【作者】 李志敏；

【导师】 谢素明；

【作者基本信息】 大连铁道学院 ， 车辆工程， 2003， 硕士

【摘要】 铁路提速货车的构架是转向架的主要承载部件，是转向架其它各零部件的安装基础，它不仅要支承车体和各种零部件，而且需要传递各种载荷，对刚度和制造精度具有较高的要求，焊接构架的残余应力与变形的控制直接关系到铁路的行车安全。如何降低焊缝接头处的残余应力和变形是焊接构架的生产过程中所亟待解决的问题。 焊接数值仿真是一个涉及许多学科的复杂的技术。在焊接过程中，特别是在复杂的焊接结构，热源的移动，伴随着焊缝熔敷金属的填充，而且材料性能随温度剧烈变化，这造成求解问题的非线性性严重和求解的困难。 本文根据施工现场的焊接规范，结合焊接过程的特点，在CAD软件I-Deas9.0中创建出几何模型，利用Fortran语言编制了实现焊接路径数据的提取与生成数据库文件的程序transform．for；编写了沿着任意一条三维曲线移动的焊接移动热源的用户子程序flux．for，其目的是使复杂焊接路径的焊接仿真变得容易进行；基于单元死活技术编写了模拟焊缝金属填充的用户子程序uactive．for；编制了能实现动态自适应网格技术的用户子程序forcdt．for，以降低求解规模。 本文在研究焊接传热问题和热机耦合问题数值方法的基础上，采用国际上通用的非线性有限元分析软件MSC．Marc，结合上述编制的用户子程序，对提速货车的焊接构架的典型焊接接头电弧焊温度场和应力场进行数值仿真，实现了焊接热源沿任意路径的移动、焊缝金属的填充以及网格的随热源移动的动态加密，得到了三维焊接热残余应力和变形的变化规律。但是由于所研究问题的复杂性，在当前计算机硬件的条件下，本文仅能对焊接的典型接头形式进行数值模拟。如果硬件条件足够好，就能够对整个提速货车的构架的焊接全过程进行有效的数值仿真。 最后，本文基于焊接收缩力理论对提速货车的构架总成及各组成梁进行了焊接变形有限元分析计算，其计算结果可以为预测构架焊接变形提供一种方法，而且可供其它列车转向架构架的焊接质量控制借鉴。更多还原

【Abstract】 Bogie frame is a critical part to bogie to burden all kinds of loads from wheels and rails, it is a cadre of assembling other parts as well. To be up to the mustard, more and more demands for stiffness and precision of manufacture are brought forward. The problem of distortion residual stresses and reduced strength of a structure in and around a welded joint in manufacturing process of welding bogie frame is important issues in the railway industry.Analysis of numerical simulation in welding is a complex technology including lots of fields. In welding process of complex structure, welding path is used which make self-programmed subroutine more difficult to accord with numerical simulation. The weld fillet and adaptive meshing are also involved in 3D numerical simulation. In order to solve above mentioned problems, special user subroutines in Fortran are completed to simulate: the moving heat source during welding used transform.for and flux.for; the weld fillet is simulated by active/deactive technique used uactive.for; the implement of adaptive meshing in 3D numerical simulation used fordctfor.The objective of this thesis is to develop and evaluate a method for introducing a moving heat source into a FE-model. The heat source should be able to move along any general 3D curve. The aim is to facilitate the simulation of welding for complex weld paths and geometries. The above techniques combined with analysis of thermal elastic plastic behavior of metals by finite element method are used to analysis welding bogie frame process of typical joints. Because of the complexities of the studied problems, only welding process of the typical joints can be simulated under the conditions of the current hardware. The welding process of total bogie frame will be simulated effectively with better hardware provided. Based on the theory of welding shrinking force and MSC.Marc software of finite element together, welding deformation is predicted not only for the total bogie frame but also for each beam in frame of this dynamical bogie. According to the all deformation results from finite element analysis, the appropriate pre-deformation and the appropriate welding parameters are selected so that the minimum welding deformation and good welding quality are finally obtained. All done in this study indicates that the new method presented in this paper is effective to reduce welding deformation and control welding quality for the frame of dynamical bogie.更多还原