Modeling the effects of residual stresses on defects in welds of steel frame connections
Modeling the effects of residual stresses on defects in welds of steel frame connections
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DOI：
10.1016/s0141-0296(99)00055-3
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发表时间：
2000-09
影响因子：
5.5
通讯作者：
C. Matos;R. H. Dodds
中科院分区：
文献类型：
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作者：
C. Matos;R. H. Dodds
这项工作描述了一个特征应变的方法，施加现实的残余应力场的3-D有限元模型的下翼缘焊缝中发现的大型，梁柱连接的类型。3-D模型结合了拉板试样的完整几何形状，旨在降低测试完整连接的成本，同时保留易断裂焊接区域的基本特征。3-D分析检查拉板配置与各种几何参数的焊缝根部焊道中的贯穿宽度和半椭圆形裂纹。数值结果包括计算应力强度因子所需的无量纲“几何”因子（Y）的值表。建议的本征应变函数所产生的残余应力场密切匹配使用2-D，焊接过程的热机械模拟计算。从相应的J积分计算得到的应力强度因子，清楚地显示出显着的断裂韧性的需求，从残余应力的结构载荷的应用程序之前。一种带槽支撑杆的替代设计显示出相当大的希望，通过将焊缝根部焊道重新定位在梁翼缘下方，从而在主要载荷路径之外，来降低断裂韧性要求。
This work describes an eigenstrain approach to impose realistic residual stress fields on 3-D finite element models for the lower-flange welds of the type found in large, beam-column connections. The 3-D models incorporate the full geometry of a pull-plate specimen designed to reduce the cost of testing full connections while retaining essential features of the fracture prone, weld region. The 3-D analyses examine pull-plate configurations with a variety of geometric parameters for both through-width and semi-elliptical cracks in the weld root pass. The numerical results include tables of values for the non-dimensional “geometry” factors (Y) needed to compute stress intensity factors. The residual stress fields generated by the proposed eigenstrain functions closely match those computed using 2-D, thermo-mechanical simulation of the welding process. Stress intensity factors, obtained from corresponding J-integral computations, show clearly the significant fracture toughness demand from residual stresses prior to application of the structural loads. An alternative design for a grooved backup bar shows considerable promise to reduce fracture toughness demands by re-positioning the weld root pass below the beam flange and thus outside the primary load path. Analyses here indicate approximately a 65% reduction in KI-values for tension loading in the flange.