U肋与顶板连接焊缝残余应力的三维数值模拟

发布时间：2018-01-16 00:16

本文关键词：U肋与顶板连接焊缝残余应力的三维数值模拟　出处：《西南交通大学》2015年硕士论文　论文类型：学位论文

【摘要】：正交异性钢桥面板因经济耐久,轻质高强等优点,被广泛运用于世界大、中跨度桥梁。但其结构复杂,板件众多,大都通过焊接方式连接,焊缝处必然存在残余应力。焊接残余应力的存在会降低钢桥面板的使用性能,如抗腐蚀、抗疲劳和稳定性能等。当前完全控制和消除焊接残余应力还不太现实,钢桥面板上还会存在很大的残余应力。为保证钢桥面板的使用安全,需要准确认识残余应力的大小及其分布规律。残余应力的试验测量耗时耗力,论文采用数值模拟技术进行定量分析,主要工作包括：(1)简单介绍了焊接残余应力的基础知识,回顾了焊接数值模拟技术的国内外发展现状,并总结了焊接模拟的相关理论和方法,包括焊接温度场和应力场的理论；(2)以港珠澳大桥为背景,采用ANSYS有限元软件建立U肋与顶板连接焊缝的三维模型,选定合理的材料参数和热源模型,使用生死单元技术模拟焊料的熔化和填充,分别进行温度场和应力场的模拟计算；(3)对模拟计算结果进行分析,得到温度场和应力场的分布规律：热源移动位置,焊缝金属温度急剧升高至熔融,随着热源的离开,温度又迅速下降最终至室温；顶板近U肋表面焊缝区的最大残余拉应力约为屈服强度的1.2倍,远焊缝区的最大残余压应力约为屈服强度的0.1倍；U肋近焊缝区的最大残余拉应力达到屈服强度,远焊缝区的最大残余压应力约为屈服强度的0.1倍；(4)分析材料参数、焊接工艺参数和几何模型参数对焊接残余应力的影响,得到更为准确的模拟计算结果,为合理的焊接工艺提供数据支持；模拟计算结果说明：U肋与顶板连接焊缝残余应力是可以用ANSYS软件进行数值模拟的；顶板和U肋残余应力的计算结果和分布趋势与前人的研究相接近;参数变化对焊接残余应力的影响很大。
[Abstract]:Orthotropic steel bridge panel is widely used in the world because of its advantages such as economic durability, light weight and high strength, but its structure is complex and its panels are numerous, most of them are connected by welding. Welding residual stress will reduce the performance of steel bridge panel, such as corrosion resistance, fatigue resistance and stability, etc. At present, it is not practical to completely control and eliminate welding residual stress. In order to ensure the safety of steel bridge panel, it is necessary to understand the magnitude and distribution of residual stress accurately, and the test measurement of residual stress is time-consuming and labor-consuming. In this paper, numerical simulation technology is used for quantitative analysis. The main work includes: 1) the basic knowledge of welding residual stress is briefly introduced, and the development status of welding numerical simulation technology at home and abroad is reviewed. The related theories and methods of welding simulation are summarized, including the theory of welding temperature field and stress field. (2) taking HongKong-Zhuhai-Macao Bridge as the background, the ANSYS finite element software is used to establish the three-dimensional model of U-rib and roof joint weld, and the reasonable material parameters and heat source model are selected. The melting and filling of solder were simulated by birth and death element technique, and the temperature field and stress field were simulated and calculated respectively. The distribution of temperature field and stress field is obtained by analyzing the simulation results: the temperature of weld metal rises sharply to melting when the heat source moves, and with the departure of heat source. The temperature drops rapidly to room temperature; The maximum residual tensile stress near the surface of U rib is about 1.2 times of yield strength, and the maximum residual compressive stress of far weld is 0.1 times of yield strength. The maximum residual tensile stress of U-rib near weld reaches yield strength, and the maximum residual compressive stress of far-weld is about 0.1 times of yield strength. 4) analyzing the influence of material parameters, welding process parameters and geometric model parameters on welding residual stress, and obtaining more accurate simulation results, which provide data support for reasonable welding process. The simulation results show that the residual stress of weld joint between U rib and roof can be numerically simulated by ANSYS software. The calculated results and distribution trend of residual stress in roof and U-rib are close to those of previous studies. The variation of parameters has great influence on welding residual stress.
【学位授予单位】：西南交通大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：U445.583

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