工形截面钢拱弹塑性稳定分析

Elasto-plastic stability analysis of steel arch with I section

通过直线梁单元以折代曲建立有限元分析模型,对工形截面钢拱结构进行弹塑性大位移分析。跟踪结构在荷载作用下的平衡路径全过程,得出结构在重力荷载、类雪荷载、半跨分布荷载作用下的破坏模态为失稳破坏,在风荷载作用下的破坏模态为强度破坏。研究结果表明:残余应力会降低结构的承载力,初始几何缺陷会改变结构的失稳模态,并降低稳定承载力;一般情况下,钢拱结构在全跨荷载作用下的稳定承载力高于半跨荷载,但当矢跨比大于0.4时,后者的稳定承载力高于前者;铰支及固支钢拱结构的优化矢跨比取值为0.2~0.3。

A finite element model of straight beam element instead of curved beam element was made to analyze the elasto-plastic large displacement of steel arch with I section. The entire process equilibrium path of the structure under load was tracked. The failure mode of the structure under dead load,snow load,half-span distributed load was unstable failure and under wind load was strength failure. It is concluded that residual stress will reduce the load bearing capacity and initial geometric imperfection will change the instability mode and reduce the stability load bearing capacity of the structure. Generally speaking,the stability load bearing capacity of the steel arch under full-span load is higher than that under half-span load,but lower when the ratio of height to span is bigger than 0. 4. The optimized ratio of height to span of steel arch with hinge support and clamped support is between 0. 2- 0. 3.