Predicting Distortion in Butt Welded Plates Using an Equivalent Plane Stress Representation Based on Inherent Shrinkage Volume

Due to the adverse effect that distortion has on assembly fit-up and fabrication costs in welded structures, the ability to predict dimensional changes resulting from joining represents an important engineering concern. While distortion can be analyzed using a full 3D finite element (FE) model, this often proves to be computationally expensive for medium and large structures. In comparison, a 2D FE model can significantly reduce the time and effort needed to analyze distortion though such analyses often have reduced accuracy. To address these issues, a plane stress modeling approach based on inherent shrinkage volume is proposed. By inversing the plastic shrinkage zone geometry, an equivalent plane stress representation and eccentric loading condition can be developed and used to predict distortion in butt welded plates. The model was validated using deflection data obtained from welded plates and found to provide good accuracy over the range of thicknesses considered. Results obtained from welding of a large municipal containment tank are also presented and further confirm the utility of the method.