Research On Heat Source Model For Numerical Welding Simulation

Study on Numerical Simulation of welding of sheet by using finite element softwareANSYS. To provide a more accurate calculation of the premise for the calculation ofstress field, adjusting the shape and size distribution of heat load in the welding process. Atpresent, computer simulation technology applied some types of heat source. But the resultsunder different source and parameters are rarely reported. The different source andparameters of this paper include: Chang the loading unit size, position and its internal heatratio, double ellipsoid heat source of different dimensions of length, ratio and heatdistribution, multi pass welding of different welding pass order. Compare the weld shape,thermal cycle curve in heat affected zone. Get the most closed actual simulation bycomparing the test and the simulation.Ordinary body heat load has limitations in computing molten pool temperaturedistribution. It accurate the result of weld temperature field by improving body heat loadalong the thickness direction. According to the thickness is divided into three parts, energyis applied by the ratio of1:2.2:2.9. It can make the weld temperature gradient in thethickness direction of small, uniform change. By adding heat loaded multilayer unit thewelding direction of length add to4mm. Keeping the same maximum temperature of weld,the welding length increased1~2times. It can effectively improve the shape of moltenpool and heat affected zone temperature change well.Improve body heat load compute the basic simulation accuracy and the calculationtime is only1/7of the double ellipsoid loaded, but not for fine adjustment and widecommand in the weld process. Double ellipsoid heat source loading can achieve moreaccurate simulation in the weld, heat affected zone and the calculation by controlling theparameters, but programming is tedious and it takes lengthy computation time. Thewelding residual stress deformation is greater than the bilateral unilateral welding after thewelding. Bilateral welding get smaller welding residual stress and deformation, stressreduced76.7%, deformation reduced66.4%from unilateral welding.By comparison, the value of simulation by improving body unit and double ellipsoid heat source loading method is close to the test value. Improved unit load under premise ofensuring the accuracy of grid density require reduced size. It saves computing time.Double ellipsoid heat source model load calculate take much more time, but it can be moreprecise adjustment of welding simulation results. In multi pass welding, alternating sideswelding can reduce the welding residual stress and deformation.