焊接残余应力对箱型梁柱节点断裂性能影响分析

发布时间：2018-01-10 20:15

本文关键词：焊接残余应力对箱型梁柱节点断裂性能影响分析　出处：《华南理工大学》2014年硕士论文　论文类型：学位论文

【摘要】：普遍认为钢框架结构具有良好的抗震性能，但在1994年美国加州北岭地震以及1995年日本阪神地震中出现了大量钢框架梁柱焊接节点脆性断裂的现象。按照规范设计的焊接节点并不能保证“强连接，弱构件”设计思想的实现。焊接带来的节点抗震性能劣化的影响不可忽视，由于计算手段的缺乏，此前大量的研究都集中在焊缝金属性能的提升，焊接工艺的改进以及改进型节点的实验，而关于节点焊接残余应力具体分布形态以及对节点性能影响的研究较少。针对以上情况，，本文摸索出了利用ANSYS软件进行焊接过程模拟以及在焊接残余应力基础上进行静力分析和断裂分析的方法。对一T型连接件进行了焊接过程模拟，模拟中使用热分析与应力分析间接耦合法和生死单元技术计算焊接温度场和焊接残余应力场，采用了随温度变化的材料性能参数。在热分析中讨论了高斯面热源、双椭球体热源、体积生热率热源这三种热源的差别。最终确定体积生热率热源为最佳热源，并在此基础上进行焊接残余应力计算，得到了焊接残余应力的“几”字形分布特点以及焊缝区处于高值三轴拉应力状态的结论。进行了两个箱型梁柱节点的性能实验，在滞回荷载作用下，两个节点发生了一致的焊缝断裂现象，梁端未能形成塑性铰，节点性能没有达到抗震要求。在对T型连接件焊接过程模拟的基础上，进行了该种节点的焊接过程模拟，并且对存在焊接残余应力的模型进行了滞回静力加载和断裂分析。分析发现焊接残余应力的存在极大提高了焊缝处各种断裂指标，是节点焊缝断裂的根本原因。断裂分析则体现了有无焊接残余应力的模型在断裂时间的显著差异。
[Abstract]:It is generally believed that the steel frame structure has good seismic performance. However, a large number of brittle fracture of Liang Zhu welded joints of steel frames were observed in the earthquakes in the Northern Ridge, California, USA, on 1994 and in Hanshin, Japan, on 1995. The welded joints designed according to the specifications are not guaranteed. " Strong connection. The effect of joint seismic performance deterioration caused by welding can not be ignored. Due to the lack of calculation means, a great deal of research has been focused on the improvement of weld metal performance. The improvement of welding process and the experiment of the improved joint are carried out, but there is little research on the distribution of residual stress and the effect on the performance of the joint. In view of the above situation. In this paper, the method of welding process simulation using ANSYS software and static analysis and fracture analysis based on welding residual stress are explored. The welding process of a T-joint is simulated. The welding temperature field and welding residual stress field are calculated by the indirect coupling method of thermal analysis and stress analysis and the birth and death element technique in the simulation. The difference of Gao Si surface heat source, double ellipsoid heat source and volumetric heat source is discussed in the thermal analysis. Finally, the volume heat generating rate heat source is determined as the best heat source. On the basis of the calculation of welding residual stress, the "several" zigzag distribution characteristics of welding residual stress and the conclusion that the weld zone is in the state of high value triaxial tensile stress is obtained. The performance experiments of two box beam-column joints are carried out. Under hysteretic load, the joint has a consistent weld fracture phenomenon, and the plastic hinge is not formed at the end of the beam. The performance of the joints did not meet the seismic requirements. Based on the simulation of the welding process of T-joints, the welding process of the joints was simulated. The model with welding residual stress is analyzed by hysteretic static loading and fracture analysis. It is found that the existence of welding residual stress greatly improves the fracture index of welding seam. The fracture analysis shows the significant difference in fracture time between the models with or without residual stress.
【学位授予单位】：华南理工大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TU391;TU312.3

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