基于APDL语言T型接头双侧同步焊有限元建模及在钢结构变形预测中应用研究

发布时间：2018-01-11 09:34

本文关键词：基于APDL语言T型接头双侧同步焊有限元建模及在钢结构变形预测中应用研究　出处：《重庆交通大学》2015年硕士论文　论文类型：学位论文

【摘要】：焊接结构具有整体性强、致密性好、经济实惠和适用于各种外形尺寸的零件等优点,在被广泛的应用于国民经济各部门中。但是焊接工艺也存在比较突出的问题,例如焊后工件中会产生较大的残余应力和残余变形。焊后应力和变形会影响工件的加工精度和使用性能。所以,为了达到优化工艺的目的需要了解不同焊接工艺的焊后残余应力和变形的大小分布。焊接数值模拟的方法可以在不具备实验条件的情况下进行研究,可以大幅度降低成本。同时,还可以预测焊接变形结果、模拟计算焊接过程以及进行焊接参数和焊接结构的优化,对实际焊接工艺进行指导。正是由于这些优点,焊接数值模拟技术越来越受到重视。本文主要针对T型接头的双侧同步焊接工艺,基于APDL语言建立了焊接过程模拟分析的有限元模型,并通过焊接实验验证了模型的准确性。通过对比分析T型接头双侧同步焊与顺序焊接的模拟结果,发现双侧同步焊接可以有效的减小应力和变形分布不均,焊接收弧端的残余应力明显大于其他区域。利用建立的新模型对大型桥梁钢箱梁中应用双侧同步焊接工艺的部分结构行了模拟计算,得到了焊接过程温度变化和焊后残余应力和残余变形结果。模拟结果表明焊接最大变形主要集中在顶板边缘,焊接残余应力集中于焊缝附近,并且应力值较大。在热弹塑性法模拟结果的基础上,本文还对T型接头双侧同步焊接固有变形分布进行了研究,结果表明沿焊缝方向的横向收缩变形先增大后减小,在起弧和收弧端由于端部效应横向固有变形略高于其附近的金属。纵向固有变形沿焊缝方向由两端向中间逐渐减小,角变形从焊接起点沿焊缝方向逐渐增大。同时,分别研究了焊接速度、焊接顺序、腹板厚度、翼板厚度和翼板宽度对固有应变的影响,结果表明,焊接速度、腹板厚度和翼板厚度对固有应变有较大影响,翼板宽度和焊接顺序在一定的范围内对固有应变有影响。通过对比热弹塑性法和固有应变计算的T型接头残余变形,发现两种方法得到的变形分布和沿翼板垂向的挠度基本吻合,验证了固有应变法预测变形的可靠性。同时,对比了壳单元和实体单元的固有应变预测T型接头焊接变形结果,发现两者结果差别较小,说明采用壳单元进行计算就能达到很好的精度。然后,利用热弹塑性法计算获得大型桥梁钢箱梁各接头的平均固有应变,并应用于大型桥梁钢结构焊接模块的变形预测计算,通过分析变形结果对焊接工艺提出了相关的一些建议。
[Abstract]:With strong integrity of welded structure, compact, economical and applicable to various shapes and sizes of the parts in the advantages, has been widely used in various sectors of the national economy. But the welding process there are many problems, such as welding workpiece will produce larger residual stress and welding residual deformation. Stress and deformation will affect the machining accuracy and performance. So, in order to need to understand the different welding process to optimize the welding residual stress and deformation after welding. The size distribution of the numerical simulation method can be studied in the experiment does not have the condition, can greatly reduce the cost at the same time. Also, can predict welding deformation results, simulation of welding process and welding parameters and welding structure optimization, the actual welding process. It is because of these advantages, the welding numerical Simulation technology has been paid more and more attention. This article mainly aims at the bilateral T joint synchronous welding process, the APDL language to establish a finite element analysis of welding process based on the model, and the accuracy of the model was verified by welding experiments. Through comparative analysis of simulation results of T type joint bilateral synchronous welding and welding, welding can be found in bilateral synchronization effectively reduce the stress and deformation of the uneven distribution of welding residual stress of the arc end is greater than that of other areas. Some structures using a new model of bilateral large bridge steel box girder synchronous welding process were simulated and calculated, the process of welding temperature and the welding residual stress and residual deformation simulation results. The results show that the welding deformation is mainly concentrated in the edge of the top plate, the welding residual stress in the weld, and the stress is larger. The thermal elastic plastic mold Based on the results of this paper intends to, for the T type joint bilateral synchronous welding inherent deformation distribution were studied. The results show that the transverse shrinkage deformation along the weld direction increases first and then decreases, arc starting and stopping at the end due to the end effect of lateral natural deformation is slightly higher than in the vicinity of the metal. The longitudinal natural deformation along the weld direction from both ends to the center gradually decreases, angular distortion from the welding starting point increases gradually along the direction of weld were studied. At the same time, welding speed, welding sequence, web thickness, flange thickness, flange width and the inherent strain. The results show that the welding speed, the thickness of the thickness of web and flange has great influence on the inherent strain, wing plate the width and welding sequence have influence on the inherent strain in a certain range. The T type joint by comparing the thermal elastic plastic inherent strain method and calculation of residual deformation, deformation distribution obtained by the two methods Along the vertical deflection and wing plate are basically consistent, verify the inherent strain deformation prediction reliability. At the same time, compared the inherent strain shell element and solid element prediction T joint welding deformation results, both found little difference between the results, using shell element calculation can achieve good accuracy. Then, using the thermo elastic plastic inherent strain method to calculate the average for each joint of the steel box girder bridge, deformation prediction and its application in large bridge steel structure welding deformation calculation module, through the analysis of results and put forward some suggestions related to the welding process.

【学位授予单位】：重庆交通大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TG404

【参考文献】