冷弯厚壁型钢轴压构件设计可靠度分析

Design reliability analysis of cold-formed thick-walled steel members under axial compression

在材性试验的基础上对冷弯厚壁型钢进行了轴压承载力试验及有限元分析。试验中发现:对于长细比较大、板件宽厚比较小的试件,破坏模式为整体失稳;对于长细比较小、板件宽厚比较大的方管柱,其破坏过程首先是柱中部产生很小的弯曲变形,随着荷载增大,整体弯曲变形也逐渐增大,并引起方管板件的局部屈曲。采用ANSYS软件进行有限元分析,其结果与试验结果接近,表明将残余应力引入有限元模型对冷弯厚壁型钢构件进行分析具有较高的精度。在此基础上,利用收集到的26组不同牌号、不同截面冷弯厚壁型钢的试验数据建立有限元模型,并引入已有的残余应力模型进行了大量的有限元分析,得到了多组冷弯厚壁型钢轴心受力构件的承载力。对冷弯厚壁型钢构件进行了设计可靠度分析,提出了Q235、Q345冷弯厚壁型钢的抗力分项系数和强度设计值的建议值,可为相关技术标准的修编提供依据。

Axial compression tests and corresponding finite element analysis were conducted on the basis of material property tests. It was shown that the failure mode of long column with a low width-thickness ratio is global instability,while the failure mode of short column with a high width-thickness ratio is that small bending deformation appeared firstly at the center of the columm,then the deformation developed with the gradually increasing load and caused local buckling in the end. The results of finite element analysis can fit well with the test results,which means the feasibility and accuracy can be achieved by using this residual stress model into finite element analysis to simulate the axial compression behavior of cold-formed thick-walled steel members. Then,the finite element model was used based on the collected 26 groups of material properties of different tubes with representative size and thickness to get the axial bearing capacity data of members,and design reliability analysis of cold-formed thick-walled steel members under axial compression was conducted. Finally,the resistance partial factor and the design strength for Q235 and Q345 coldformed thick-walled steel were proposed for the reference in current revising of related design codes.