海上风电桩用S355J2G3厚板FGB埋弧焊接头残余应力与变形的数值模拟OA

A thermo-mechanical coupled finite element model for FGB submerged arc welding(SAW)was established for 20 mm thick S355J2G3 low-alloy high-strength steel plates used in offshore wind power piles.The temperature field,stress field,and deformation characteristics under four welding sequences—single-side single-pass,single-side double-pass,single-side triple-pass,and double-side multi-pass—were compared.The stress and temperature field models were validated by blind-hole drilling method and thermocouple measurements,respectively.Results show that the overheated zone width in the heat-affected zone(HAZ)extending 38.3 mm,posing a significant risk of grain coarsening.As the number of weld passes in-creases,the peak molten pool temperature and overheated zone width decrease by 22.4%and 23.7%,respectively,effec-tively mitigating microstructural overheating.Welding residual stress is dominated by longitudinal tensile stress,peaking at 585 MPa in single-side single-pass welding.Increasing the number of passes reduces this peak by 6.3%,and double-side welding achieves a further 2.6%reduction.Although multi-pass welding lowers the residual stress peak,it induces Z-direction stress reversal and Y-direction alternating stress,increasing the risk of lamellar tearing.Z-direction deformation ac-counts for 52%-78%of total deformation,with the maximum deformation of 1.8 mm in single-side welding exhibiting a"V"-shaped profile,whereas double-side double-pass welding demonstrates superior deformation control.This study provides theoretical support and process guidance for residual stress control and structural deformation optimization in thick high-strength steel plate welding.