Optimizing Cutting Strategies to Minimize Plastic Deformation in the Contour Method Applied to Different Weld Geometries

Plastic deformation due to stress redistribution is a key challenge when applying the contour method to measure residual stresses in components with high-stress levels and gradients, such as welded joints. Previous studies have shown that optimizing the cutting path can minimize this effect.

In this work, a numerical approach is adopted to optimize the cutting path on two different configurations of high-thickness high-strength steel welds: a butt weld and a T-joint. The results of a thermo-mechanical simulation of the welding process are considered as initial conditions in a finite element model of the welded joints that is used to test the influence of the cutting path. Thanks to a Python routine, multiple cutting strategies are screened by considering elastoplastic behavior and removing nodes after nodes the symmetry conditions along the cutting path. Optimization results have shown that different strategies should be employed for butt welds and T-joints configurations to minimize cutting induced plastic deformation which can be explained by the fact that a thick T-joint is indeed composed of two separated weld seams and thus two stress zones. Furthermore, the sensitivity of the results to material behavior modeling is examined by comparing a purely isotropic hardening model with a mixed kinematic/isotropic hardening law.

On-going investigations on the application of this methodology on titanium Wire Laser Additive Manufacturing specimens will also be presented.