Experimental Study of Constructal Theory Application in Selecting Welding Paths with the Approach of Residual Stress Reduction in Weldments

In the present investigation, the basics of constructal theory are being used to suggest new welding paths in order to reduce residual stresses in weldments. Thin aluminum plates have been experimentally welded with a GTA welding instrument. The produced residual stresses in weldments are measured by X-ray diffraction method. Doing so, the experiments are qualitative measurement of residual stress at different points of welded plates. The analysis is based on the comparison of the produced residual stresses in different welding models which have received a fixed amount of heat input during welding. In order to have a tool for further comparison, a numerical modelling is also developed. Then, the shape of experimental residual stress distribution has been resulted in a good comparison with the results of the present numerical simulation. A reference point (point A), in which an almost equal amount of input heat is received in all models, is considered to make the comparison between different models more meaningful. Finally, the amount of residual stress at various points, specially the selected point (A), in different welding models showed that the constructal welding paths resulted in less residual stress in weldments. Furthermore, the effect of welding sequences in the amount of generated residual stresses confirmed the available data in literature.