基于结构光投影的焊接熔池图像获取与处理

建立一种主动视觉传感系统,以小功率激光器作为主动光源投射激光到特制光栅上,在焊接熔池表面形成变形激光条纹,用加了窄带滤光片和中性滤光片的CCD在系统另一侧实时拍摄熔池图像。选取合适的激光入射角度和CCD拍摄角度,较好的避开弧光对熔池图像的干扰,采集到熔池区变形激光条纹。对熔池图像特征进行分析,变形的激光条纹反映了熔池的下塌或上凸状态;成功提取熔池边缘和激光条纹边缘;通过标定、计算得到熔池正面几何参数,为今后实时检测焊接熔池表面的三维信息奠定了基础。     

基于FLUENT的TIG焊瞬态熔池三维形态的数值模拟

根据流体力学和传热学原理,建立了 TIG 焊瞬态熔池三维数值分析模型.电弧热源模型采用典型的高斯热源分布模型,模型考虑熔池液态金属对流传热、熔池外工件的固态导热、焊接过程中的相变潜热、熔池流体的紊流特性、材料的热物理性能参数随温度变化等因素.用 enthalpy-porosity 方法处理工件熔化/凝固过程中的问题,FLUENT RNG k-ε湍流模型对 TIG 焊熔池模型进行求解.给出了熔池形状的可视化图形结果,熔池形状特征参数随时间的动态变化.结果表明,计算值与实测值吻合良好.

Abstract：

Based on theories of fluid dynamics and heat zransfer, a transient three-dimensional model of TIG weld pools is established, in which Gaussian distribution is used to describe the heat flux source of arc. Many factors are considered in the model including the convective heat transfer of liquid metal and the heat conduction of solid metal, latent heat in welding process, the turbulence characteristics of welding pool fluid, material thermo physical properties as the function of temperature and so on. The enthalpy-porosity technology is adopted to solve the problem with workpiece phase transformation. The graphics results of weld pools and the variation of shape parameters with time are given by using FLUENT RNG k-ε model to calculate the TIG wielding pool. The experiments show that the calculated results agree well with measured value.