GTAW焊熔池形态的数值模拟及视觉检测

AbstractABSTRACTWith the rising demands of welding quality,the development of weldingautomation and intelligence has become an inevitable trend.And its key problem isthat realization automatic control of welding pool dynamic process.Acquisition thedynamic information of pool by theoretical or experimental methods has importantpractical significance.In this paper,using numerical simulation technology and visioninspection to numerical simulation and inspection GTAW welding pool,systematicstudied GTAW welding pool in theory and experiments.In the process of numerical simulation,a three-dimensional transient numericalmodel of GTAW welding is established.In the model,many factors are consideredincluding convective heat transfer of liquid metal and heat conduction of solid metal,latent heat in welding process,turbulence characteristics of welding pool fluid,material thermo physical properties as the function of temperature and so on.Modelof arc heat source is used double-elliptic distribution modes for heat flux,it will helpimprove welding pool shape and increase the calculation accuracy.Solving thenumerical analysis model by FLUENT software,then extract and analysis the resultinformation such as temperature field,flow field and welding pool shape.Andwelding pool behaviors in different welding current condition is analyzed.In the process of visual inspection,an active visual inspection system is used toshoot welding pool.A low-power semiconductor laser is an active light source in thesystem,then project grating fringe on the welding pool surface,narrow band filter andspatial filtering are used to filtering out the disturbance of arc,through 4f systemusing CCD shoot welding pool and gains clear images.Then extraction of the weldingpool shape and shape parameters and so on after image processing,to achieve visualinspection of welding pool.Numerical simulation technology and visual inspection are used to study GTAWwelding pool,analysis of the study results,then compared the numerical simulationresults and visual inspection results,the comparison results show two data in goodⅢ