国产Q460高强度钢材焊接工字形截面残余应力试验及分布模型研究

焊接残余应力是影响钢结构受压构件整体稳定性能的一种重要初始缺陷. 为研究国产Q460高强度钢材焊接工字形截面的残余应力分布, 该文采用分割法对8个不同截面尺寸和焊缝类型的截面试件进行了测量. 基于近2000组测量数据, 得到了不同试件全截面的残余应力分布和拉、压应力大小, 并研究了腹板和翼缘的板件宽厚比、板件厚度、焊缝类型以及腹板和翼缘的相关性等因素对残余应力的影响. 试验结果表明, 残余压应力的数值大小与截面尺寸直接相关而基本不受焊缝类型的影响, 残余拉应力的大小则与截面尺寸没有相关性；由于翼缘和腹板内的残余应力能够分别满足自平衡条件, 二者没有相互间的影响作用. 最后, 该文提出了能够准确描述试验结果和截面尺寸影响的国产Q460高强钢焊接工字形截面的残余应力分布模型和计算公式.

EXPERIMENTAL INVESTIGATION AND MODELING OF RESIDUAL STRESS IN I SECTIONS WELDED BY Q460HIGH STRENGTH STEEL

Residual stress is one of the most important initial imperfections for the overall buckling behavior of steel compression members. An experimental investigation was carried out to quantify the residual stress in I sections welded by Q460 high strength steel , using a sectioning method. 8 section specimens with various dimensions and weld types were measured, and the magnitude and distribution of both compressive and tensile residual stresses were obtained through nearly 2000 original data. Based on the experimental results, the effects from sectional dimensions (i.e. width-thickness ratio and plate thickness), the weld type and the interaction between flanges and web were clarified. It was found that the compressive residual stress was significantly related to sectional dimension, but no clear correlation was indicated with the weld size. The tensile residual stress hardly correlated to the sectional dimension. No residual stress interaction between flanges and web was found due to the stress equilibrium within each individual plate. Besides, a distribution model was proposed, which well described the experimental results and effects from sectional dimensions.