R. Kumar, E. Johnson, M. El-Zein, Deere and Company, Moline, IL; M. Coulombe, J. A. Goldak, Carleton University, Ottawa, ON, Canada; S. Tchernov, Goldak Technologies Inc., Ottawa, ON, Cambodia
To solve the transient temperature field for a given welding problem, we seek a model equation for the convection coefficient as a function of temperature at a point on the surface of the structure being welded. The model equation contains 1 to 5 parameters. To estimate the parameter values that minimize the deviation between the transient temperature measured at several points with thermocouples and the transient temperature computed in a transient thermal analysis of welding the structure, an inverse problem is solved. The L2 norms of the deviation in temperature for the model equation with optimized parameters and Vinokurov's model equation are compared. In addition the effect of deviations in the parameters from their optimal values on the computed temperature and then on the distortion and residual stress is estimated from a thermal-microstructure- stress analyses of welding the structure.
Summary: To solve the transient temperature field for a given welding problem,we seek a model equation for the convection coefficient as a function of temperature at a point on the surface of the structure being welded. The function is modeled numerically and verified to experiemental results.
