基于断裂力学的高强度钢材梁柱节点受力性能分析

发布时间：2018-11-04 07:46

【摘要】：为了研究国产Q460C高强度结构钢材梁柱节点的断裂行为,该文基于断裂力学理论,计算了Q460C高强度钢材焊缝及热影响区材料的断裂韧性,并且采用三维有限元断裂模型,以I型裂纹尖端应力强度因子KI和J积分为定量的评价指标,分析了焊缝及热影响区不同长度的裂纹对梁柱节点断裂韧性的需求。弹性分析表明,KI沿梁翼缘宽度方向呈W形分布,最大值出现在翼缘中心,且与名义弯曲应力呈线性关系,而焊根裂纹的断裂韧性需求比热影响区裂纹更高。弹塑性分析表明,JI最大值出现在翼缘的边缘,热影响区裂纹的断裂韧性需求比焊根裂纹更高。研究结果表明,Q460C高强度钢材梁柱节点的断裂由焊根裂纹控制,断裂承载力与梁全截面塑性承载力相近,临界转角小于0.02rad,因此建议通过改善焊接工艺或局部构造来保证节点拥有足够的转动能力。
[Abstract]:In order to study the fracture behavior of Liang Zhu joints of domestic Q460C high strength structural steels, the fracture toughness of Q460C high strength steel welds and heat-affected zone materials is calculated based on the theory of fracture mechanics, and the 3D finite element fracture model is used. Taking the stress intensity factor (KI) and J-integral of mode I crack tip as quantitative evaluation indexes, the fracture toughness of Liang Zhu joints with different length cracks in weld and heat affected zone is analyzed. The elastic analysis shows that KI is distributed in W shape along the width of beam flange, and the maximum value appears in the center of flange and has a linear relationship with nominal bending stress. However, the fracture toughness of weld root crack is higher than that of heat affected zone crack. The elastic-plastic analysis shows that the maximum value of JI appears at the edge of the flange, and the fracture toughness of the crack in the heat-affected zone is higher than that of the root crack. The results show that the fracture of Liang Zhu joint of Q460C high strength steel is controlled by welding root crack, the fracture bearing capacity is close to the plastic bearing capacity of full section of beam, and the critical turning angle is less than 0.02 rad. Therefore, it is suggested to improve the welding process or local structure to ensure that the joint has sufficient rotation capacity.
【作者单位】：土木工程安全与耐久教育部重点实验室清华大学土木工程系;
【基金】：北京高等学校青年英才计划项目(YETP0077)
【分类号】：TU391

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