卷边槽形截面冷弯厚壁型钢冷弯效应

Experimental Study on Coldforming Effect of Coldformed Thickwalled Steel with Lipped Channel Sections

摘要:

为研究开口冷弯厚壁型钢中冷弯效应对截面屈服强度的影响，进行了材性拉伸和短柱轴压试验.首先，选取了5根壁厚分别为3，8，12和16 mm、屈服强度分别为Q235和Q345的冷弯卷边槽钢，对其截面中的腹板、翼缘、卷边、弯角部位分别取样进行材性拉伸试验，在此基础上提出了冷弯厚壁卷边槽钢截面屈服强度分布模型.然后，选取了与材性试验相同规格的5根短柱进行轴心受压试验，以进一步研究全截面屈服强度的提高情况.最后，将短柱试验结果与屈服强度分布模型、主要国外相关规范公式的计算结果分别进行了对比.结果发现，冷弯强化效应对冷弯厚壁型钢的屈服强度影响较大，其影响程度主要取决于板件宽厚比；屈服强度分布模型、各国规范公式计算结果与试验值接近，但均略偏于不安全，其中我国规范GB 50018—2002计算的值最接近试验值，且离散系数小，适用性最好.

Abstract:

In order to investigate the coldforming effect on yield strength distribution of coldformed thickwalled steel with open section, coupon test and axial compression test were carried out. Firstly, 5 types of coldformed lipped channel sections with thickness of 3, 8, 12 and 16mm, and two yield strength grades of Q235, Q345 were chosen to conduct coupon test for the web, flange, curling, corner parts, respectively, and a corresponding distribution model for the yield strength distribution of coldformed thickwalled steel with lipped channel section was put forward. Then, the axial compression tests of 5 stub columns with the same section as the coupon test were carried out for further investigation on the coldforming effect. Finally, the results of stub column test, the results based on the proposed yield strength distribution model, and the results based on the related codes in various countries were compared. It is shown that, the yield strength distribution of coldformed thickwalled steel with open section is greatly influenced by the coldforming effect, and mainly depends on the width to thickness ratio of the plate involved; the estimation based on the proposed yield strength distribution model is close to that based on of the codes in various countries, as well as the test results, although the latest is slightly larger. Moreover, among them, the results based on the Chinese code, GB 50018—2002, is closest to the experimental values with smallest variation coefficient, which means a best applicability.