桥钢厚板焊接残余应力数值模拟及试验研究

发布时间：2018-02-13 22:12

本文关键词： 钢桥厚板焊接残余应力数值模拟盲孔法逐层铣削法　出处：《西南交通大学》2017年硕士论文　论文类型：学位论文

【摘要】：目前,在工厂制造的桥梁钢结构一般采用焊接作为构件的连接方式,现场拼装也逐渐从栓焊向全焊连接发展,因此,焊接残余应力日益成为影响钢桥构件力学性能和使用寿命的突出因素。相较于薄板,钢桥焊接结构中材料板厚通常较大,焊接残余应力分布更为复杂,不宜忽略厚度方向的残余应力以及残余应力在厚度方向上的变化情况。针对这一问题,本文以45mm厚度的Q345qD对接焊钢板为对象,运用数值模拟和试验测量相结合的方法,对桥梁用结构钢厚板焊接残余应力的分布规律进行了研究,主要工作如下:(1)简要介绍了我国焊接钢桥的发展和厚板在钢桥建设中的应用情况,并说明焊接钢桥的疲劳和厚板层状撕裂两个典型问题都与焊接残余应力密切相关;分别概括了焊接残余应力的定义、产生、分类以及对结构的影响,并从基础理论、数值模拟技术和测量方法三个方面总结了焊接残余应力相关问题的研究进展。(2)系统地论述了有限元方法在焊接温度场和应力场分析中的应用,有针对性地介绍了焊接传热基本形式、焊接温度场有限元基本方程和热弹塑性方法等相关的基础分析理论。(3)基于有限元软件ANSYS,对厚板焊接温度场和应力场进行了三维实时动态分析。其中,利用前处理软件HYPERMESH建立了试件的有限元模型,详细阐述了在软件中实现多层多道焊焊接数值模拟的过程。通过有限元计算,得到了焊接过程中试件温度场和应力场的分布和变化规律,并最终得到了焊接残余应力在厚板上的分布情况。(4)采用盲孔法和逐层铣削法分别对厚板表层和内部纵向残余应力进行了测量,通过与数值模拟结果的对比,从一定程度上验证了有限元计算结果的合理性。基于计算结果,提出了本文所研究特定试件的焊接残余应力分布简化图示,可为桥梁工程中与焊接残余应力相关的研究或计算提供参考。通过本文的研究结论,可初步了解桥钢厚板焊接残余应力分布规律,对未来进一步研究钢桥典型构件或构造中焊接残余应力的分布、控制和消除等问题有积极意义。
[Abstract]:At present, the bridge steel structure manufactured in the factory generally adopts welding as the connection mode of the component, and the field assembly is gradually developing from the bolt welding to the full welding connection, so, Welding residual stress is increasingly becoming a prominent factor affecting the mechanical properties and service life of steel bridge members. Compared with thin plates, steel bridge welding structures are usually larger in thickness and more complicated in distribution of welding residual stresses. The residual stress in the thickness direction and the variation of the residual stress in the thickness direction should not be ignored. In view of this problem, the Q345qD butt welded steel plate with 45mm thickness is taken as the object, and the method of combining numerical simulation with experimental measurement is used. The distribution law of welding residual stress of thick steel plates for bridges is studied. The main work is as follows: 1) the development of welded steel bridges in China and the application of thick plates in the construction of steel bridges are briefly introduced. It is shown that the fatigue of welded steel bridge and the laminated tear of thick plate are closely related to the welding residual stress, and the definition, generation, classification and influence on the structure of the welding residual stress are summarized respectively, and the basic theory is given. This paper summarizes the research progress of welding residual stress in three aspects: numerical simulation technique and measurement method. The application of finite element method in the analysis of welding temperature field and stress field is systematically discussed. The basic forms of welding heat transfer are introduced. Based on the finite element software ANSYS3, 3D dynamic analysis of welding temperature field and stress field of thick plate is carried out. The finite element model of the specimen is established by using the pre-processing software HYPERMESH, and the process of numerical simulation of multi-layer and multi-pass welding in the software is described in detail. The distribution and variation of the temperature field and stress field in the welding process are obtained. Finally, the distribution of welding residual stress on the thick plate is obtained. The blind hole method and the layer by layer milling method are used to measure the longitudinal residual stress of the thick plate, and the results are compared with the numerical simulation results. The rationality of the finite element method is verified to a certain extent. Based on the calculation results, a simplified diagram of welding residual stress distribution of a particular specimen studied in this paper is presented. It can be used as a reference for the research and calculation of welding residual stress in bridge engineering. Through the conclusion of this paper, the distribution law of welding residual stress of bridge steel thick plate can be preliminarily understood. It is of great significance to further study the distribution, control and elimination of welding residual stress in typical steel bridge components or structures in the future.
【学位授予单位】：西南交通大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TG404;U445.583

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