装载机后车架焊接顺序优化的数值仿真

Numerical simulation on welding sequence optimization of loader rear frame

利用热弹塑性有限元法和Marc对装载机后车架的焊接变形进行数值仿真.分别用壳单元和实体单元进行仿真,对比焊接角变形,结果表明两者精度比较相似.建立后车架壳单元热-力耦合模型,定性对比在相同约束条件下焊接顺序对整个后车架结构内缩变形和面外弯曲变形的影响.结果表明,在先焊接框架焊缝的条件下,整体结构刚度增大,各种变形较小;其中,当采用正/反面焊缝、立焊缝依次焊接时,大梁下挠峰值最小,为0.002 m,从而确定后车架最佳焊接顺序方案,在该顺序下的变形模拟值与实测值吻合良好.

The numerical simulation is performed on welding deformation of loader rear frame using thermo-elastoplastic finite element method and Marc. The welding angular deformation obtained by simulation using shell element is compared with that obtained by simulation using solid element, which shows that the accuracies of both the simulation results are in good consistency. A thermal-mechanical coupling model of rear frame using shell element is built. Under the same constraint conditions, the effects of welding sequences on the in-plane shrinkage deformation and out-of-plane bending deformation of whole rear frame are compared qualitatively. The results show that, under the condition of welding frame welds firstly, the rigidity of the whole structure increases and all kinds of deformations become smaller; under the welding sequence, if the front/reverse side welds and vertical welds are welded in turn, the beam bottom deflection peak is 0. 002 m, which is the lowest value compared with that obtained by other sequences; so the optimal welding sequence is determined, under which the simulated values of deformation are in good consistence with the measured values.