小截面焊接工字钢残余应力分布试验研究

Experimental study on residual stresses distribution on small welded I-shaped section

为研究小截面焊接工字钢残余应力分布规律,采用分割法,对某经振动台试验后的拉链柱式中心支撑钢框架结构中18个焊接工字形小截面试件的残余应力进行了测量。基于测量数据,得到了残余应力分布和拉、压残余应力的大小,研究了板件宽厚比对残余应力的影响。结果表明,较小截面试件的残余应力与翼缘、腹板宽厚比之间并无明显规律。建议翼缘端部和腹板的中部残余压应力值取0.5f_y(f_y为钢材屈服强度),翼缘中部和腹板端部残余拉应力值取0.8 f_y。基于此,提出了小截面焊接工字钢残余应力分布的简化计算模型,并将模型计算值与试验值进行了对比,绝大部分的实测残余应力值均在简化计算模型计算值的包络范围内。

In order to investigate the residual stresses of small welded I-shaped sections,an experimental program including eighteen sections,which were cut from a zipper frame after the shaking table test,was conducted by using the sectioning method. Based on the test data,the residual stress distribution and the magnitudes of these specimens were obtained,and the effect of the width-to-thickness ratio on the residual stress was studied. The results show that the residual stresses are not directly related to the width-to-thickness ratio. It is suggested that the value of the compressive residual stresses are 0. 5 f_y( f_yis yield strength of steel) for the end of flange and the middle of web,and the tensile residual stresses are 0. 8 f_yfor the middle of flange and the end of web. Based on these results,the residual stress distribution model for small welded I-shaped sections was established and compared with the test results. The comparison result shows that most of the test residual stresses fall within the envelope of the residual stress distribution model.