循环荷载下钢压弯构件的长细比限值

Limit slenderness ratios of steel beam-columns under cyclic load

根据能量等效性假设、热力学第二定律,推出损伤材料的弹性本构方程;采用混合强化准则,考虑Bauschinger效应、屈服平台、硬化(软化)效应及损伤和损伤演化影响,建立了结构钢弹塑性各向异性损伤本构关系。结合构建的本构关系,采用八节点超参数壳体单元,推导了用U.L.格式及Cauchy应力描述的板壳双重非线性有限元方程,并编制了计算程序。利用U.L.格式的壳体大挠度双重非线性有限元分析方法,分析长细比、轴压比对工形截面钢压弯构件滞回性能的影响,提出不需考虑整体稳定的最大长细比建议相关公式、压弯构件长细比限值建议公式。

The elastic anisotropic damage model was put forward based on the hypothesis of energy equivalent and the second law of the thermodynamics. The elastoplastic anisotropic damage model of the constructional steel was also advanced, which includes the mixed hardening criterion, Bauschinger effect, yield plateau, hardening(softening) influence, damage and damage evolution. Based on the constitutive model of the constructional steel and the 8node degenerate shell element, the Updated Lagrange(U.L.) formulations for FEM analysis were derived. After developing and debugging program, the method of double nonlinear shell FEM was adopted to analyze the Isection steel beamcolumns under the action of cyclic loads. The interaction formulas of maximum slenderness ratios without considering the overall buckling and limit slenderness ratios of the Isection steel beamcolumns under the action of cyclic loads were established.