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1、单轴对称焊接工字梁残余应力研究摘要：焊接残余应力是影响梁整体稳定的重要因素，在梁整体稳定设计中应该考虑残余应力对梁的影响。我国现行钢结构规范(GB50017-2003 )中只提出了双轴对称焊接工字梁的整体稳定系数，其他截面只能借用，合适与否，需要进一步的证明。因此，本文对单轴对称焊接工字梁的残余应力进行研究，为其整体稳定设计提供参考。本文以焊接过程的有限元理论为基础，总结前人的经验和成果，应用大型通用软件ANSYS对焊接过程进行三维数值模拟，首先采用间接法，对现有单双轴对称截面焊接工字梁实验进行模拟，以生热率的形式施加热源，同时通过“控制单元的生死”有效模拟了焊缝金属的填充、熔化和凝固过程，有
2、限元计算结果与试验结果比较吻合，证实了计算模型的有效性，为用有限元分析焊接工字形截面梁残余应力提供了一种方法，并对单双轴对称截面焊接工字梁残余应力进行计算对可知：单轴对称截面梁上下翼缘残余应力分布曲线与双轴对称截面上下翼缘残余应力分布区曲线类似，呈抛物线分布，但单轴对称截面上下翼缘残余应力在数值上并不完全相同，残余压应力在数值上有一定差别；单轴对称截面梁腹板残余应力分布曲线与双轴对称截面腹板残余应力分布曲线不同，腹板两端的残余应力并不成对称分布，靠近下翼缘一侧的残余压应力要小于靠近上翼缘一侧的残余压应力，呈梯形分布。这是由于上下翼缘宽度不同造成温度场分布不同，从而导致残余应力的不对称分布。通过
3、研究梁翼缘宽厚比、腹板高厚比、上下翼缘宽度比等参数对单轴对称截面残余应力影响可知：在保持上翼缘宽度不变的情况下，改变翼缘的厚度，随着翼缘宽厚比逐渐减小，上下翼缘和腹板的残余应力逐渐减小，受拉区有增大趋势；在保持腹板厚度不变的情况下，改变腹板的高度，随着腹板高厚比逐渐增大，上下翼缘的残余应力逐渐减小，受拉区逐渐增大，腹板上下残余拉应力逐渐减小，但是随着腹板面积的逐渐加大，腹板上下残余压应力逐渐加大，受压区有增大趋势；在保持上翼缘宽度不变的情况下，改变下翼缘的宽度，随着上下翼缘宽度比逐渐减小，上下翼缘和腹板残余应力有所增加，上下翼缘残余应力在分布趋势和数值上趋于一致，腹板上下残余压应力在数值上也趋
4、于一致，梯度逐渐减小，单轴对称截面残余应力在分布曲线上趋于双轴对称截面残余应力经典分布。通过对单轴对称焊接工字梁残余应力的模拟计算，为以后焊接结构的优化设计提供重要依据。关键词：焊接残余应力；数值模拟；单轴对称工字梁；生死单元 AbstractWelding residual stress is the effect of the whole stability of the important factors beam, the overall stability in beam design should be considered in the influence of the resi
5、dual stress of the beam. Our current steel structure specifications (GB50017-2003) only put forward the dual axle welding symmetrically strander overall stability coefficient of the beam, and other section can only borrow, if appropriate, need to be further proof. Therefore, this paper single beam w
6、elding of axisymmetric encountered residual stress in research, for its overall stability provides referen-ce for the design.In this paper, the finite element welding process based on the theory, summed up the experiences and results, a large general-purpose application software ANSYS three-dimensio
7、nal numerical simulation of welding process, first using the indirect method, symmetrical cross-section of existing single-axis beam welders experiment simulation, in order to impose the form of heat rate of heat at the same time through the control unit of the life and death Effective simulation of
8、 the weld metal filling, melting and solidification process, finite element analysis good agreement with the experimental results, confirming the effective computational model sex, for the use of finite element analysis-shaped cross-section beam welders provide a method of residual stress, and singl
9、e-axis symmetrical cross-section beam welders for residual stress calculation shows that: the upper and lower flange section beam axis symmetrical residual stress distribution curve symmetrical cross-section from top to bottom flange with the biaxial residual stress distribution curve is similar to
10、a parabolic distribution, but the uniaxial symmetry section of the upper and lower flange residual stress are not identical in value, the residual compressive stress there are some differences in values; uniaxial symmetry beams with web biaxial residual stress distribution curve symmetrical cross-se
11、ction of different web residual stress distribution curve, the residual stress at both ends of the web is not as symmetrical, close to the lower flange side of the residual compressive stress is less than one near the top flange side of the residual compressive stress, trapezoidal distribution. This
12、 is due to the different upper and lower flange width of the temperature distribution caused by different, resulting in asymmetric distribution of residual stress.By studying the beam flange width to thickness ratio, web thickness ratio, the upper and lower flange width and other parameters of the u
13、niaxial symmetry than the cross-section shows the residual stress effects: on the flange width to maintain the same in the case, change the thickness of the flange, with the flange width to thickness ratio decreases, the upper and lower flange and web of residual stress gradually decreases with incr
14、ease in tension zone trends; web thickness while maintaining the same circumstances, to change the height of the web, with the abdominal plate thickness ratio increases, the upper and lower flange of the residual stress gradually decreases gradually increasing tension zone, the web up and down the r
15、esidual tensile stress decreases, but with the gradual increase in the area of web, web up and down the residual stress gradually increased, there is increasing trend of compression zone; on the flange width to maintain the same in the case, change the width of lower flange, with the upper and lower
16、 flange width ratio decreases, the upper and lower flange and web an increase in residual stress, residual stress in the upper and lower flange distribution line on the trends and values, the residual compressive stress in the upper and lower webs value is also consistent, gradient decreases, the residual stress in the uniaxial symmetry cross-section on the distribution curve residual stress tends to biaxial symmetry classic cross-section distribution. Uniaxial s
