冷成型钢开口截面轴压构件的数值模拟与承载力研究

Finite Element Analysis of and Loading Capacity Study for Cold-formed Steel Open Section Axial Columns

采用有限元分析方法研究两端固支的冷成型钢开口截面轴压柱的力学性能。首先,基于已有的冷成型钢材性测试和短柱试验结果,建立有限元模型对冷成型钢试件进行模拟,并基于试验结果验证模型的准确性。用验证后的模型分析腹板高厚比、翼板宽厚比和翼缘加劲尺寸对冷成型钢开口截面轴压构件承载力的影响。最后,利用有限元分析结果评估直接强度法的适用性。可以发现:(1)构件平均应力值随着腹板高厚比的增加而减小;当构件长度大于1500 mm时,随着翼板宽厚比的增加而先增加后减小;随着翼缘加劲高度的增加而先增加后趋于不变。(2)直接强度法过高估计了构件承载力,需引入修正的直接强度法。

It uses the finite element analysis to study the mechanical properties of cold-formed steel that is open section axially compressed columns fixed at both ends.First,based on the existing material properties test of cold-formed steel sample,and the accuracy of the model is verified based on the test results.Then,it analyzes with the validated model the impact of the web height-to-thickness ratio,the flange width-to thickness ratio,the dimension of edge stiffener on the distortional buckling load-bearing capacity of cold-formed steel open section axial compression component.Finally,it evaluates the applicability of the direct strength method(DSM)with the finite element analysis results.It can be seen that:(1)the average stress value of the component decreases when web height-to-thickness ratio increases;and when the length of member more than 1500 mm,the value first increases then decreases with the increase of the flange width-to-thickness ratio;and the value first increases and then tend to be constant with the increase of the dimension of edge stiffener.(2)The DSM over-estimates the load-bearing capacity of the components than an optimized DSM needs to be introduced.