焊接残余应力对钢框架节点承载力影响研究

Research of Jonit Capacity of Stell Structure Affected By Residusal Stress Produced By Weld

为了研究焊接残余应力对钢框架承载力的影响,本文采用有限元分析模型,通过改变翼缘厚度和翼缘宽度提取不同分析模型的残余应力值,分析其变化规律,利用残余应力的平均值来分析残余应力对应力强度因子和对梁节点下翼缘拉应力的影响,通过比较得出结论:考虑残余应力后,I型裂纹尖端应力强度因子K_I增大,而且随着翼缘厚度和宽度的增加,残余应力对K_I的影响逐渐增大,但即使考虑残余应力,K_I也远小于平面应变断裂韧度K_(IC);考虑残余应力后梁翼缘拉应力都比不考虑残余应力时大,但随着翼缘厚度的增大,梁翼缘拉应力减小的幅度逐渐增大,而翼缘宽度增大后,梁翼缘拉应力反而有所增加,由此可见提高焊缝抗拉强度,增大梁翼缘厚度比加宽梁翼缘更有效。

In order to research the effect of residual stress produced by weld to the performance of joint of steel structure,the finite elment model is used. The residual stress value and distribution are obtained by changing the depth and width of flab. The average value of residual stress is used to estimate the influence of strength factor and tension stress of bottom flab of beam column joint. Comparing the results,it is concluded that： considering the residual stress,K_I（ stress intensity factor） will become bigger,along with the increase of width and depth of flab;the influence produced by residual stress on KIwill become bigger,but KIis more little than K_（IC） caculated from plane-strain; considering the residual stress,the tension stress is bigger than the stress that neglects residual stress,while the depth of flab increases,the tension stress of flab will reduce; so in order to increase the capacity of weld,to increase the depth of flab is an effective method than increasing the width of flab.