冷凝罐接管与筒节焊接应力的有限元分析

Finite element analysis of welding stress between cylinder and shell ring of cooling canister

通过ANSYS有限元软件,对冷凝罐接管与筒节多层焊的焊接过程进行了数值模拟,针对马鞍形接头的空间轨迹编写了沿焊道移动的热源方程,并采用逐层激活与逐步激活的生死单元技术实现了接头的熔敷过程模拟,使模拟与实际施焊过程相符。通过模拟研究了焊接过程动态温度场、应力场和焊接残余应力的分布状况。结果表明:焊接残余应力主要集中在接头的焊缝区和热影响区,周向应力与径向应力均在内层焊道中较高。在焊缝外表面沿接管周向应力为拉伸应力,其余为压应力,内表面三向均为拉伸应力。筒节一侧的焊趾与焊根部位应力较高,且为三向拉伸应力,是裂纹易发部位。本研究所建立的沿马鞍形轨迹移动的热源方程能用于该类接头的焊接过程研究。

In this article,the muhi-layer welding process between cylinder and shell ring of cooling canister was simulated by ANSYS FEM.The joint of welding deposition process was achieved, and the dynamic temperature field,stress field of welding process and the distribution of welding residual stress was researched by composing moving heat source equation of the saddle shape joint ,and using the skill of step by step ＂kill and born element＂ and the skill of layer by layer ＂kill and born element＂.The results showed that residual stress of welding was mainly concentrated in the weld seam area and heat affected zone Over the outer surface of the weld along the shell ring circumferential stress is tensile stress ,compression stress for the rest.The inner surface three-dimensional stress are tensile stress.Circumferential stress and radial stress were higher in the inner weld.The stress in weld toe and weld root area closing to cylinder were higher, and three direction stresses were tensile stress.The crack was easy to occur in these areas.The moving heat source equation along the saddle path established in this article can be used to analyze the welding process of such joint.