Integrated Digital Reconstruction of Welded Components: Supporting Improved Fatigue Life Prediction

In the design of offshore jacket foundations, fatigue life is crucial. Post-weld treatment has been proposed to enhance the fatigue performance of welded joints, where particularly high-frequency mechanical impact (HFMI) treatment has been shown to improve fatigue performance significantly. Automated HFMI treatment has enhanced the quality assurance of post-weld treatment and can lead to cost-effective design when combined with accurate fatigue life prediction. To accurately predict the fatigue life in complex or multi-axial joints, the finite element method (FEM) is commonly used but relies on a basic CAD depiction of the weld, which fails to consider the actual weld geometry and defects. Including the actual weld geometry in the FE model improves fatigue life prediction and possible crack location prediction but requires a digital reconstruction of the weld. Current digital reconstruction methods are time-consuming or require specialised scanning equipment and potential component relocation. Instead, the proposed framework uses an industrial manipulator paired with a line scanner to integrate digital reconstruction into the automated HFMI treatment setup. This approach applies prevalent image processing, simple filtering techniques, and non-linear optimisation for aligning and merging overlapping scans. A screened Poisson surface reconstruction finalises the 3D model to create a meshed surface. The outcome is a generic, cost-effective, flexible, and rapid method that enables the digital reconstruction of welded parts, aiding in component design, overall quality assurance, and documentation of the HFMI treatment.