【作者】 顾立志；

【导师】 廉金瑞；

【作者基本信息】 天津大学 ， 材料加工工程， 2005， 硕士

【摘要】 焊接是一个涉及到电弧物理、传热、冶金和力学等学科的复杂的物理化学过程。焊接现象包括焊接时的电磁、传热过程、金属的熔化和凝固以及冷却时的相变、焊接应力和变形等等。因为焊接过程的复杂性,所以很难通过实验的方法对焊接过程产热和应力分布进行研究。借用计算机技术,对焊接现象进行数值模拟,是国内外焊接工作者的热门研究课题,并且得到了越来越广泛的应用。本文运用有限元法(FEM),对铝合金筒体结构的焊接过程进行研究,分析了焊接过程的热、力行为; 探讨了结构焊接温度场、应力场的分布规律。在阐述有限单元法基本理论和基本推导方程的基础上,以大型有限元分析软件ANSYS作为分析手段,建立全位置焊接移动热源的三维有限元计算模型,对筒体结构的焊接温度场进行动态模拟,并以瞬态温度场分析为基础,进行焊接残余应力的热弹塑性分析。计算结果表明,筒体内侧焊缝和近缝区的环向和轴向残余应力均为拉应力,随着离开焊缝距离的增加,由拉应力逐渐过渡到压应力。在筒体外表面焊缝中心处的轴向残余应力为压应力,而环向残余应力为拉应力。通过有关实验,对部分模拟结果进行验证,表明计算值和实际测量值基本吻合。更多还原

【Abstract】 Welding is a complicated physicochemical process which involves in electromagnetism, heat transferring, metal melting and freezing, phase-change, welding stress and deformation and so on. Because of the complexity of welding process, the research of weld process produce hot and stress through method of experiment is very difficulty. With the development of computer science and technology, numerical simulation of welding phenomena has become a hot research topic domestically and abroad and has also been put into wide use. Finite Element Method (FEM) is used here to simulate the temperature field and the residual stress field in the Canister structures, to analysis the hot, stress behavior in weld process. Probe the distribution rule of stress field and temperature field. On the basis of finite element theory and fundamental equation, ANSYS, as a large FEM analysis software used here, a three-dimensional finite element numerical simulation is founded, to simulate the temperature and stress field of this kind of canister structures. Distributions of axial and hoop residual stresses at the weld and weld vicinity on inner surface of canister are tensile, and they are gradually transferred into compressive with increase of distance away from the weld joint. The axial residual stresses at the weld and weld vicinity on outer surface of canister is compressive while the hoop one is tensile. Some experiments were carried out to verify the simulation results. The experimental results show mostly conformity compared with the FEA results.更多还原