压水堆蒸汽发生器安全端异种金属焊接残余应力场分析

发布时间：2018-04-05 06:19

本文选题：蒸汽发生器安全端　切入点：ABAQUS　出处：《西安科技大学》2015年硕士论文

【摘要】：压水堆蒸汽发生器安全端在焊接过程中会产生较大的残余应力,而焊接残余应力是导致安全端焊接接头产生应力腐蚀开裂的主要原因之一。焊接接头残余应力大小和分布受到几何结构和焊接热应力等因素的影响。为了了解压水堆蒸汽发生器安全端异种金属焊接接头残余应力的大小和分布情况,本文采用ABAQUS软件对压水堆核电站蒸汽发生器安全端焊接过程进行数值仿真分析,主要研究内容如下:以异种金属平板对接焊为研究对象,建立了焊接结构三维有限元模型,编制了DFLUX热源模型,并利用ABAQUS软件计算得出了焊接过程中的瞬时温度场;通过分析瞬时温度场中的热源分布和热循环曲线,得出了焊接过程温度场的分布特征;采用顺序耦合方法将温度场以热载荷的形式加载到应力分析模型,得到了异种金属平板对接焊残余应力场分布规律。采用1/8圆筒对接焊简化模型,以及考虑实际焊接环境下热载荷和力学边界条件的前提下,对压水堆蒸汽发生器安全端异种金属焊接接头的温度场和残余应力场进行了数值模拟分析。得出了蒸汽发生器安全端焊接过程中瞬时温度场分布特征和残余应力场分布规律。本研究为准确分析压水堆蒸汽发生器安全端异种金属焊接接头残余应力分布提供了一定的基础,也为安全端焊接接头应力腐蚀开裂及疲劳断裂的分析提供一定参考。
[Abstract]:The welding residual stress at the safe end of PWR steam generator will produce large residual stress during welding, and the welding residual stress is one of the main reasons for the stress corrosion cracking of welded joints at the safe end.The size and distribution of residual stress of welded joints are affected by geometric structure and welding thermal stress.In order to understand the magnitude and distribution of residual stress in the safety end of PWR steam generator, the welding process of safe end of PWR steam generator is simulated by ABAQUS software.The main research contents are as follows: taking dissimilar metal plate butt welding as the research object, the three-dimensional finite element model of welding structure is established, the DFLUX heat source model is compiled, and the instantaneous temperature field in welding process is calculated by using ABAQUS software.By analyzing the heat source distribution and the thermal cycle curve in the instantaneous temperature field, the distribution characteristics of the temperature field in the welding process are obtained, and the temperature field is loaded into the stress analysis model in the form of thermal load by the sequential coupling method.The distribution of residual stress field in butt welding of dissimilar metal plate is obtained.The simplified model of 1 / 8 cylinder butt welding is adopted, and the thermal load and mechanical boundary conditions are considered in the actual welding environment.The temperature field and residual stress field of dissimilar metal welded joints at the safe end of PWR steam generator are numerically simulated and analyzed.The distribution characteristics of instantaneous temperature field and residual stress field in the welding process of the safe end of steam generator are obtained.This study provides a basis for the accurate analysis of residual stress distribution of dissimilar metal welded joints at the safe end of PWR steam generator, and also provides a reference for the analysis of stress corrosion cracking and fatigue fracture of welded joints at safe ends.
【学位授予单位】：西安科技大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TM623.91;TG404

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