Monitoring And Numerical Simulation On Steel Butt Welding

Welding is one of the main connection of steel structure. Welding parts of uneven heating and cooling because of highly concentrated heat source input,after cooling residual stress and deformation will be produced in the weldment in the weld area and its neighborhood location. The strength, toughness and cracking resistance of the structural member will be reduced, thus affecting the stress state of the entire structure. It is helpful for welding construction to analyze temperature and stress fields after the welding and cooling process. Traditional detection of welding method is not conducive to engineering application because of structural damage and high price. Finite element simulation with a certain accuracy can overcome the shortcomings of traditional methods. The results show:This topic based on Tianjin BinHai New Area project, carries out work in the following areas:1. Arrange Vibrating string type steel plates on the steel plate shear wall in the vicinity of the weld centerline, real-time monitor CO2 gas shielded welding, collect residual stress values at different cooling time by using the data acquisition device, study the distribution of welding residual stresses during welding construction. The results show:produce tensile residual stresses in the middle of the longitudinal and transverse weld area, produce compressive residual stresses at both ends of the longitudinal and transverse weld area.2. Use ANSYS software to establish CO2 gas shielded welding of steel plates welding model. In this paper, use the direct coupling method to model, simulate the welding process and cooling process. In particular, determine a reasonable model size through the trial.3. Analyze the distribution of temperature field and stress field by using ANSYS post-processor, compare with real-time monitor data. Compare site fit the measured data with numerical simulation data to verify the applicability of the numerical simulation. Finite element simulation can better show the residual stress distribution.4. Simulate the preheating, welding speed, arc effective heating radius, arc voltage and welding current which important influence on welding. The results show:preheating is helpful to reduce the temperature gradient of the weld region and reduce the generation of welding residual stress; the increase of welding speed and the effective radius arc heating helps reduce the maximum temperature of the welding; the decrease of arc voltage and welding current helps reduce the maximum temperature of the welding.