单轴对称焊接工字形截面残余应力试验研究

发布时间：2018-05-20 08:11

本文选题：单轴对称 + 残余应力　；参考：《沈阳建筑大学》2014年硕士论文

【摘要】：焊接工字形截面是钢梁常采用的截面形式之一,而单轴对称焊接工字形梁与双轴对称焊接工字形梁相比有较好的应用价值及经济效益,因此其被越来越多的应用于实际工程。在焊接过程中,不均匀温度场会使截面内部产生残余应力,因为焊接残余应力是影响梁稳定性能不可忽视的因素之一,所以在计算梁整体稳定承载力时应当考虑焊接残余应力的影响。目前,对双轴对称焊接工字形截面的残余应力分布研究相对成熟,而对单轴对称焊接工字形截面的研究较少,未见成熟的残余应力分布模型。本文结合以上研究现状,通过试验分析了单轴对称焊接工字形截面(剪切边)纵向残余应力大小及其在截面上的分布规律,为建立单轴对称焊接工字形截面残余应力的分布模型和深入研究考虑残余应力影响下单轴对称工字形连续梁的稳定性能奠定了基础。盲孔法具有操作方便、适合现场操作、经济省时等优点,是一种被广泛使用的试验方法。本文先采用盲孔法测量了双轴对称焊接工字形截面(剪切边)的残余应力,将试验结果与已有的双轴对称焊接工字形截面残余应力分布模型对比发现,试验值整体趋势与分布模型吻合较好,随后采用盲孔法对15个单轴对称焊接工字形截面(剪切边)的残余应力进行了测量,研究了腹板高厚比、翼缘宽厚比、翼缘宽度、施焊顺序等参数对残余应力分布的影响。试验结果表明：(1)残余应力在翼缘与腹板焊接处为拉应力,在翼缘边缘和腹板中部为压应力。腹板中部靠近宽翼缘一侧的残余压应力峰值大于靠近窄翼缘一侧的压应力峰值。(2)当保持腹板厚度不变,腹板高厚比的增大时,翼缘和腹板上的残余拉应力有减小趋势,但并不明显。而翼缘、腹板上的压应力峰值分别减小和增大。(3)当翼缘厚度和宽窄翼缘宽度比保持不变时,随着翼缘宽厚比的增大,分布于腹板上的残余应力大小和形状基本不变。翼缘上的残余拉、压应力大小有减小的趋势。(4)其余参数不变,只增加宽翼缘宽度时,窄翼缘上的残余应力大小和分布未见明显变化。宽翼缘和腹板上的残余拉应力峰值有较小的递减趋势,而分布于宽翼缘和腹板残余压应力数值有较明显的降低。当只增加窄翼缘宽度时,分布于宽翼缘的残余应力无明显变化。腹板和窄翼缘上的残余拉应力呈减小趋势,但并不明显,残余压力则呈较明显的减小趋势。(5)施焊顺序对翼缘上的残余应力及腹板上的残余拉应力大小有一定影响,而对腹板上的残余压应力影响甚微。采用交错焊接可有效降低截面上的残余拉应力大小,且先对宽翼缘一侧进行施焊时的残余拉应力峰值小于先对窄翼缘进行施焊时的残余拉应力峰值。
[Abstract]:Welding I-shaped section is one of the common cross section forms of steel beam, and the uniaxial symmetrical welded I-shaped beam has better application value and economic benefit than that of double-axisymmetric welded I-shaped beam, so it is more and more used in practical engineering. In the welding process, the non-uniform temperature field will cause the residual stress in the section, because the welding residual stress is one of the factors which can not be ignored to affect the stability of the beam. Therefore, the influence of welding residual stress should be taken into account in the calculation of the overall stable bearing capacity of the beam. At present, the research on the distribution of residual stress in I-shaped section of double-axisymmetric welding is relatively mature, but there is little research on I-shaped section of single-axis symmetrical welding, and no mature model of residual stress distribution has been found. In this paper, the longitudinal residual stress of I-shaped section (shear edge) of uniaxial symmetrical welding and its distribution on the section are analyzed through experiments combined with the above research status. It lays a foundation for the establishment of the distribution model of the residual stress in the I-shaped section of uniaxial symmetry welding and for the further study of the stability of the I-shaped continuous beam with the consideration of the influence of the residual stress. Blind hole method is a widely used test method because it is easy to operate, suitable for field operation and economical and time saving. In this paper, the residual stress of I-shaped section (shear edge) of double-axisymmetric welding is measured by blind hole method. The experimental results are compared with the existing model of distribution of residual stress in I-shaped section of double-axisymmetric welding. The overall trend of the test data is in good agreement with the distribution model. Then the residual stress of 15 uniaxial symmetrical welded I-shaped sections (shear edges) is measured by blind hole method. The ratio of height to thickness of web and the width of flange are studied. Effects of welding sequence and other parameters on residual stress distribution. The experimental results show that the residual stress is tensile stress at the welding of the flange and web, and compressive stress at the edge of the flange and the middle of the web. The peak value of residual compressive stress near the side of the wide flange in the middle of the web is larger than that near the side of the narrow flange. 2) when the thickness of the web remains constant, the ratio of height to thickness of the web increases, the residual tensile stress on the flange and web decreases. But it's not obvious. When the flange thickness and the width ratio of the flange remain constant, the residual stress distribution on the web is almost unchanged with the increase of the flange width ratio. The residual stress on the flange has a decreasing trend. (4) the other parameters remain unchanged, but when the width of the flange is increased, the magnitude and distribution of the residual stress on the narrow flange have no obvious change. The peak value of residual tensile stress on wide flange and web has a small decreasing trend, while the value of residual compressive stress distributed in wide flange and web is obviously reduced. When the width of the flange is increased only, the residual stress distributed in the wide flange has no obvious change. The residual tensile stress on the web and the narrow flange is decreasing, but it is not obvious, but the residual pressure is decreasing obviously. The welding sequence has a certain influence on the residual stress on the flange and the residual tensile stress on the web. However, there is little effect on the residual compressive stress on the web. The residual tensile stress on the cross section can be reduced effectively by staggered welding, and the peak value of residual tensile stress on the wide flange is lower than that on the narrow flange.
【学位授予单位】：沈阳建筑大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TU391

【相似文献】