Effects of mechanical constraints on angular distortion of welding joints

During the manufacture of steel structures, welding deformations have undesirable effects on the accuracy of assembly, external appearance, buckling strength, fatigue strength, etc. In particular, in such large steel structures as ships, welding deformations produced during assembly lead to variations in dimensions which require considerable time and expense for repair, resulting in a decrease in productivity. In the present work a new method is presented to derive the constraint coefficient from the degree of angular deformation caused by welding, as measured experimentally by varying the shape of welded joints and the magnitude of constraints and from analysis results obtained via the elastic finite element method. The equivalent load was then calculated using this constraint coefficient. The validity of the numerical analysis involved in this new method was confirmed by its agreement with the experimental results. Regarding the effects of the constraints in relation to the shape of the welded joints, when the constraint coefficients are not considered for butt welding, the quantity of deformation predicted by analysis is greater than that produced in experiments and consequently butt welding is strongly affected by the constraints. However, for fillet welding, the quantity of deformation is hardly affected regardless of constraint coefficient considerations.