反应堆压力容器内壁环形锻件焊接残余应力三维有限元数值模拟

某新型反应堆压力容器内壁设计了环形锻件与筒体内壁焊接的环形焊接结构。该种结构形式的焊缝首次在反应堆压力容器中出现，无成熟经验可以借鉴。为了了解该种复杂结构形式及大厚度焊缝的焊接残余应力幅值及分布规律，基于ANSYS有限元分析软件，建立了反应堆压力容器内壁环形锻件多层多道焊接三维有限元模型。在此基础上，以带状移动温度热源作为焊接热源模型计算出多层多道焊接的瞬态温度场结果，采用热-力间接耦合法，得到了焊接应力场计算结果。模拟结果表明，焊缝区域环向应力从上表面到下表面分布趋势为拉应力-压应力-拉应力，呈现自平衡的分布形式。根部焊道区域的环向应力为拉应力。焊缝上轴向应力最大为300 MPa左右；焊缝上下表面径向应力较大，达到400～500 MPa左右；峰值等效应力出现在焊缝根部区域，幅值最大约700 MPa。

Three-dimensional Finite Element Simulation on Welding Residual Stress for Reactor Pressure Vessel Inner Shell Circle Forging

A circular forging is welded to the inner wall of a new -type reactor pressure vessel（RPV）. This kind of welded structure is first adopted in RPV and there is no expierence for reference .To investi-gate the distribution of welding residual stress in this kind of welded structure ,the three-dimensional fi-nite element analysis was performed based on the finite element analysis software ANSYS .A moving strip heat source was taken as the welding heat source model to calculate the transient temperature field and a thermal-mechanical coupling method was used to obtain the welding stress field .The simulation results show that the circumferential stress within welding region distributes as tesnile stress , compressing stress and tensile stress from the top to the bottom and demonstrates a rule of self -balance .The circumferential stress at the weld root is tensile stress .The maximum axial stress within the weld is about 300 MPa.The radial stress at the top and bottom surface is relatively large （up to 400 to 500 MPa）.The equivalent peak stress is appear at the weld root and is up to about 700 MPa.