运载火箭贮箱筒段环缝焊接应力变形数值模拟

Numerical Simulation on Stress and Deformation of Circular Seam Welding Between Cylinder Sections of Launch Vehicle Tank

以5m直径大型运载火箭贮箱筒段为研究对象，对该筒段进行了环缝焊接过程的有限元模拟，得到了焊接过程的温度场分布情况以及简化工装约束条件下焊接后和约束卸载后的应力变形情况。结果表明，筒段的整体变形以径向变形为主；焊后最大应力出现在焊缝，最大应力429MPa，由于应变强化而高于屈服强度；焊缝处的应力除外表面轴向应力为压应力，其他皆为拉应力。

Taking a cylinder section of the large launch vehicle tank with a diameter of 5 m as the research subject, the welding of circular seam was simulated by finite element analysis, from which the distributions of temperature field during welding as well as the situations of the stress and deformation after welding and when the tooling-constraint was unloaded were obtained respectively under the simplified tooling-constraint condition. The results show that axial deformation is the major part of the whole deformation of the cylinder section. The stress of weld, which is 429 MPa, is the maximum stress, and it is higher than the yield stress due to strain hardening. The outside surface axial stress of weld is compressive, while the other of weld is tensile.