大面积拼焊平台结构的焊接变形预测

为了对大面积厚板拼焊平台结构进行焊接变形预测，首先进行了缩比件焊接试验，并测试了焊接过程中的角变形，然后进行了实际焊道数量及焊道集中分组后缩比件的焊接数值模拟，验证了焊接有限元模型输入的准确性及焊道集中分组方案的合理性；最后根据建立的焊道集中规则建立了平台结构的焊接有限元模型，进行了焊接变形的预测.结果表明，实际焊道数量及焊道集中分组后缩比件焊接角变形的数值模拟结果与测试结果一致，角变形约为1.6°，验证了将实际焊接工艺中15层27道简化为5层5道的焊道集中方案的准确性；平台结构的焊接变形表现为局部下塌或上凸的面外变形，是由上下坡口不对称产生的焊接角变形及底部钢架支撑作用共同产生的，面外变形范围为−5.2 ~ 4.4 mm.

Prediction of welding distortion of large scale welded platform structure

In order to carry out welding distortion prediction of large scale thick plate welded platform structure, a mock-up was welded first using actual welding process, during which angular distortion induced by welding was measured. And then welding numerical simulations of mock-ups having actual number of bead and lumped number of bead were conducted to verify the accuracy of the relevant input parameters of welding FE model and the reasonableness of the lumped-weld scheme by comparing their angular distortion results. Finally, welding FE model of the platform was established based on the scheme of lumped-weld, and welding induced distortion of the structure was analyzed. The results shows that the angular distortions of FE model and lumped-weld FE model are both similar to the test value of the mock-up, which is about 1.6°. That is to say the accuracy of the lumped-weld scheme that simplifies the 15-layer 27-pass in actual welding process to 5-layer 5-pass was verified. The welding distortion of the platform structure is localized falling or convex outward deformation resulting from welding angular distortion caused by the asymmetry of the upper and lower grooves and the support effect of the bottom steel frame. The surface outward deformation range is about −5.2 to 4.4 mm.