不同焊接顺序下加筋板变形及残余应力的三维有限元研究

针对焊接过程的二维有限元计算与实际情况存在一定差别的问题，使用三维热弹-塑性有限元法对不同焊接顺序下加筋板焊接过程进行了仿真，获得了加筋板焊接引起的温度场、位移场和应力场。结果表明：在4点约束条件下，加筋板横截面的变形为中垂变形，纵筋的变形为中拱变形，方案1横截面变形更小，方案2纵筋变形更小。焊接引起的加筋板残余应力主要表现为横向应力，其在近焊缝区为拉应力，达到材料屈服强度，远离焊缝区表现为压应力，达到0.2倍材料屈服强度。加强筋横向应力峰值出现在起弧端和收弧端，约为0.85倍材料屈服强度，纵向应力峰值出现在焊接起弧端，约为0.3倍材料屈服强度。在加筋板横截面位置，焊接顺序主要影响加强筋处的残余应力；在加强筋位置，焊接顺序主要影响纵向应力。每组焊缝同时同向焊接，且每根纵筋从左向右依次焊接的焊接方案产生更小的残余应力。

3-dimesional FEM investigation of welding-induced deformation and residual stress of a stiffened panel under different welding sequences

In view of the difference between the two dimensional finite element calculation of welding process and the actual situation, the welding process of stiffened plate under different welding sequence is simulated by using the three-dimensional thermo elastic plastic finite element method, and the temperature field, displacement field and stress field of the stiffened plate welding are obtained. The results show that under the 4 point constraint conditions, the deformation of the cross section of the stiffened plate is the vertical deformation, the deformation of the longitudinal reinforcement is the middle arch deformation, the 1 cross section of the scheme is smaller and the 2 longitudinal reinforcement of the scheme is smaller. The residual stress of the stiffened plate caused by welding is mainly transverse stress, which is tensile stress in the near weld zone, the yield strength of the material is reached, the compressive stress is shown far away from the weld zone, and the yield strength of the material is 0.2 times. The transverse stress peak of the reinforcement appears at the end of the arc and the end of the arc, which is about 0.85 times the yield strength of the material, and the peak stress of the longitudinal stress appears at the end of the welding arc, which is about 0.3 times the yield strength of the material. In the cross section position of stiffened plate, the welding sequence mainly affects the residual stress at the stiffener, and the welding sequence mainly affects the longitudinal stress in the reinforcement position. Each weld is welded at the same time, and the welding program of each longitudinal rib from left to right will produce smaller residual stress.