Numerical Simulation In Robotic Double-sided Double Arc Multi-pass Welding Of Mid-thick Plates

Mid-thick plates structures are widely used in shipbuilding. Theconventional welding procedure adopts manual arc welding, it has lowproductivity and seriously restrict the development of the shipbuildingindustry. Double-sided double arc welding(DSAW) can improve weldingefficiency and reduce welding defects. In this paper, ABAQUS is used tocarry on numerical simulation research on robot DSAW multi-pass weldingof mid-thick plates. Theory basis for DSAW multi-pass welding processparameters design is provided by finite element analysis of temperature andstress field.First, sheet butt welding model is built to discuss how shape parameters‘a’and ‘b’influence temperature field numerical calculation result.Secondly, three-dimensional finite element model of DSAW backingwelding is set up. We use it to study the influence of different weldingparameters on backing welding temperature field and method to control temperature variation. Calculation results show that different weldingparameters lead to different molten pool sizes, peak temperature and coolingtime. The arc spacing should be controlled between20mm and60mm, thepreheat temperature should be less than200℃.Furthermore, temperature and stress fields with40mm arc spacing and150℃preheat temperature are simulated. The results show that stressconcentration appear on border of weld and groove, the Von Mises equivalentstress is about280MPa at welding root. We do some experiment verificationon backing welding temperature field, which shows that the practical datatallies with the simulated data.Finally, we use three-dimension finite element method to analyzetemperature distribution of multi-layer and multi-pass welding. The resultsshow that thermal cycle curve of backing welding appears to be bimodal orsimilar unimodal structure and unimodal structure of filling bead welding.The interpass temperature of multi-pass welding is controlled between180℃and200℃.