钢-混凝土简支组合梁的非线性有限元分析

Non-linear finite element analysis of steel-concrete simply supported composite beams

钢-混凝土组合梁能够充分发挥钢梁的抗拉强度和混凝土的抗压性能,是一种性能优越的组合结构。根据组合梁的特点,选取适合的单元类型及本构关系,探讨其网格划分和加载方式,建立了一套适用于组合梁的有限元建模方法。模拟已有试验,对比分析荷载-挠度曲线,两者计算结果吻合良好,验证了所建有限元模型是可靠的。然后利用有限元模型对组合梁的滑移特点进行了分析,得出了一些有益的结论:极限状态下,最大滑移并不在梁端,而在距梁端约200 mm的位置,说明这个部位分配的剪力最大,并且抗剪连接度越高,这种情况越明显;抗剪连接度较低时,组合梁混凝土强度等级对滑移影响不大,抗剪连接度较高时,相同荷载作用下,组合梁混凝土强度等级越高,界面产生的滑移越大。可以根据组合梁的这些特点,合理布置抗剪栓钉,减小界面滑移,提高组合梁的承载力。

Composite steel-concrete beams can bring full play to the tensile strength of steel beams and the compressive properties of concrete,which is a combination structure with superior performance.By selecting suitable unit type,consti.tutive relation based on the characteristics of composite beams,we chose proper grid division and loading method,and a set of finite element modeling methods suitable for composite beams were established.The simulation results show that the calculation results are in good agreement with the load-deflection curve,which verifies that the proposed finite ele.ment model is reliable.Then the sliding characteristics of the composite beams are analyzed by using the finite element model.Beneficial conclusions are that the maximum slippage is not in the beam end,but in the position of about 200 mm from the beam end in the limit state,which indicates that the shear strength of this part is the largest,and the higher the shear connectivity,the more obvious this situation is.When the shear connection is low,the strength grade of composite beams has little effect on slip.When the shear connection is high,the higher the strength grade of the composite beam un.der the same load,the greater the slip of the interface.According to these characteristics of the composite beam,arrang.ing the shear bolt reasonably can reduce the slip of the interface and improve the bearing capacity of the composite beam.