗震性能分析研究奠定了坚实基础。

Plastic matrix and elastic-plastic matrix of space beams with thin-wall tube section

The space shells now in wide use are mostly made up of high-frequency welded thin-wall tubes. In order to accurately analyze the space shell, we have to get the correct stress-strain relation(constitutive model) of the thinwall tube. This paper has derived the plastic matrix and elastic-plastic matrix of ideal elastic-plastic materials. With the special stress state of micro-beam units in space shells with the thin-wall tube section, taken into consideration the elastic-plastic stress-strain relation (constitutive model) of the space beams with the thin-wall tube section is eventually established successfully. Also, this stress-stain relation(constitutive model) is the necessary basic theory for researches on elastic-plastic dynamic response and characteristics of space shells.